USB: xHCI: bus power management implementation

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / usb / host / uhci-hcd.c

/*
 * Universal Host Controller Interface driver for USB.
 *
 * Maintainer: Alan Stern <stern@rowland.harvard.edu>
 *
 * (C) Copyright 1999 Linus Torvalds
 * (C) Copyright 1999-2002 Johannes Erdfelt, johannes@erdfelt.com
 * (C) Copyright 1999 Randy Dunlap
 * (C) Copyright 1999 Georg Acher, acher@in.tum.de
 * (C) Copyright 1999 Deti Fliegl, deti@fliegl.de
 * (C) Copyright 1999 Thomas Sailer, sailer@ife.ee.ethz.ch
 * (C) Copyright 1999 Roman Weissgaerber, weissg@vienna.at
 * (C) Copyright 2000 Yggdrasil Computing, Inc. (port of new PCI interface
 *               support from usb-ohci.c by Adam Richter, adam@yggdrasil.com).
 * (C) Copyright 1999 Gregory P. Smith (from usb-ohci.c)
 * (C) Copyright 2004-2007 Alan Stern, stern@rowland.harvard.edu
 *
 * Intel documents this fairly well, and as far as I know there
 * are no royalties or anything like that, but even so there are
 * people who decided that they want to do the same thing in a
 * completely different way.
 *
 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/pm.h>
#include <linux/dmapool.h>
#include <linux/dma-mapping.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <linux/bitops.h>
#include <linux/dmi.h>

#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>

#include "uhci-hcd.h"
#include "pci-quirks.h"

/*
 * Version Information
 */
#define DRIVER_AUTHOR "Linus 'Frodo Rabbit' Torvalds, Johannes Erdfelt, \
Randy Dunlap, Georg Acher, Deti Fliegl, Thomas Sailer, Roman Weissgaerber, \
Alan Stern"
#define DRIVER_DESC "USB Universal Host Controller Interface driver"

/* for flakey hardware, ignore overcurrent indicators */
static int ignore_oc;
module_param(ignore_oc, bool, S_IRUGO);
MODULE_PARM_DESC(ignore_oc, "ignore hardware overcurrent indications");

/*
 * debug = 0, no debugging messages
 * debug = 1, dump failed URBs except for stalls
 * debug = 2, dump all failed URBs (including stalls)
 *            show all queues in /sys/kernel/debug/uhci/[pci_addr]
 * debug = 3, show all TDs in URBs when dumping
 */
#ifdef DEBUG
#define DEBUG_CONFIGURED        1
static int debug = 1;
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug level");

#else
#define DEBUG_CONFIGURED        0
#define debug                   0
#endif

static char *errbuf;
#define ERRBUF_LEN    (32 * 1024)

static struct kmem_cache *uhci_up_cachep;       /* urb_priv */

static void suspend_rh(struct uhci_hcd *uhci, enum uhci_rh_state new_state);
static void wakeup_rh(struct uhci_hcd *uhci);
static void uhci_get_current_frame_number(struct uhci_hcd *uhci);

/*
 * Calculate the link pointer DMA value for the first Skeleton QH in a frame.
 */
static __le32 uhci_frame_skel_link(struct uhci_hcd *uhci, int frame)
{
        int skelnum;

        /*
         * The interrupt queues will be interleaved as evenly as possible.
         * There's not much to be done about period-1 interrupts; they have
         * to occur in every frame.  But we can schedule period-2 interrupts
         * in odd-numbered frames, period-4 interrupts in frames congruent
         * to 2 (mod 4), and so on.  This way each frame only has two
         * interrupt QHs, which will help spread out bandwidth utilization.
         *
         * ffs (Find First bit Set) does exactly what we need:
         * 1,3,5,...  => ffs = 0 => use period-2 QH = skelqh[8],
         * 2,6,10,... => ffs = 1 => use period-4 QH = skelqh[7], etc.
         * ffs >= 7 => not on any high-period queue, so use
         *      period-1 QH = skelqh[9].
         * Add in UHCI_NUMFRAMES to insure at least one bit is set.
         */
        skelnum = 8 - (int) __ffs(frame | UHCI_NUMFRAMES);
        if (skelnum <= 1)
                skelnum = 9;
        return LINK_TO_QH(uhci->skelqh[skelnum]);
}

#include "uhci-debug.c"
#include "uhci-q.c"
#include "uhci-hub.c"

/*
 * Finish up a host controller reset and update the recorded state.
 */
static void finish_reset(struct uhci_hcd *uhci)
{
        int port;

