Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm...

[linux-2.6.git] / drivers / usb / host / fusbh200-hcd.c

/*
 * Faraday FUSBH200 EHCI-like driver
 *
 * Copyright (c) 2013 Faraday Technology Corporation
 *
 * Author: Yuan-Hsin Chen <yhchen@faraday-tech.com>
 *         Feng-Hsin Chiang <john453@faraday-tech.com>
 *         Po-Yu Chuang <ratbert.chuang@gmail.com>
 *
 * Most of code borrowed from the Linux-3.7 EHCI driver
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/device.h>
#include <linux/dmapool.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/hrtimer.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <linux/moduleparam.h>
#include <linux/dma-mapping.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/platform_device.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/unaligned.h>

/*-------------------------------------------------------------------------*/
#define DRIVER_AUTHOR "Yuan-Hsin Chen"
#define DRIVER_DESC "FUSBH200 Host Controller (EHCI) Driver"

static const char       hcd_name [] = "fusbh200_hcd";

#undef VERBOSE_DEBUG
#undef FUSBH200_URB_TRACE

#ifdef DEBUG
#define FUSBH200_STATS
#endif

/* magic numbers that can affect system performance */
#define FUSBH200_TUNE_CERR              3       /* 0-3 qtd retries; 0 == don't stop */
#define FUSBH200_TUNE_RL_HS             4       /* nak throttle; see 4.9 */
#define FUSBH200_TUNE_RL_TT             0
#define FUSBH200_TUNE_MULT_HS   1       /* 1-3 transactions/uframe; 4.10.3 */
#define FUSBH200_TUNE_MULT_TT   1
/*
 * Some drivers think it's safe to schedule isochronous transfers more than
 * 256 ms into the future (partly as a result of an old bug in the scheduling
 * code).  In an attempt to avoid trouble, we will use a minimum scheduling
 * length of 512 frames instead of 256.
 */
#define FUSBH200_TUNE_FLS               1       /* (medium) 512-frame schedule */

/* Initial IRQ latency:  faster than hw default */
static int log2_irq_thresh = 0;         // 0 to 6
module_param (log2_irq_thresh, int, S_IRUGO);
MODULE_PARM_DESC (log2_irq_thresh, "log2 IRQ latency, 1-64 microframes");

/* initial park setting:  slower than hw default */
static unsigned park = 0;
module_param (park, uint, S_IRUGO);
MODULE_PARM_DESC (park, "park setting; 1-3 back-to-back async packets");

/* for link power management(LPM) feature */
static unsigned int hird;
module_param(hird, int, S_IRUGO);
MODULE_PARM_DESC(hird, "host initiated resume duration, +1 for each 75us");

#define INTR_MASK (STS_IAA | STS_FATAL | STS_PCD | STS_ERR | STS_INT)

#include "fusbh200.h"

/*-------------------------------------------------------------------------*/

#define fusbh200_dbg(fusbh200, fmt, args...) \
        dev_dbg (fusbh200_to_hcd(fusbh200)->self.controller , fmt , ## args )
#define fusbh200_err(fusbh200, fmt, args...) \
        dev_err (fusbh200_to_hcd(fusbh200)->self.controller , fmt , ## args )
#define fusbh200_info(fusbh200, fmt, args...) \
        dev_info (fusbh200_to_hcd(fusbh200)->self.controller , fmt , ## args )
#define fusbh200_warn(fusbh200, fmt, args...) \
        dev_warn (fusbh200_to_hcd(fusbh200)->self.controller , fmt , ## args )

#ifdef VERBOSE_DEBUG
#       define fusbh200_vdbg fusbh200_dbg
#else
        static inline void fusbh200_vdbg(struct fusbh200_hcd *fusbh200, ...) {}
#endif

#ifdef  DEBUG

/* check the values in the HCSPARAMS register
 * (host controller _Structural_ parameters)
 * see EHCI spec, Table 2-4 for each value
 */
static void dbg_hcs_params (struct fusbh200_hcd *fusbh200, char *label)
{
        u32     params = fusbh200_readl(fusbh200, &fusbh200->caps->hcs_params);

        fusbh200_dbg (fusbh200,
                "%s hcs_params 0x%x ports=%d\n",
                label, params,
                HCS_N_PORTS (params)
                );
}
#else

static inline void dbg_hcs_params (struct fusbh200_hcd *fusbh200, char *label) {}

#endif

#ifdef  DEBUG

/* check the values in the HCCPARAMS register
 * (host controller _Capability_ parameters)
 * see EHCI Spec, Table 2-5 for each value
 * */
static void dbg_hcc_params (struct fusbh200_hcd *fusbh200, char *label)
{
        u32     params = fusbh200_readl(fusbh200, &fusbh200->caps->hcc_params);

        fusbh200_dbg (fusbh200,
                "%s hcc_params %04x uframes %s%s\n",
                label,
                params,
                HCC_PGM_FRAMELISTLEN(params) ? "256/512/1024" : "1024",
                HCC_CANPARK(params) ? " park" : "");
}
#else

static inline void dbg_hcc_params (struct fusbh200_hcd *fusbh200, char *label) {}

#endif

#ifdef  DEBUG

static void __maybe_unused
dbg_qtd (const char *label, struct fusbh200_hcd *fusbh200, struct fusbh200_qtd *qtd)
{
        fusbh200_dbg(fusbh200, "%s td %p n%08x %08x t%08x p0=%08x\n", label, qtd,
                hc32_to_cpup(fusbh200, &qtd->hw_next),
                hc32_to_cpup(fusbh200, &qtd->hw_alt_next),
                hc32_to_cpup(fusbh200, &qtd->hw_token),
                hc32_to_cpup(fusbh200, &qtd->hw_buf [0]));
        if (qtd->hw_buf [1])
                fusbh200_dbg(fusbh200, "  p1=%08x p2=%08x p3=%08x p4=%08x\n",
                        hc32_to_cpup(fusbh200, &qtd->hw_buf[1]),
                        hc32_to_cpup(fusbh200, &qtd->hw_buf[2]),
                        hc32_to_cpup(fusbh200, &qtd->hw_buf[3]),
                        hc32_to_cpup(fusbh200, &qtd->hw_buf[4]));
}

static void __maybe_unused
dbg_qh (const char *label, struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        struct fusbh200_qh_hw *hw = qh->hw;

        fusbh200_dbg (fusbh200, "%s qh %p n%08x info %x %x qtd %x\n", label,
                qh, hw->hw_next, hw->hw_info1, hw->hw_info2, hw->hw_current);
        dbg_qtd("overlay", fusbh200, (struct fusbh200_qtd *) &hw->hw_qtd_next);
}

static void __maybe_unused
dbg_itd (const char *label, struct fusbh200_hcd *fusbh200, struct fusbh200_itd *itd)
{
        fusbh200_dbg (fusbh200, "%s [%d] itd %p, next %08x, urb %p\n",
                label, itd->frame, itd, hc32_to_cpu(fusbh200, itd->hw_next),
                itd->urb);
        fusbh200_dbg (fusbh200,
                "  trans: %08x %08x %08x %08x %08x %08x %08x %08x\n",
                hc32_to_cpu(fusbh200, itd->hw_transaction[0]),
                hc32_to_cpu(fusbh200, itd->hw_transaction[1]),
                hc32_to_cpu(fusbh200, itd->hw_transaction[2]),
                hc32_to_cpu(fusbh200, itd->hw_transaction[3]),
                hc32_to_cpu(fusbh200, itd->hw_transaction[4]),
                hc32_to_cpu(fusbh200, itd->hw_transaction[5]),
                hc32_to_cpu(fusbh200, itd->hw_transaction[6]),
                hc32_to_cpu(fusbh200, itd->hw_transaction[7]));
        fusbh200_dbg (fusbh200,
                "  buf:   %08x %08x %08x %08x %08x %08x %08x\n",
                hc32_to_cpu(fusbh200, itd->hw_bufp[0]),
                hc32_to_cpu(fusbh200, itd->hw_bufp[1]),
                hc32_to_cpu(fusbh200, itd->hw_bufp[2]),
                hc32_to_cpu(fusbh200, itd->hw_bufp[3]),
                hc32_to_cpu(fusbh200, itd->hw_bufp[4]),
                hc32_to_cpu(fusbh200, itd->hw_bufp[5]),
                hc32_to_cpu(fusbh200, itd->hw_bufp[6]));
        fusbh200_dbg (fusbh200, "  index: %d %d %d %d %d %d %d %d\n",
                itd->index[0], itd->index[1], itd->index[2],
                itd->index[3], itd->index[4], itd->index[5],
                itd->index[6], itd->index[7]);
}

static int __maybe_unused
dbg_status_buf (char *buf, unsigned len, const char *label, u32 status)
{
        return scnprintf (buf, len,
                "%s%sstatus %04x%s%s%s%s%s%s%s%s%s%s",
                label, label [0] ? " " : "", status,
                (status & STS_ASS) ? " Async" : "",
                (status & STS_PSS) ? " Periodic" : "",
                (status & STS_RECL) ? " Recl" : "",
                (status & STS_HALT) ? " Halt" : "",
                (status & STS_IAA) ? " IAA" : "",
                (status & STS_FATAL) ? " FATAL" : "",
                (status & STS_FLR) ? " FLR" : "",
                (status & STS_PCD) ? " PCD" : "",
                (status & STS_ERR) ? " ERR" : "",
                (status & STS_INT) ? " INT" : ""
                );
}

static int __maybe_unused
dbg_intr_buf (char *buf, unsigned len, const char *label, u32 enable)
{
        return scnprintf (buf, len,
                "%s%sintrenable %02x%s%s%s%s%s%s",
                label, label [0] ? " " : "", enable,
                (enable & STS_IAA) ? " IAA" : "",
                (enable & STS_FATAL) ? " FATAL" : "",
                (enable & STS_FLR) ? " FLR" : "",
                (enable & STS_PCD) ? " PCD" : "",
                (enable & STS_ERR) ? " ERR" : "",
                (enable & STS_INT) ? " INT" : ""
                );
}

static const char *const fls_strings [] =
    { "1024", "512", "256", "??" };

static int
dbg_command_buf (char *buf, unsigned len, const char *label, u32 command)
{
        return scnprintf (buf, len,
                "%s%scommand %07x %s=%d ithresh=%d%s%s%s "
                "period=%s%s %s",
                label, label [0] ? " " : "", command,
                (command & CMD_PARK) ? " park" : "(park)",
                CMD_PARK_CNT (command),
                (command >> 16) & 0x3f,
                (command & CMD_IAAD) ? " IAAD" : "",
                (command & CMD_ASE) ? " Async" : "",
                (command & CMD_PSE) ? " Periodic" : "",
                fls_strings [(command >> 2) & 0x3],
                (command & CMD_RESET) ? " Reset" : "",
                (command & CMD_RUN) ? "RUN" : "HALT"
                );
}

static int
dbg_port_buf (char *buf, unsigned len, const char *label, int port, u32 status)
{
        char    *sig;

        /* signaling state */
        switch (status & (3 << 10)) {
        case 0 << 10: sig = "se0"; break;
        case 1 << 10: sig = "k"; break;         /* low speed */
        case 2 << 10: sig = "j"; break;
        default: sig = "?"; break;
        }

        return scnprintf (buf, len,
                "%s%sport:%d status %06x %d "
                "sig=%s%s%s%s%s%s%s%s",
                label, label [0] ? " " : "", port, status,
                status>>25,/*device address */
                sig,
                (status & PORT_RESET) ? " RESET" : "",
                (status & PORT_SUSPEND) ? " SUSPEND" : "",
                (status & PORT_RESUME) ? " RESUME" : "",
                (status & PORT_PEC) ? " PEC" : "",
                (status & PORT_PE) ? " PE" : "",
                (status & PORT_CSC) ? " CSC" : "",
                (status & PORT_CONNECT) ? " CONNECT" : "");
}

#else
static inline void __maybe_unused
dbg_qh (char *label, struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{}

static inline int __maybe_unused
dbg_status_buf (char *buf, unsigned len, const char *label, u32 status)
{ return 0; }

static inline int __maybe_unused
dbg_command_buf (char *buf, unsigned len, const char *label, u32 command)
{ return 0; }

static inline int __maybe_unused
dbg_intr_buf (char *buf, unsigned len, const char *label, u32 enable)
{ return 0; }

static inline int __maybe_unused
dbg_port_buf (char *buf, unsigned len, const char *label, int port, u32 status)
{ return 0; }

#endif  /* DEBUG */

/* functions have the "wrong" filename when they're output... */
#define dbg_status(fusbh200, label, status) { \
        char _buf [80]; \
        dbg_status_buf (_buf, sizeof _buf, label, status); \
        fusbh200_dbg (fusbh200, "%s\n", _buf); \
}

#define dbg_cmd(fusbh200, label, command) { \
        char _buf [80]; \
        dbg_command_buf (_buf, sizeof _buf, label, command); \
        fusbh200_dbg (fusbh200, "%s\n", _buf); \
}

#define dbg_port(fusbh200, label, port, status) { \
        char _buf [80]; \
        dbg_port_buf (_buf, sizeof _buf, label, port, status); \
        fusbh200_dbg (fusbh200, "%s\n", _buf); \
}

/*-------------------------------------------------------------------------*/

#ifdef STUB_DEBUG_FILES

static inline void create_debug_files (struct fusbh200_hcd *bus) { }
static inline void remove_debug_files (struct fusbh200_hcd *bus) { }

#else

/* troubleshooting help: expose state in debugfs */

static int debug_async_open(struct inode *, struct file *);
static int debug_periodic_open(struct inode *, struct file *);
static int debug_registers_open(struct inode *, struct file *);
static int debug_async_open(struct inode *, struct file *);

static ssize_t debug_output(struct file*, char __user*, size_t, loff_t*);
static int debug_close(struct inode *, struct file *);

static const struct file_operations debug_async_fops = {
        .owner          = THIS_MODULE,
        .open           = debug_async_open,
        .read           = debug_output,
        .release        = debug_close,
        .llseek         = default_llseek,
};
static const struct file_operations debug_periodic_fops = {
        .owner          = THIS_MODULE,
        .open           = debug_periodic_open,
        .read           = debug_output,
        .release        = debug_close,
        .llseek         = default_llseek,
};
static const struct file_operations debug_registers_fops = {
        .owner          = THIS_MODULE,
        .open           = debug_registers_open,
        .read           = debug_output,
        .release        = debug_close,
        .llseek         = default_llseek,
};

static struct dentry *fusbh200_debug_root;

struct debug_buffer {
        ssize_t (*fill_func)(struct debug_buffer *);    /* fill method */
        struct usb_bus *bus;
        struct mutex mutex;     /* protect filling of buffer */
        size_t count;           /* number of characters filled into buffer */
        char *output_buf;
        size_t alloc_size;
};

#define speed_char(info1) ({ char tmp; \
                switch (info1 & (3 << 12)) { \
                case QH_FULL_SPEED: tmp = 'f'; break; \
                case QH_LOW_SPEED:  tmp = 'l'; break; \
                case QH_HIGH_SPEED: tmp = 'h'; break; \
                default: tmp = '?'; break; \
                } tmp; })

static inline char token_mark(struct fusbh200_hcd *fusbh200, __hc32 token)
{
        __u32 v = hc32_to_cpu(fusbh200, token);

        if (v & QTD_STS_ACTIVE)
                return '*';
        if (v & QTD_STS_HALT)
                return '-';
        if (!IS_SHORT_READ (v))
                return ' ';
        /* tries to advance through hw_alt_next */
        return '/';
}

static void qh_lines (
        struct fusbh200_hcd *fusbh200,
        struct fusbh200_qh *qh,
        char **nextp,
        unsigned *sizep
)
{
        u32                     scratch;
        u32                     hw_curr;
        struct fusbh200_qtd             *td;
        unsigned                temp;
        unsigned                size = *sizep;
        char                    *next = *nextp;
        char                    mark;
        __le32                  list_end = FUSBH200_LIST_END(fusbh200);
        struct fusbh200_qh_hw   *hw = qh->hw;

        if (hw->hw_qtd_next == list_end)        /* NEC does this */
                mark = '@';
        else
                mark = token_mark(fusbh200, hw->hw_token);
        if (mark == '/') {      /* qh_alt_next controls qh advance? */
                if ((hw->hw_alt_next & QTD_MASK(fusbh200))
                                == fusbh200->async->hw->hw_alt_next)
                        mark = '#';     /* blocked */
                else if (hw->hw_alt_next == list_end)
                        mark = '.';     /* use hw_qtd_next */
                /* else alt_next points to some other qtd */
        }
        scratch = hc32_to_cpup(fusbh200, &hw->hw_info1);
        hw_curr = (mark == '*') ? hc32_to_cpup(fusbh200, &hw->hw_current) : 0;
        temp = scnprintf (next, size,
                        "qh/%p dev%d %cs ep%d %08x %08x (%08x%c %s nak%d)",
                        qh, scratch & 0x007f,
                        speed_char (scratch),
                        (scratch >> 8) & 0x000f,
                        scratch, hc32_to_cpup(fusbh200, &hw->hw_info2),
                        hc32_to_cpup(fusbh200, &hw->hw_token), mark,
                        (cpu_to_hc32(fusbh200, QTD_TOGGLE) & hw->hw_token)
                                ? "data1" : "data0",
                        (hc32_to_cpup(fusbh200, &hw->hw_alt_next) >> 1) & 0x0f);
        size -= temp;
        next += temp;

        /* hc may be modifying the list as we read it ... */
        list_for_each_entry(td, &qh->qtd_list, qtd_list) {
                scratch = hc32_to_cpup(fusbh200, &td->hw_token);
                mark = ' ';
                if (hw_curr == td->qtd_dma)
                        mark = '*';
                else if (hw->hw_qtd_next == cpu_to_hc32(fusbh200, td->qtd_dma))
                        mark = '+';
                else if (QTD_LENGTH (scratch)) {
                        if (td->hw_alt_next == fusbh200->async->hw->hw_alt_next)
                                mark = '#';
                        else if (td->hw_alt_next != list_end)
                                mark = '/';
                }
                temp = snprintf (next, size,
                                "\n\t%p%c%s len=%d %08x urb %p",
                                td, mark, ({ char *tmp;
                                 switch ((scratch>>8)&0x03) {
                                 case 0: tmp = "out"; break;
                                 case 1: tmp = "in"; break;
                                 case 2: tmp = "setup"; break;
                                 default: tmp = "?"; break;
                                 } tmp;}),
                                (scratch >> 16) & 0x7fff,
                                scratch,
                                td->urb);
                if (size < temp)
                        temp = size;
                size -= temp;
                next += temp;
                if (temp == size)
                        goto done;
        }

        temp = snprintf (next, size, "\n");
        if (size < temp)
                temp = size;
        size -= temp;
        next += temp;

done:
        *sizep = size;
        *nextp = next;
}

static ssize_t fill_async_buffer(struct debug_buffer *buf)
{
        struct usb_hcd          *hcd;
        struct fusbh200_hcd     *fusbh200;
        unsigned long           flags;
        unsigned                temp, size;
        char                    *next;
        struct fusbh200_qh              *qh;

        hcd = bus_to_hcd(buf->bus);
        fusbh200 = hcd_to_fusbh200 (hcd);
        next = buf->output_buf;
        size = buf->alloc_size;

        *next = 0;

        /* dumps a snapshot of the async schedule.
         * usually empty except for long-term bulk reads, or head.
         * one QH per line, and TDs we know about
         */
        spin_lock_irqsave (&fusbh200->lock, flags);
        for (qh = fusbh200->async->qh_next.qh; size > 0 && qh; qh = qh->qh_next.qh)
                qh_lines (fusbh200, qh, &next, &size);
        if (fusbh200->async_unlink && size > 0) {
                temp = scnprintf(next, size, "\nunlink =\n");
                size -= temp;
                next += temp;

                for (qh = fusbh200->async_unlink; size > 0 && qh;
                                qh = qh->unlink_next)
                        qh_lines (fusbh200, qh, &next, &size);
        }
        spin_unlock_irqrestore (&fusbh200->lock, flags);

        return strlen(buf->output_buf);
}

#define DBG_SCHED_LIMIT 64
static ssize_t fill_periodic_buffer(struct debug_buffer *buf)
{
        struct usb_hcd          *hcd;
        struct fusbh200_hcd             *fusbh200;
        unsigned long           flags;
        union fusbh200_shadow   p, *seen;
        unsigned                temp, size, seen_count;
        char                    *next;
        unsigned                i;
        __hc32                  tag;

        if (!(seen = kmalloc (DBG_SCHED_LIMIT * sizeof *seen, GFP_ATOMIC)))
                return 0;
        seen_count = 0;

        hcd = bus_to_hcd(buf->bus);
        fusbh200 = hcd_to_fusbh200 (hcd);
        next = buf->output_buf;
        size = buf->alloc_size;

        temp = scnprintf (next, size, "size = %d\n", fusbh200->periodic_size);
        size -= temp;
        next += temp;

        /* dump a snapshot of the periodic schedule.
         * iso changes, interrupt usually doesn't.
         */
        spin_lock_irqsave (&fusbh200->lock, flags);
        for (i = 0; i < fusbh200->periodic_size; i++) {
                p = fusbh200->pshadow [i];
                if (likely (!p.ptr))
                        continue;
                tag = Q_NEXT_TYPE(fusbh200, fusbh200->periodic [i]);

                temp = scnprintf (next, size, "%4d: ", i);
                size -= temp;
                next += temp;

                do {
                        struct fusbh200_qh_hw *hw;

                        switch (hc32_to_cpu(fusbh200, tag)) {
                        case Q_TYPE_QH:
                                hw = p.qh->hw;
                                temp = scnprintf (next, size, " qh%d-%04x/%p",
                                                p.qh->period,
                                                hc32_to_cpup(fusbh200,
                                                        &hw->hw_info2)
                                                        /* uframe masks */
                                                        & (QH_CMASK | QH_SMASK),
                                                p.qh);
                                size -= temp;
                                next += temp;
                                /* don't repeat what follows this qh */
                                for (temp = 0; temp < seen_count; temp++) {
                                        if (seen [temp].ptr != p.ptr)
                                                continue;
                                        if (p.qh->qh_next.ptr) {
                                                temp = scnprintf (next, size,
                                                        " ...");
                                                size -= temp;
                                                next += temp;
                                        }
                                        break;
                                }
                                /* show more info the first time around */
                                if (temp == seen_count) {
                                        u32     scratch = hc32_to_cpup(fusbh200,
                                                        &hw->hw_info1);
                                        struct fusbh200_qtd     *qtd;
                                        char            *type = "";

                                        /* count tds, get ep direction */
                                        temp = 0;
                                        list_for_each_entry (qtd,
                                                        &p.qh->qtd_list,
                                                        qtd_list) {
                                                temp++;
                                                switch (0x03 & (hc32_to_cpu(
                                                        fusbh200,
                                                        qtd->hw_token) >> 8)) {
                                                case 0: type = "out"; continue;
                                                case 1: type = "in"; continue;
                                                }
                                        }

                                        temp = scnprintf (next, size,
                                                " (%c%d ep%d%s "
                                                "[%d/%d] q%d p%d)",
                                                speed_char (scratch),
                                                scratch & 0x007f,
                                                (scratch >> 8) & 0x000f, type,
                                                p.qh->usecs, p.qh->c_usecs,
                                                temp,
                                                0x7ff & (scratch >> 16));

                                        if (seen_count < DBG_SCHED_LIMIT)
                                                seen [seen_count++].qh = p.qh;
                                } else
                                        temp = 0;
                                tag = Q_NEXT_TYPE(fusbh200, hw->hw_next);
                                p = p.qh->qh_next;
                                break;
                        case Q_TYPE_FSTN:
                                temp = scnprintf (next, size,
                                        " fstn-%8x/%p", p.fstn->hw_prev,
                                        p.fstn);
                                tag = Q_NEXT_TYPE(fusbh200, p.fstn->hw_next);
                                p = p.fstn->fstn_next;
                                break;
                        case Q_TYPE_ITD:
                                temp = scnprintf (next, size,
                                        " itd/%p", p.itd);
                                tag = Q_NEXT_TYPE(fusbh200, p.itd->hw_next);
                                p = p.itd->itd_next;
                                break;
                        }
                        size -= temp;
                        next += temp;
                } while (p.ptr);

                temp = scnprintf (next, size, "\n");
                size -= temp;
                next += temp;
        }
        spin_unlock_irqrestore (&fusbh200->lock, flags);
        kfree (seen);

        return buf->alloc_size - size;
}
#undef DBG_SCHED_LIMIT

static const char *rh_state_string(struct fusbh200_hcd *fusbh200)
{
        switch (fusbh200->rh_state) {
        case FUSBH200_RH_HALTED:
                return "halted";
        case FUSBH200_RH_SUSPENDED:
                return "suspended";
        case FUSBH200_RH_RUNNING:
                return "running";
        case FUSBH200_RH_STOPPING:
                return "stopping";
        }
        return "?";
}

static ssize_t fill_registers_buffer(struct debug_buffer *buf)
{
        struct usb_hcd          *hcd;
        struct fusbh200_hcd     *fusbh200;
        unsigned long           flags;
        unsigned                temp, size, i;
        char                    *next, scratch [80];
        static char             fmt [] = "%*s\n";
        static char             label [] = "";

        hcd = bus_to_hcd(buf->bus);
        fusbh200 = hcd_to_fusbh200 (hcd);
        next = buf->output_buf;
        size = buf->alloc_size;

        spin_lock_irqsave (&fusbh200->lock, flags);

        if (!HCD_HW_ACCESSIBLE(hcd)) {
                size = scnprintf (next, size,
                        "bus %s, device %s\n"
                        "%s\n"
                        "SUSPENDED (no register access)\n",
                        hcd->self.controller->bus->name,
                        dev_name(hcd->self.controller),
                        hcd->product_desc);
                goto done;
        }

        /* Capability Registers */
        i = HC_VERSION(fusbh200, fusbh200_readl(fusbh200, &fusbh200->caps->hc_capbase));
        temp = scnprintf (next, size,
                "bus %s, device %s\n"
                "%s\n"
                "EHCI %x.%02x, rh state %s\n",
                hcd->self.controller->bus->name,
                dev_name(hcd->self.controller),
                hcd->product_desc,
                i >> 8, i & 0x0ff, rh_state_string(fusbh200));
        size -= temp;
        next += temp;

        // FIXME interpret both types of params
        i = fusbh200_readl(fusbh200, &fusbh200->caps->hcs_params);
        temp = scnprintf (next, size, "structural params 0x%08x\n", i);
        size -= temp;
        next += temp;

        i = fusbh200_readl(fusbh200, &fusbh200->caps->hcc_params);
        temp = scnprintf (next, size, "capability params 0x%08x\n", i);
        size -= temp;
        next += temp;

        /* Operational Registers */
        temp = dbg_status_buf (scratch, sizeof scratch, label,
                        fusbh200_readl(fusbh200, &fusbh200->regs->status));
        temp = scnprintf (next, size, fmt, temp, scratch);
        size -= temp;
        next += temp;

        temp = dbg_command_buf (scratch, sizeof scratch, label,
                        fusbh200_readl(fusbh200, &fusbh200->regs->command));
        temp = scnprintf (next, size, fmt, temp, scratch);
        size -= temp;
        next += temp;

        temp = dbg_intr_buf (scratch, sizeof scratch, label,
                        fusbh200_readl(fusbh200, &fusbh200->regs->intr_enable));
        temp = scnprintf (next, size, fmt, temp, scratch);
        size -= temp;
        next += temp;

        temp = scnprintf (next, size, "uframe %04x\n",
                        fusbh200_read_frame_index(fusbh200));
        size -= temp;
        next += temp;

        if (fusbh200->async_unlink) {
                temp = scnprintf(next, size, "async unlink qh %p\n",
                                fusbh200->async_unlink);
                size -= temp;
                next += temp;
        }

#ifdef FUSBH200_STATS
        temp = scnprintf (next, size,
                "irq normal %ld err %ld iaa %ld (lost %ld)\n",
                fusbh200->stats.normal, fusbh200->stats.error, fusbh200->stats.iaa,
                fusbh200->stats.lost_iaa);
        size -= temp;
        next += temp;

        temp = scnprintf (next, size, "complete %ld unlink %ld\n",
                fusbh200->stats.complete, fusbh200->stats.unlink);
        size -= temp;
        next += temp;
#endif

done:
        spin_unlock_irqrestore (&fusbh200->lock, flags);

        return buf->alloc_size - size;
}

static struct debug_buffer *alloc_buffer(struct usb_bus *bus,
                                ssize_t (*fill_func)(struct debug_buffer *))
{
        struct debug_buffer *buf;

        buf = kzalloc(sizeof(struct debug_buffer), GFP_KERNEL);

        if (buf) {
                buf->bus = bus;
                buf->fill_func = fill_func;
                mutex_init(&buf->mutex);
                buf->alloc_size = PAGE_SIZE;
        }

        return buf;
}

static int fill_buffer(struct debug_buffer *buf)
{
        int ret = 0;

        if (!buf->output_buf)
                buf->output_buf = vmalloc(buf->alloc_size);

        if (!buf->output_buf) {
                ret = -ENOMEM;
                goto out;
        }

        ret = buf->fill_func(buf);

        if (ret >= 0) {
                buf->count = ret;
                ret = 0;
        }

out:
        return ret;
}

static ssize_t debug_output(struct file *file, char __user *user_buf,
                            size_t len, loff_t *offset)
{
        struct debug_buffer *buf = file->private_data;
        int ret = 0;

        mutex_lock(&buf->mutex);
        if (buf->count == 0) {
                ret = fill_buffer(buf);
                if (ret != 0) {
                        mutex_unlock(&buf->mutex);
                        goto out;
                }
        }
        mutex_unlock(&buf->mutex);

        ret = simple_read_from_buffer(user_buf, len, offset,
                                      buf->output_buf, buf->count);

out:
        return ret;

}

static int debug_close(struct inode *inode, struct file *file)
{
        struct debug_buffer *buf = file->private_data;

        if (buf) {
                vfree(buf->output_buf);
                kfree(buf);
        }

        return 0;
}
static int debug_async_open(struct inode *inode, struct file *file)
{
        file->private_data = alloc_buffer(inode->i_private, fill_async_buffer);

        return file->private_data ? 0 : -ENOMEM;
}

static int debug_periodic_open(struct inode *inode, struct file *file)
{
        struct debug_buffer *buf;
        buf = alloc_buffer(inode->i_private, fill_periodic_buffer);
        if (!buf)
                return -ENOMEM;

        buf->alloc_size = (sizeof(void *) == 4 ? 6 : 8)*PAGE_SIZE;
        file->private_data = buf;
        return 0;
}

static int debug_registers_open(struct inode *inode, struct file *file)
{
        file->private_data = alloc_buffer(inode->i_private,
                                          fill_registers_buffer);

        return file->private_data ? 0 : -ENOMEM;
}

static inline void create_debug_files (struct fusbh200_hcd *fusbh200)
{
        struct usb_bus *bus = &fusbh200_to_hcd(fusbh200)->self;

        fusbh200->debug_dir = debugfs_create_dir(bus->bus_name, fusbh200_debug_root);
        if (!fusbh200->debug_dir)
                return;

        if (!debugfs_create_file("async", S_IRUGO, fusbh200->debug_dir, bus,
                                                &debug_async_fops))
                goto file_error;

        if (!debugfs_create_file("periodic", S_IRUGO, fusbh200->debug_dir, bus,
                                                &debug_periodic_fops))
                goto file_error;

        if (!debugfs_create_file("registers", S_IRUGO, fusbh200->debug_dir, bus,
                                                    &debug_registers_fops))
                goto file_error;

        return;

file_error:
        debugfs_remove_recursive(fusbh200->debug_dir);
}

static inline void remove_debug_files (struct fusbh200_hcd *fusbh200)
{
        debugfs_remove_recursive(fusbh200->debug_dir);
}

#endif /* STUB_DEBUG_FILES */
/*-------------------------------------------------------------------------*/

/*
 * handshake - spin reading hc until handshake completes or fails
 * @ptr: address of hc register to be read
 * @mask: bits to look at in result of read
 * @done: value of those bits when handshake succeeds
 * @usec: timeout in microseconds
 *
 * Returns negative errno, or zero on success
 *
 * Success happens when the "mask" bits have the specified value (hardware
 * handshake done).  There are two failure modes:  "usec" have passed (major
 * hardware flakeout), or the register reads as all-ones (hardware removed).
 *
 * That last failure should_only happen in cases like physical cardbus eject
 * before driver shutdown. But it also seems to be caused by bugs in cardbus
 * bridge shutdown:  shutting down the bridge before the devices using it.
 */
static int handshake (struct fusbh200_hcd *fusbh200, void __iomem *ptr,
                      u32 mask, u32 done, int usec)
{
        u32     result;

        do {
                result = fusbh200_readl(fusbh200, ptr);
                if (result == ~(u32)0)          /* card removed */
                        return -ENODEV;
                result &= mask;
                if (result == done)
                        return 0;
                udelay (1);
                usec--;
        } while (usec > 0);
        return -ETIMEDOUT;
}

/*
 * Force HC to halt state from unknown (EHCI spec section 2.3).
 * Must be called with interrupts enabled and the lock not held.
 */
static int fusbh200_halt (struct fusbh200_hcd *fusbh200)
{
        u32     temp;

        spin_lock_irq(&fusbh200->lock);

        /* disable any irqs left enabled by previous code */
        fusbh200_writel(fusbh200, 0, &fusbh200->regs->intr_enable);

        /*
         * This routine gets called during probe before fusbh200->command
         * has been initialized, so we can't rely on its value.
         */
        fusbh200->command &= ~CMD_RUN;
        temp = fusbh200_readl(fusbh200, &fusbh200->regs->command);
        temp &= ~(CMD_RUN | CMD_IAAD);
        fusbh200_writel(fusbh200, temp, &fusbh200->regs->command);

        spin_unlock_irq(&fusbh200->lock);
        synchronize_irq(fusbh200_to_hcd(fusbh200)->irq);

        return handshake(fusbh200, &fusbh200->regs->status,
                          STS_HALT, STS_HALT, 16 * 125);
}

/*
 * Reset a non-running (STS_HALT == 1) controller.
 * Must be called with interrupts enabled and the lock not held.
 */
static int fusbh200_reset (struct fusbh200_hcd *fusbh200)
{
        int     retval;
        u32     command = fusbh200_readl(fusbh200, &fusbh200->regs->command);

        /* If the EHCI debug controller is active, special care must be
         * taken before and after a host controller reset */
        if (fusbh200->debug && !dbgp_reset_prep(fusbh200_to_hcd(fusbh200)))
                fusbh200->debug = NULL;

        command |= CMD_RESET;
        dbg_cmd (fusbh200, "reset", command);
        fusbh200_writel(fusbh200, command, &fusbh200->regs->command);
        fusbh200->rh_state = FUSBH200_RH_HALTED;
        fusbh200->next_statechange = jiffies;
        retval = handshake (fusbh200, &fusbh200->regs->command,
                            CMD_RESET, 0, 250 * 1000);

        if (retval)
                return retval;

        if (fusbh200->debug)
                dbgp_external_startup(fusbh200_to_hcd(fusbh200));

        fusbh200->port_c_suspend = fusbh200->suspended_ports =
                        fusbh200->resuming_ports = 0;
        return retval;
}

/*
 * Idle the controller (turn off the schedules).
 * Must be called with interrupts enabled and the lock not held.
 */
static void fusbh200_quiesce (struct fusbh200_hcd *fusbh200)
{
        u32     temp;

        if (fusbh200->rh_state != FUSBH200_RH_RUNNING)
                return;

        /* wait for any schedule enables/disables to take effect */
        temp = (fusbh200->command << 10) & (STS_ASS | STS_PSS);
        handshake(fusbh200, &fusbh200->regs->status, STS_ASS | STS_PSS, temp, 16 * 125);

        /* then disable anything that's still active */
        spin_lock_irq(&fusbh200->lock);
        fusbh200->command &= ~(CMD_ASE | CMD_PSE);
        fusbh200_writel(fusbh200, fusbh200->command, &fusbh200->regs->command);
        spin_unlock_irq(&fusbh200->lock);

        /* hardware can take 16 microframes to turn off ... */
        handshake(fusbh200, &fusbh200->regs->status, STS_ASS | STS_PSS, 0, 16 * 125);
}

/*-------------------------------------------------------------------------*/

static void end_unlink_async(struct fusbh200_hcd *fusbh200);
static void unlink_empty_async(struct fusbh200_hcd *fusbh200);
static void fusbh200_work(struct fusbh200_hcd *fusbh200);
static void start_unlink_intr(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh);
static void end_unlink_intr(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh);

/*-------------------------------------------------------------------------*/

/* Set a bit in the USBCMD register */
static void fusbh200_set_command_bit(struct fusbh200_hcd *fusbh200, u32 bit)
{
        fusbh200->command |= bit;
        fusbh200_writel(fusbh200, fusbh200->command, &fusbh200->regs->command);

        /* unblock posted write */
        fusbh200_readl(fusbh200, &fusbh200->regs->command);
}

/* Clear a bit in the USBCMD register */
static void fusbh200_clear_command_bit(struct fusbh200_hcd *fusbh200, u32 bit)
{
        fusbh200->command &= ~bit;
        fusbh200_writel(fusbh200, fusbh200->command, &fusbh200->regs->command);

        /* unblock posted write */
        fusbh200_readl(fusbh200, &fusbh200->regs->command);
}

/*-------------------------------------------------------------------------*/

/*
 * EHCI timer support...  Now using hrtimers.
 *
 * Lots of different events are triggered from fusbh200->hrtimer.  Whenever
 * the timer routine runs, it checks each possible event; events that are
 * currently enabled and whose expiration time has passed get handled.
 * The set of enabled events is stored as a collection of bitflags in
 * fusbh200->enabled_hrtimer_events, and they are numbered in order of
 * increasing delay values (ranging between 1 ms and 100 ms).
 *
 * Rather than implementing a sorted list or tree of all pending events,
 * we keep track only of the lowest-numbered pending event, in
 * fusbh200->next_hrtimer_event.  Whenever fusbh200->hrtimer gets restarted, its
 * expiration time is set to the timeout value for this event.
 *
 * As a result, events might not get handled right away; the actual delay
 * could be anywhere up to twice the requested delay.  This doesn't
 * matter, because none of the events are especially time-critical.  The
 * ones that matter most all have a delay of 1 ms, so they will be
 * handled after 2 ms at most, which is okay.  In addition to this, we
 * allow for an expiration range of 1 ms.
 */

/*
 * Delay lengths for the hrtimer event types.
 * Keep this list sorted by delay length, in the same order as
 * the event types indexed by enum fusbh200_hrtimer_event in fusbh200.h.
 */
static unsigned event_delays_ns[] = {
        1 * NSEC_PER_MSEC,      /* FUSBH200_HRTIMER_POLL_ASS */
        1 * NSEC_PER_MSEC,      /* FUSBH200_HRTIMER_POLL_PSS */
        1 * NSEC_PER_MSEC,      /* FUSBH200_HRTIMER_POLL_DEAD */
        1125 * NSEC_PER_USEC,   /* FUSBH200_HRTIMER_UNLINK_INTR */
        2 * NSEC_PER_MSEC,      /* FUSBH200_HRTIMER_FREE_ITDS */
        6 * NSEC_PER_MSEC,      /* FUSBH200_HRTIMER_ASYNC_UNLINKS */
        10 * NSEC_PER_MSEC,     /* FUSBH200_HRTIMER_IAA_WATCHDOG */
        10 * NSEC_PER_MSEC,     /* FUSBH200_HRTIMER_DISABLE_PERIODIC */
        15 * NSEC_PER_MSEC,     /* FUSBH200_HRTIMER_DISABLE_ASYNC */
        100 * NSEC_PER_MSEC,    /* FUSBH200_HRTIMER_IO_WATCHDOG */
};

/* Enable a pending hrtimer event */
static void fusbh200_enable_event(struct fusbh200_hcd *fusbh200, unsigned event,
                bool resched)
{
        ktime_t         *timeout = &fusbh200->hr_timeouts[event];

        if (resched)
                *timeout = ktime_add(ktime_get(),
                                ktime_set(0, event_delays_ns[event]));
        fusbh200->enabled_hrtimer_events |= (1 << event);

        /* Track only the lowest-numbered pending event */
        if (event < fusbh200->next_hrtimer_event) {
                fusbh200->next_hrtimer_event = event;
                hrtimer_start_range_ns(&fusbh200->hrtimer, *timeout,
                                NSEC_PER_MSEC, HRTIMER_MODE_ABS);
        }
}


/* Poll the STS_ASS status bit; see when it agrees with CMD_ASE */
static void fusbh200_poll_ASS(struct fusbh200_hcd *fusbh200)
{
        unsigned        actual, want;

        /* Don't enable anything if the controller isn't running (e.g., died) */
        if (fusbh200->rh_state != FUSBH200_RH_RUNNING)
                return;

        want = (fusbh200->command & CMD_ASE) ? STS_ASS : 0;
        actual = fusbh200_readl(fusbh200, &fusbh200->regs->status) & STS_ASS;

        if (want != actual) {

                /* Poll again later, but give up after about 20 ms */
                if (fusbh200->ASS_poll_count++ < 20) {
                        fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_POLL_ASS, true);
                        return;
                }
                fusbh200_dbg(fusbh200, "Waited too long for the async schedule status (%x/%x), giving up\n",
                                want, actual);
        }
        fusbh200->ASS_poll_count = 0;

        /* The status is up-to-date; restart or stop the schedule as needed */
        if (want == 0) {        /* Stopped */
                if (fusbh200->async_count > 0)
                        fusbh200_set_command_bit(fusbh200, CMD_ASE);

        } else {                /* Running */
                if (fusbh200->async_count == 0) {

                        /* Turn off the schedule after a while */
                        fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_DISABLE_ASYNC,
                                        true);
                }
        }
}

/* Turn off the async schedule after a brief delay */
static void fusbh200_disable_ASE(struct fusbh200_hcd *fusbh200)
{
        fusbh200_clear_command_bit(fusbh200, CMD_ASE);
}


/* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */
static void fusbh200_poll_PSS(struct fusbh200_hcd *fusbh200)
{
        unsigned        actual, want;

        /* Don't do anything if the controller isn't running (e.g., died) */
        if (fusbh200->rh_state != FUSBH200_RH_RUNNING)
                return;

        want = (fusbh200->command & CMD_PSE) ? STS_PSS : 0;
        actual = fusbh200_readl(fusbh200, &fusbh200->regs->status) & STS_PSS;

        if (want != actual) {

                /* Poll again later, but give up after about 20 ms */
                if (fusbh200->PSS_poll_count++ < 20) {
                        fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_POLL_PSS, true);
                        return;
                }
                fusbh200_dbg(fusbh200, "Waited too long for the periodic schedule status (%x/%x), giving up\n",
                                want, actual);
        }
        fusbh200->PSS_poll_count = 0;

        /* The status is up-to-date; restart or stop the schedule as needed */
        if (want == 0) {        /* Stopped */
                if (fusbh200->periodic_count > 0)
                        fusbh200_set_command_bit(fusbh200, CMD_PSE);

        } else {                /* Running */
                if (fusbh200->periodic_count == 0) {

                        /* Turn off the schedule after a while */
                        fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_DISABLE_PERIODIC,
                                        true);
                }
        }
}

/* Turn off the periodic schedule after a brief delay */
static void fusbh200_disable_PSE(struct fusbh200_hcd *fusbh200)
{
        fusbh200_clear_command_bit(fusbh200, CMD_PSE);
}


/* Poll the STS_HALT status bit; see when a dead controller stops */
static void fusbh200_handle_controller_death(struct fusbh200_hcd *fusbh200)
{
        if (!(fusbh200_readl(fusbh200, &fusbh200->regs->status) & STS_HALT)) {

                /* Give up after a few milliseconds */
                if (fusbh200->died_poll_count++ < 5) {
                        /* Try again later */
                        fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_POLL_DEAD, true);
                        return;
                }
                fusbh200_warn(fusbh200, "Waited too long for the controller to stop, giving up\n");
        }

        /* Clean up the mess */
        fusbh200->rh_state = FUSBH200_RH_HALTED;
        fusbh200_writel(fusbh200, 0, &fusbh200->regs->intr_enable);
        fusbh200_work(fusbh200);
        end_unlink_async(fusbh200);

        /* Not in process context, so don't try to reset the controller */
}


/* Handle unlinked interrupt QHs once they are gone from the hardware */
static void fusbh200_handle_intr_unlinks(struct fusbh200_hcd *fusbh200)
{
        bool            stopped = (fusbh200->rh_state < FUSBH200_RH_RUNNING);

        /*
         * Process all the QHs on the intr_unlink list that were added
         * before the current unlink cycle began.  The list is in
         * temporal order, so stop when we reach the first entry in the
         * current cycle.  But if the root hub isn't running then
         * process all the QHs on the list.
         */
        fusbh200->intr_unlinking = true;
        while (fusbh200->intr_unlink) {
                struct fusbh200_qh      *qh = fusbh200->intr_unlink;

                if (!stopped && qh->unlink_cycle == fusbh200->intr_unlink_cycle)
                        break;
                fusbh200->intr_unlink = qh->unlink_next;
                qh->unlink_next = NULL;
                end_unlink_intr(fusbh200, qh);
        }

        /* Handle remaining entries later */
        if (fusbh200->intr_unlink) {
                fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_UNLINK_INTR, true);
                ++fusbh200->intr_unlink_cycle;
        }
        fusbh200->intr_unlinking = false;
}


/* Start another free-iTDs/siTDs cycle */
static void start_free_itds(struct fusbh200_hcd *fusbh200)
{
        if (!(fusbh200->enabled_hrtimer_events & BIT(FUSBH200_HRTIMER_FREE_ITDS))) {
                fusbh200->last_itd_to_free = list_entry(
                                fusbh200->cached_itd_list.prev,
                                struct fusbh200_itd, itd_list);
                fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_FREE_ITDS, true);
        }
}

/* Wait for controller to stop using old iTDs and siTDs */
static void end_free_itds(struct fusbh200_hcd *fusbh200)
{
        struct fusbh200_itd             *itd, *n;

        if (fusbh200->rh_state < FUSBH200_RH_RUNNING) {
                fusbh200->last_itd_to_free = NULL;
        }

        list_for_each_entry_safe(itd, n, &fusbh200->cached_itd_list, itd_list) {
                list_del(&itd->itd_list);
                dma_pool_free(fusbh200->itd_pool, itd, itd->itd_dma);
                if (itd == fusbh200->last_itd_to_free)
                        break;
        }

        if (!list_empty(&fusbh200->cached_itd_list))
                start_free_itds(fusbh200);
}


/* Handle lost (or very late) IAA interrupts */
static void fusbh200_iaa_watchdog(struct fusbh200_hcd *fusbh200)
{
        if (fusbh200->rh_state != FUSBH200_RH_RUNNING)
                return;

        /*
         * Lost IAA irqs wedge things badly; seen first with a vt8235.
         * So we need this watchdog, but must protect it against both
         * (a) SMP races against real IAA firing and retriggering, and
         * (b) clean HC shutdown, when IAA watchdog was pending.
         */
        if (fusbh200->async_iaa) {
                u32 cmd, status;

                /* If we get here, IAA is *REALLY* late.  It's barely
                 * conceivable that the system is so busy that CMD_IAAD
                 * is still legitimately set, so let's be sure it's
                 * clear before we read STS_IAA.  (The HC should clear
                 * CMD_IAAD when it sets STS_IAA.)
                 */
                cmd = fusbh200_readl(fusbh200, &fusbh200->regs->command);

                /*
                 * If IAA is set here it either legitimately triggered
                 * after the watchdog timer expired (_way_ late, so we'll
                 * still count it as lost) ... or a silicon erratum:
                 * - VIA seems to set IAA without triggering the IRQ;
                 * - IAAD potentially cleared without setting IAA.
                 */
                status = fusbh200_readl(fusbh200, &fusbh200->regs->status);
                if ((status & STS_IAA) || !(cmd & CMD_IAAD)) {
                        COUNT(fusbh200->stats.lost_iaa);
                        fusbh200_writel(fusbh200, STS_IAA, &fusbh200->regs->status);
                }

                fusbh200_vdbg(fusbh200, "IAA watchdog: status %x cmd %x\n",
                                status, cmd);
                end_unlink_async(fusbh200);
        }
}


/* Enable the I/O watchdog, if appropriate */
static void turn_on_io_watchdog(struct fusbh200_hcd *fusbh200)
{
        /* Not needed if the controller isn't running or it's already enabled */
        if (fusbh200->rh_state != FUSBH200_RH_RUNNING ||
                        (fusbh200->enabled_hrtimer_events &
                                BIT(FUSBH200_HRTIMER_IO_WATCHDOG)))
                return;

        /*
         * Isochronous transfers always need the watchdog.
         * For other sorts we use it only if the flag is set.
         */
        if (fusbh200->isoc_count > 0 || (fusbh200->need_io_watchdog &&
                        fusbh200->async_count + fusbh200->intr_count > 0))
                fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_IO_WATCHDOG, true);
}


/*
 * Handler functions for the hrtimer event types.
 * Keep this array in the same order as the event types indexed by
 * enum fusbh200_hrtimer_event in fusbh200.h.
 */
static void (*event_handlers[])(struct fusbh200_hcd *) = {
        fusbh200_poll_ASS,                      /* FUSBH200_HRTIMER_POLL_ASS */
        fusbh200_poll_PSS,                      /* FUSBH200_HRTIMER_POLL_PSS */
        fusbh200_handle_controller_death,       /* FUSBH200_HRTIMER_POLL_DEAD */
        fusbh200_handle_intr_unlinks,   /* FUSBH200_HRTIMER_UNLINK_INTR */
        end_free_itds,                  /* FUSBH200_HRTIMER_FREE_ITDS */
        unlink_empty_async,             /* FUSBH200_HRTIMER_ASYNC_UNLINKS */
        fusbh200_iaa_watchdog,          /* FUSBH200_HRTIMER_IAA_WATCHDOG */
        fusbh200_disable_PSE,           /* FUSBH200_HRTIMER_DISABLE_PERIODIC */
        fusbh200_disable_ASE,           /* FUSBH200_HRTIMER_DISABLE_ASYNC */
        fusbh200_work,                  /* FUSBH200_HRTIMER_IO_WATCHDOG */
};

static enum hrtimer_restart fusbh200_hrtimer_func(struct hrtimer *t)
{
        struct fusbh200_hcd     *fusbh200 = container_of(t, struct fusbh200_hcd, hrtimer);
        ktime_t         now;
        unsigned long   events;
        unsigned long   flags;
        unsigned        e;

        spin_lock_irqsave(&fusbh200->lock, flags);

        events = fusbh200->enabled_hrtimer_events;
        fusbh200->enabled_hrtimer_events = 0;
        fusbh200->next_hrtimer_event = FUSBH200_HRTIMER_NO_EVENT;

        /*
         * Check each pending event.  If its time has expired, handle
         * the event; otherwise re-enable it.
         */
        now = ktime_get();
        for_each_set_bit(e, &events, FUSBH200_HRTIMER_NUM_EVENTS) {
                if (now.tv64 >= fusbh200->hr_timeouts[e].tv64)
                        event_handlers[e](fusbh200);
                else
                        fusbh200_enable_event(fusbh200, e, false);
        }

        spin_unlock_irqrestore(&fusbh200->lock, flags);
        return HRTIMER_NORESTART;
}

/*-------------------------------------------------------------------------*/

#define fusbh200_bus_suspend    NULL
#define fusbh200_bus_resume     NULL

/*-------------------------------------------------------------------------*/

static int check_reset_complete (
        struct fusbh200_hcd     *fusbh200,
        int             index,
        u32 __iomem     *status_reg,
        int             port_status
) {
        if (!(port_status & PORT_CONNECT))
                return port_status;