        /* HCRESET doesn't affect the Suspend, Reset, and Resume Detect
         * bits in the port status and control registers.
         * We have to clear them by hand.
         */
        for (port = 0; port < uhci->rh_numports; ++port)
                outw(0, uhci->io_addr + USBPORTSC1 + (port * 2));

        uhci->port_c_suspend = uhci->resuming_ports = 0;
        uhci->rh_state = UHCI_RH_RESET;
        uhci->is_stopped = UHCI_IS_STOPPED;
        uhci_to_hcd(uhci)->state = HC_STATE_HALT;
        clear_bit(HCD_FLAG_POLL_RH, &uhci_to_hcd(uhci)->flags);

        uhci->dead = 0;         /* Full reset resurrects the controller */
}

/*
 * Last rites for a defunct/nonfunctional controller
 * or one we don't want to use any more.
 */
static void uhci_hc_died(struct uhci_hcd *uhci)
{
        uhci_get_current_frame_number(uhci);
        uhci_reset_hc(to_pci_dev(uhci_dev(uhci)), uhci->io_addr);
        finish_reset(uhci);
        uhci->dead = 1;

        /* The current frame may already be partway finished */
        ++uhci->frame_number;
}

/*
 * Initialize a controller that was newly discovered or has lost power
 * or otherwise been reset while it was suspended.  In none of these cases
 * can we be sure of its previous state.
 */
static void check_and_reset_hc(struct uhci_hcd *uhci)
{
        if (uhci_check_and_reset_hc(to_pci_dev(uhci_dev(uhci)), uhci->io_addr))
                finish_reset(uhci);
}

/*
 * Store the basic register settings needed by the controller.
 */
static void configure_hc(struct uhci_hcd *uhci)
{
        struct pci_dev *pdev = to_pci_dev(uhci_dev(uhci));

        /* Set the frame length to the default: 1 ms exactly */
        outb(USBSOF_DEFAULT, uhci->io_addr + USBSOF);

        /* Store the frame list base address */
        outl(uhci->frame_dma_handle, uhci->io_addr + USBFLBASEADD);

        /* Set the current frame number */
        outw(uhci->frame_number & UHCI_MAX_SOF_NUMBER,
                        uhci->io_addr + USBFRNUM);

        /* Mark controller as not halted before we enable interrupts */
        uhci_to_hcd(uhci)->state = HC_STATE_SUSPENDED;
        mb();

        /* Enable PIRQ */
        pci_write_config_word(pdev, USBLEGSUP, USBLEGSUP_DEFAULT);

        /* Disable platform-specific non-PME# wakeup */
        if (pdev->vendor == PCI_VENDOR_ID_INTEL)
                pci_write_config_byte(pdev, USBRES_INTEL, 0);
}


static int resume_detect_interrupts_are_broken(struct uhci_hcd *uhci)
{
        int port;

        /* If we have to ignore overcurrent events then almost by definition
         * we can't depend on resume-detect interrupts. */
        if (ignore_oc)
                return 1;

        switch (to_pci_dev(uhci_dev(uhci))->vendor) {
            default:
                break;

            case PCI_VENDOR_ID_GENESYS:
                /* Genesys Logic's GL880S controllers don't generate
                 * resume-detect interrupts.
                 */
                return 1;

            case PCI_VENDOR_ID_INTEL:
                /* Some of Intel's USB controllers have a bug that causes
                 * resume-detect interrupts if any port has an over-current
                 * condition.  To make matters worse, some motherboards
                 * hardwire unused USB ports' over-current inputs active!
                 * To prevent problems, we will not enable resume-detect
                 * interrupts if any ports are OC.
                 */
                for (port = 0; port < uhci->rh_numports; ++port) {
                        if (inw(uhci->io_addr + USBPORTSC1 + port * 2) &
                                        USBPORTSC_OC)
                                return 1;
                }
                break;
        }
        return 0;
}

static int global_suspend_mode_is_broken(struct uhci_hcd *uhci)
{
        int port;
        const char *sys_info;
        static char bad_Asus_board[] = "A7V8X";