        /* if reset finished and it's still not enabled -- handoff */
        if (!(port_status & PORT_PE)) {
                /* with integrated TT, there's nobody to hand it to! */
                fusbh200_dbg (fusbh200,
                        "Failed to enable port %d on root hub TT\n",
                        index+1);
                return port_status;
        } else {
                fusbh200_dbg(fusbh200, "port %d reset complete, port enabled\n",
                        index + 1);
        }

        return port_status;
}

/*-------------------------------------------------------------------------*/


/* build "status change" packet (one or two bytes) from HC registers */

static int
fusbh200_hub_status_data (struct usb_hcd *hcd, char *buf)
{
        struct fusbh200_hcd     *fusbh200 = hcd_to_fusbh200 (hcd);
        u32             temp, status;
        u32             mask;
        int             retval = 1;
        unsigned long   flags;

        /* init status to no-changes */
        buf [0] = 0;

        /* Inform the core about resumes-in-progress by returning
         * a non-zero value even if there are no status changes.
         */
        status = fusbh200->resuming_ports;

        mask = PORT_CSC | PORT_PEC;
        // PORT_RESUME from hardware ~= PORT_STAT_C_SUSPEND

        /* no hub change reports (bit 0) for now (power, ...) */

        /* port N changes (bit N)? */
        spin_lock_irqsave (&fusbh200->lock, flags);

        temp = fusbh200_readl(fusbh200, &fusbh200->regs->port_status);

        /*
         * Return status information even for ports with OWNER set.
         * Otherwise khubd wouldn't see the disconnect event when a
         * high-speed device is switched over to the companion
         * controller by the user.
         */

        if ((temp & mask) != 0 || test_bit(0, &fusbh200->port_c_suspend)
                        || (fusbh200->reset_done[0] && time_after_eq(
                                jiffies, fusbh200->reset_done[0]))) {
                buf [0] |= 1 << 1;
                status = STS_PCD;
        }
        /* FIXME autosuspend idle root hubs */
        spin_unlock_irqrestore (&fusbh200->lock, flags);
        return status ? retval : 0;
}

/*-------------------------------------------------------------------------*/

static void
fusbh200_hub_descriptor (
        struct fusbh200_hcd             *fusbh200,
        struct usb_hub_descriptor       *desc
) {
        int             ports = HCS_N_PORTS (fusbh200->hcs_params);
        u16             temp;

        desc->bDescriptorType = 0x29;
        desc->bPwrOn2PwrGood = 10;      /* fusbh200 1.0, 2.3.9 says 20ms max */
        desc->bHubContrCurrent = 0;

        desc->bNbrPorts = ports;
        temp = 1 + (ports / 8);
        desc->bDescLength = 7 + 2 * temp;

        /* two bitmaps:  ports removable, and usb 1.0 legacy PortPwrCtrlMask */
        memset(&desc->u.hs.DeviceRemovable[0], 0, temp);
        memset(&desc->u.hs.DeviceRemovable[temp], 0xff, temp);

        temp = 0x0008;          /* per-port overcurrent reporting */
        temp |= 0x0002;         /* no power switching */
        desc->wHubCharacteristics = cpu_to_le16(temp);
}

/*-------------------------------------------------------------------------*/

static int fusbh200_hub_control (
        struct usb_hcd  *hcd,
        u16             typeReq,
        u16             wValue,
        u16             wIndex,
        char            *buf,
        u16             wLength
) {
        struct fusbh200_hcd     *fusbh200 = hcd_to_fusbh200 (hcd);
        int             ports = HCS_N_PORTS (fusbh200->hcs_params);
        u32 __iomem     *status_reg = &fusbh200->regs->port_status;
        u32             temp, temp1, status;
        unsigned long   flags;
        int             retval = 0;
        unsigned        selector;

        /*
         * FIXME:  support SetPortFeatures USB_PORT_FEAT_INDICATOR.
         * HCS_INDICATOR may say we can change LEDs to off/amber/green.
         * (track current state ourselves) ... blink for diagnostics,
         * power, "this is the one", etc.  EHCI spec supports this.
         */

        spin_lock_irqsave (&fusbh200->lock, flags);
        switch (typeReq) {
        case ClearHubFeature:
                switch (wValue) {
                case C_HUB_LOCAL_POWER:
                case C_HUB_OVER_CURRENT:
                        /* no hub-wide feature/status flags */
                        break;
                default:
                        goto error;
                }
                break;
        case ClearPortFeature:
                if (!wIndex || wIndex > ports)
                        goto error;
                wIndex--;
                temp = fusbh200_readl(fusbh200, status_reg);
                temp &= ~PORT_RWC_BITS;

                /*
                 * Even if OWNER is set, so the port is owned by the
                 * companion controller, khubd needs to be able to clear
                 * the port-change status bits (especially
                 * USB_PORT_STAT_C_CONNECTION).
                 */

                switch (wValue) {
                case USB_PORT_FEAT_ENABLE:
                        fusbh200_writel(fusbh200, temp & ~PORT_PE, status_reg);
                        break;
                case USB_PORT_FEAT_C_ENABLE:
                        fusbh200_writel(fusbh200, temp | PORT_PEC, status_reg);
                        break;
                case USB_PORT_FEAT_SUSPEND:
                        if (temp & PORT_RESET)
                                goto error;
                        if (!(temp & PORT_SUSPEND))
                                break;
                        if ((temp & PORT_PE) == 0)
                                goto error;

                        /* resume signaling for 20 msec */
                        fusbh200_writel(fusbh200, temp | PORT_RESUME, status_reg);
                        fusbh200->reset_done[wIndex] = jiffies
                                        + msecs_to_jiffies(20);
                        break;
                case USB_PORT_FEAT_C_SUSPEND:
                        clear_bit(wIndex, &fusbh200->port_c_suspend);
                        break;
                case USB_PORT_FEAT_C_CONNECTION:
                        fusbh200_writel(fusbh200, temp | PORT_CSC, status_reg);
                        break;
                case USB_PORT_FEAT_C_OVER_CURRENT:
                        fusbh200_writel(fusbh200, temp | BMISR_OVC, &fusbh200->regs->bmisr);
                        break;
                case USB_PORT_FEAT_C_RESET:
                        /* GetPortStatus clears reset */
                        break;
                default:
                        goto error;
                }
                fusbh200_readl(fusbh200, &fusbh200->regs->command);     /* unblock posted write */
                break;
        case GetHubDescriptor:
                fusbh200_hub_descriptor (fusbh200, (struct usb_hub_descriptor *)
                        buf);
                break;
        case GetHubStatus:
                /* no hub-wide feature/status flags */
                memset (buf, 0, 4);
                //cpu_to_le32s ((u32 *) buf);
                break;
        case GetPortStatus:
                if (!wIndex || wIndex > ports)
                        goto error;
                wIndex--;
                status = 0;
                temp = fusbh200_readl(fusbh200, status_reg);

                // wPortChange bits
                if (temp & PORT_CSC)
                        status |= USB_PORT_STAT_C_CONNECTION << 16;
                if (temp & PORT_PEC)
                        status |= USB_PORT_STAT_C_ENABLE << 16;

                temp1 = fusbh200_readl(fusbh200, &fusbh200->regs->bmisr);
                if (temp1 & BMISR_OVC)
                        status |= USB_PORT_STAT_C_OVERCURRENT << 16;

                /* whoever resumes must GetPortStatus to complete it!! */
                if (temp & PORT_RESUME) {

                        /* Remote Wakeup received? */
                        if (!fusbh200->reset_done[wIndex]) {
                                /* resume signaling for 20 msec */
                                fusbh200->reset_done[wIndex] = jiffies
                                                + msecs_to_jiffies(20);
                                /* check the port again */
                                mod_timer(&fusbh200_to_hcd(fusbh200)->rh_timer,
                                                fusbh200->reset_done[wIndex]);
                        }

                        /* resume completed? */
                        else if (time_after_eq(jiffies,
                                        fusbh200->reset_done[wIndex])) {
                                clear_bit(wIndex, &fusbh200->suspended_ports);
                                set_bit(wIndex, &fusbh200->port_c_suspend);
                                fusbh200->reset_done[wIndex] = 0;

                                /* stop resume signaling */
                                temp = fusbh200_readl(fusbh200, status_reg);
                                fusbh200_writel(fusbh200,
                                        temp & ~(PORT_RWC_BITS | PORT_RESUME),
                                        status_reg);
                                clear_bit(wIndex, &fusbh200->resuming_ports);
                                retval = handshake(fusbh200, status_reg,
                                           PORT_RESUME, 0, 2000 /* 2msec */);
                                if (retval != 0) {
                                        fusbh200_err(fusbh200,
                                                "port %d resume error %d\n",
                                                wIndex + 1, retval);
                                        goto error;
                                }
                                temp &= ~(PORT_SUSPEND|PORT_RESUME|(3<<10));
                        }
                }

                /* whoever resets must GetPortStatus to complete it!! */
                if ((temp & PORT_RESET)
                                && time_after_eq(jiffies,
                                        fusbh200->reset_done[wIndex])) {
                        status |= USB_PORT_STAT_C_RESET << 16;
                        fusbh200->reset_done [wIndex] = 0;
                        clear_bit(wIndex, &fusbh200->resuming_ports);

                        /* force reset to complete */
                        fusbh200_writel(fusbh200, temp & ~(PORT_RWC_BITS | PORT_RESET),
                                        status_reg);
                        /* REVISIT:  some hardware needs 550+ usec to clear
                         * this bit; seems too long to spin routinely...
                         */
                        retval = handshake(fusbh200, status_reg,
                                        PORT_RESET, 0, 1000);
                        if (retval != 0) {
                                fusbh200_err (fusbh200, "port %d reset error %d\n",
                                        wIndex + 1, retval);
                                goto error;
                        }

                        /* see what we found out */
                        temp = check_reset_complete (fusbh200, wIndex, status_reg,
                                        fusbh200_readl(fusbh200, status_reg));
                }

                if (!(temp & (PORT_RESUME|PORT_RESET))) {
                        fusbh200->reset_done[wIndex] = 0;
                        clear_bit(wIndex, &fusbh200->resuming_ports);
                }

                /* transfer dedicated ports to the companion hc */
                if ((temp & PORT_CONNECT) &&
                                test_bit(wIndex, &fusbh200->companion_ports)) {
                        temp &= ~PORT_RWC_BITS;
                        fusbh200_writel(fusbh200, temp, status_reg);
                        fusbh200_dbg(fusbh200, "port %d --> companion\n", wIndex + 1);
                        temp = fusbh200_readl(fusbh200, status_reg);
                }

                /*
                 * Even if OWNER is set, there's no harm letting khubd
                 * see the wPortStatus values (they should all be 0 except
                 * for PORT_POWER anyway).
                 */

                if (temp & PORT_CONNECT) {
                        status |= USB_PORT_STAT_CONNECTION;
                        status |= fusbh200_port_speed(fusbh200, temp);
                }
                if (temp & PORT_PE)
                        status |= USB_PORT_STAT_ENABLE;

                /* maybe the port was unsuspended without our knowledge */
                if (temp & (PORT_SUSPEND|PORT_RESUME)) {
                        status |= USB_PORT_STAT_SUSPEND;
                } else if (test_bit(wIndex, &fusbh200->suspended_ports)) {
                        clear_bit(wIndex, &fusbh200->suspended_ports);
                        clear_bit(wIndex, &fusbh200->resuming_ports);
                        fusbh200->reset_done[wIndex] = 0;
                        if (temp & PORT_PE)
                                set_bit(wIndex, &fusbh200->port_c_suspend);
                }

                temp1 = fusbh200_readl(fusbh200, &fusbh200->regs->bmisr);
                if (temp1 & BMISR_OVC)
                        status |= USB_PORT_STAT_OVERCURRENT;
                if (temp & PORT_RESET)
                        status |= USB_PORT_STAT_RESET;
                if (test_bit(wIndex, &fusbh200->port_c_suspend))
                        status |= USB_PORT_STAT_C_SUSPEND << 16;

#ifndef VERBOSE_DEBUG
        if (status & ~0xffff)   /* only if wPortChange is interesting */
#endif
                dbg_port (fusbh200, "GetStatus", wIndex + 1, temp);
                put_unaligned_le32(status, buf);
                break;
        case SetHubFeature:
                switch (wValue) {
                case C_HUB_LOCAL_POWER:
                case C_HUB_OVER_CURRENT:
                        /* no hub-wide feature/status flags */
                        break;
                default:
                        goto error;
                }
                break;
        case SetPortFeature:
                selector = wIndex >> 8;
                wIndex &= 0xff;

                if (!wIndex || wIndex > ports)
                        goto error;
                wIndex--;
                temp = fusbh200_readl(fusbh200, status_reg);
                temp &= ~PORT_RWC_BITS;
                switch (wValue) {
                case USB_PORT_FEAT_SUSPEND:
                        if ((temp & PORT_PE) == 0
                                        || (temp & PORT_RESET) != 0)
                                goto error;

                        /* After above check the port must be connected.
                         * Set appropriate bit thus could put phy into low power
                         * mode if we have hostpc feature
                         */
                        fusbh200_writel(fusbh200, temp | PORT_SUSPEND, status_reg);
                        set_bit(wIndex, &fusbh200->suspended_ports);
                        break;
                case USB_PORT_FEAT_RESET:
                        if (temp & PORT_RESUME)
                                goto error;
                        /* line status bits may report this as low speed,
                         * which can be fine if this root hub has a
                         * transaction translator built in.
                         */
                        fusbh200_vdbg (fusbh200, "port %d reset\n", wIndex + 1);
                        temp |= PORT_RESET;
                        temp &= ~PORT_PE;

                        /*
                         * caller must wait, then call GetPortStatus
                         * usb 2.0 spec says 50 ms resets on root
                         */
                        fusbh200->reset_done [wIndex] = jiffies
                                        + msecs_to_jiffies (50);
                        fusbh200_writel(fusbh200, temp, status_reg);
                        break;

                /* For downstream facing ports (these):  one hub port is put
                 * into test mode according to USB2 11.24.2.13, then the hub
                 * must be reset (which for root hub now means rmmod+modprobe,
                 * or else system reboot).  See EHCI 2.3.9 and 4.14 for info
                 * about the EHCI-specific stuff.
                 */
                case USB_PORT_FEAT_TEST:
                        if (!selector || selector > 5)
                                goto error;
                        spin_unlock_irqrestore(&fusbh200->lock, flags);
                        fusbh200_quiesce(fusbh200);
                        spin_lock_irqsave(&fusbh200->lock, flags);

                        /* Put all enabled ports into suspend */
                        temp = fusbh200_readl(fusbh200, status_reg) & ~PORT_RWC_BITS;
                        if (temp & PORT_PE)
                                fusbh200_writel(fusbh200, temp | PORT_SUSPEND,
                                                status_reg);

                        spin_unlock_irqrestore(&fusbh200->lock, flags);
                        fusbh200_halt(fusbh200);
                        spin_lock_irqsave(&fusbh200->lock, flags);

                        temp = fusbh200_readl(fusbh200, status_reg);
                        temp |= selector << 16;
                        fusbh200_writel(fusbh200, temp, status_reg);
                        break;

                default:
                        goto error;
                }
                fusbh200_readl(fusbh200, &fusbh200->regs->command);     /* unblock posted writes */
                break;

        default:
error:
                /* "stall" on error */
                retval = -EPIPE;
        }
        spin_unlock_irqrestore (&fusbh200->lock, flags);
        return retval;
}

static void __maybe_unused fusbh200_relinquish_port(struct usb_hcd *hcd,
                int portnum)
{
        return;
}

static int __maybe_unused fusbh200_port_handed_over(struct usb_hcd *hcd,
                int portnum)
{
        return 0;
}
/*-------------------------------------------------------------------------*/
/*
 * There's basically three types of memory:
 *      - data used only by the HCD ... kmalloc is fine
 *      - async and periodic schedules, shared by HC and HCD ... these
 *        need to use dma_pool or dma_alloc_coherent
 *      - driver buffers, read/written by HC ... single shot DMA mapped
 *
 * There's also "register" data (e.g. PCI or SOC), which is memory mapped.
 * No memory seen by this driver is pageable.
 */

/*-------------------------------------------------------------------------*/

/* Allocate the key transfer structures from the previously allocated pool */

static inline void fusbh200_qtd_init(struct fusbh200_hcd *fusbh200, struct fusbh200_qtd *qtd,
                                  dma_addr_t dma)
{
        memset (qtd, 0, sizeof *qtd);
        qtd->qtd_dma = dma;
        qtd->hw_token = cpu_to_hc32(fusbh200, QTD_STS_HALT);
        qtd->hw_next = FUSBH200_LIST_END(fusbh200);
        qtd->hw_alt_next = FUSBH200_LIST_END(fusbh200);
        INIT_LIST_HEAD (&qtd->qtd_list);
}

static struct fusbh200_qtd *fusbh200_qtd_alloc (struct fusbh200_hcd *fusbh200, gfp_t flags)
{
        struct fusbh200_qtd             *qtd;
        dma_addr_t              dma;

        qtd = dma_pool_alloc (fusbh200->qtd_pool, flags, &dma);
        if (qtd != NULL) {
                fusbh200_qtd_init(fusbh200, qtd, dma);
        }
        return qtd;
}

static inline void fusbh200_qtd_free (struct fusbh200_hcd *fusbh200, struct fusbh200_qtd *qtd)
{
        dma_pool_free (fusbh200->qtd_pool, qtd, qtd->qtd_dma);
}


static void qh_destroy(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        /* clean qtds first, and know this is not linked */
        if (!list_empty (&qh->qtd_list) || qh->qh_next.ptr) {
                fusbh200_dbg (fusbh200, "unused qh not empty!\n");
                BUG ();
        }
        if (qh->dummy)
                fusbh200_qtd_free (fusbh200, qh->dummy);
        dma_pool_free(fusbh200->qh_pool, qh->hw, qh->qh_dma);
        kfree(qh);
}

static struct fusbh200_qh *fusbh200_qh_alloc (struct fusbh200_hcd *fusbh200, gfp_t flags)
{
        struct fusbh200_qh              *qh;
        dma_addr_t              dma;

        qh = kzalloc(sizeof *qh, GFP_ATOMIC);
        if (!qh)
                goto done;
        qh->hw = (struct fusbh200_qh_hw *)
                dma_pool_alloc(fusbh200->qh_pool, flags, &dma);
        if (!qh->hw)
                goto fail;
        memset(qh->hw, 0, sizeof *qh->hw);
        qh->qh_dma = dma;
        // INIT_LIST_HEAD (&qh->qh_list);
        INIT_LIST_HEAD (&qh->qtd_list);

        /* dummy td enables safe urb queuing */
        qh->dummy = fusbh200_qtd_alloc (fusbh200, flags);
        if (qh->dummy == NULL) {
                fusbh200_dbg (fusbh200, "no dummy td\n");
                goto fail1;
        }
done:
        return qh;
fail1:
        dma_pool_free(fusbh200->qh_pool, qh->hw, qh->qh_dma);
fail:
        kfree(qh);
        return NULL;
}

/*-------------------------------------------------------------------------*/

/* The queue heads and transfer descriptors are managed from pools tied
 * to each of the "per device" structures.
 * This is the initialisation and cleanup code.
 */

static void fusbh200_mem_cleanup (struct fusbh200_hcd *fusbh200)
{
        if (fusbh200->async)
                qh_destroy(fusbh200, fusbh200->async);
        fusbh200->async = NULL;

        if (fusbh200->dummy)
                qh_destroy(fusbh200, fusbh200->dummy);
        fusbh200->dummy = NULL;

        /* DMA consistent memory and pools */
        if (fusbh200->qtd_pool)
                dma_pool_destroy (fusbh200->qtd_pool);
        fusbh200->qtd_pool = NULL;

        if (fusbh200->qh_pool) {
                dma_pool_destroy (fusbh200->qh_pool);
                fusbh200->qh_pool = NULL;
        }

        if (fusbh200->itd_pool)
                dma_pool_destroy (fusbh200->itd_pool);
        fusbh200->itd_pool = NULL;

        if (fusbh200->periodic)
                dma_free_coherent (fusbh200_to_hcd(fusbh200)->self.controller,
                        fusbh200->periodic_size * sizeof (u32),
                        fusbh200->periodic, fusbh200->periodic_dma);
        fusbh200->periodic = NULL;

        /* shadow periodic table */
        kfree(fusbh200->pshadow);
        fusbh200->pshadow = NULL;
}

/* remember to add cleanup code (above) if you add anything here */
static int fusbh200_mem_init (struct fusbh200_hcd *fusbh200, gfp_t flags)
{
        int i;

        /* QTDs for control/bulk/intr transfers */
        fusbh200->qtd_pool = dma_pool_create ("fusbh200_qtd",
                        fusbh200_to_hcd(fusbh200)->self.controller,
                        sizeof (struct fusbh200_qtd),
                        32 /* byte alignment (for hw parts) */,
                        4096 /* can't cross 4K */);
        if (!fusbh200->qtd_pool) {
                goto fail;
        }

        /* QHs for control/bulk/intr transfers */
        fusbh200->qh_pool = dma_pool_create ("fusbh200_qh",
                        fusbh200_to_hcd(fusbh200)->self.controller,
                        sizeof(struct fusbh200_qh_hw),
                        32 /* byte alignment (for hw parts) */,
                        4096 /* can't cross 4K */);
        if (!fusbh200->qh_pool) {
                goto fail;
        }
        fusbh200->async = fusbh200_qh_alloc (fusbh200, flags);
        if (!fusbh200->async) {
                goto fail;
        }

        /* ITD for high speed ISO transfers */
        fusbh200->itd_pool = dma_pool_create ("fusbh200_itd",
                        fusbh200_to_hcd(fusbh200)->self.controller,
                        sizeof (struct fusbh200_itd),
                        64 /* byte alignment (for hw parts) */,
                        4096 /* can't cross 4K */);
        if (!fusbh200->itd_pool) {
                goto fail;
        }

        /* Hardware periodic table */
        fusbh200->periodic = (__le32 *)
                dma_alloc_coherent (fusbh200_to_hcd(fusbh200)->self.controller,
                        fusbh200->periodic_size * sizeof(__le32),
                        &fusbh200->periodic_dma, 0);
        if (fusbh200->periodic == NULL) {
                goto fail;
        }

                for (i = 0; i < fusbh200->periodic_size; i++)
                        fusbh200->periodic[i] = FUSBH200_LIST_END(fusbh200);

        /* software shadow of hardware table */
        fusbh200->pshadow = kcalloc(fusbh200->periodic_size, sizeof(void *), flags);
        if (fusbh200->pshadow != NULL)
                return 0;

fail:
        fusbh200_dbg (fusbh200, "couldn't init memory\n");
        fusbh200_mem_cleanup (fusbh200);
        return -ENOMEM;
}
/*-------------------------------------------------------------------------*/
/*
 * EHCI hardware queue manipulation ... the core.  QH/QTD manipulation.
 *
 * Control, bulk, and interrupt traffic all use "qh" lists.  They list "qtd"
 * entries describing USB transactions, max 16-20kB/entry (with 4kB-aligned
 * buffers needed for the larger number).  We use one QH per endpoint, queue
 * multiple urbs (all three types) per endpoint.  URBs may need several qtds.
 *
 * ISO traffic uses "ISO TD" (itd) records, and (along with
 * interrupts) needs careful scheduling.  Performance improvements can be
 * an ongoing challenge.  That's in "ehci-sched.c".
 *
 * USB 1.1 devices are handled (a) by "companion" OHCI or UHCI root hubs,
 * or otherwise through transaction translators (TTs) in USB 2.0 hubs using
 * (b) special fields in qh entries or (c) split iso entries.  TTs will
 * buffer low/full speed data so the host collects it at high speed.
 */

/*-------------------------------------------------------------------------*/

/* fill a qtd, returning how much of the buffer we were able to queue up */

static int
qtd_fill(struct fusbh200_hcd *fusbh200, struct fusbh200_qtd *qtd, dma_addr_t buf,
                  size_t len, int token, int maxpacket)
{
        int     i, count;
        u64     addr = buf;

        /* one buffer entry per 4K ... first might be short or unaligned */
        qtd->hw_buf[0] = cpu_to_hc32(fusbh200, (u32)addr);
        qtd->hw_buf_hi[0] = cpu_to_hc32(fusbh200, (u32)(addr >> 32));
        count = 0x1000 - (buf & 0x0fff);        /* rest of that page */
        if (likely (len < count))               /* ... iff needed */
                count = len;
        else {
                buf +=  0x1000;
                buf &= ~0x0fff;

                /* per-qtd limit: from 16K to 20K (best alignment) */
                for (i = 1; count < len && i < 5; i++) {
                        addr = buf;
                        qtd->hw_buf[i] = cpu_to_hc32(fusbh200, (u32)addr);
                        qtd->hw_buf_hi[i] = cpu_to_hc32(fusbh200,
                                        (u32)(addr >> 32));
                        buf += 0x1000;
                        if ((count + 0x1000) < len)
                                count += 0x1000;
                        else
                                count = len;
                }

                /* short packets may only terminate transfers */
                if (count != len)
                        count -= (count % maxpacket);
        }
        qtd->hw_token = cpu_to_hc32(fusbh200, (count << 16) | token);
        qtd->length = count;

        return count;
}

/*-------------------------------------------------------------------------*/

static inline void
qh_update (struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh, struct fusbh200_qtd *qtd)
{
        struct fusbh200_qh_hw *hw = qh->hw;

        /* writes to an active overlay are unsafe */
        BUG_ON(qh->qh_state != QH_STATE_IDLE);

        hw->hw_qtd_next = QTD_NEXT(fusbh200, qtd->qtd_dma);
        hw->hw_alt_next = FUSBH200_LIST_END(fusbh200);