        /* One of Asus's motherboards has a bug which causes it to
         * wake up immediately from suspend-to-RAM if any of the ports
         * are connected.  In such cases we will not set EGSM.
         */
        sys_info = dmi_get_system_info(DMI_BOARD_NAME);
        if (sys_info && !strcmp(sys_info, bad_Asus_board)) {
                for (port = 0; port < uhci->rh_numports; ++port) {
                        if (inw(uhci->io_addr + USBPORTSC1 + port * 2) &
                                        USBPORTSC_CCS)
                                return 1;
                }
        }

        return 0;
}

static void suspend_rh(struct uhci_hcd *uhci, enum uhci_rh_state new_state)
__releases(uhci->lock)
__acquires(uhci->lock)
{
        int auto_stop;
        int int_enable, egsm_enable, wakeup_enable;
        struct usb_device *rhdev = uhci_to_hcd(uhci)->self.root_hub;

        auto_stop = (new_state == UHCI_RH_AUTO_STOPPED);
        dev_dbg(&rhdev->dev, "%s%s\n", __func__,
                        (auto_stop ? " (auto-stop)" : ""));

        /* Start off by assuming Resume-Detect interrupts and EGSM work
         * and that remote wakeups should be enabled.
         */
        egsm_enable = USBCMD_EGSM;
        uhci->RD_enable = 1;
        int_enable = USBINTR_RESUME;
        wakeup_enable = 1;

        /* In auto-stop mode wakeups must always be detected, but
         * Resume-Detect interrupts may be prohibited.  (In the absence
         * of CONFIG_PM, they are always disallowed.)
         */
        if (auto_stop) {
                if (!device_may_wakeup(&rhdev->dev))
                        int_enable = 0;

        /* In bus-suspend mode wakeups may be disabled, but if they are
         * allowed then so are Resume-Detect interrupts.
         */
        } else {
#ifdef CONFIG_PM
                if (!rhdev->do_remote_wakeup)
                        wakeup_enable = 0;
#endif
        }

        /* EGSM causes the root hub to echo a 'K' signal (resume) out any
         * port which requests a remote wakeup.  According to the USB spec,
         * every hub is supposed to do this.  But if we are ignoring
         * remote-wakeup requests anyway then there's no point to it.
         * We also shouldn't enable EGSM if it's broken.
         */
        if (!wakeup_enable || global_suspend_mode_is_broken(uhci))
                egsm_enable = 0;

        /* If we're ignoring wakeup events then there's no reason to
         * enable Resume-Detect interrupts.  We also shouldn't enable
         * them if they are broken or disallowed.
         *
         * This logic may lead us to enabling RD but not EGSM.  The UHCI
         * spec foolishly says that RD works only when EGSM is on, but
         * there's no harm in enabling it anyway -- perhaps some chips
         * will implement it!
         */
        if (!wakeup_enable || resume_detect_interrupts_are_broken(uhci) ||
                        !int_enable)
                uhci->RD_enable = int_enable = 0;

        outw(int_enable, uhci->io_addr + USBINTR);
        outw(egsm_enable | USBCMD_CF, uhci->io_addr + USBCMD);
        mb();
        udelay(5);

        /* If we're auto-stopping then no devices have been attached
         * for a while, so there shouldn't be any active URBs and the
         * controller should stop after a few microseconds.  Otherwise
         * we will give the controller one frame to stop.
         */
        if (!auto_stop && !(inw(uhci->io_addr + USBSTS) & USBSTS_HCH)) {
                uhci->rh_state = UHCI_RH_SUSPENDING;
                spin_unlock_irq(&uhci->lock);
                msleep(1);
                spin_lock_irq(&uhci->lock);
                if (uhci->dead)
                        return;
        }
        if (!(inw(uhci->io_addr + USBSTS) & USBSTS_HCH))
                dev_warn(uhci_dev(uhci), "Controller not stopped yet!\n");

        uhci_get_current_frame_number(uhci);

        uhci->rh_state = new_state;
        uhci->is_stopped = UHCI_IS_STOPPED;

        /* If interrupts don't work and remote wakeup is enabled then
         * the suspended root hub needs to be polled.
         */
        if (!int_enable && wakeup_enable)
                set_bit(HCD_FLAG_POLL_RH, &uhci_to_hcd(uhci)->flags);
        else
                clear_bit(HCD_FLAG_POLL_RH, &uhci_to_hcd(uhci)->flags);

        uhci_scan_schedule(uhci);
        uhci_fsbr_off(uhci);
}

static void start_rh(struct uhci_hcd *uhci)
{
        uhci_to_hcd(uhci)->state = HC_STATE_RUNNING;
        uhci->is_stopped = 0;