        /* Except for control endpoints, we make hardware maintain data
         * toggle (like OHCI) ... here (re)initialize the toggle in the QH,
         * and set the pseudo-toggle in udev. Only usb_clear_halt() will
         * ever clear it.
         */
        if (!(hw->hw_info1 & cpu_to_hc32(fusbh200, QH_TOGGLE_CTL))) {
                unsigned        is_out, epnum;

                is_out = qh->is_out;
                epnum = (hc32_to_cpup(fusbh200, &hw->hw_info1) >> 8) & 0x0f;
                if (unlikely (!usb_gettoggle (qh->dev, epnum, is_out))) {
                        hw->hw_token &= ~cpu_to_hc32(fusbh200, QTD_TOGGLE);
                        usb_settoggle (qh->dev, epnum, is_out, 1);
                }
        }

        hw->hw_token &= cpu_to_hc32(fusbh200, QTD_TOGGLE | QTD_STS_PING);
}

/* if it weren't for a common silicon quirk (writing the dummy into the qh
 * overlay, so qh->hw_token wrongly becomes inactive/halted), only fault
 * recovery (including urb dequeue) would need software changes to a QH...
 */
static void
qh_refresh (struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        struct fusbh200_qtd *qtd;

        if (list_empty (&qh->qtd_list))
                qtd = qh->dummy;
        else {
                qtd = list_entry (qh->qtd_list.next,
                                struct fusbh200_qtd, qtd_list);
                /*
                 * first qtd may already be partially processed.
                 * If we come here during unlink, the QH overlay region
                 * might have reference to the just unlinked qtd. The
                 * qtd is updated in qh_completions(). Update the QH
                 * overlay here.
                 */
                if (cpu_to_hc32(fusbh200, qtd->qtd_dma) == qh->hw->hw_current) {
                        qh->hw->hw_qtd_next = qtd->hw_next;
                        qtd = NULL;
                }
        }

        if (qtd)
                qh_update (fusbh200, qh, qtd);
}

/*-------------------------------------------------------------------------*/

static void qh_link_async(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh);

static void fusbh200_clear_tt_buffer_complete(struct usb_hcd *hcd,
                struct usb_host_endpoint *ep)
{
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200(hcd);
        struct fusbh200_qh              *qh = ep->hcpriv;
        unsigned long           flags;

        spin_lock_irqsave(&fusbh200->lock, flags);
        qh->clearing_tt = 0;
        if (qh->qh_state == QH_STATE_IDLE && !list_empty(&qh->qtd_list)
                        && fusbh200->rh_state == FUSBH200_RH_RUNNING)
                qh_link_async(fusbh200, qh);
        spin_unlock_irqrestore(&fusbh200->lock, flags);
}

static void fusbh200_clear_tt_buffer(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh,
                struct urb *urb, u32 token)
{

        /* If an async split transaction gets an error or is unlinked,
         * the TT buffer may be left in an indeterminate state.  We
         * have to clear the TT buffer.
         *
         * Note: this routine is never called for Isochronous transfers.
         */
        if (urb->dev->tt && !usb_pipeint(urb->pipe) && !qh->clearing_tt) {
#ifdef DEBUG
                struct usb_device *tt = urb->dev->tt->hub;
                dev_dbg(&tt->dev,
                        "clear tt buffer port %d, a%d ep%d t%08x\n",
                        urb->dev->ttport, urb->dev->devnum,
                        usb_pipeendpoint(urb->pipe), token);
#endif /* DEBUG */
                if (urb->dev->tt->hub !=
                    fusbh200_to_hcd(fusbh200)->self.root_hub) {
                        if (usb_hub_clear_tt_buffer(urb) == 0)
                                qh->clearing_tt = 1;
                }
        }
}

static int qtd_copy_status (
        struct fusbh200_hcd *fusbh200,
        struct urb *urb,
        size_t length,
        u32 token
)
{
        int     status = -EINPROGRESS;

        /* count IN/OUT bytes, not SETUP (even short packets) */
        if (likely (QTD_PID (token) != 2))
                urb->actual_length += length - QTD_LENGTH (token);

        /* don't modify error codes */
        if (unlikely(urb->unlinked))
                return status;

        /* force cleanup after short read; not always an error */
        if (unlikely (IS_SHORT_READ (token)))
                status = -EREMOTEIO;

        /* serious "can't proceed" faults reported by the hardware */
        if (token & QTD_STS_HALT) {
                if (token & QTD_STS_BABBLE) {
                        /* FIXME "must" disable babbling device's port too */
                        status = -EOVERFLOW;
                /* CERR nonzero + halt --> stall */
                } else if (QTD_CERR(token)) {
                        status = -EPIPE;

                /* In theory, more than one of the following bits can be set
                 * since they are sticky and the transaction is retried.
                 * Which to test first is rather arbitrary.
                 */
                } else if (token & QTD_STS_MMF) {
                        /* fs/ls interrupt xfer missed the complete-split */
                        status = -EPROTO;
                } else if (token & QTD_STS_DBE) {
                        status = (QTD_PID (token) == 1) /* IN ? */
                                ? -ENOSR  /* hc couldn't read data */
                                : -ECOMM; /* hc couldn't write data */
                } else if (token & QTD_STS_XACT) {
                        /* timeout, bad CRC, wrong PID, etc */
                        fusbh200_dbg(fusbh200, "devpath %s ep%d%s 3strikes\n",
                                urb->dev->devpath,
                                usb_pipeendpoint(urb->pipe),
                                usb_pipein(urb->pipe) ? "in" : "out");
                        status = -EPROTO;
                } else {        /* unknown */
                        status = -EPROTO;
                }

                fusbh200_vdbg (fusbh200,
                        "dev%d ep%d%s qtd token %08x --> status %d\n",
                        usb_pipedevice (urb->pipe),
                        usb_pipeendpoint (urb->pipe),
                        usb_pipein (urb->pipe) ? "in" : "out",
                        token, status);
        }

        return status;
}

static void
fusbh200_urb_done(struct fusbh200_hcd *fusbh200, struct urb *urb, int status)
__releases(fusbh200->lock)
__acquires(fusbh200->lock)
{
        if (likely (urb->hcpriv != NULL)) {
                struct fusbh200_qh      *qh = (struct fusbh200_qh *) urb->hcpriv;

                /* S-mask in a QH means it's an interrupt urb */
                if ((qh->hw->hw_info2 & cpu_to_hc32(fusbh200, QH_SMASK)) != 0) {

                        /* ... update hc-wide periodic stats (for usbfs) */
                        fusbh200_to_hcd(fusbh200)->self.bandwidth_int_reqs--;
                }
        }

        if (unlikely(urb->unlinked)) {
                COUNT(fusbh200->stats.unlink);
        } else {
                /* report non-error and short read status as zero */
                if (status == -EINPROGRESS || status == -EREMOTEIO)
                        status = 0;
                COUNT(fusbh200->stats.complete);
        }

#ifdef FUSBH200_URB_TRACE
        fusbh200_dbg (fusbh200,
                "%s %s urb %p ep%d%s status %d len %d/%d\n",
                __func__, urb->dev->devpath, urb,
                usb_pipeendpoint (urb->pipe),
                usb_pipein (urb->pipe) ? "in" : "out",
                status,
                urb->actual_length, urb->transfer_buffer_length);
#endif

        /* complete() can reenter this HCD */
        usb_hcd_unlink_urb_from_ep(fusbh200_to_hcd(fusbh200), urb);
        spin_unlock (&fusbh200->lock);
        usb_hcd_giveback_urb(fusbh200_to_hcd(fusbh200), urb, status);
        spin_lock (&fusbh200->lock);
}

static int qh_schedule (struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh);

/*
 * Process and free completed qtds for a qh, returning URBs to drivers.
 * Chases up to qh->hw_current.  Returns number of completions called,
 * indicating how much "real" work we did.
 */
static unsigned
qh_completions (struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        struct fusbh200_qtd             *last, *end = qh->dummy;
        struct list_head        *entry, *tmp;
        int                     last_status;
        int                     stopped;
        unsigned                count = 0;
        u8                      state;
        struct fusbh200_qh_hw   *hw = qh->hw;

        if (unlikely (list_empty (&qh->qtd_list)))
                return count;

        /* completions (or tasks on other cpus) must never clobber HALT
         * till we've gone through and cleaned everything up, even when
         * they add urbs to this qh's queue or mark them for unlinking.
         *
         * NOTE:  unlinking expects to be done in queue order.
         *
         * It's a bug for qh->qh_state to be anything other than
         * QH_STATE_IDLE, unless our caller is scan_async() or
         * scan_intr().
         */
        state = qh->qh_state;
        qh->qh_state = QH_STATE_COMPLETING;
        stopped = (state == QH_STATE_IDLE);

 rescan:
        last = NULL;
        last_status = -EINPROGRESS;
        qh->needs_rescan = 0;

        /* remove de-activated QTDs from front of queue.
         * after faults (including short reads), cleanup this urb
         * then let the queue advance.
         * if queue is stopped, handles unlinks.
         */
        list_for_each_safe (entry, tmp, &qh->qtd_list) {
                struct fusbh200_qtd     *qtd;
                struct urb      *urb;
                u32             token = 0;

                qtd = list_entry (entry, struct fusbh200_qtd, qtd_list);
                urb = qtd->urb;

                /* clean up any state from previous QTD ...*/
                if (last) {
                        if (likely (last->urb != urb)) {
                                fusbh200_urb_done(fusbh200, last->urb, last_status);
                                count++;
                                last_status = -EINPROGRESS;
                        }
                        fusbh200_qtd_free (fusbh200, last);
                        last = NULL;
                }

                /* ignore urbs submitted during completions we reported */
                if (qtd == end)
                        break;

                /* hardware copies qtd out of qh overlay */
                rmb ();
                token = hc32_to_cpu(fusbh200, qtd->hw_token);

                /* always clean up qtds the hc de-activated */
 retry_xacterr:
                if ((token & QTD_STS_ACTIVE) == 0) {

                        /* Report Data Buffer Error: non-fatal but useful */
                        if (token & QTD_STS_DBE)
                                fusbh200_dbg(fusbh200,
                                        "detected DataBufferErr for urb %p ep%d%s len %d, qtd %p [qh %p]\n",
                                        urb,
                                        usb_endpoint_num(&urb->ep->desc),
                                        usb_endpoint_dir_in(&urb->ep->desc) ? "in" : "out",
                                        urb->transfer_buffer_length,
                                        qtd,
                                        qh);

                        /* on STALL, error, and short reads this urb must
                         * complete and all its qtds must be recycled.
                         */
                        if ((token & QTD_STS_HALT) != 0) {

                                /* retry transaction errors until we
                                 * reach the software xacterr limit
                                 */
                                if ((token & QTD_STS_XACT) &&
                                                QTD_CERR(token) == 0 &&
                                                ++qh->xacterrs < QH_XACTERR_MAX &&
                                                !urb->unlinked) {
                                        fusbh200_dbg(fusbh200,
        "detected XactErr len %zu/%zu retry %d\n",
        qtd->length - QTD_LENGTH(token), qtd->length, qh->xacterrs);

                                        /* reset the token in the qtd and the
                                         * qh overlay (which still contains
                                         * the qtd) so that we pick up from
                                         * where we left off
                                         */
                                        token &= ~QTD_STS_HALT;
                                        token |= QTD_STS_ACTIVE |
                                                        (FUSBH200_TUNE_CERR << 10);
                                        qtd->hw_token = cpu_to_hc32(fusbh200,
                                                        token);
                                        wmb();
                                        hw->hw_token = cpu_to_hc32(fusbh200,
                                                        token);
                                        goto retry_xacterr;
                                }
                                stopped = 1;

                        /* magic dummy for some short reads; qh won't advance.
                         * that silicon quirk can kick in with this dummy too.
                         *
                         * other short reads won't stop the queue, including
                         * control transfers (status stage handles that) or
                         * most other single-qtd reads ... the queue stops if
                         * URB_SHORT_NOT_OK was set so the driver submitting
                         * the urbs could clean it up.
                         */
                        } else if (IS_SHORT_READ (token)
                                        && !(qtd->hw_alt_next
                                                & FUSBH200_LIST_END(fusbh200))) {
                                stopped = 1;
                        }

                /* stop scanning when we reach qtds the hc is using */
                } else if (likely (!stopped
                                && fusbh200->rh_state >= FUSBH200_RH_RUNNING)) {
                        break;

                /* scan the whole queue for unlinks whenever it stops */
                } else {
                        stopped = 1;

                        /* cancel everything if we halt, suspend, etc */
                        if (fusbh200->rh_state < FUSBH200_RH_RUNNING)
                                last_status = -ESHUTDOWN;

                        /* this qtd is active; skip it unless a previous qtd
                         * for its urb faulted, or its urb was canceled.
                         */
                        else if (last_status == -EINPROGRESS && !urb->unlinked)
                                continue;

                        /* qh unlinked; token in overlay may be most current */
                        if (state == QH_STATE_IDLE
                                        && cpu_to_hc32(fusbh200, qtd->qtd_dma)
                                                == hw->hw_current) {
                                token = hc32_to_cpu(fusbh200, hw->hw_token);

                                /* An unlink may leave an incomplete
                                 * async transaction in the TT buffer.
                                 * We have to clear it.
                                 */
                                fusbh200_clear_tt_buffer(fusbh200, qh, urb, token);
                        }
                }

                /* unless we already know the urb's status, collect qtd status
                 * and update count of bytes transferred.  in common short read
                 * cases with only one data qtd (including control transfers),
                 * queue processing won't halt.  but with two or more qtds (for
                 * example, with a 32 KB transfer), when the first qtd gets a
                 * short read the second must be removed by hand.
                 */
                if (last_status == -EINPROGRESS) {
                        last_status = qtd_copy_status(fusbh200, urb,
                                        qtd->length, token);
                        if (last_status == -EREMOTEIO
                                        && (qtd->hw_alt_next
                                                & FUSBH200_LIST_END(fusbh200)))
                                last_status = -EINPROGRESS;

                        /* As part of low/full-speed endpoint-halt processing
                         * we must clear the TT buffer (11.17.5).
                         */
                        if (unlikely(last_status != -EINPROGRESS &&
                                        last_status != -EREMOTEIO)) {
                                /* The TT's in some hubs malfunction when they
                                 * receive this request following a STALL (they
                                 * stop sending isochronous packets).  Since a
                                 * STALL can't leave the TT buffer in a busy
                                 * state (if you believe Figures 11-48 - 11-51
                                 * in the USB 2.0 spec), we won't clear the TT
                                 * buffer in this case.  Strictly speaking this
                                 * is a violation of the spec.
                                 */
                                if (last_status != -EPIPE)
                                        fusbh200_clear_tt_buffer(fusbh200, qh, urb,
                                                        token);
                        }
                }

                /* if we're removing something not at the queue head,
                 * patch the hardware queue pointer.
                 */
                if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
                        last = list_entry (qtd->qtd_list.prev,
                                        struct fusbh200_qtd, qtd_list);
                        last->hw_next = qtd->hw_next;
                }

                /* remove qtd; it's recycled after possible urb completion */
                list_del (&qtd->qtd_list);
                last = qtd;

                /* reinit the xacterr counter for the next qtd */
                qh->xacterrs = 0;
        }

        /* last urb's completion might still need calling */
        if (likely (last != NULL)) {
                fusbh200_urb_done(fusbh200, last->urb, last_status);
                count++;
                fusbh200_qtd_free (fusbh200, last);
        }

        /* Do we need to rescan for URBs dequeued during a giveback? */
        if (unlikely(qh->needs_rescan)) {
                /* If the QH is already unlinked, do the rescan now. */
                if (state == QH_STATE_IDLE)
                        goto rescan;

                /* Otherwise we have to wait until the QH is fully unlinked.
                 * Our caller will start an unlink if qh->needs_rescan is
                 * set.  But if an unlink has already started, nothing needs
                 * to be done.
                 */
                if (state != QH_STATE_LINKED)
                        qh->needs_rescan = 0;
        }

        /* restore original state; caller must unlink or relink */
        qh->qh_state = state;

        /* be sure the hardware's done with the qh before refreshing
         * it after fault cleanup, or recovering from silicon wrongly
         * overlaying the dummy qtd (which reduces DMA chatter).
         */
        if (stopped != 0 || hw->hw_qtd_next == FUSBH200_LIST_END(fusbh200)) {
                switch (state) {
                case QH_STATE_IDLE:
                        qh_refresh(fusbh200, qh);
                        break;
                case QH_STATE_LINKED:
                        /* We won't refresh a QH that's linked (after the HC
                         * stopped the queue).  That avoids a race:
                         *  - HC reads first part of QH;
                         *  - CPU updates that first part and the token;
                         *  - HC reads rest of that QH, including token
                         * Result:  HC gets an inconsistent image, and then
                         * DMAs to/from the wrong memory (corrupting it).
                         *
                         * That should be rare for interrupt transfers,
                         * except maybe high bandwidth ...
                         */

                        /* Tell the caller to start an unlink */
                        qh->needs_rescan = 1;
                        break;
                /* otherwise, unlink already started */
                }
        }

        return count;
}

/*-------------------------------------------------------------------------*/

// high bandwidth multiplier, as encoded in highspeed endpoint descriptors
#define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03))
// ... and packet size, for any kind of endpoint descriptor
#define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff)

/*
 * reverse of qh_urb_transaction:  free a list of TDs.
 * used for cleanup after errors, before HC sees an URB's TDs.
 */
static void qtd_list_free (
        struct fusbh200_hcd             *fusbh200,
        struct urb              *urb,
        struct list_head        *qtd_list
) {
        struct list_head        *entry, *temp;

        list_for_each_safe (entry, temp, qtd_list) {
                struct fusbh200_qtd     *qtd;

                qtd = list_entry (entry, struct fusbh200_qtd, qtd_list);
                list_del (&qtd->qtd_list);
                fusbh200_qtd_free (fusbh200, qtd);
        }
}

/*
 * create a list of filled qtds for this URB; won't link into qh.
 */
static struct list_head *
qh_urb_transaction (
        struct fusbh200_hcd             *fusbh200,
        struct urb              *urb,
        struct list_head        *head,
        gfp_t                   flags
) {
        struct fusbh200_qtd             *qtd, *qtd_prev;
        dma_addr_t              buf;
        int                     len, this_sg_len, maxpacket;
        int                     is_input;
        u32                     token;
        int                     i;
        struct scatterlist      *sg;

        /*
         * URBs map to sequences of QTDs:  one logical transaction
         */
        qtd = fusbh200_qtd_alloc (fusbh200, flags);
        if (unlikely (!qtd))
                return NULL;
        list_add_tail (&qtd->qtd_list, head);
        qtd->urb = urb;

        token = QTD_STS_ACTIVE;
        token |= (FUSBH200_TUNE_CERR << 10);
        /* for split transactions, SplitXState initialized to zero */

        len = urb->transfer_buffer_length;
        is_input = usb_pipein (urb->pipe);
        if (usb_pipecontrol (urb->pipe)) {
                /* SETUP pid */
                qtd_fill(fusbh200, qtd, urb->setup_dma,
                                sizeof (struct usb_ctrlrequest),
                                token | (2 /* "setup" */ << 8), 8);

                /* ... and always at least one more pid */
                token ^= QTD_TOGGLE;
                qtd_prev = qtd;
                qtd = fusbh200_qtd_alloc (fusbh200, flags);
                if (unlikely (!qtd))
                        goto cleanup;
                qtd->urb = urb;
                qtd_prev->hw_next = QTD_NEXT(fusbh200, qtd->qtd_dma);
                list_add_tail (&qtd->qtd_list, head);

                /* for zero length DATA stages, STATUS is always IN */
                if (len == 0)
                        token |= (1 /* "in" */ << 8);
        }

        /*
         * data transfer stage:  buffer setup
         */
        i = urb->num_mapped_sgs;
        if (len > 0 && i > 0) {
                sg = urb->sg;
                buf = sg_dma_address(sg);

                /* urb->transfer_buffer_length may be smaller than the
                 * size of the scatterlist (or vice versa)
                 */
                this_sg_len = min_t(int, sg_dma_len(sg), len);
        } else {
                sg = NULL;
                buf = urb->transfer_dma;
                this_sg_len = len;
        }

        if (is_input)
                token |= (1 /* "in" */ << 8);
        /* else it's already initted to "out" pid (0 << 8) */

        maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input));

        /*
         * buffer gets wrapped in one or more qtds;
         * last one may be "short" (including zero len)
         * and may serve as a control status ack
         */
        for (;;) {
                int this_qtd_len;

                this_qtd_len = qtd_fill(fusbh200, qtd, buf, this_sg_len, token,
                                maxpacket);
                this_sg_len -= this_qtd_len;
                len -= this_qtd_len;
                buf += this_qtd_len;

                /*
                 * short reads advance to a "magic" dummy instead of the next
                 * qtd ... that forces the queue to stop, for manual cleanup.
                 * (this will usually be overridden later.)
                 */
                if (is_input)
                        qtd->hw_alt_next = fusbh200->async->hw->hw_alt_next;

                /* qh makes control packets use qtd toggle; maybe switch it */
                if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0)
                        token ^= QTD_TOGGLE;

                if (likely(this_sg_len <= 0)) {
                        if (--i <= 0 || len <= 0)
                                break;
                        sg = sg_next(sg);
                        buf = sg_dma_address(sg);
                        this_sg_len = min_t(int, sg_dma_len(sg), len);
                }

                qtd_prev = qtd;
                qtd = fusbh200_qtd_alloc (fusbh200, flags);
                if (unlikely (!qtd))
                        goto cleanup;
                qtd->urb = urb;
                qtd_prev->hw_next = QTD_NEXT(fusbh200, qtd->qtd_dma);
                list_add_tail (&qtd->qtd_list, head);
        }

        /*
         * unless the caller requires manual cleanup after short reads,
         * have the alt_next mechanism keep the queue running after the
         * last data qtd (the only one, for control and most other cases).
         */
        if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
                                || usb_pipecontrol (urb->pipe)))
                qtd->hw_alt_next = FUSBH200_LIST_END(fusbh200);

        /*
         * control requests may need a terminating data "status" ack;
         * other OUT ones may need a terminating short packet
         * (zero length).
         */
        if (likely (urb->transfer_buffer_length != 0)) {
                int     one_more = 0;

                if (usb_pipecontrol (urb->pipe)) {
                        one_more = 1;
                        token ^= 0x0100;        /* "in" <--> "out"  */
                        token |= QTD_TOGGLE;    /* force DATA1 */
                } else if (usb_pipeout(urb->pipe)
                                && (urb->transfer_flags & URB_ZERO_PACKET)
                                && !(urb->transfer_buffer_length % maxpacket)) {
                        one_more = 1;
                }
                if (one_more) {
                        qtd_prev = qtd;
                        qtd = fusbh200_qtd_alloc (fusbh200, flags);
                        if (unlikely (!qtd))
                                goto cleanup;
                        qtd->urb = urb;
                        qtd_prev->hw_next = QTD_NEXT(fusbh200, qtd->qtd_dma);
                        list_add_tail (&qtd->qtd_list, head);

                        /* never any data in such packets */
                        qtd_fill(fusbh200, qtd, 0, 0, token, 0);
                }
        }

        /* by default, enable interrupt on urb completion */
        if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT)))
                qtd->hw_token |= cpu_to_hc32(fusbh200, QTD_IOC);
        return head;

cleanup:
        qtd_list_free (fusbh200, urb, head);
        return NULL;
}

/*-------------------------------------------------------------------------*/

// Would be best to create all qh's from config descriptors,
// when each interface/altsetting is established.  Unlink
// any previous qh and cancel its urbs first; endpoints are
// implicitly reset then (data toggle too).
// That'd mean updating how usbcore talks to HCDs. (2.7?)


/*
 * Each QH holds a qtd list; a QH is used for everything except iso.
 *
 * For interrupt urbs, the scheduler must set the microframe scheduling
 * mask(s) each time the QH gets scheduled.  For highspeed, that's
 * just one microframe in the s-mask.  For split interrupt transactions
 * there are additional complications: c-mask, maybe FSTNs.
 */
static struct fusbh200_qh *
qh_make (
        struct fusbh200_hcd             *fusbh200,
        struct urb              *urb,
        gfp_t                   flags
) {
        struct fusbh200_qh              *qh = fusbh200_qh_alloc (fusbh200, flags);
        u32                     info1 = 0, info2 = 0;
        int                     is_input, type;
        int                     maxp = 0;
        struct usb_tt           *tt = urb->dev->tt;
        struct fusbh200_qh_hw   *hw;

        if (!qh)
                return qh;

        /*
         * init endpoint/device data for this QH
         */
        info1 |= usb_pipeendpoint (urb->pipe) << 8;
        info1 |= usb_pipedevice (urb->pipe) << 0;

        is_input = usb_pipein (urb->pipe);
        type = usb_pipetype (urb->pipe);
        maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input);

        /* 1024 byte maxpacket is a hardware ceiling.  High bandwidth
         * acts like up to 3KB, but is built from smaller packets.
         */
        if (max_packet(maxp) > 1024) {
                fusbh200_dbg(fusbh200, "bogus qh maxpacket %d\n", max_packet(maxp));
                goto done;
        }

        /* Compute interrupt scheduling parameters just once, and save.
         * - allowing for high bandwidth, how many nsec/uframe are used?
         * - split transactions need a second CSPLIT uframe; same question
         * - splits also need a schedule gap (for full/low speed I/O)
         * - qh has a polling interval
         *
         * For control/bulk requests, the HC or TT handles these.
         */
        if (type == PIPE_INTERRUPT) {
                qh->usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH,
                                is_input, 0,
                                hb_mult(maxp) * max_packet(maxp)));
                qh->start = NO_FRAME;

                if (urb->dev->speed == USB_SPEED_HIGH) {
                        qh->c_usecs = 0;
                        qh->gap_uf = 0;

                        qh->period = urb->interval >> 3;
                        if (qh->period == 0 && urb->interval != 1) {
                                /* NOTE interval 2 or 4 uframes could work.
                                 * But interval 1 scheduling is simpler, and
                                 * includes high bandwidth.
                                 */
                                urb->interval = 1;
                        } else if (qh->period > fusbh200->periodic_size) {
                                qh->period = fusbh200->periodic_size;
                                urb->interval = qh->period << 3;
                        }
                } else {
                        int             think_time;

                        /* gap is f(FS/LS transfer times) */
                        qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed,
                                        is_input, 0, maxp) / (125 * 1000);

                        /* FIXME this just approximates SPLIT/CSPLIT times */
                        if (is_input) {         // SPLIT, gap, CSPLIT+DATA
                                qh->c_usecs = qh->usecs + HS_USECS (0);
                                qh->usecs = HS_USECS (1);
                        } else {                // SPLIT+DATA, gap, CSPLIT
                                qh->usecs += HS_USECS (1);
                                qh->c_usecs = HS_USECS (0);
                        }

                        think_time = tt ? tt->think_time : 0;
                        qh->tt_usecs = NS_TO_US (think_time +
                                        usb_calc_bus_time (urb->dev->speed,
                                        is_input, 0, max_packet (maxp)));
                        qh->period = urb->interval;
                        if (qh->period > fusbh200->periodic_size) {
                                qh->period = fusbh200->periodic_size;
                                urb->interval = qh->period;
                        }
                }
        }

        /* support for tt scheduling, and access to toggles */
        qh->dev = urb->dev;

        /* using TT? */
        switch (urb->dev->speed) {
        case USB_SPEED_LOW:
                info1 |= QH_LOW_SPEED;
                /* FALL THROUGH */

        case USB_SPEED_FULL:
                /* EPS 0 means "full" */
                if (type != PIPE_INTERRUPT)
                        info1 |= (FUSBH200_TUNE_RL_TT << 28);
                if (type == PIPE_CONTROL) {
                        info1 |= QH_CONTROL_EP;         /* for TT */
                        info1 |= QH_TOGGLE_CTL;         /* toggle from qtd */
                }
                info1 |= maxp << 16;

                info2 |= (FUSBH200_TUNE_MULT_TT << 30);

                /* Some Freescale processors have an erratum in which the
                 * port number in the queue head was 0..N-1 instead of 1..N.
                 */
                if (fusbh200_has_fsl_portno_bug(fusbh200))
                        info2 |= (urb->dev->ttport-1) << 23;
                else
                        info2 |= urb->dev->ttport << 23;

                /* set the address of the TT; for TDI's integrated
                 * root hub tt, leave it zeroed.
                 */
                if (tt && tt->hub != fusbh200_to_hcd(fusbh200)->self.root_hub)
                        info2 |= tt->hub->devnum << 16;

                /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets c-mask } */

                break;

        case USB_SPEED_HIGH:            /* no TT involved */
                info1 |= QH_HIGH_SPEED;
                if (type == PIPE_CONTROL) {
                        info1 |= (FUSBH200_TUNE_RL_HS << 28);
                        info1 |= 64 << 16;      /* usb2 fixed maxpacket */
                        info1 |= QH_TOGGLE_CTL; /* toggle from qtd */
                        info2 |= (FUSBH200_TUNE_MULT_HS << 30);
                } else if (type == PIPE_BULK) {
                        info1 |= (FUSBH200_TUNE_RL_HS << 28);
                        /* The USB spec says that high speed bulk endpoints
                         * always use 512 byte maxpacket.  But some device
                         * vendors decided to ignore that, and MSFT is happy
                         * to help them do so.  So now people expect to use
                         * such nonconformant devices with Linux too; sigh.
                         */
                        info1 |= max_packet(maxp) << 16;
                        info2 |= (FUSBH200_TUNE_MULT_HS << 30);
                } else {                /* PIPE_INTERRUPT */
                        info1 |= max_packet (maxp) << 16;
                        info2 |= hb_mult (maxp) << 30;
                }
                break;
        default:
                fusbh200_dbg(fusbh200, "bogus dev %p speed %d\n", urb->dev,
                        urb->dev->speed);
done:
                qh_destroy(fusbh200, qh);
                return NULL;
        }

        /* NOTE:  if (PIPE_INTERRUPT) { scheduler sets s-mask } */

        /* init as live, toggle clear, advance to dummy */
        qh->qh_state = QH_STATE_IDLE;
        hw = qh->hw;
        hw->hw_info1 = cpu_to_hc32(fusbh200, info1);
        hw->hw_info2 = cpu_to_hc32(fusbh200, info2);
        qh->is_out = !is_input;
        usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
        qh_refresh (fusbh200, qh);
        return qh;
}

/*-------------------------------------------------------------------------*/

static void enable_async(struct fusbh200_hcd *fusbh200)
{
        if (fusbh200->async_count++)
                return;

        /* Stop waiting to turn off the async schedule */
        fusbh200->enabled_hrtimer_events &= ~BIT(FUSBH200_HRTIMER_DISABLE_ASYNC);

        /* Don't start the schedule until ASS is 0 */
        fusbh200_poll_ASS(fusbh200);
        turn_on_io_watchdog(fusbh200);
}

static void disable_async(struct fusbh200_hcd *fusbh200)
{
        if (--fusbh200->async_count)
                return;

        /* The async schedule and async_unlink list are supposed to be empty */
        WARN_ON(fusbh200->async->qh_next.qh || fusbh200->async_unlink);

        /* Don't turn off the schedule until ASS is 1 */
        fusbh200_poll_ASS(fusbh200);
}

/* move qh (and its qtds) onto async queue; maybe enable queue.  */

static void qh_link_async (struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        __hc32          dma = QH_NEXT(fusbh200, qh->qh_dma);
        struct fusbh200_qh      *head;

        /* Don't link a QH if there's a Clear-TT-Buffer pending */
        if (unlikely(qh->clearing_tt))
                return;

        WARN_ON(qh->qh_state != QH_STATE_IDLE);

        /* clear halt and/or toggle; and maybe recover from silicon quirk */
        qh_refresh(fusbh200, qh);

        /* splice right after start */
        head = fusbh200->async;
        qh->qh_next = head->qh_next;
        qh->hw->hw_next = head->hw->hw_next;
        wmb ();

        head->qh_next.qh = qh;
        head->hw->hw_next = dma;

        qh->xacterrs = 0;
        qh->qh_state = QH_STATE_LINKED;
        /* qtd completions reported later by interrupt */

        enable_async(fusbh200);
}

/*-------------------------------------------------------------------------*/

/*
 * For control/bulk/interrupt, return QH with these TDs appended.
 * Allocates and initializes the QH if necessary.
 * Returns null if it can't allocate a QH it needs to.
 * If the QH has TDs (urbs) already, that's great.
 */
static struct fusbh200_qh *qh_append_tds (
        struct fusbh200_hcd             *fusbh200,
        struct urb              *urb,
        struct list_head        *qtd_list,
        int                     epnum,
        void                    **ptr
)
{
        struct fusbh200_qh              *qh = NULL;
        __hc32                  qh_addr_mask = cpu_to_hc32(fusbh200, 0x7f);

        qh = (struct fusbh200_qh *) *ptr;
        if (unlikely (qh == NULL)) {
                /* can't sleep here, we have fusbh200->lock... */
                qh = qh_make (fusbh200, urb, GFP_ATOMIC);
                *ptr = qh;
        }
        if (likely (qh != NULL)) {
                struct fusbh200_qtd     *qtd;

                if (unlikely (list_empty (qtd_list)))
                        qtd = NULL;
                else
                        qtd = list_entry (qtd_list->next, struct fusbh200_qtd,
                                        qtd_list);

                /* control qh may need patching ... */
                if (unlikely (epnum == 0)) {

                        /* usb_reset_device() briefly reverts to address 0 */
                        if (usb_pipedevice (urb->pipe) == 0)
                                qh->hw->hw_info1 &= ~qh_addr_mask;
                }

                /* just one way to queue requests: swap with the dummy qtd.
                 * only hc or qh_refresh() ever modify the overlay.
                 */
                if (likely (qtd != NULL)) {
                        struct fusbh200_qtd             *dummy;
                        dma_addr_t              dma;
                        __hc32                  token;

                        /* to avoid racing the HC, use the dummy td instead of
                         * the first td of our list (becomes new dummy).  both
                         * tds stay deactivated until we're done, when the
                         * HC is allowed to fetch the old dummy (4.10.2).
                         */
                        token = qtd->hw_token;
                        qtd->hw_token = HALT_BIT(fusbh200);

                        dummy = qh->dummy;

                        dma = dummy->qtd_dma;
                        *dummy = *qtd;
                        dummy->qtd_dma = dma;

                        list_del (&qtd->qtd_list);
                        list_add (&dummy->qtd_list, qtd_list);
                        list_splice_tail(qtd_list, &qh->qtd_list);

                        fusbh200_qtd_init(fusbh200, qtd, qtd->qtd_dma);
                        qh->dummy = qtd;

                        /* hc must see the new dummy at list end */
                        dma = qtd->qtd_dma;
                        qtd = list_entry (qh->qtd_list.prev,
                                        struct fusbh200_qtd, qtd_list);
                        qtd->hw_next = QTD_NEXT(fusbh200, dma);

                        /* let the hc process these next qtds */
                        wmb ();
                        dummy->hw_token = token;

                        urb->hcpriv = qh;
                }
        }
        return qh;
}

/*-------------------------------------------------------------------------*/

static int
submit_async (
        struct fusbh200_hcd             *fusbh200,
        struct urb              *urb,
        struct list_head        *qtd_list,
        gfp_t                   mem_flags
) {
        int                     epnum;
        unsigned long           flags;
        struct fusbh200_qh              *qh = NULL;
        int                     rc;

        epnum = urb->ep->desc.bEndpointAddress;

#ifdef FUSBH200_URB_TRACE
        {
                struct fusbh200_qtd *qtd;
                qtd = list_entry(qtd_list->next, struct fusbh200_qtd, qtd_list);
                fusbh200_dbg(fusbh200,
                         "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
                         __func__, urb->dev->devpath, urb,
                         epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
                         urb->transfer_buffer_length,
                         qtd, urb->ep->hcpriv);
        }
#endif

        spin_lock_irqsave (&fusbh200->lock, flags);
        if (unlikely(!HCD_HW_ACCESSIBLE(fusbh200_to_hcd(fusbh200)))) {
                rc = -ESHUTDOWN;
                goto done;
        }
        rc = usb_hcd_link_urb_to_ep(fusbh200_to_hcd(fusbh200), urb);
        if (unlikely(rc))
                goto done;

        qh = qh_append_tds(fusbh200, urb, qtd_list, epnum, &urb->ep->hcpriv);
        if (unlikely(qh == NULL)) {
                usb_hcd_unlink_urb_from_ep(fusbh200_to_hcd(fusbh200), urb);
                rc = -ENOMEM;
                goto done;
        }

        /* Control/bulk operations through TTs don't need scheduling,
         * the HC and TT handle it when the TT has a buffer ready.
         */
        if (likely (qh->qh_state == QH_STATE_IDLE))
                qh_link_async(fusbh200, qh);
 done:
        spin_unlock_irqrestore (&fusbh200->lock, flags);
        if (unlikely (qh == NULL))
                qtd_list_free (fusbh200, urb, qtd_list);
        return rc;
}

/*-------------------------------------------------------------------------*/

static void single_unlink_async(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        struct fusbh200_qh              *prev;

        /* Add to the end of the list of QHs waiting for the next IAAD */
        qh->qh_state = QH_STATE_UNLINK;
        if (fusbh200->async_unlink)
                fusbh200->async_unlink_last->unlink_next = qh;
        else
                fusbh200->async_unlink = qh;
        fusbh200->async_unlink_last = qh;

        /* Unlink it from the schedule */
        prev = fusbh200->async;
        while (prev->qh_next.qh != qh)
                prev = prev->qh_next.qh;

        prev->hw->hw_next = qh->hw->hw_next;
        prev->qh_next = qh->qh_next;
        if (fusbh200->qh_scan_next == qh)
                fusbh200->qh_scan_next = qh->qh_next.qh;
}

static void start_iaa_cycle(struct fusbh200_hcd *fusbh200, bool nested)
{
        /*
         * Do nothing if an IAA cycle is already running or
         * if one will be started shortly.
         */
        if (fusbh200->async_iaa || fusbh200->async_unlinking)
                return;

        /* Do all the waiting QHs at once */
        fusbh200->async_iaa = fusbh200->async_unlink;
        fusbh200->async_unlink = NULL;

        /* If the controller isn't running, we don't have to wait for it */
        if (unlikely(fusbh200->rh_state < FUSBH200_RH_RUNNING)) {
                if (!nested)            /* Avoid recursion */
                        end_unlink_async(fusbh200);

        /* Otherwise start a new IAA cycle */
        } else if (likely(fusbh200->rh_state == FUSBH200_RH_RUNNING)) {
                /* Make sure the unlinks are all visible to the hardware */
                wmb();

                fusbh200_writel(fusbh200, fusbh200->command | CMD_IAAD,
                                &fusbh200->regs->command);
                fusbh200_readl(fusbh200, &fusbh200->regs->command);
                fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_IAA_WATCHDOG, true);
        }
}

/* the async qh for the qtds being unlinked are now gone from the HC */

static void end_unlink_async(struct fusbh200_hcd *fusbh200)
{
        struct fusbh200_qh              *qh;

        /* Process the idle QHs */
 restart:
        fusbh200->async_unlinking = true;
        while (fusbh200->async_iaa) {
                qh = fusbh200->async_iaa;
                fusbh200->async_iaa = qh->unlink_next;
                qh->unlink_next = NULL;

                qh->qh_state = QH_STATE_IDLE;
                qh->qh_next.qh = NULL;

                qh_completions(fusbh200, qh);
                if (!list_empty(&qh->qtd_list) &&
                                fusbh200->rh_state == FUSBH200_RH_RUNNING)
                        qh_link_async(fusbh200, qh);
                disable_async(fusbh200);
        }
        fusbh200->async_unlinking = false;

        /* Start a new IAA cycle if any QHs are waiting for it */
        if (fusbh200->async_unlink) {
                start_iaa_cycle(fusbh200, true);
                if (unlikely(fusbh200->rh_state < FUSBH200_RH_RUNNING))
                        goto restart;
        }
}

static void unlink_empty_async(struct fusbh200_hcd *fusbh200)
{
        struct fusbh200_qh              *qh, *next;
        bool                    stopped = (fusbh200->rh_state < FUSBH200_RH_RUNNING);
        bool                    check_unlinks_later = false;

        /* Unlink all the async QHs that have been empty for a timer cycle */
        next = fusbh200->async->qh_next.qh;
        while (next) {
                qh = next;
                next = qh->qh_next.qh;

                if (list_empty(&qh->qtd_list) &&
                                qh->qh_state == QH_STATE_LINKED) {
                        if (!stopped && qh->unlink_cycle ==
                                        fusbh200->async_unlink_cycle)
                                check_unlinks_later = true;
                        else
                                single_unlink_async(fusbh200, qh);
                }
        }

        /* Start a new IAA cycle if any QHs are waiting for it */
        if (fusbh200->async_unlink)
                start_iaa_cycle(fusbh200, false);

        /* QHs that haven't been empty for long enough will be handled later */
        if (check_unlinks_later) {
                fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_ASYNC_UNLINKS, true);
                ++fusbh200->async_unlink_cycle;
        }
}

/* makes sure the async qh will become idle */
/* caller must own fusbh200->lock */

static void start_unlink_async(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        /*
         * If the QH isn't linked then there's nothing we can do
         * unless we were called during a giveback, in which case
         * qh_completions() has to deal with it.
         */
        if (qh->qh_state != QH_STATE_LINKED) {
                if (qh->qh_state == QH_STATE_COMPLETING)
                        qh->needs_rescan = 1;
                return;
        }

        single_unlink_async(fusbh200, qh);
        start_iaa_cycle(fusbh200, false);
}

/*-------------------------------------------------------------------------*/

static void scan_async (struct fusbh200_hcd *fusbh200)
{
        struct fusbh200_qh              *qh;
        bool                    check_unlinks_later = false;

        fusbh200->qh_scan_next = fusbh200->async->qh_next.qh;
        while (fusbh200->qh_scan_next) {
                qh = fusbh200->qh_scan_next;
                fusbh200->qh_scan_next = qh->qh_next.qh;
 rescan:
                /* clean any finished work for this qh */
                if (!list_empty(&qh->qtd_list)) {
                        int temp;

                        /*
                         * Unlinks could happen here; completion reporting
                         * drops the lock.  That's why fusbh200->qh_scan_next
                         * always holds the next qh to scan; if the next qh
                         * gets unlinked then fusbh200->qh_scan_next is adjusted
                         * in single_unlink_async().
                         */
                        temp = qh_completions(fusbh200, qh);
                        if (qh->needs_rescan) {
                                start_unlink_async(fusbh200, qh);
                        } else if (list_empty(&qh->qtd_list)
                                        && qh->qh_state == QH_STATE_LINKED) {
                                qh->unlink_cycle = fusbh200->async_unlink_cycle;
                                check_unlinks_later = true;
                        } else if (temp != 0)
                                goto rescan;
                }
        }

        /*
         * Unlink empty entries, reducing DMA usage as well
         * as HCD schedule-scanning costs.  Delay for any qh
         * we just scanned, there's a not-unusual case that it
         * doesn't stay idle for long.
         */
        if (check_unlinks_later && fusbh200->rh_state == FUSBH200_RH_RUNNING &&
                        !(fusbh200->enabled_hrtimer_events &
                                BIT(FUSBH200_HRTIMER_ASYNC_UNLINKS))) {
                fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_ASYNC_UNLINKS, true);
                ++fusbh200->async_unlink_cycle;
        }
}
/*-------------------------------------------------------------------------*/
/*
 * EHCI scheduled transaction support:  interrupt, iso, split iso
 * These are called "periodic" transactions in the EHCI spec.
 *
 * Note that for interrupt transfers, the QH/QTD manipulation is shared
 * with the "asynchronous" transaction support (control/bulk transfers).
 * The only real difference is in how interrupt transfers are scheduled.
 *
 * For ISO, we make an "iso_stream" head to serve the same role as a QH.
 * It keeps track of every ITD (or SITD) that's linked, and holds enough
 * pre-calculated schedule data to make appending to the queue be quick.
 */

static int fusbh200_get_frame (struct usb_hcd *hcd);

/*-------------------------------------------------------------------------*/

/*
 * periodic_next_shadow - return "next" pointer on shadow list
 * @periodic: host pointer to qh/itd
 * @tag: hardware tag for type of this record
 */
static union fusbh200_shadow *
periodic_next_shadow(struct fusbh200_hcd *fusbh200, union fusbh200_shadow *periodic,
                __hc32 tag)
{
        switch (hc32_to_cpu(fusbh200, tag)) {
        case Q_TYPE_QH:
                return &periodic->qh->qh_next;
        case Q_TYPE_FSTN:
                return &periodic->fstn->fstn_next;
        default:
                return &periodic->itd->itd_next;
        }
}

static __hc32 *
shadow_next_periodic(struct fusbh200_hcd *fusbh200, union fusbh200_shadow *periodic,
                __hc32 tag)
{
        switch (hc32_to_cpu(fusbh200, tag)) {
        /* our fusbh200_shadow.qh is actually software part */
        case Q_TYPE_QH:
                return &periodic->qh->hw->hw_next;
        /* others are hw parts */
        default:
                return periodic->hw_next;
        }
}

/* caller must hold fusbh200->lock */
static void periodic_unlink (struct fusbh200_hcd *fusbh200, unsigned frame, void *ptr)
{
        union fusbh200_shadow   *prev_p = &fusbh200->pshadow[frame];
        __hc32                  *hw_p = &fusbh200->periodic[frame];
        union fusbh200_shadow   here = *prev_p;

        /* find predecessor of "ptr"; hw and shadow lists are in sync */
        while (here.ptr && here.ptr != ptr) {
                prev_p = periodic_next_shadow(fusbh200, prev_p,
                                Q_NEXT_TYPE(fusbh200, *hw_p));
                hw_p = shadow_next_periodic(fusbh200, &here,
                                Q_NEXT_TYPE(fusbh200, *hw_p));
                here = *prev_p;
        }
        /* an interrupt entry (at list end) could have been shared */
        if (!here.ptr)
                return;

        /* update shadow and hardware lists ... the old "next" pointers
         * from ptr may still be in use, the caller updates them.
         */
        *prev_p = *periodic_next_shadow(fusbh200, &here,
                        Q_NEXT_TYPE(fusbh200, *hw_p));

        *hw_p = *shadow_next_periodic(fusbh200, &here,
                                Q_NEXT_TYPE(fusbh200, *hw_p));
}

/* how many of the uframe's 125 usecs are allocated? */
static unsigned short
periodic_usecs (struct fusbh200_hcd *fusbh200, unsigned frame, unsigned uframe)
{
        __hc32                  *hw_p = &fusbh200->periodic [frame];
        union fusbh200_shadow   *q = &fusbh200->pshadow [frame];
        unsigned                usecs = 0;
        struct fusbh200_qh_hw   *hw;

        while (q->ptr) {
                switch (hc32_to_cpu(fusbh200, Q_NEXT_TYPE(fusbh200, *hw_p))) {
                case Q_TYPE_QH:
                        hw = q->qh->hw;
                        /* is it in the S-mask? */
                        if (hw->hw_info2 & cpu_to_hc32(fusbh200, 1 << uframe))
                                usecs += q->qh->usecs;
                        /* ... or C-mask? */
                        if (hw->hw_info2 & cpu_to_hc32(fusbh200,
                                        1 << (8 + uframe)))
                                usecs += q->qh->c_usecs;
                        hw_p = &hw->hw_next;
                        q = &q->qh->qh_next;
                        break;
                // case Q_TYPE_FSTN:
                default:
                        /* for "save place" FSTNs, count the relevant INTR
                         * bandwidth from the previous frame
                         */
                        if (q->fstn->hw_prev != FUSBH200_LIST_END(fusbh200)) {
                                fusbh200_dbg (fusbh200, "ignoring FSTN cost ...\n");
                        }
                        hw_p = &q->fstn->hw_next;
                        q = &q->fstn->fstn_next;
                        break;
                case Q_TYPE_ITD:
                        if (q->itd->hw_transaction[uframe])
                                usecs += q->itd->stream->usecs;
                        hw_p = &q->itd->hw_next;
                        q = &q->itd->itd_next;
                        break;
                }
        }
#ifdef  DEBUG
        if (usecs > fusbh200->uframe_periodic_max)
                fusbh200_err (fusbh200, "uframe %d sched overrun: %d usecs\n",
                        frame * 8 + uframe, usecs);
#endif
        return usecs;
}

/*-------------------------------------------------------------------------*/

static int same_tt (struct usb_device *dev1, struct usb_device *dev2)
{
        if (!dev1->tt || !dev2->tt)
                return 0;
        if (dev1->tt != dev2->tt)
                return 0;
        if (dev1->tt->multi)
                return dev1->ttport == dev2->ttport;
        else
                return 1;
}

/* return true iff the device's transaction translator is available
 * for a periodic transfer starting at the specified frame, using
 * all the uframes in the mask.
 */
static int tt_no_collision (
        struct fusbh200_hcd             *fusbh200,
        unsigned                period,
        struct usb_device       *dev,
        unsigned                frame,
        u32                     uf_mask
)
{
        if (period == 0)        /* error */
                return 0;

        /* note bandwidth wastage:  split never follows csplit
         * (different dev or endpoint) until the next uframe.
         * calling convention doesn't make that distinction.
         */
        for (; frame < fusbh200->periodic_size; frame += period) {
                union fusbh200_shadow   here;
                __hc32                  type;
                struct fusbh200_qh_hw   *hw;

                here = fusbh200->pshadow [frame];
                type = Q_NEXT_TYPE(fusbh200, fusbh200->periodic [frame]);
                while (here.ptr) {
                        switch (hc32_to_cpu(fusbh200, type)) {
                        case Q_TYPE_ITD:
                                type = Q_NEXT_TYPE(fusbh200, here.itd->hw_next);
                                here = here.itd->itd_next;
                                continue;
                        case Q_TYPE_QH:
                                hw = here.qh->hw;
                                if (same_tt (dev, here.qh->dev)) {
                                        u32             mask;

                                        mask = hc32_to_cpu(fusbh200,
                                                        hw->hw_info2);
                                        /* "knows" no gap is needed */
                                        mask |= mask >> 8;
                                        if (mask & uf_mask)
                                                break;
                                }
                                type = Q_NEXT_TYPE(fusbh200, hw->hw_next);
                                here = here.qh->qh_next;
                                continue;
                        // case Q_TYPE_FSTN:
                        default:
                                fusbh200_dbg (fusbh200,
                                        "periodic frame %d bogus type %d\n",
                                        frame, type);
                        }

                        /* collision or error */
                        return 0;
                }
        }

        /* no collision */
        return 1;
}

/*-------------------------------------------------------------------------*/

static void enable_periodic(struct fusbh200_hcd *fusbh200)
{
        if (fusbh200->periodic_count++)
                return;

        /* Stop waiting to turn off the periodic schedule */
        fusbh200->enabled_hrtimer_events &= ~BIT(FUSBH200_HRTIMER_DISABLE_PERIODIC);

        /* Don't start the schedule until PSS is 0 */
        fusbh200_poll_PSS(fusbh200);
        turn_on_io_watchdog(fusbh200);
}

static void disable_periodic(struct fusbh200_hcd *fusbh200)
{
        if (--fusbh200->periodic_count)
                return;

        /* Don't turn off the schedule until PSS is 1 */
        fusbh200_poll_PSS(fusbh200);
}

/*-------------------------------------------------------------------------*/

/* periodic schedule slots have iso tds (normal or split) first, then a
 * sparse tree for active interrupt transfers.
 *
 * this just links in a qh; caller guarantees uframe masks are set right.
 * no FSTN support (yet; fusbh200 0.96+)
 */
static void qh_link_periodic(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        unsigned        i;
        unsigned        period = qh->period;

        dev_dbg (&qh->dev->dev,
                "link qh%d-%04x/%p start %d [%d/%d us]\n",
                period, hc32_to_cpup(fusbh200, &qh->hw->hw_info2)
                        & (QH_CMASK | QH_SMASK),
                qh, qh->start, qh->usecs, qh->c_usecs);

        /* high bandwidth, or otherwise every microframe */
        if (period == 0)
                period = 1;

        for (i = qh->start; i < fusbh200->periodic_size; i += period) {
                union fusbh200_shadow   *prev = &fusbh200->pshadow[i];
                __hc32                  *hw_p = &fusbh200->periodic[i];
                union fusbh200_shadow   here = *prev;
                __hc32                  type = 0;

                /* skip the iso nodes at list head */
                while (here.ptr) {
                        type = Q_NEXT_TYPE(fusbh200, *hw_p);
                        if (type == cpu_to_hc32(fusbh200, Q_TYPE_QH))
                                break;
                        prev = periodic_next_shadow(fusbh200, prev, type);
                        hw_p = shadow_next_periodic(fusbh200, &here, type);
                        here = *prev;
                }