        /* Mark it configured and running with a 64-byte max packet.
         * All interrupts are enabled, even though RESUME won't do anything.
         */
        outw(USBCMD_RS | USBCMD_CF | USBCMD_MAXP, uhci->io_addr + USBCMD);
        outw(USBINTR_TIMEOUT | USBINTR_RESUME | USBINTR_IOC | USBINTR_SP,
                        uhci->io_addr + USBINTR);
        mb();
        uhci->rh_state = UHCI_RH_RUNNING;
        set_bit(HCD_FLAG_POLL_RH, &uhci_to_hcd(uhci)->flags);
}

static void wakeup_rh(struct uhci_hcd *uhci)
__releases(uhci->lock)
__acquires(uhci->lock)
{
        dev_dbg(&uhci_to_hcd(uhci)->self.root_hub->dev,
                        "%s%s\n", __func__,
                        uhci->rh_state == UHCI_RH_AUTO_STOPPED ?
                                " (auto-start)" : "");

        /* If we are auto-stopped then no devices are attached so there's
         * no need for wakeup signals.  Otherwise we send Global Resume
         * for 20 ms.
         */
        if (uhci->rh_state == UHCI_RH_SUSPENDED) {
                unsigned egsm;

                /* Keep EGSM on if it was set before */
                egsm = inw(uhci->io_addr + USBCMD) & USBCMD_EGSM;
                uhci->rh_state = UHCI_RH_RESUMING;
                outw(USBCMD_FGR | USBCMD_CF | egsm, uhci->io_addr + USBCMD);
                spin_unlock_irq(&uhci->lock);
                msleep(20);
                spin_lock_irq(&uhci->lock);
                if (uhci->dead)
                        return;

                /* End Global Resume and wait for EOP to be sent */
                outw(USBCMD_CF, uhci->io_addr + USBCMD);
                mb();
                udelay(4);
                if (inw(uhci->io_addr + USBCMD) & USBCMD_FGR)
                        dev_warn(uhci_dev(uhci), "FGR not stopped yet!\n");
        }

        start_rh(uhci);

        /* Restart root hub polling */
        mod_timer(&uhci_to_hcd(uhci)->rh_timer, jiffies);
}

static irqreturn_t uhci_irq(struct usb_hcd *hcd)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        unsigned short status;

        /*
         * Read the interrupt status, and write it back to clear the
         * interrupt cause.  Contrary to the UHCI specification, the
         * "HC Halted" status bit is persistent: it is RO, not R/WC.
         */
        status = inw(uhci->io_addr + USBSTS);
        if (!(status & ~USBSTS_HCH))    /* shared interrupt, not mine */
                return IRQ_NONE;
        outw(status, uhci->io_addr + USBSTS);           /* Clear it */

        if (status & ~(USBSTS_USBINT | USBSTS_ERROR | USBSTS_RD)) {
                if (status & USBSTS_HSE)
                        dev_err(uhci_dev(uhci), "host system error, "
                                        "PCI problems?\n");
                if (status & USBSTS_HCPE)
                        dev_err(uhci_dev(uhci), "host controller process "
                                        "error, something bad happened!\n");
                if (status & USBSTS_HCH) {
                        spin_lock(&uhci->lock);
                        if (uhci->rh_state >= UHCI_RH_RUNNING) {
                                dev_err(uhci_dev(uhci),
                                        "host controller halted, "
                                        "very bad!\n");
                                if (debug > 1 && errbuf) {
                                        /* Print the schedule for debugging */
                                        uhci_sprint_schedule(uhci,
                                                        errbuf, ERRBUF_LEN);
                                        lprintk(errbuf);
                                }
                                uhci_hc_died(uhci);

                                /* Force a callback in case there are
                                 * pending unlinks */
                                mod_timer(&hcd->rh_timer, jiffies);
                        }
                        spin_unlock(&uhci->lock);
                }
        }

        if (status & USBSTS_RD)
                usb_hcd_poll_rh_status(hcd);
        else {
                spin_lock(&uhci->lock);
                uhci_scan_schedule(uhci);
                spin_unlock(&uhci->lock);
        }

        return IRQ_HANDLED;
}

/*
 * Store the current frame number in uhci->frame_number if the controller
 * is runnning.  Expand from 11 bits (of which we use only 10) to a
 * full-sized integer.
 *
 * Like many other parts of the driver, this code relies on being polled
 * more than once per second as long as the controller is running.
 */
static void uhci_get_current_frame_number(struct uhci_hcd *uhci)
{
        if (!uhci->is_stopped) {
                unsigned delta;

                delta = (inw(uhci->io_addr + USBFRNUM) - uhci->frame_number) &
                                (UHCI_NUMFRAMES - 1);
                uhci->frame_number += delta;
        }
}