                /* sorting each branch by period (slow-->fast)
                 * enables sharing interior tree nodes
                 */
                while (here.ptr && qh != here.qh) {
                        if (qh->period > here.qh->period)
                                break;
                        prev = &here.qh->qh_next;
                        hw_p = &here.qh->hw->hw_next;
                        here = *prev;
                }
                /* link in this qh, unless some earlier pass did that */
                if (qh != here.qh) {
                        qh->qh_next = here;
                        if (here.qh)
                                qh->hw->hw_next = *hw_p;
                        wmb ();
                        prev->qh = qh;
                        *hw_p = QH_NEXT (fusbh200, qh->qh_dma);
                }
        }
        qh->qh_state = QH_STATE_LINKED;
        qh->xacterrs = 0;

        /* update per-qh bandwidth for usbfs */
        fusbh200_to_hcd(fusbh200)->self.bandwidth_allocated += qh->period
                ? ((qh->usecs + qh->c_usecs) / qh->period)
                : (qh->usecs * 8);

        list_add(&qh->intr_node, &fusbh200->intr_qh_list);

        /* maybe enable periodic schedule processing */
        ++fusbh200->intr_count;
        enable_periodic(fusbh200);
}

static void qh_unlink_periodic(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        unsigned        i;
        unsigned        period;

        /*
         * If qh is for a low/full-speed device, simply unlinking it
         * could interfere with an ongoing split transaction.  To unlink
         * it safely would require setting the QH_INACTIVATE bit and
         * waiting at least one frame, as described in EHCI 4.12.2.5.
         *
         * We won't bother with any of this.  Instead, we assume that the
         * only reason for unlinking an interrupt QH while the current URB
         * is still active is to dequeue all the URBs (flush the whole
         * endpoint queue).
         *
         * If rebalancing the periodic schedule is ever implemented, this
         * approach will no longer be valid.
         */

        /* high bandwidth, or otherwise part of every microframe */
        if ((period = qh->period) == 0)
                period = 1;

        for (i = qh->start; i < fusbh200->periodic_size; i += period)
                periodic_unlink (fusbh200, i, qh);

        /* update per-qh bandwidth for usbfs */
        fusbh200_to_hcd(fusbh200)->self.bandwidth_allocated -= qh->period
                ? ((qh->usecs + qh->c_usecs) / qh->period)
                : (qh->usecs * 8);

        dev_dbg (&qh->dev->dev,
                "unlink qh%d-%04x/%p start %d [%d/%d us]\n",
                qh->period,
                hc32_to_cpup(fusbh200, &qh->hw->hw_info2) & (QH_CMASK | QH_SMASK),
                qh, qh->start, qh->usecs, qh->c_usecs);

        /* qh->qh_next still "live" to HC */
        qh->qh_state = QH_STATE_UNLINK;
        qh->qh_next.ptr = NULL;

        if (fusbh200->qh_scan_next == qh)
                fusbh200->qh_scan_next = list_entry(qh->intr_node.next,
                                struct fusbh200_qh, intr_node);
        list_del(&qh->intr_node);
}

static void start_unlink_intr(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        /* If the QH isn't linked then there's nothing we can do
         * unless we were called during a giveback, in which case
         * qh_completions() has to deal with it.
         */
        if (qh->qh_state != QH_STATE_LINKED) {
                if (qh->qh_state == QH_STATE_COMPLETING)
                        qh->needs_rescan = 1;
                return;
        }

        qh_unlink_periodic (fusbh200, qh);

        /* Make sure the unlinks are visible before starting the timer */
        wmb();

        /*
         * The EHCI spec doesn't say how long it takes the controller to
         * stop accessing an unlinked interrupt QH.  The timer delay is
         * 9 uframes; presumably that will be long enough.
         */
        qh->unlink_cycle = fusbh200->intr_unlink_cycle;

        /* New entries go at the end of the intr_unlink list */
        if (fusbh200->intr_unlink)
                fusbh200->intr_unlink_last->unlink_next = qh;
        else
                fusbh200->intr_unlink = qh;
        fusbh200->intr_unlink_last = qh;

        if (fusbh200->intr_unlinking)
                ;       /* Avoid recursive calls */
        else if (fusbh200->rh_state < FUSBH200_RH_RUNNING)
                fusbh200_handle_intr_unlinks(fusbh200);
        else if (fusbh200->intr_unlink == qh) {
                fusbh200_enable_event(fusbh200, FUSBH200_HRTIMER_UNLINK_INTR, true);
                ++fusbh200->intr_unlink_cycle;
        }
}

static void end_unlink_intr(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        struct fusbh200_qh_hw   *hw = qh->hw;
        int                     rc;

        qh->qh_state = QH_STATE_IDLE;
        hw->hw_next = FUSBH200_LIST_END(fusbh200);

        qh_completions(fusbh200, qh);

        /* reschedule QH iff another request is queued */
        if (!list_empty(&qh->qtd_list) && fusbh200->rh_state == FUSBH200_RH_RUNNING) {
                rc = qh_schedule(fusbh200, qh);

                /* An error here likely indicates handshake failure
                 * or no space left in the schedule.  Neither fault
                 * should happen often ...
                 *
                 * FIXME kill the now-dysfunctional queued urbs
                 */
                if (rc != 0)
                        fusbh200_err(fusbh200, "can't reschedule qh %p, err %d\n",
                                        qh, rc);
        }

        /* maybe turn off periodic schedule */
        --fusbh200->intr_count;
        disable_periodic(fusbh200);
}

/*-------------------------------------------------------------------------*/

static int check_period (
        struct fusbh200_hcd *fusbh200,
        unsigned        frame,
        unsigned        uframe,
        unsigned        period,
        unsigned        usecs
) {
        int             claimed;

        /* complete split running into next frame?
         * given FSTN support, we could sometimes check...
         */
        if (uframe >= 8)
                return 0;

        /* convert "usecs we need" to "max already claimed" */
        usecs = fusbh200->uframe_periodic_max - usecs;

        /* we "know" 2 and 4 uframe intervals were rejected; so
         * for period 0, check _every_ microframe in the schedule.
         */
        if (unlikely (period == 0)) {
                do {
                        for (uframe = 0; uframe < 7; uframe++) {
                                claimed = periodic_usecs (fusbh200, frame, uframe);
                                if (claimed > usecs)
                                        return 0;
                        }
                } while ((frame += 1) < fusbh200->periodic_size);

        /* just check the specified uframe, at that period */
        } else {
                do {
                        claimed = periodic_usecs (fusbh200, frame, uframe);
                        if (claimed > usecs)
                                return 0;
                } while ((frame += period) < fusbh200->periodic_size);
        }

        // success!
        return 1;
}

static int check_intr_schedule (
        struct fusbh200_hcd             *fusbh200,
        unsigned                frame,
        unsigned                uframe,
        const struct fusbh200_qh        *qh,
        __hc32                  *c_maskp
)
{
        int             retval = -ENOSPC;
        u8              mask = 0;

        if (qh->c_usecs && uframe >= 6)         /* FSTN territory? */
                goto done;

        if (!check_period (fusbh200, frame, uframe, qh->period, qh->usecs))
                goto done;
        if (!qh->c_usecs) {
                retval = 0;
                *c_maskp = 0;
                goto done;
        }

        /* Make sure this tt's buffer is also available for CSPLITs.
         * We pessimize a bit; probably the typical full speed case
         * doesn't need the second CSPLIT.
         *
         * NOTE:  both SPLIT and CSPLIT could be checked in just
         * one smart pass...
         */
        mask = 0x03 << (uframe + qh->gap_uf);
        *c_maskp = cpu_to_hc32(fusbh200, mask << 8);

        mask |= 1 << uframe;
        if (tt_no_collision (fusbh200, qh->period, qh->dev, frame, mask)) {
                if (!check_period (fusbh200, frame, uframe + qh->gap_uf + 1,
                                        qh->period, qh->c_usecs))
                        goto done;
                if (!check_period (fusbh200, frame, uframe + qh->gap_uf,
                                        qh->period, qh->c_usecs))
                        goto done;
                retval = 0;
        }
done:
        return retval;
}

/* "first fit" scheduling policy used the first time through,
 * or when the previous schedule slot can't be re-used.
 */
static int qh_schedule(struct fusbh200_hcd *fusbh200, struct fusbh200_qh *qh)
{
        int             status;
        unsigned        uframe;
        __hc32          c_mask;
        unsigned        frame;          /* 0..(qh->period - 1), or NO_FRAME */
        struct fusbh200_qh_hw   *hw = qh->hw;

        qh_refresh(fusbh200, qh);
        hw->hw_next = FUSBH200_LIST_END(fusbh200);
        frame = qh->start;

        /* reuse the previous schedule slots, if we can */
        if (frame < qh->period) {
                uframe = ffs(hc32_to_cpup(fusbh200, &hw->hw_info2) & QH_SMASK);
                status = check_intr_schedule (fusbh200, frame, --uframe,
                                qh, &c_mask);
        } else {
                uframe = 0;
                c_mask = 0;
                status = -ENOSPC;
        }

        /* else scan the schedule to find a group of slots such that all
         * uframes have enough periodic bandwidth available.
         */
        if (status) {
                /* "normal" case, uframing flexible except with splits */
                if (qh->period) {
                        int             i;

                        for (i = qh->period; status && i > 0; --i) {
                                frame = ++fusbh200->random_frame % qh->period;
                                for (uframe = 0; uframe < 8; uframe++) {
                                        status = check_intr_schedule (fusbh200,
                                                        frame, uframe, qh,
                                                        &c_mask);
                                        if (status == 0)
                                                break;
                                }
                        }

                /* qh->period == 0 means every uframe */
                } else {
                        frame = 0;
                        status = check_intr_schedule (fusbh200, 0, 0, qh, &c_mask);
                }
                if (status)
                        goto done;
                qh->start = frame;

                /* reset S-frame and (maybe) C-frame masks */
                hw->hw_info2 &= cpu_to_hc32(fusbh200, ~(QH_CMASK | QH_SMASK));
                hw->hw_info2 |= qh->period
                        ? cpu_to_hc32(fusbh200, 1 << uframe)
                        : cpu_to_hc32(fusbh200, QH_SMASK);
                hw->hw_info2 |= c_mask;
        } else
                fusbh200_dbg (fusbh200, "reused qh %p schedule\n", qh);

        /* stuff into the periodic schedule */
        qh_link_periodic(fusbh200, qh);
done:
        return status;
}

static int intr_submit (
        struct fusbh200_hcd             *fusbh200,
        struct urb              *urb,
        struct list_head        *qtd_list,
        gfp_t                   mem_flags
) {
        unsigned                epnum;
        unsigned long           flags;
        struct fusbh200_qh              *qh;
        int                     status;
        struct list_head        empty;

        /* get endpoint and transfer/schedule data */
        epnum = urb->ep->desc.bEndpointAddress;

        spin_lock_irqsave (&fusbh200->lock, flags);

        if (unlikely(!HCD_HW_ACCESSIBLE(fusbh200_to_hcd(fusbh200)))) {
                status = -ESHUTDOWN;
                goto done_not_linked;
        }
        status = usb_hcd_link_urb_to_ep(fusbh200_to_hcd(fusbh200), urb);
        if (unlikely(status))
                goto done_not_linked;

        /* get qh and force any scheduling errors */
        INIT_LIST_HEAD (&empty);
        qh = qh_append_tds(fusbh200, urb, &empty, epnum, &urb->ep->hcpriv);
        if (qh == NULL) {
                status = -ENOMEM;
                goto done;
        }
        if (qh->qh_state == QH_STATE_IDLE) {
                if ((status = qh_schedule (fusbh200, qh)) != 0)
                        goto done;
        }

        /* then queue the urb's tds to the qh */
        qh = qh_append_tds(fusbh200, urb, qtd_list, epnum, &urb->ep->hcpriv);
        BUG_ON (qh == NULL);

        /* ... update usbfs periodic stats */
        fusbh200_to_hcd(fusbh200)->self.bandwidth_int_reqs++;

done:
        if (unlikely(status))
                usb_hcd_unlink_urb_from_ep(fusbh200_to_hcd(fusbh200), urb);
done_not_linked:
        spin_unlock_irqrestore (&fusbh200->lock, flags);
        if (status)
                qtd_list_free (fusbh200, urb, qtd_list);

        return status;
}

static void scan_intr(struct fusbh200_hcd *fusbh200)
{
        struct fusbh200_qh              *qh;

        list_for_each_entry_safe(qh, fusbh200->qh_scan_next, &fusbh200->intr_qh_list,
                        intr_node) {
 rescan:
                /* clean any finished work for this qh */
                if (!list_empty(&qh->qtd_list)) {
                        int temp;

                        /*
                         * Unlinks could happen here; completion reporting
                         * drops the lock.  That's why fusbh200->qh_scan_next
                         * always holds the next qh to scan; if the next qh
                         * gets unlinked then fusbh200->qh_scan_next is adjusted
                         * in qh_unlink_periodic().
                         */
                        temp = qh_completions(fusbh200, qh);
                        if (unlikely(qh->needs_rescan ||
                                        (list_empty(&qh->qtd_list) &&
                                                qh->qh_state == QH_STATE_LINKED)))
                                start_unlink_intr(fusbh200, qh);
                        else if (temp != 0)
                                goto rescan;
                }
        }
}

/*-------------------------------------------------------------------------*/

/* fusbh200_iso_stream ops work with both ITD and SITD */

static struct fusbh200_iso_stream *
iso_stream_alloc (gfp_t mem_flags)
{
        struct fusbh200_iso_stream *stream;

        stream = kzalloc(sizeof *stream, mem_flags);
        if (likely (stream != NULL)) {
                INIT_LIST_HEAD(&stream->td_list);
                INIT_LIST_HEAD(&stream->free_list);
                stream->next_uframe = -1;
        }
        return stream;
}

static void
iso_stream_init (
        struct fusbh200_hcd             *fusbh200,
        struct fusbh200_iso_stream      *stream,
        struct usb_device       *dev,
        int                     pipe,
        unsigned                interval
)
{
        u32                     buf1;
        unsigned                epnum, maxp;
        int                     is_input;
        long                    bandwidth;
        unsigned                multi;

        /*
         * this might be a "high bandwidth" highspeed endpoint,
         * as encoded in the ep descriptor's wMaxPacket field
         */
        epnum = usb_pipeendpoint (pipe);
        is_input = usb_pipein (pipe) ? USB_DIR_IN : 0;
        maxp = usb_maxpacket(dev, pipe, !is_input);
        if (is_input) {
                buf1 = (1 << 11);
        } else {
                buf1 = 0;
        }

        maxp = max_packet(maxp);
        multi = hb_mult(maxp);
        buf1 |= maxp;
        maxp *= multi;

        stream->buf0 = cpu_to_hc32(fusbh200, (epnum << 8) | dev->devnum);
        stream->buf1 = cpu_to_hc32(fusbh200, buf1);
        stream->buf2 = cpu_to_hc32(fusbh200, multi);

        /* usbfs wants to report the average usecs per frame tied up
         * when transfers on this endpoint are scheduled ...
         */
        if (dev->speed == USB_SPEED_FULL) {
                interval <<= 3;
                stream->usecs = NS_TO_US(usb_calc_bus_time(dev->speed,
                                is_input, 1, maxp));
                stream->usecs /= 8;
        } else {
                stream->highspeed = 1;
                stream->usecs = HS_USECS_ISO (maxp);
        }
        bandwidth = stream->usecs * 8;
        bandwidth /= interval;

        stream->bandwidth = bandwidth;
        stream->udev = dev;
        stream->bEndpointAddress = is_input | epnum;
        stream->interval = interval;
        stream->maxp = maxp;
}

static struct fusbh200_iso_stream *
iso_stream_find (struct fusbh200_hcd *fusbh200, struct urb *urb)
{
        unsigned                epnum;
        struct fusbh200_iso_stream      *stream;
        struct usb_host_endpoint *ep;
        unsigned long           flags;

        epnum = usb_pipeendpoint (urb->pipe);
        if (usb_pipein(urb->pipe))
                ep = urb->dev->ep_in[epnum];
        else
                ep = urb->dev->ep_out[epnum];

        spin_lock_irqsave (&fusbh200->lock, flags);
        stream = ep->hcpriv;

        if (unlikely (stream == NULL)) {
                stream = iso_stream_alloc(GFP_ATOMIC);
                if (likely (stream != NULL)) {
                        ep->hcpriv = stream;
                        stream->ep = ep;
                        iso_stream_init(fusbh200, stream, urb->dev, urb->pipe,
                                        urb->interval);
                }

        /* if dev->ep [epnum] is a QH, hw is set */
        } else if (unlikely (stream->hw != NULL)) {
                fusbh200_dbg (fusbh200, "dev %s ep%d%s, not iso??\n",
                        urb->dev->devpath, epnum,
                        usb_pipein(urb->pipe) ? "in" : "out");
                stream = NULL;
        }

        spin_unlock_irqrestore (&fusbh200->lock, flags);
        return stream;
}

/*-------------------------------------------------------------------------*/

/* fusbh200_iso_sched ops can be ITD-only or SITD-only */

static struct fusbh200_iso_sched *
iso_sched_alloc (unsigned packets, gfp_t mem_flags)
{
        struct fusbh200_iso_sched       *iso_sched;
        int                     size = sizeof *iso_sched;

        size += packets * sizeof (struct fusbh200_iso_packet);
        iso_sched = kzalloc(size, mem_flags);
        if (likely (iso_sched != NULL)) {
                INIT_LIST_HEAD (&iso_sched->td_list);
        }
        return iso_sched;
}

static inline void
itd_sched_init(
        struct fusbh200_hcd             *fusbh200,
        struct fusbh200_iso_sched       *iso_sched,
        struct fusbh200_iso_stream      *stream,
        struct urb              *urb
)
{
        unsigned        i;
        dma_addr_t      dma = urb->transfer_dma;

        /* how many uframes are needed for these transfers */
        iso_sched->span = urb->number_of_packets * stream->interval;

        /* figure out per-uframe itd fields that we'll need later
         * when we fit new itds into the schedule.
         */
        for (i = 0; i < urb->number_of_packets; i++) {
                struct fusbh200_iso_packet      *uframe = &iso_sched->packet [i];
                unsigned                length;
                dma_addr_t              buf;
                u32                     trans;

                length = urb->iso_frame_desc [i].length;
                buf = dma + urb->iso_frame_desc [i].offset;

                trans = FUSBH200_ISOC_ACTIVE;
                trans |= buf & 0x0fff;
                if (unlikely (((i + 1) == urb->number_of_packets))
                                && !(urb->transfer_flags & URB_NO_INTERRUPT))
                        trans |= FUSBH200_ITD_IOC;
                trans |= length << 16;
                uframe->transaction = cpu_to_hc32(fusbh200, trans);

                /* might need to cross a buffer page within a uframe */
                uframe->bufp = (buf & ~(u64)0x0fff);
                buf += length;
                if (unlikely ((uframe->bufp != (buf & ~(u64)0x0fff))))
                        uframe->cross = 1;
        }
}

static void
iso_sched_free (
        struct fusbh200_iso_stream      *stream,
        struct fusbh200_iso_sched       *iso_sched
)
{
        if (!iso_sched)
                return;
        // caller must hold fusbh200->lock!
        list_splice (&iso_sched->td_list, &stream->free_list);
        kfree (iso_sched);
}

static int
itd_urb_transaction (
        struct fusbh200_iso_stream      *stream,
        struct fusbh200_hcd             *fusbh200,
        struct urb              *urb,
        gfp_t                   mem_flags
)
{
        struct fusbh200_itd             *itd;
        dma_addr_t              itd_dma;
        int                     i;
        unsigned                num_itds;
        struct fusbh200_iso_sched       *sched;
        unsigned long           flags;

        sched = iso_sched_alloc (urb->number_of_packets, mem_flags);
        if (unlikely (sched == NULL))
                return -ENOMEM;

        itd_sched_init(fusbh200, sched, stream, urb);

        if (urb->interval < 8)
                num_itds = 1 + (sched->span + 7) / 8;
        else
                num_itds = urb->number_of_packets;

        /* allocate/init ITDs */
        spin_lock_irqsave (&fusbh200->lock, flags);
        for (i = 0; i < num_itds; i++) {

                /*
                 * Use iTDs from the free list, but not iTDs that may
                 * still be in use by the hardware.
                 */
                if (likely(!list_empty(&stream->free_list))) {
                        itd = list_first_entry(&stream->free_list,
                                        struct fusbh200_itd, itd_list);
                        if (itd->frame == fusbh200->now_frame)
                                goto alloc_itd;
                        list_del (&itd->itd_list);
                        itd_dma = itd->itd_dma;
                } else {
 alloc_itd:
                        spin_unlock_irqrestore (&fusbh200->lock, flags);
                        itd = dma_pool_alloc (fusbh200->itd_pool, mem_flags,
                                        &itd_dma);
                        spin_lock_irqsave (&fusbh200->lock, flags);
                        if (!itd) {
                                iso_sched_free(stream, sched);
                                spin_unlock_irqrestore(&fusbh200->lock, flags);
                                return -ENOMEM;
                        }
                }

                memset (itd, 0, sizeof *itd);
                itd->itd_dma = itd_dma;
                list_add (&itd->itd_list, &sched->td_list);
        }
        spin_unlock_irqrestore (&fusbh200->lock, flags);

        /* temporarily store schedule info in hcpriv */
        urb->hcpriv = sched;
        urb->error_count = 0;
        return 0;
}

/*-------------------------------------------------------------------------*/

static inline int
itd_slot_ok (
        struct fusbh200_hcd             *fusbh200,
        u32                     mod,
        u32                     uframe,
        u8                      usecs,
        u32                     period
)
{
        uframe %= period;
        do {
                /* can't commit more than uframe_periodic_max usec */
                if (periodic_usecs (fusbh200, uframe >> 3, uframe & 0x7)
                                > (fusbh200->uframe_periodic_max - usecs))
                        return 0;

                /* we know urb->interval is 2^N uframes */
                uframe += period;
        } while (uframe < mod);
        return 1;
}

/*
 * This scheduler plans almost as far into the future as it has actual
 * periodic schedule slots.  (Affected by TUNE_FLS, which defaults to
 * "as small as possible" to be cache-friendlier.)  That limits the size
 * transfers you can stream reliably; avoid more than 64 msec per urb.
 * Also avoid queue depths of less than fusbh200's worst irq latency (affected
 * by the per-urb URB_NO_INTERRUPT hint, the log2_irq_thresh module parameter,
 * and other factors); or more than about 230 msec total (for portability,
 * given FUSBH200_TUNE_FLS and the slop).  Or, write a smarter scheduler!
 */

#define SCHEDULE_SLOP   80      /* microframes */

static int
iso_stream_schedule (
        struct fusbh200_hcd             *fusbh200,
        struct urb              *urb,
        struct fusbh200_iso_stream      *stream
)
{
        u32                     now, next, start, period, span;
        int                     status;
        unsigned                mod = fusbh200->periodic_size << 3;
        struct fusbh200_iso_sched       *sched = urb->hcpriv;

        period = urb->interval;
        span = sched->span;

        if (span > mod - SCHEDULE_SLOP) {
                fusbh200_dbg (fusbh200, "iso request %p too long\n", urb);
                status = -EFBIG;
                goto fail;
        }

        now = fusbh200_read_frame_index(fusbh200) & (mod - 1);

        /* Typical case: reuse current schedule, stream is still active.
         * Hopefully there are no gaps from the host falling behind
         * (irq delays etc), but if there are we'll take the next
         * slot in the schedule, implicitly assuming URB_ISO_ASAP.
         */
        if (likely (!list_empty (&stream->td_list))) {
                u32     excess;

                /* For high speed devices, allow scheduling within the
                 * isochronous scheduling threshold.  For full speed devices
                 * and Intel PCI-based controllers, don't (work around for
                 * Intel ICH9 bug).
                 */
                if (!stream->highspeed && fusbh200->fs_i_thresh)
                        next = now + fusbh200->i_thresh;
                else
                        next = now;

                /* Fell behind (by up to twice the slop amount)?
                 * We decide based on the time of the last currently-scheduled
                 * slot, not the time of the next available slot.
                 */
                excess = (stream->next_uframe - period - next) & (mod - 1);
                if (excess >= mod - 2 * SCHEDULE_SLOP)
                        start = next + excess - mod + period *
                                        DIV_ROUND_UP(mod - excess, period);
                else
                        start = next + excess + period;
                if (start - now >= mod) {
                        fusbh200_dbg(fusbh200, "request %p would overflow (%d+%d >= %d)\n",
                                        urb, start - now - period, period,
                                        mod);
                        status = -EFBIG;
                        goto fail;
                }
        }

        /* need to schedule; when's the next (u)frame we could start?
         * this is bigger than fusbh200->i_thresh allows; scheduling itself
         * isn't free, the slop should handle reasonably slow cpus.  it
         * can also help high bandwidth if the dma and irq loads don't
         * jump until after the queue is primed.
         */
        else {
                int done = 0;
                start = SCHEDULE_SLOP + (now & ~0x07);

                /* NOTE:  assumes URB_ISO_ASAP, to limit complexity/bugs */

                /* find a uframe slot with enough bandwidth.
                 * Early uframes are more precious because full-speed
                 * iso IN transfers can't use late uframes,
                 * and therefore they should be allocated last.
                 */
                next = start;
                start += period;
                do {
                        start--;
                        /* check schedule: enough space? */
                        if (itd_slot_ok(fusbh200, mod, start,
                                        stream->usecs, period))
                                done = 1;
                } while (start > next && !done);

                /* no room in the schedule */
                if (!done) {
                        fusbh200_dbg(fusbh200, "iso resched full %p (now %d max %d)\n",
                                urb, now, now + mod);
                        status = -ENOSPC;
                        goto fail;
                }
        }

        /* Tried to schedule too far into the future? */
        if (unlikely(start - now + span - period
                                >= mod - 2 * SCHEDULE_SLOP)) {
                fusbh200_dbg(fusbh200, "request %p would overflow (%d+%d >= %d)\n",
                                urb, start - now, span - period,
                                mod - 2 * SCHEDULE_SLOP);
                status = -EFBIG;
                goto fail;
        }

        stream->next_uframe = start & (mod - 1);

        /* report high speed start in uframes; full speed, in frames */
        urb->start_frame = stream->next_uframe;
        if (!stream->highspeed)
                urb->start_frame >>= 3;

        /* Make sure scan_isoc() sees these */
        if (fusbh200->isoc_count == 0)
                fusbh200->next_frame = now >> 3;
        return 0;

 fail:
        iso_sched_free(stream, sched);
        urb->hcpriv = NULL;
        return status;
}

/*-------------------------------------------------------------------------*/

static inline void
itd_init(struct fusbh200_hcd *fusbh200, struct fusbh200_iso_stream *stream,
                struct fusbh200_itd *itd)
{
        int i;

        /* it's been recently zeroed */
        itd->hw_next = FUSBH200_LIST_END(fusbh200);
        itd->hw_bufp [0] = stream->buf0;
        itd->hw_bufp [1] = stream->buf1;
        itd->hw_bufp [2] = stream->buf2;

        for (i = 0; i < 8; i++)
                itd->index[i] = -1;

        /* All other fields are filled when scheduling */
}

static inline void
itd_patch(
        struct fusbh200_hcd             *fusbh200,
        struct fusbh200_itd             *itd,
        struct fusbh200_iso_sched       *iso_sched,
        unsigned                index,
        u16                     uframe
)
{
        struct fusbh200_iso_packet      *uf = &iso_sched->packet [index];
        unsigned                pg = itd->pg;

        // BUG_ON (pg == 6 && uf->cross);

        uframe &= 0x07;
        itd->index [uframe] = index;

        itd->hw_transaction[uframe] = uf->transaction;
        itd->hw_transaction[uframe] |= cpu_to_hc32(fusbh200, pg << 12);
        itd->hw_bufp[pg] |= cpu_to_hc32(fusbh200, uf->bufp & ~(u32)0);
        itd->hw_bufp_hi[pg] |= cpu_to_hc32(fusbh200, (u32)(uf->bufp >> 32));

        /* iso_frame_desc[].offset must be strictly increasing */
        if (unlikely (uf->cross)) {
                u64     bufp = uf->bufp + 4096;

                itd->pg = ++pg;
                itd->hw_bufp[pg] |= cpu_to_hc32(fusbh200, bufp & ~(u32)0);
                itd->hw_bufp_hi[pg] |= cpu_to_hc32(fusbh200, (u32)(bufp >> 32));
        }
}

static inline void
itd_link (struct fusbh200_hcd *fusbh200, unsigned frame, struct fusbh200_itd *itd)
{
        union fusbh200_shadow   *prev = &fusbh200->pshadow[frame];
        __hc32                  *hw_p = &fusbh200->periodic[frame];
        union fusbh200_shadow   here = *prev;
        __hc32                  type = 0;

        /* skip any iso nodes which might belong to previous microframes */
        while (here.ptr) {
                type = Q_NEXT_TYPE(fusbh200, *hw_p);
                if (type == cpu_to_hc32(fusbh200, Q_TYPE_QH))
                        break;
                prev = periodic_next_shadow(fusbh200, prev, type);
                hw_p = shadow_next_periodic(fusbh200, &here, type);
                here = *prev;
        }

        itd->itd_next = here;
        itd->hw_next = *hw_p;
        prev->itd = itd;
        itd->frame = frame;
        wmb ();
        *hw_p = cpu_to_hc32(fusbh200, itd->itd_dma | Q_TYPE_ITD);
}

/* fit urb's itds into the selected schedule slot; activate as needed */
static void itd_link_urb(
        struct fusbh200_hcd             *fusbh200,
        struct urb              *urb,
        unsigned                mod,
        struct fusbh200_iso_stream      *stream
)
{
        int                     packet;
        unsigned                next_uframe, uframe, frame;
        struct fusbh200_iso_sched       *iso_sched = urb->hcpriv;
        struct fusbh200_itd             *itd;

        next_uframe = stream->next_uframe & (mod - 1);

        if (unlikely (list_empty(&stream->td_list))) {
                fusbh200_to_hcd(fusbh200)->self.bandwidth_allocated
                                += stream->bandwidth;
                fusbh200_vdbg (fusbh200,
                        "schedule devp %s ep%d%s-iso period %d start %d.%d\n",
                        urb->dev->devpath, stream->bEndpointAddress & 0x0f,
                        (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
                        urb->interval,
                        next_uframe >> 3, next_uframe & 0x7);
        }

        /* fill iTDs uframe by uframe */
        for (packet = 0, itd = NULL; packet < urb->number_of_packets; ) {
                if (itd == NULL) {
                        /* ASSERT:  we have all necessary itds */
                        // BUG_ON (list_empty (&iso_sched->td_list));

                        /* ASSERT:  no itds for this endpoint in this uframe */

                        itd = list_entry (iso_sched->td_list.next,
                                        struct fusbh200_itd, itd_list);
                        list_move_tail (&itd->itd_list, &stream->td_list);
                        itd->stream = stream;
                        itd->urb = urb;
                        itd_init (fusbh200, stream, itd);
                }

                uframe = next_uframe & 0x07;
                frame = next_uframe >> 3;

                itd_patch(fusbh200, itd, iso_sched, packet, uframe);

                next_uframe += stream->interval;
                next_uframe &= mod - 1;
                packet++;

                /* link completed itds into the schedule */
                if (((next_uframe >> 3) != frame)
                                || packet == urb->number_of_packets) {
                        itd_link(fusbh200, frame & (fusbh200->periodic_size - 1), itd);
                        itd = NULL;
                }
        }
        stream->next_uframe = next_uframe;

        /* don't need that schedule data any more */
        iso_sched_free (stream, iso_sched);
        urb->hcpriv = NULL;

        ++fusbh200->isoc_count;
        enable_periodic(fusbh200);
}

#define ISO_ERRS (FUSBH200_ISOC_BUF_ERR | FUSBH200_ISOC_BABBLE | FUSBH200_ISOC_XACTERR)

/* Process and recycle a completed ITD.  Return true iff its urb completed,
 * and hence its completion callback probably added things to the hardware
 * schedule.
 *
 * Note that we carefully avoid recycling this descriptor until after any
 * completion callback runs, so that it won't be reused quickly.  That is,
 * assuming (a) no more than two urbs per frame on this endpoint, and also
 * (b) only this endpoint's completions submit URBs.  It seems some silicon
 * corrupts things if you reuse completed descriptors very quickly...
 */
static bool itd_complete(struct fusbh200_hcd *fusbh200, struct fusbh200_itd *itd)
{
        struct urb                              *urb = itd->urb;
        struct usb_iso_packet_descriptor        *desc;
        u32                                     t;
        unsigned                                uframe;
        int                                     urb_index = -1;
        struct fusbh200_iso_stream                      *stream = itd->stream;
        struct usb_device                       *dev;
        bool                                    retval = false;

        /* for each uframe with a packet */
        for (uframe = 0; uframe < 8; uframe++) {
                if (likely (itd->index[uframe] == -1))
                        continue;
                urb_index = itd->index[uframe];
                desc = &urb->iso_frame_desc [urb_index];

                t = hc32_to_cpup(fusbh200, &itd->hw_transaction [uframe]);
                itd->hw_transaction [uframe] = 0;

                /* report transfer status */
                if (unlikely (t & ISO_ERRS)) {
                        urb->error_count++;
                        if (t & FUSBH200_ISOC_BUF_ERR)
                                desc->status = usb_pipein (urb->pipe)
                                        ? -ENOSR  /* hc couldn't read */
                                        : -ECOMM; /* hc couldn't write */
                        else if (t & FUSBH200_ISOC_BABBLE)
                                desc->status = -EOVERFLOW;
                        else /* (t & FUSBH200_ISOC_XACTERR) */
                                desc->status = -EPROTO;

                        /* HC need not update length with this error */
                        if (!(t & FUSBH200_ISOC_BABBLE)) {
                                desc->actual_length = fusbh200_itdlen(urb, desc, t);
                                urb->actual_length += desc->actual_length;
                        }
                } else if (likely ((t & FUSBH200_ISOC_ACTIVE) == 0)) {
                        desc->status = 0;
                        desc->actual_length = fusbh200_itdlen(urb, desc, t);
                        urb->actual_length += desc->actual_length;
                } else {
                        /* URB was too late */
                        desc->status = -EXDEV;
                }
        }

        /* handle completion now? */
        if (likely ((urb_index + 1) != urb->number_of_packets))
                goto done;

        /* ASSERT: it's really the last itd for this urb
        list_for_each_entry (itd, &stream->td_list, itd_list)
                BUG_ON (itd->urb == urb);
         */

        /* give urb back to the driver; completion often (re)submits */
        dev = urb->dev;
        fusbh200_urb_done(fusbh200, urb, 0);
        retval = true;
        urb = NULL;

        --fusbh200->isoc_count;
        disable_periodic(fusbh200);

        if (unlikely(list_is_singular(&stream->td_list))) {
                fusbh200_to_hcd(fusbh200)->self.bandwidth_allocated
                                -= stream->bandwidth;
                fusbh200_vdbg (fusbh200,
                        "deschedule devp %s ep%d%s-iso\n",
                        dev->devpath, stream->bEndpointAddress & 0x0f,
                        (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
        }

done:
        itd->urb = NULL;

        /* Add to the end of the free list for later reuse */
        list_move_tail(&itd->itd_list, &stream->free_list);

        /* Recycle the iTDs when the pipeline is empty (ep no longer in use) */
        if (list_empty(&stream->td_list)) {
                list_splice_tail_init(&stream->free_list,
                                &fusbh200->cached_itd_list);
                start_free_itds(fusbh200);
        }

        return retval;
}

/*-------------------------------------------------------------------------*/

static int itd_submit (struct fusbh200_hcd *fusbh200, struct urb *urb,
        gfp_t mem_flags)
{
        int                     status = -EINVAL;
        unsigned long           flags;
        struct fusbh200_iso_stream      *stream;

        /* Get iso_stream head */
        stream = iso_stream_find (fusbh200, urb);
        if (unlikely (stream == NULL)) {
                fusbh200_dbg (fusbh200, "can't get iso stream\n");
                return -ENOMEM;
        }
        if (unlikely (urb->interval != stream->interval &&
                      fusbh200_port_speed(fusbh200, 0) == USB_PORT_STAT_HIGH_SPEED)) {
                        fusbh200_dbg (fusbh200, "can't change iso interval %d --> %d\n",
                                stream->interval, urb->interval);
                        goto done;
        }

#ifdef FUSBH200_URB_TRACE
        fusbh200_dbg (fusbh200,
                "%s %s urb %p ep%d%s len %d, %d pkts %d uframes [%p]\n",
                __func__, urb->dev->devpath, urb,
                usb_pipeendpoint (urb->pipe),
                usb_pipein (urb->pipe) ? "in" : "out",
                urb->transfer_buffer_length,
                urb->number_of_packets, urb->interval,
                stream);
#endif

        /* allocate ITDs w/o locking anything */
        status = itd_urb_transaction (stream, fusbh200, urb, mem_flags);
        if (unlikely (status < 0)) {
                fusbh200_dbg (fusbh200, "can't init itds\n");
                goto done;
        }

        /* schedule ... need to lock */
        spin_lock_irqsave (&fusbh200->lock, flags);
        if (unlikely(!HCD_HW_ACCESSIBLE(fusbh200_to_hcd(fusbh200)))) {
                status = -ESHUTDOWN;
                goto done_not_linked;
        }
        status = usb_hcd_link_urb_to_ep(fusbh200_to_hcd(fusbh200), urb);
        if (unlikely(status))
                goto done_not_linked;
        status = iso_stream_schedule(fusbh200, urb, stream);
        if (likely (status == 0))
                itd_link_urb (fusbh200, urb, fusbh200->periodic_size << 3, stream);
        else
                usb_hcd_unlink_urb_from_ep(fusbh200_to_hcd(fusbh200), urb);
 done_not_linked:
        spin_unlock_irqrestore (&fusbh200->lock, flags);
 done:
        return status;
}

/*-------------------------------------------------------------------------*/

static void scan_isoc(struct fusbh200_hcd *fusbh200)
{
        unsigned        uf, now_frame, frame;
        unsigned        fmask = fusbh200->periodic_size - 1;
        bool            modified, live;

        /*
         * When running, scan from last scan point up to "now"
         * else clean up by scanning everything that's left.
         * Touches as few pages as possible:  cache-friendly.
         */
        if (fusbh200->rh_state >= FUSBH200_RH_RUNNING) {
                uf = fusbh200_read_frame_index(fusbh200);
                now_frame = (uf >> 3) & fmask;
                live = true;
        } else  {
                now_frame = (fusbh200->next_frame - 1) & fmask;
                live = false;
        }
        fusbh200->now_frame = now_frame;

        frame = fusbh200->next_frame;
        for (;;) {
                union fusbh200_shadow   q, *q_p;
                __hc32                  type, *hw_p;

restart:
                /* scan each element in frame's queue for completions */
                q_p = &fusbh200->pshadow [frame];
                hw_p = &fusbh200->periodic [frame];
                q.ptr = q_p->ptr;
                type = Q_NEXT_TYPE(fusbh200, *hw_p);
                modified = false;

                while (q.ptr != NULL) {
                        switch (hc32_to_cpu(fusbh200, type)) {
                        case Q_TYPE_ITD:
                                /* If this ITD is still active, leave it for
                                 * later processing ... check the next entry.
                                 * No need to check for activity unless the
                                 * frame is current.
                                 */
                                if (frame == now_frame && live) {
                                        rmb();
                                        for (uf = 0; uf < 8; uf++) {
                                                if (q.itd->hw_transaction[uf] &
                                                            ITD_ACTIVE(fusbh200))
                                                        break;
                                        }
                                        if (uf < 8) {
                                                q_p = &q.itd->itd_next;
                                                hw_p = &q.itd->hw_next;
                                                type = Q_NEXT_TYPE(fusbh200,
                                                        q.itd->hw_next);
                                                q = *q_p;
                                                break;
                                        }
                                }

                                /* Take finished ITDs out of the schedule
                                 * and process them:  recycle, maybe report
                                 * URB completion.  HC won't cache the
                                 * pointer for much longer, if at all.
                                 */
                                *q_p = q.itd->itd_next;
                                *hw_p = q.itd->hw_next;
                                type = Q_NEXT_TYPE(fusbh200, q.itd->hw_next);
                                wmb();
                                modified = itd_complete (fusbh200, q.itd);
                                q = *q_p;
                                break;
                        default:
                                fusbh200_dbg(fusbh200, "corrupt type %d frame %d shadow %p\n",
                                        type, frame, q.ptr);
                                // BUG ();
                                /* FALL THROUGH */
                        case Q_TYPE_QH:
                        case Q_TYPE_FSTN:
                                /* End of the iTDs and siTDs */
                                q.ptr = NULL;
                                break;
                        }

                        /* assume completion callbacks modify the queue */
                        if (unlikely(modified && fusbh200->isoc_count > 0))
                                goto restart;
                }

                /* Stop when we have reached the current frame */
                if (frame == now_frame)
                        break;
                frame = (frame + 1) & fmask;
        }
        fusbh200->next_frame = now_frame;
}
/*-------------------------------------------------------------------------*/
/*
 * Display / Set uframe_periodic_max
 */
static ssize_t show_uframe_periodic_max(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        struct fusbh200_hcd             *fusbh200;
        int                     n;

        fusbh200 = hcd_to_fusbh200(bus_to_hcd(dev_get_drvdata(dev)));
        n = scnprintf(buf, PAGE_SIZE, "%d\n", fusbh200->uframe_periodic_max);
        return n;
}


static ssize_t store_uframe_periodic_max(struct device *dev,
                                        struct device_attribute *attr,
                                        const char *buf, size_t count)
{
        struct fusbh200_hcd             *fusbh200;
        unsigned                uframe_periodic_max;
        unsigned                frame, uframe;
        unsigned short          allocated_max;
        unsigned long           flags;
        ssize_t                 ret;

        fusbh200 = hcd_to_fusbh200(bus_to_hcd(dev_get_drvdata(dev)));
        if (kstrtouint(buf, 0, &uframe_periodic_max) < 0)
                return -EINVAL;

        if (uframe_periodic_max < 100 || uframe_periodic_max >= 125) {
                fusbh200_info(fusbh200, "rejecting invalid request for "
                                "uframe_periodic_max=%u\n", uframe_periodic_max);
                return -EINVAL;
        }

        ret = -EINVAL;

        /*
         * lock, so that our checking does not race with possible periodic
         * bandwidth allocation through submitting new urbs.
         */
        spin_lock_irqsave (&fusbh200->lock, flags);

        /*
         * for request to decrease max periodic bandwidth, we have to check
         * every microframe in the schedule to see whether the decrease is
         * possible.
         */
        if (uframe_periodic_max < fusbh200->uframe_periodic_max) {
                allocated_max = 0;

                for (frame = 0; frame < fusbh200->periodic_size; ++frame)
                        for (uframe = 0; uframe < 7; ++uframe)
                                allocated_max = max(allocated_max,
                                                    periodic_usecs (fusbh200, frame, uframe));

                if (allocated_max > uframe_periodic_max) {
                        fusbh200_info(fusbh200,
                                "cannot decrease uframe_periodic_max becase "
                                "periodic bandwidth is already allocated "
                                "(%u > %u)\n",
                                allocated_max, uframe_periodic_max);
                        goto out_unlock;
                }
        }

        /* increasing is always ok */

        fusbh200_info(fusbh200, "setting max periodic bandwidth to %u%% "
                        "(== %u usec/uframe)\n",
                        100*uframe_periodic_max/125, uframe_periodic_max);

        if (uframe_periodic_max != 100)
                fusbh200_warn(fusbh200, "max periodic bandwidth set is non-standard\n");

        fusbh200->uframe_periodic_max = uframe_periodic_max;
        ret = count;

out_unlock:
        spin_unlock_irqrestore (&fusbh200->lock, flags);
        return ret;
}
static DEVICE_ATTR(uframe_periodic_max, 0644, show_uframe_periodic_max, store_uframe_periodic_max);


static inline int create_sysfs_files(struct fusbh200_hcd *fusbh200)
{
        struct device   *controller = fusbh200_to_hcd(fusbh200)->self.controller;
        int     i = 0;

        if (i)
                goto out;

        i = device_create_file(controller, &dev_attr_uframe_periodic_max);
out:
        return i;
}

static inline void remove_sysfs_files(struct fusbh200_hcd *fusbh200)
{
        struct device   *controller = fusbh200_to_hcd(fusbh200)->self.controller;

        device_remove_file(controller, &dev_attr_uframe_periodic_max);
}
/*-------------------------------------------------------------------------*/

/* On some systems, leaving remote wakeup enabled prevents system shutdown.
 * The firmware seems to think that powering off is a wakeup event!
 * This routine turns off remote wakeup and everything else, on all ports.
 */
static void fusbh200_turn_off_all_ports(struct fusbh200_hcd *fusbh200)
{
        u32 __iomem *status_reg = &fusbh200->regs->port_status;

        fusbh200_writel(fusbh200, PORT_RWC_BITS, status_reg);
}

/*
 * Halt HC, turn off all ports, and let the BIOS use the companion controllers.
 * Must be called with interrupts enabled and the lock not held.
 */
static void fusbh200_silence_controller(struct fusbh200_hcd *fusbh200)
{
        fusbh200_halt(fusbh200);

        spin_lock_irq(&fusbh200->lock);
        fusbh200->rh_state = FUSBH200_RH_HALTED;
        fusbh200_turn_off_all_ports(fusbh200);
        spin_unlock_irq(&fusbh200->lock);
}

/* fusbh200_shutdown kick in for silicon on any bus (not just pci, etc).
 * This forcibly disables dma and IRQs, helping kexec and other cases
 * where the next system software may expect clean state.
 */
static void fusbh200_shutdown(struct usb_hcd *hcd)
{
        struct fusbh200_hcd     *fusbh200 = hcd_to_fusbh200(hcd);

        spin_lock_irq(&fusbh200->lock);
        fusbh200->shutdown = true;
        fusbh200->rh_state = FUSBH200_RH_STOPPING;
        fusbh200->enabled_hrtimer_events = 0;
        spin_unlock_irq(&fusbh200->lock);

        fusbh200_silence_controller(fusbh200);

        hrtimer_cancel(&fusbh200->hrtimer);
}

/*-------------------------------------------------------------------------*/

/*
 * fusbh200_work is called from some interrupts, timers, and so on.
 * it calls driver completion functions, after dropping fusbh200->lock.
 */
static void fusbh200_work (struct fusbh200_hcd *fusbh200)
{
        /* another CPU may drop fusbh200->lock during a schedule scan while
         * it reports urb completions.  this flag guards against bogus
         * attempts at re-entrant schedule scanning.
         */
        if (fusbh200->scanning) {
                fusbh200->need_rescan = true;
                return;
        }
        fusbh200->scanning = true;

 rescan:
        fusbh200->need_rescan = false;
        if (fusbh200->async_count)
                scan_async(fusbh200);
        if (fusbh200->intr_count > 0)
                scan_intr(fusbh200);
        if (fusbh200->isoc_count > 0)
                scan_isoc(fusbh200);
        if (fusbh200->need_rescan)
                goto rescan;
        fusbh200->scanning = false;

        /* the IO watchdog guards against hardware or driver bugs that
         * misplace IRQs, and should let us run completely without IRQs.
         * such lossage has been observed on both VT6202 and VT8235.
         */
        turn_on_io_watchdog(fusbh200);
}

/*
 * Called when the fusbh200_hcd module is removed.
 */
static void fusbh200_stop (struct usb_hcd *hcd)
{
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200 (hcd);

        fusbh200_dbg (fusbh200, "stop\n");

        /* no more interrupts ... */

        spin_lock_irq(&fusbh200->lock);
        fusbh200->enabled_hrtimer_events = 0;
        spin_unlock_irq(&fusbh200->lock);

        fusbh200_quiesce(fusbh200);
        fusbh200_silence_controller(fusbh200);
        fusbh200_reset (fusbh200);

        hrtimer_cancel(&fusbh200->hrtimer);
        remove_sysfs_files(fusbh200);
        remove_debug_files (fusbh200);

        /* root hub is shut down separately (first, when possible) */
        spin_lock_irq (&fusbh200->lock);
        end_free_itds(fusbh200);
        spin_unlock_irq (&fusbh200->lock);
        fusbh200_mem_cleanup (fusbh200);

#ifdef  FUSBH200_STATS
        fusbh200_dbg(fusbh200, "irq normal %ld err %ld iaa %ld (lost %ld)\n",
                fusbh200->stats.normal, fusbh200->stats.error, fusbh200->stats.iaa,
                fusbh200->stats.lost_iaa);
        fusbh200_dbg (fusbh200, "complete %ld unlink %ld\n",
                fusbh200->stats.complete, fusbh200->stats.unlink);
#endif

        dbg_status (fusbh200, "fusbh200_stop completed",
                    fusbh200_readl(fusbh200, &fusbh200->regs->status));
}

/* one-time init, only for memory state */
static int hcd_fusbh200_init(struct usb_hcd *hcd)
{
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200(hcd);
        u32                     temp;
        int                     retval;
        u32                     hcc_params;
        struct fusbh200_qh_hw   *hw;

        spin_lock_init(&fusbh200->lock);

        /*
         * keep io watchdog by default, those good HCDs could turn off it later
         */
        fusbh200->need_io_watchdog = 1;

        hrtimer_init(&fusbh200->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
        fusbh200->hrtimer.function = fusbh200_hrtimer_func;
        fusbh200->next_hrtimer_event = FUSBH200_HRTIMER_NO_EVENT;

        hcc_params = fusbh200_readl(fusbh200, &fusbh200->caps->hcc_params);

        /*
         * by default set standard 80% (== 100 usec/uframe) max periodic
         * bandwidth as required by USB 2.0
         */
        fusbh200->uframe_periodic_max = 100;

        /*
         * hw default: 1K periodic list heads, one per frame.
         * periodic_size can shrink by USBCMD update if hcc_params allows.
         */
        fusbh200->periodic_size = DEFAULT_I_TDPS;
        INIT_LIST_HEAD(&fusbh200->intr_qh_list);
        INIT_LIST_HEAD(&fusbh200->cached_itd_list);

        if (HCC_PGM_FRAMELISTLEN(hcc_params)) {
                /* periodic schedule size can be smaller than default */
                switch (FUSBH200_TUNE_FLS) {
                case 0: fusbh200->periodic_size = 1024; break;
                case 1: fusbh200->periodic_size = 512; break;
                case 2: fusbh200->periodic_size = 256; break;
                default:        BUG();
                }
        }
        if ((retval = fusbh200_mem_init(fusbh200, GFP_KERNEL)) < 0)
                return retval;

        /* controllers may cache some of the periodic schedule ... */
        fusbh200->i_thresh = 2;

        /*
         * dedicate a qh for the async ring head, since we couldn't unlink
         * a 'real' qh without stopping the async schedule [4.8].  use it
         * as the 'reclamation list head' too.
         * its dummy is used in hw_alt_next of many tds, to prevent the qh
         * from automatically advancing to the next td after short reads.
         */
        fusbh200->async->qh_next.qh = NULL;
        hw = fusbh200->async->hw;
        hw->hw_next = QH_NEXT(fusbh200, fusbh200->async->qh_dma);
        hw->hw_info1 = cpu_to_hc32(fusbh200, QH_HEAD);
        hw->hw_token = cpu_to_hc32(fusbh200, QTD_STS_HALT);
        hw->hw_qtd_next = FUSBH200_LIST_END(fusbh200);
        fusbh200->async->qh_state = QH_STATE_LINKED;
        hw->hw_alt_next = QTD_NEXT(fusbh200, fusbh200->async->dummy->qtd_dma);

        /* clear interrupt enables, set irq latency */
        if (log2_irq_thresh < 0 || log2_irq_thresh > 6)
                log2_irq_thresh = 0;
        temp = 1 << (16 + log2_irq_thresh);
        if (HCC_CANPARK(hcc_params)) {
                /* HW default park == 3, on hardware that supports it (like
                 * NVidia and ALI silicon), maximizes throughput on the async
                 * schedule by avoiding QH fetches between transfers.
                 *
                 * With fast usb storage devices and NForce2, "park" seems to
                 * make problems:  throughput reduction (!), data errors...
                 */
                if (park) {
                        park = min(park, (unsigned) 3);
                        temp |= CMD_PARK;
                        temp |= park << 8;
                }
                fusbh200_dbg(fusbh200, "park %d\n", park);
        }
        if (HCC_PGM_FRAMELISTLEN(hcc_params)) {
                /* periodic schedule size can be smaller than default */
                temp &= ~(3 << 2);
                temp |= (FUSBH200_TUNE_FLS << 2);
        }
        fusbh200->command = temp;