/*
 * De-allocate all resources
 */
static void release_uhci(struct uhci_hcd *uhci)
{
        int i;

        if (DEBUG_CONFIGURED) {
                spin_lock_irq(&uhci->lock);
                uhci->is_initialized = 0;
                spin_unlock_irq(&uhci->lock);

                debugfs_remove(uhci->dentry);
        }

        for (i = 0; i < UHCI_NUM_SKELQH; i++)
                uhci_free_qh(uhci, uhci->skelqh[i]);

        uhci_free_td(uhci, uhci->term_td);

        dma_pool_destroy(uhci->qh_pool);

        dma_pool_destroy(uhci->td_pool);

        kfree(uhci->frame_cpu);

        dma_free_coherent(uhci_dev(uhci),
                        UHCI_NUMFRAMES * sizeof(*uhci->frame),
                        uhci->frame, uhci->frame_dma_handle);
}

static int uhci_init(struct usb_hcd *hcd)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        unsigned io_size = (unsigned) hcd->rsrc_len;
        int port;

        uhci->io_addr = (unsigned long) hcd->rsrc_start;

        /* The UHCI spec says devices must have 2 ports, and goes on to say
         * they may have more but gives no way to determine how many there
         * are.  However according to the UHCI spec, Bit 7 of the port
         * status and control register is always set to 1.  So we try to
         * use this to our advantage.  Another common failure mode when
         * a nonexistent register is addressed is to return all ones, so
         * we test for that also.
         */
        for (port = 0; port < (io_size - USBPORTSC1) / 2; port++) {
                unsigned int portstatus;

                portstatus = inw(uhci->io_addr + USBPORTSC1 + (port * 2));
                if (!(portstatus & 0x0080) || portstatus == 0xffff)
                        break;
        }
        if (debug)
                dev_info(uhci_dev(uhci), "detected %d ports\n", port);

        /* Anything greater than 7 is weird so we'll ignore it. */
        if (port > UHCI_RH_MAXCHILD) {
                dev_info(uhci_dev(uhci), "port count misdetected? "
                                "forcing to 2 ports\n");
                port = 2;
        }
        uhci->rh_numports = port;

        /* Kick BIOS off this hardware and reset if the controller
         * isn't already safely quiescent.
         */
        check_and_reset_hc(uhci);
        return 0;
}

/* Make sure the controller is quiescent and that we're not using it
 * any more.  This is mainly for the benefit of programs which, like kexec,
 * expect the hardware to be idle: not doing DMA or generating IRQs.
 *
 * This routine may be called in a damaged or failing kernel.  Hence we
 * do not acquire the spinlock before shutting down the controller.
 */
static void uhci_shutdown(struct pci_dev *pdev)
{
        struct usb_hcd *hcd = (struct usb_hcd *) pci_get_drvdata(pdev);

        uhci_hc_died(hcd_to_uhci(hcd));
}

/*
 * Allocate a frame list, and then setup the skeleton
 *
 * The hardware doesn't really know any difference
 * in the queues, but the order does matter for the
 * protocols higher up.  The order in which the queues
 * are encountered by the hardware is:
 *
 *  - All isochronous events are handled before any
 *    of the queues. We don't do that here, because
 *    we'll create the actual TD entries on demand.
 *  - The first queue is the high-period interrupt queue.
 *  - The second queue is the period-1 interrupt and async
 *    (low-speed control, full-speed control, then bulk) queue.
 *  - The third queue is the terminating bandwidth reclamation queue,
 *    which contains no members, loops back to itself, and is present
 *    only when FSBR is on and there are no full-speed control or bulk QHs.
 */
static int uhci_start(struct usb_hcd *hcd)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        int retval = -EBUSY;
        int i;
        struct dentry __maybe_unused *dentry;

        hcd->uses_new_polling = 1;

        spin_lock_init(&uhci->lock);
        setup_timer(&uhci->fsbr_timer, uhci_fsbr_timeout,
                        (unsigned long) uhci);
        INIT_LIST_HEAD(&uhci->idle_qh_list);
        init_waitqueue_head(&uhci->waitqh);