        /* Accept arbitrarily long scatter-gather lists */
        if (!(hcd->driver->flags & HCD_LOCAL_MEM))
                hcd->self.sg_tablesize = ~0;
        return 0;
}

/* start HC running; it's halted, hcd_fusbh200_init() has been run (once) */
static int fusbh200_run (struct usb_hcd *hcd)
{
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200 (hcd);
        u32                     temp;
        u32                     hcc_params;

        hcd->uses_new_polling = 1;

        /* EHCI spec section 4.1 */

        fusbh200_writel(fusbh200, fusbh200->periodic_dma, &fusbh200->regs->frame_list);
        fusbh200_writel(fusbh200, (u32)fusbh200->async->qh_dma, &fusbh200->regs->async_next);

        /*
         * hcc_params controls whether fusbh200->regs->segment must (!!!)
         * be used; it constrains QH/ITD/SITD and QTD locations.
         * pci_pool consistent memory always uses segment zero.
         * streaming mappings for I/O buffers, like pci_map_single(),
         * can return segments above 4GB, if the device allows.
         *
         * NOTE:  the dma mask is visible through dma_supported(), so
         * drivers can pass this info along ... like NETIF_F_HIGHDMA,
         * Scsi_Host.highmem_io, and so forth.  It's readonly to all
         * host side drivers though.
         */
        hcc_params = fusbh200_readl(fusbh200, &fusbh200->caps->hcc_params);

        // Philips, Intel, and maybe others need CMD_RUN before the
        // root hub will detect new devices (why?); NEC doesn't
        fusbh200->command &= ~(CMD_IAAD|CMD_PSE|CMD_ASE|CMD_RESET);
        fusbh200->command |= CMD_RUN;
        fusbh200_writel(fusbh200, fusbh200->command, &fusbh200->regs->command);
        dbg_cmd (fusbh200, "init", fusbh200->command);

        /*
         * Start, enabling full USB 2.0 functionality ... usb 1.1 devices
         * are explicitly handed to companion controller(s), so no TT is
         * involved with the root hub.  (Except where one is integrated,
         * and there's no companion controller unless maybe for USB OTG.)
         *
         * Turning on the CF flag will transfer ownership of all ports
         * from the companions to the EHCI controller.  If any of the
         * companions are in the middle of a port reset at the time, it
         * could cause trouble.  Write-locking ehci_cf_port_reset_rwsem
         * guarantees that no resets are in progress.  After we set CF,
         * a short delay lets the hardware catch up; new resets shouldn't
         * be started before the port switching actions could complete.
         */
        down_write(&ehci_cf_port_reset_rwsem);
        fusbh200->rh_state = FUSBH200_RH_RUNNING;
        fusbh200_readl(fusbh200, &fusbh200->regs->command);     /* unblock posted writes */
        msleep(5);
        up_write(&ehci_cf_port_reset_rwsem);
        fusbh200->last_periodic_enable = ktime_get_real();

        temp = HC_VERSION(fusbh200, fusbh200_readl(fusbh200, &fusbh200->caps->hc_capbase));
        fusbh200_info (fusbh200,
                "USB %x.%x started, EHCI %x.%02x\n",
                ((fusbh200->sbrn & 0xf0)>>4), (fusbh200->sbrn & 0x0f),
                temp >> 8, temp & 0xff);

        fusbh200_writel(fusbh200, INTR_MASK,
                    &fusbh200->regs->intr_enable); /* Turn On Interrupts */

        /* GRR this is run-once init(), being done every time the HC starts.
         * So long as they're part of class devices, we can't do it init()
         * since the class device isn't created that early.
         */
        create_debug_files(fusbh200);
        create_sysfs_files(fusbh200);

        return 0;
}

static int fusbh200_setup(struct usb_hcd *hcd)
{
        struct fusbh200_hcd *fusbh200 = hcd_to_fusbh200(hcd);
        int retval;

        fusbh200->regs = (void __iomem *)fusbh200->caps +
            HC_LENGTH(fusbh200, fusbh200_readl(fusbh200, &fusbh200->caps->hc_capbase));
        dbg_hcs_params(fusbh200, "reset");
        dbg_hcc_params(fusbh200, "reset");

        /* cache this readonly data; minimize chip reads */
        fusbh200->hcs_params = fusbh200_readl(fusbh200, &fusbh200->caps->hcs_params);

        fusbh200->sbrn = HCD_USB2;

        /* data structure init */
        retval = hcd_fusbh200_init(hcd);
        if (retval)
                return retval;

        retval = fusbh200_halt(fusbh200);
        if (retval)
                return retval;

        fusbh200_reset(fusbh200);

        return 0;
}

/*-------------------------------------------------------------------------*/

static irqreturn_t fusbh200_irq (struct usb_hcd *hcd)
{
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200 (hcd);
        u32                     status, masked_status, pcd_status = 0, cmd;
        int                     bh;

        spin_lock (&fusbh200->lock);

        status = fusbh200_readl(fusbh200, &fusbh200->regs->status);

        /* e.g. cardbus physical eject */
        if (status == ~(u32) 0) {
                fusbh200_dbg (fusbh200, "device removed\n");
                goto dead;
        }

        /*
         * We don't use STS_FLR, but some controllers don't like it to
         * remain on, so mask it out along with the other status bits.
         */
        masked_status = status & (INTR_MASK | STS_FLR);

        /* Shared IRQ? */
        if (!masked_status || unlikely(fusbh200->rh_state == FUSBH200_RH_HALTED)) {
                spin_unlock(&fusbh200->lock);
                return IRQ_NONE;
        }

        /* clear (just) interrupts */
        fusbh200_writel(fusbh200, masked_status, &fusbh200->regs->status);
        cmd = fusbh200_readl(fusbh200, &fusbh200->regs->command);
        bh = 0;

#ifdef  VERBOSE_DEBUG
        /* unrequested/ignored: Frame List Rollover */
        dbg_status (fusbh200, "irq", status);
#endif

        /* INT, ERR, and IAA interrupt rates can be throttled */

        /* normal [4.15.1.2] or error [4.15.1.1] completion */
        if (likely ((status & (STS_INT|STS_ERR)) != 0)) {
                if (likely ((status & STS_ERR) == 0))
                        COUNT (fusbh200->stats.normal);
                else
                        COUNT (fusbh200->stats.error);
                bh = 1;
        }

        /* complete the unlinking of some qh [4.15.2.3] */
        if (status & STS_IAA) {

                /* Turn off the IAA watchdog */
                fusbh200->enabled_hrtimer_events &= ~BIT(FUSBH200_HRTIMER_IAA_WATCHDOG);

                /*
                 * Mild optimization: Allow another IAAD to reset the
                 * hrtimer, if one occurs before the next expiration.
                 * In theory we could always cancel the hrtimer, but
                 * tests show that about half the time it will be reset
                 * for some other event anyway.
                 */
                if (fusbh200->next_hrtimer_event == FUSBH200_HRTIMER_IAA_WATCHDOG)
                        ++fusbh200->next_hrtimer_event;

                /* guard against (alleged) silicon errata */
                if (cmd & CMD_IAAD)
                        fusbh200_dbg(fusbh200, "IAA with IAAD still set?\n");
                if (fusbh200->async_iaa) {
                        COUNT(fusbh200->stats.iaa);
                        end_unlink_async(fusbh200);
                } else
                        fusbh200_dbg(fusbh200, "IAA with nothing unlinked?\n");
        }

        /* remote wakeup [4.3.1] */
        if (status & STS_PCD) {
                int pstatus;
                u32 __iomem *status_reg = &fusbh200->regs->port_status;

                /* kick root hub later */
                pcd_status = status;

                /* resume root hub? */
                if (fusbh200->rh_state == FUSBH200_RH_SUSPENDED)
                        usb_hcd_resume_root_hub(hcd);

                pstatus = fusbh200_readl(fusbh200, status_reg);

                if (test_bit(0, &fusbh200->suspended_ports) &&
                                ((pstatus & PORT_RESUME) ||
                                        !(pstatus & PORT_SUSPEND)) &&
                                (pstatus & PORT_PE) &&
                                fusbh200->reset_done[0] == 0) {

                        /* start 20 msec resume signaling from this port,
                         * and make khubd collect PORT_STAT_C_SUSPEND to
                         * stop that signaling.  Use 5 ms extra for safety,
                         * like usb_port_resume() does.
                         */
                        fusbh200->reset_done[0] = jiffies + msecs_to_jiffies(25);
                        set_bit(0, &fusbh200->resuming_ports);
                        fusbh200_dbg (fusbh200, "port 1 remote wakeup\n");
                        mod_timer(&hcd->rh_timer, fusbh200->reset_done[0]);
                }
        }

        /* PCI errors [4.15.2.4] */
        if (unlikely ((status & STS_FATAL) != 0)) {
                fusbh200_err(fusbh200, "fatal error\n");
                dbg_cmd(fusbh200, "fatal", cmd);
                dbg_status(fusbh200, "fatal", status);
dead:
                usb_hc_died(hcd);

                /* Don't let the controller do anything more */
                fusbh200->shutdown = true;
                fusbh200->rh_state = FUSBH200_RH_STOPPING;
                fusbh200->command &= ~(CMD_RUN | CMD_ASE | CMD_PSE);
                fusbh200_writel(fusbh200, fusbh200->command, &fusbh200->regs->command);
                fusbh200_writel(fusbh200, 0, &fusbh200->regs->intr_enable);
                fusbh200_handle_controller_death(fusbh200);

                /* Handle completions when the controller stops */
                bh = 0;
        }

        if (bh)
                fusbh200_work (fusbh200);
        spin_unlock (&fusbh200->lock);
        if (pcd_status)
                usb_hcd_poll_rh_status(hcd);
        return IRQ_HANDLED;
}

/*-------------------------------------------------------------------------*/

/*
 * non-error returns are a promise to giveback() the urb later
 * we drop ownership so next owner (or urb unlink) can get it
 *
 * urb + dev is in hcd.self.controller.urb_list
 * we're queueing TDs onto software and hardware lists
 *
 * hcd-specific init for hcpriv hasn't been done yet
 *
 * NOTE:  control, bulk, and interrupt share the same code to append TDs
 * to a (possibly active) QH, and the same QH scanning code.
 */
static int fusbh200_urb_enqueue (
        struct usb_hcd  *hcd,
        struct urb      *urb,
        gfp_t           mem_flags
) {
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200 (hcd);
        struct list_head        qtd_list;

        INIT_LIST_HEAD (&qtd_list);

        switch (usb_pipetype (urb->pipe)) {
        case PIPE_CONTROL:
                /* qh_completions() code doesn't handle all the fault cases
                 * in multi-TD control transfers.  Even 1KB is rare anyway.
                 */
                if (urb->transfer_buffer_length > (16 * 1024))
                        return -EMSGSIZE;
                /* FALLTHROUGH */
        /* case PIPE_BULK: */
        default:
                if (!qh_urb_transaction (fusbh200, urb, &qtd_list, mem_flags))
                        return -ENOMEM;
                return submit_async(fusbh200, urb, &qtd_list, mem_flags);

        case PIPE_INTERRUPT:
                if (!qh_urb_transaction (fusbh200, urb, &qtd_list, mem_flags))
                        return -ENOMEM;
                return intr_submit(fusbh200, urb, &qtd_list, mem_flags);

        case PIPE_ISOCHRONOUS:
                return itd_submit (fusbh200, urb, mem_flags);
        }
}

/* remove from hardware lists
 * completions normally happen asynchronously
 */

static int fusbh200_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
{
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200 (hcd);
        struct fusbh200_qh              *qh;
        unsigned long           flags;
        int                     rc;

        spin_lock_irqsave (&fusbh200->lock, flags);
        rc = usb_hcd_check_unlink_urb(hcd, urb, status);
        if (rc)
                goto done;

        switch (usb_pipetype (urb->pipe)) {
        // case PIPE_CONTROL:
        // case PIPE_BULK:
        default:
                qh = (struct fusbh200_qh *) urb->hcpriv;
                if (!qh)
                        break;
                switch (qh->qh_state) {
                case QH_STATE_LINKED:
                case QH_STATE_COMPLETING:
                        start_unlink_async(fusbh200, qh);
                        break;
                case QH_STATE_UNLINK:
                case QH_STATE_UNLINK_WAIT:
                        /* already started */
                        break;
                case QH_STATE_IDLE:
                        /* QH might be waiting for a Clear-TT-Buffer */
                        qh_completions(fusbh200, qh);
                        break;
                }
                break;

        case PIPE_INTERRUPT:
                qh = (struct fusbh200_qh *) urb->hcpriv;
                if (!qh)
                        break;
                switch (qh->qh_state) {
                case QH_STATE_LINKED:
                case QH_STATE_COMPLETING:
                        start_unlink_intr(fusbh200, qh);
                        break;
                case QH_STATE_IDLE:
                        qh_completions (fusbh200, qh);
                        break;
                default:
                        fusbh200_dbg (fusbh200, "bogus qh %p state %d\n",
                                        qh, qh->qh_state);
                        goto done;
                }
                break;

        case PIPE_ISOCHRONOUS:
                // itd...

                // wait till next completion, do it then.
                // completion irqs can wait up to 1024 msec,
                break;
        }
done:
        spin_unlock_irqrestore (&fusbh200->lock, flags);
        return rc;
}

/*-------------------------------------------------------------------------*/

// bulk qh holds the data toggle

static void
fusbh200_endpoint_disable (struct usb_hcd *hcd, struct usb_host_endpoint *ep)
{
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200 (hcd);
        unsigned long           flags;
        struct fusbh200_qh              *qh, *tmp;

        /* ASSERT:  any requests/urbs are being unlinked */
        /* ASSERT:  nobody can be submitting urbs for this any more */

rescan:
        spin_lock_irqsave (&fusbh200->lock, flags);
        qh = ep->hcpriv;
        if (!qh)
                goto done;

        /* endpoints can be iso streams.  for now, we don't
         * accelerate iso completions ... so spin a while.
         */
        if (qh->hw == NULL) {
                struct fusbh200_iso_stream      *stream = ep->hcpriv;

                if (!list_empty(&stream->td_list))
                        goto idle_timeout;

                /* BUG_ON(!list_empty(&stream->free_list)); */
                kfree(stream);
                goto done;
        }

        if (fusbh200->rh_state < FUSBH200_RH_RUNNING)
                qh->qh_state = QH_STATE_IDLE;
        switch (qh->qh_state) {
        case QH_STATE_LINKED:
        case QH_STATE_COMPLETING:
                for (tmp = fusbh200->async->qh_next.qh;
                                tmp && tmp != qh;
                                tmp = tmp->qh_next.qh)
                        continue;
                /* periodic qh self-unlinks on empty, and a COMPLETING qh
                 * may already be unlinked.
                 */
                if (tmp)
                        start_unlink_async(fusbh200, qh);
                /* FALL THROUGH */
        case QH_STATE_UNLINK:           /* wait for hw to finish? */
        case QH_STATE_UNLINK_WAIT:
idle_timeout:
                spin_unlock_irqrestore (&fusbh200->lock, flags);
                schedule_timeout_uninterruptible(1);
                goto rescan;
        case QH_STATE_IDLE:             /* fully unlinked */
                if (qh->clearing_tt)
                        goto idle_timeout;
                if (list_empty (&qh->qtd_list)) {
                        qh_destroy(fusbh200, qh);
                        break;
                }
                /* else FALL THROUGH */
        default:
                /* caller was supposed to have unlinked any requests;
                 * that's not our job.  just leak this memory.
                 */
                fusbh200_err (fusbh200, "qh %p (#%02x) state %d%s\n",
                        qh, ep->desc.bEndpointAddress, qh->qh_state,
                        list_empty (&qh->qtd_list) ? "" : "(has tds)");
                break;
        }
 done:
        ep->hcpriv = NULL;
        spin_unlock_irqrestore (&fusbh200->lock, flags);
}

static void
fusbh200_endpoint_reset(struct usb_hcd *hcd, struct usb_host_endpoint *ep)
{
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200(hcd);
        struct fusbh200_qh              *qh;
        int                     eptype = usb_endpoint_type(&ep->desc);
        int                     epnum = usb_endpoint_num(&ep->desc);
        int                     is_out = usb_endpoint_dir_out(&ep->desc);
        unsigned long           flags;

        if (eptype != USB_ENDPOINT_XFER_BULK && eptype != USB_ENDPOINT_XFER_INT)
                return;

        spin_lock_irqsave(&fusbh200->lock, flags);
        qh = ep->hcpriv;

        /* For Bulk and Interrupt endpoints we maintain the toggle state
         * in the hardware; the toggle bits in udev aren't used at all.
         * When an endpoint is reset by usb_clear_halt() we must reset
         * the toggle bit in the QH.
         */
        if (qh) {
                usb_settoggle(qh->dev, epnum, is_out, 0);
                if (!list_empty(&qh->qtd_list)) {
                        WARN_ONCE(1, "clear_halt for a busy endpoint\n");
                } else if (qh->qh_state == QH_STATE_LINKED ||
                                qh->qh_state == QH_STATE_COMPLETING) {

                        /* The toggle value in the QH can't be updated
                         * while the QH is active.  Unlink it now;
                         * re-linking will call qh_refresh().
                         */
                        if (eptype == USB_ENDPOINT_XFER_BULK)
                                start_unlink_async(fusbh200, qh);
                        else
                                start_unlink_intr(fusbh200, qh);
                }
        }
        spin_unlock_irqrestore(&fusbh200->lock, flags);
}

static int fusbh200_get_frame (struct usb_hcd *hcd)
{
        struct fusbh200_hcd             *fusbh200 = hcd_to_fusbh200 (hcd);
        return (fusbh200_read_frame_index(fusbh200) >> 3) % fusbh200->periodic_size;
}

/*-------------------------------------------------------------------------*/

/*
 * The EHCI in ChipIdea HDRC cannot be a separate module or device,
 * because its registers (and irq) are shared between host/gadget/otg
 * functions  and in order to facilitate role switching we cannot
 * give the fusbh200 driver exclusive access to those.
 */
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR (DRIVER_AUTHOR);
MODULE_LICENSE ("GPL");

static const struct hc_driver fusbh200_fusbh200_hc_driver = {
        .description            = hcd_name,
        .product_desc           = "Faraday USB2.0 Host Controller",
        .hcd_priv_size          = sizeof(struct fusbh200_hcd),

        /*
         * generic hardware linkage
         */
        .irq                    = fusbh200_irq,
        .flags                  = HCD_MEMORY | HCD_USB2,

        /*
         * basic lifecycle operations
         */
        .reset                  = hcd_fusbh200_init,
        .start                  = fusbh200_run,
        .stop                   = fusbh200_stop,
        .shutdown               = fusbh200_shutdown,

        /*
         * managing i/o requests and associated device resources
         */
        .urb_enqueue            = fusbh200_urb_enqueue,
        .urb_dequeue            = fusbh200_urb_dequeue,
        .endpoint_disable       = fusbh200_endpoint_disable,
        .endpoint_reset         = fusbh200_endpoint_reset,

        /*
         * scheduling support
         */
        .get_frame_number       = fusbh200_get_frame,

        /*
         * root hub support
         */
        .hub_status_data        = fusbh200_hub_status_data,
        .hub_control            = fusbh200_hub_control,
        .bus_suspend            = fusbh200_bus_suspend,
        .bus_resume             = fusbh200_bus_resume,

        .relinquish_port        = fusbh200_relinquish_port,
        .port_handed_over       = fusbh200_port_handed_over,

        .clear_tt_buffer_complete = fusbh200_clear_tt_buffer_complete,
};

static void fusbh200_init(struct fusbh200_hcd *fusbh200)
{
        u32 reg;

        reg = fusbh200_readl(fusbh200, &fusbh200->regs->bmcsr);
        reg |= BMCSR_INT_POLARITY;
        reg &= ~BMCSR_VBUS_OFF;
        fusbh200_writel(fusbh200, reg, &fusbh200->regs->bmcsr);

        reg = fusbh200_readl(fusbh200, &fusbh200->regs->bmier);
        fusbh200_writel(fusbh200, reg | BMIER_OVC_EN | BMIER_VBUS_ERR_EN,
                &fusbh200->regs->bmier);
}

/**
 * fusbh200_hcd_probe - initialize faraday FUSBH200 HCDs
 *
 * Allocates basic resources for this USB host controller, and
 * then invokes the start() method for the HCD associated with it
 * through the hotplug entry's driver_data.
 */
static int fusbh200_hcd_probe(struct platform_device *pdev)
{
        struct device                   *dev = &pdev->dev;
        struct usb_hcd                  *hcd;
        struct resource                 *res;
        int                             irq;
        int                             retval = -ENODEV;
        struct fusbh200_hcd             *fusbh200;

        if (usb_disabled())
                return -ENODEV;

        pdev->dev.power.power_state = PMSG_ON;

        res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
        if (!res) {
                dev_err(dev,
                        "Found HC with no IRQ. Check %s setup!\n",
                        dev_name(dev));
                return -ENODEV;
        }

        irq = res->start;

        hcd = usb_create_hcd(&fusbh200_fusbh200_hc_driver, dev,
                        dev_name(dev));
        if (!hcd) {
                dev_err(dev, "failed to create hcd with err %d\n", retval);
                retval = -ENOMEM;
                goto fail_create_hcd;
        }

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(dev,
                        "Found HC with no register addr. Check %s setup!\n",
                        dev_name(dev));
                retval = -ENODEV;
                goto fail_request_resource;
        }

        hcd->rsrc_start = res->start;
        hcd->rsrc_len = resource_size(res);
        hcd->has_tt = 1;

        if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len,
                                fusbh200_fusbh200_hc_driver.description)) {
                dev_dbg(dev, "controller already in use\n");
                retval = -EBUSY;
                goto fail_request_resource;
        }

        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
        if (!res) {
                dev_err(dev,
                        "Found HC with no register addr. Check %s setup!\n",
                        dev_name(dev));
                retval = -ENODEV;
                goto fail_request_resource;
        }

        hcd->regs = ioremap_nocache(res->start, resource_size(res));
        if (hcd->regs == NULL) {
                dev_dbg(dev, "error mapping memory\n");
                retval = -EFAULT;
                goto fail_ioremap;
        }

        fusbh200 = hcd_to_fusbh200(hcd);

        fusbh200->caps = hcd->regs;

        retval = fusbh200_setup(hcd);
        if (retval)
                goto fail_add_hcd;

        fusbh200_init(fusbh200);

        retval = usb_add_hcd(hcd, irq, IRQF_SHARED);
        if (retval) {
                dev_err(dev, "failed to add hcd with err %d\n", retval);
                goto fail_add_hcd;
        }

        return retval;

fail_add_hcd:
        iounmap(hcd->regs);
fail_ioremap:
        release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
fail_request_resource:
        usb_put_hcd(hcd);
fail_create_hcd:
        dev_err(dev, "init %s fail, %d\n", dev_name(dev), retval);
        return retval;
}

/**
 * fusbh200_hcd_remove - shutdown processing for EHCI HCDs
 * @dev: USB Host Controller being removed
 *
 * Reverses the effect of fotg2xx_usb_hcd_probe(), first invoking
 * the HCD's stop() method.  It is always called from a thread
 * context, normally "rmmod", "apmd", or something similar.
 */
static int fusbh200_hcd_remove(struct platform_device *pdev)
{
        struct device *dev      = &pdev->dev;
        struct usb_hcd *hcd     = dev_get_drvdata(dev);

        if (!hcd)
                return 0;

        usb_remove_hcd(hcd);
        iounmap(hcd->regs);
        release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
        usb_put_hcd(hcd);

        return 0;
}

static struct platform_driver fusbh200_hcd_fusbh200_driver = {
        .driver = {
                .name   = "fusbh200",
        },
        .probe  = fusbh200_hcd_probe,
        .remove = fusbh200_hcd_remove,
};

static int __init fusbh200_hcd_init(void)
{
        int retval = 0;

        if (usb_disabled())
                return -ENODEV;

        printk(KERN_INFO "%s: " DRIVER_DESC "\n", hcd_name);
        set_bit(USB_EHCI_LOADED, &usb_hcds_loaded);
        if (test_bit(USB_UHCI_LOADED, &usb_hcds_loaded) ||
                        test_bit(USB_OHCI_LOADED, &usb_hcds_loaded))
                printk(KERN_WARNING "Warning! fusbh200_hcd should always be loaded"
                                " before uhci_hcd and ohci_hcd, not after\n");

        pr_debug("%s: block sizes: qh %Zd qtd %Zd itd %Zd\n",
                 hcd_name,
                 sizeof(struct fusbh200_qh), sizeof(struct fusbh200_qtd),
                 sizeof(struct fusbh200_itd));

#ifdef DEBUG
        fusbh200_debug_root = debugfs_create_dir("fusbh200", usb_debug_root);
        if (!fusbh200_debug_root) {
                retval = -ENOENT;
                goto err_debug;
        }
#endif

        retval = platform_driver_register(&fusbh200_hcd_fusbh200_driver);
        if (retval < 0)
                goto clean;
        return retval;

        platform_driver_unregister(&fusbh200_hcd_fusbh200_driver);
clean:
#ifdef DEBUG
        debugfs_remove(fusbh200_debug_root);
        fusbh200_debug_root = NULL;
err_debug:
#endif
        clear_bit(USB_EHCI_LOADED, &usb_hcds_loaded);
        return retval;
}
module_init(fusbh200_hcd_init);

static void __exit fusbh200_hcd_cleanup(void)
{
        platform_driver_unregister(&fusbh200_hcd_fusbh200_driver);
#ifdef DEBUG
        debugfs_remove(fusbh200_debug_root);
#endif
        clear_bit(USB_EHCI_LOADED, &usb_hcds_loaded);
}
module_exit(fusbh200_hcd_cleanup);