#ifdef UHCI_DEBUG_OPS
        dentry = debugfs_create_file(hcd->self.bus_name,
                        S_IFREG|S_IRUGO|S_IWUSR, uhci_debugfs_root,
                        uhci, &uhci_debug_operations);
        if (!dentry) {
                dev_err(uhci_dev(uhci), "couldn't create uhci debugfs entry\n");
                return -ENOMEM;
        }
        uhci->dentry = dentry;
#endif

        uhci->frame = dma_alloc_coherent(uhci_dev(uhci),
                        UHCI_NUMFRAMES * sizeof(*uhci->frame),
                        &uhci->frame_dma_handle, 0);
        if (!uhci->frame) {
                dev_err(uhci_dev(uhci), "unable to allocate "
                                "consistent memory for frame list\n");
                goto err_alloc_frame;
        }
        memset(uhci->frame, 0, UHCI_NUMFRAMES * sizeof(*uhci->frame));

        uhci->frame_cpu = kcalloc(UHCI_NUMFRAMES, sizeof(*uhci->frame_cpu),
                        GFP_KERNEL);
        if (!uhci->frame_cpu) {
                dev_err(uhci_dev(uhci), "unable to allocate "
                                "memory for frame pointers\n");
                goto err_alloc_frame_cpu;
        }

        uhci->td_pool = dma_pool_create("uhci_td", uhci_dev(uhci),
                        sizeof(struct uhci_td), 16, 0);
        if (!uhci->td_pool) {
                dev_err(uhci_dev(uhci), "unable to create td dma_pool\n");
                goto err_create_td_pool;
        }

        uhci->qh_pool = dma_pool_create("uhci_qh", uhci_dev(uhci),
                        sizeof(struct uhci_qh), 16, 0);
        if (!uhci->qh_pool) {
                dev_err(uhci_dev(uhci), "unable to create qh dma_pool\n");
                goto err_create_qh_pool;
        }

        uhci->term_td = uhci_alloc_td(uhci);
        if (!uhci->term_td) {
                dev_err(uhci_dev(uhci), "unable to allocate terminating TD\n");
                goto err_alloc_term_td;
        }

        for (i = 0; i < UHCI_NUM_SKELQH; i++) {
                uhci->skelqh[i] = uhci_alloc_qh(uhci, NULL, NULL);
                if (!uhci->skelqh[i]) {
                        dev_err(uhci_dev(uhci), "unable to allocate QH\n");
                        goto err_alloc_skelqh;
                }
        }

        /*
         * 8 Interrupt queues; link all higher int queues to int1 = async
         */
        for (i = SKEL_ISO + 1; i < SKEL_ASYNC; ++i)
                uhci->skelqh[i]->link = LINK_TO_QH(uhci->skel_async_qh);
        uhci->skel_async_qh->link = UHCI_PTR_TERM;
        uhci->skel_term_qh->link = LINK_TO_QH(uhci->skel_term_qh);

        /* This dummy TD is to work around a bug in Intel PIIX controllers */
        uhci_fill_td(uhci->term_td, 0, uhci_explen(0) |
                        (0x7f << TD_TOKEN_DEVADDR_SHIFT) | USB_PID_IN, 0);
        uhci->term_td->link = UHCI_PTR_TERM;
        uhci->skel_async_qh->element = uhci->skel_term_qh->element =
                        LINK_TO_TD(uhci->term_td);

        /*
         * Fill the frame list: make all entries point to the proper
         * interrupt queue.
         */
        for (i = 0; i < UHCI_NUMFRAMES; i++) {

                /* Only place we don't use the frame list routines */
                uhci->frame[i] = uhci_frame_skel_link(uhci, i);
        }

        /*
         * Some architectures require a full mb() to enforce completion of
         * the memory writes above before the I/O transfers in configure_hc().
         */
        mb();

        configure_hc(uhci);
        uhci->is_initialized = 1;
        spin_lock_irq(&uhci->lock);
        start_rh(uhci);
        spin_unlock_irq(&uhci->lock);
        return 0;

/*
 * error exits:
 */
err_alloc_skelqh:
        for (i = 0; i < UHCI_NUM_SKELQH; i++) {
                if (uhci->skelqh[i])
                        uhci_free_qh(uhci, uhci->skelqh[i]);
        }

        uhci_free_td(uhci, uhci->term_td);

err_alloc_term_td:
        dma_pool_destroy(uhci->qh_pool);

err_create_qh_pool:
        dma_pool_destroy(uhci->td_pool);

err_create_td_pool:
        kfree(uhci->frame_cpu);

err_alloc_frame_cpu:
        dma_free_coherent(uhci_dev(uhci),
                        UHCI_NUMFRAMES * sizeof(*uhci->frame),
                        uhci->frame, uhci->frame_dma_handle);

err_alloc_frame:
        debugfs_remove(uhci->dentry);

        return retval;
}

static void uhci_stop(struct usb_hcd *hcd)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);

        spin_lock_irq(&uhci->lock);
        if (HCD_HW_ACCESSIBLE(hcd) && !uhci->dead)
                uhci_hc_died(uhci);
        uhci_scan_schedule(uhci);
        spin_unlock_irq(&uhci->lock);
        synchronize_irq(hcd->irq);

        del_timer_sync(&uhci->fsbr_timer);
        release_uhci(uhci);
}

#ifdef CONFIG_PM
static int uhci_rh_suspend(struct usb_hcd *hcd)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        int rc = 0;

        spin_lock_irq(&uhci->lock);
        if (!HCD_HW_ACCESSIBLE(hcd))
                rc = -ESHUTDOWN;
        else if (uhci->dead)
                ;               /* Dead controllers tell no tales */

        /* Once the controller is stopped, port resumes that are already
         * in progress won't complete.  Hence if remote wakeup is enabled
         * for the root hub and any ports are in the middle of a resume or
         * remote wakeup, we must fail the suspend.
         */
        else if (hcd->self.root_hub->do_remote_wakeup &&
                        uhci->resuming_ports) {
                dev_dbg(uhci_dev(uhci), "suspend failed because a port "
                                "is resuming\n");
                rc = -EBUSY;
        } else
                suspend_rh(uhci, UHCI_RH_SUSPENDED);
        spin_unlock_irq(&uhci->lock);
        return rc;
}

static int uhci_rh_resume(struct usb_hcd *hcd)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        int rc = 0;

        spin_lock_irq(&uhci->lock);
        if (!HCD_HW_ACCESSIBLE(hcd))
                rc = -ESHUTDOWN;
        else if (!uhci->dead)
                wakeup_rh(uhci);
        spin_unlock_irq(&uhci->lock);
        return rc;
}

static int uhci_pci_suspend(struct usb_hcd *hcd, bool do_wakeup)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        struct pci_dev *pdev = to_pci_dev(uhci_dev(uhci));
        int rc = 0;

        dev_dbg(uhci_dev(uhci), "%s\n", __func__);

        spin_lock_irq(&uhci->lock);
        if (!HCD_HW_ACCESSIBLE(hcd) || uhci->dead)
                goto done_okay;         /* Already suspended or dead */

        if (uhci->rh_state > UHCI_RH_SUSPENDED) {
                dev_warn(uhci_dev(uhci), "Root hub isn't suspended!\n");
                rc = -EBUSY;
                goto done;
        };

        /* All PCI host controllers are required to disable IRQ generation
         * at the source, so we must turn off PIRQ.
         */
        pci_write_config_word(pdev, USBLEGSUP, 0);
        clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);

        /* Enable platform-specific non-PME# wakeup */
        if (do_wakeup) {
                if (pdev->vendor == PCI_VENDOR_ID_INTEL)
                        pci_write_config_byte(pdev, USBRES_INTEL,
                                        USBPORT1EN | USBPORT2EN);
        }

done_okay:
        clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
done:
        spin_unlock_irq(&uhci->lock);
        return rc;
}

static int uhci_pci_resume(struct usb_hcd *hcd, bool hibernated)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);

        dev_dbg(uhci_dev(uhci), "%s\n", __func__);

        /* Since we aren't in D3 any more, it's safe to set this flag
         * even if the controller was dead.
         */
        set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);

        spin_lock_irq(&uhci->lock);

        /* Make sure resume from hibernation re-enumerates everything */
        if (hibernated)
                uhci_hc_died(uhci);

        /* The firmware or a boot kernel may have changed the controller
         * settings during a system wakeup.  Check it and reconfigure
         * to avoid problems.
         */
        check_and_reset_hc(uhci);

        /* If the controller was dead before, it's back alive now */
        configure_hc(uhci);

        /* Tell the core if the controller had to be reset */
        if (uhci->rh_state == UHCI_RH_RESET)
                usb_root_hub_lost_power(hcd->self.root_hub);

        spin_unlock_irq(&uhci->lock);

        /* If interrupts don't work and remote wakeup is enabled then
         * the suspended root hub needs to be polled.
         */
        if (!uhci->RD_enable && hcd->self.root_hub->do_remote_wakeup)
                set_bit(HCD_FLAG_POLL_RH, &hcd->flags);

        /* Does the root hub have a port wakeup pending? */
        usb_hcd_poll_rh_status(hcd);
        return 0;
}
#endif

/* Wait until a particular device/endpoint's QH is idle, and free it */
static void uhci_hcd_endpoint_disable(struct usb_hcd *hcd,
                struct usb_host_endpoint *hep)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        struct uhci_qh *qh;

        spin_lock_irq(&uhci->lock);
        qh = (struct uhci_qh *) hep->hcpriv;
        if (qh == NULL)
                goto done;

        while (qh->state != QH_STATE_IDLE) {
                ++uhci->num_waiting;
                spin_unlock_irq(&uhci->lock);
                wait_event_interruptible(uhci->waitqh,
                                qh->state == QH_STATE_IDLE);
                spin_lock_irq(&uhci->lock);
                --uhci->num_waiting;
        }

        uhci_free_qh(uhci, qh);
done:
        spin_unlock_irq(&uhci->lock);
}

static int uhci_hcd_get_frame_number(struct usb_hcd *hcd)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        unsigned frame_number;
        unsigned delta;

        /* Minimize latency by avoiding the spinlock */
        frame_number = uhci->frame_number;
        barrier();
        delta = (inw(uhci->io_addr + USBFRNUM) - frame_number) &
                        (UHCI_NUMFRAMES - 1);
        return frame_number + delta;
}

static const char hcd_name[] = "uhci_hcd";

static const struct hc_driver uhci_driver = {
        .description =          hcd_name,
        .product_desc =         "UHCI Host Controller",
        .hcd_priv_size =        sizeof(struct uhci_hcd),

        /* Generic hardware linkage */
        .irq =                  uhci_irq,
        .flags =                HCD_USB11,

        /* Basic lifecycle operations */
        .reset =                uhci_init,
        .start =                uhci_start,
#ifdef CONFIG_PM
        .pci_suspend =          uhci_pci_suspend,
        .pci_resume =           uhci_pci_resume,
        .bus_suspend =          uhci_rh_suspend,
        .bus_resume =           uhci_rh_resume,
#endif
        .stop =                 uhci_stop,

        .urb_enqueue =          uhci_urb_enqueue,
        .urb_dequeue =          uhci_urb_dequeue,

        .endpoint_disable =     uhci_hcd_endpoint_disable,
        .get_frame_number =     uhci_hcd_get_frame_number,

        .hub_status_data =      uhci_hub_status_data,
        .hub_control =          uhci_hub_control,
};

static const struct pci_device_id uhci_pci_ids[] = { {
        /* handle any USB UHCI controller */
        PCI_DEVICE_CLASS(PCI_CLASS_SERIAL_USB_UHCI, ~0),
        .driver_data =  (unsigned long) &uhci_driver,
        }, { /* end: all zeroes */ }
};

MODULE_DEVICE_TABLE(pci, uhci_pci_ids);

static struct pci_driver uhci_pci_driver = {
        .name =         (char *)hcd_name,
        .id_table =     uhci_pci_ids,

        .probe =        usb_hcd_pci_probe,
        .remove =       usb_hcd_pci_remove,
        .shutdown =     uhci_shutdown,

#ifdef CONFIG_PM_SLEEP
        .driver =       {
                .pm =   &usb_hcd_pci_pm_ops
        },
#endif
};
 
static int __init uhci_hcd_init(void)
{
        int retval = -ENOMEM;

        if (usb_disabled())
                return -ENODEV;

        printk(KERN_INFO "uhci_hcd: " DRIVER_DESC "%s\n",
                        ignore_oc ? ", overcurrent ignored" : "");
        set_bit(USB_UHCI_LOADED, &usb_hcds_loaded);

        if (DEBUG_CONFIGURED) {
                errbuf = kmalloc(ERRBUF_LEN, GFP_KERNEL);
                if (!errbuf)
                        goto errbuf_failed;
                uhci_debugfs_root = debugfs_create_dir("uhci", usb_debug_root);
                if (!uhci_debugfs_root)
                        goto debug_failed;
        }

        uhci_up_cachep = kmem_cache_create("uhci_urb_priv",
                sizeof(struct urb_priv), 0, 0, NULL);
        if (!uhci_up_cachep)
                goto up_failed;

        retval = pci_register_driver(&uhci_pci_driver);
        if (retval)
                goto init_failed;

        return 0;

init_failed:
        kmem_cache_destroy(uhci_up_cachep);

up_failed:
        debugfs_remove(uhci_debugfs_root);

debug_failed:
        kfree(errbuf);

errbuf_failed:

        clear_bit(USB_UHCI_LOADED, &usb_hcds_loaded);
        return retval;
}

static void __exit uhci_hcd_cleanup(void) 
{
        pci_unregister_driver(&uhci_pci_driver);
        kmem_cache_destroy(uhci_up_cachep);
        debugfs_remove(uhci_debugfs_root);
        kfree(errbuf);
        clear_bit(USB_UHCI_LOADED, &usb_hcds_loaded);
}

module_init(uhci_hcd_init);
module_exit(uhci_hcd_cleanup);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");