Import 2.3.18pre1

[davej-history.git] / drivers / usb / uhci.c

/*
 * Universal Host Controller Interface driver for USB.
 *
 * (C) Copyright 1999 Linus Torvalds
 * (C) Copyright 1999 Johannes Erdfelt
 * (C) Copyright 1999 Randy Dunlap
 *
 * 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.
 *
 * Oh, well. The intel version is the more common by far. As such,
 * that's the one I care about right now.
 *
 * WARNING! The USB documentation is downright evil. Most of it
 * is just crap, written by a committee. You're better off ignoring
 * most of it, the important stuff is:
 *  - the low-level protocol (fairly simple but lots of small details)
 *  - working around the horridness of the rest
 */

/* 4/4/1999 added data toggle for interrupt pipes -keryan */
/* 5/16/1999 added global toggles for bulk and control */
/* 6/25/1999 added fix for data toggles on bidirectional bulk endpoints */ 
/*
 * 1999-09-02: Thomas Sailer <sailer@ife.ee.ethz.ch>
 *             Added explicit frame list manipulation routines
 *             for inserting/removing iso td's to/from the frame list.
 *             START_ABSOLUTE fixes
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/malloc.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/spinlock.h>

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

#include "uhci.h"

#ifdef CONFIG_APM
#include <linux/apm_bios.h>
static int handle_apm_event(apm_event_t event);
static int apm_resume = 0;
#endif

static int uhci_debug = 1;

#define compile_assert(x) do { switch (0) { case 1: case !(x): } } while (0)

static DECLARE_WAIT_QUEUE_HEAD(uhci_configure);

static kmem_cache_t *uhci_td_cachep;
static kmem_cache_t *uhci_qh_cachep;

static LIST_HEAD(uhci_list);

#define UHCI_DEBUG

/*
 * function prototypes
 */

static int uhci_get_current_frame_number (struct usb_device *usb_dev);

static int uhci_init_isoc (struct usb_device *usb_dev,
                                unsigned int pipe,
                                int frame_count,
                                void *context,
                                struct usb_isoc_desc **isocdesc);

static void uhci_free_isoc (struct usb_isoc_desc *isocdesc);

static int uhci_run_isoc (struct usb_isoc_desc *isocdesc,
                                struct usb_isoc_desc *pr_isocdesc);

static int uhci_kill_isoc (struct usb_isoc_desc *isocdesc);

/*
 * Map status to standard result codes
 *
 * <status> is (td->status & 0xFE0000) [a.k.a. uhci_status_bits(td->status)
 * <dir_out> is True for output TDs and False for input TDs.
 */
static int uhci_map_status(int status, int dir_out)
{
        if (!status)
                return USB_ST_NOERROR;
        if (status & TD_CTRL_BITSTUFF)                  /* Bitstuff error */
                return USB_ST_BITSTUFF;
        if (status & TD_CTRL_CRCTIMEO) {                /* CRC/Timeout */
                if (dir_out)
                        return USB_ST_NORESPONSE;
                else
                        return USB_ST_CRC;
        }
        if (status & TD_CTRL_NAK)                       /* NAK */
                return USB_ST_TIMEOUT;
        if (status & TD_CTRL_BABBLE)                    /* Babble */
                return USB_ST_STALL;
        if (status & TD_CTRL_DBUFERR)                   /* Buffer error */
                return USB_ST_BUFFERUNDERRUN;
        if (status & TD_CTRL_STALLED)                   /* Stalled */
                return USB_ST_STALL;
        if (status & TD_CTRL_ACTIVE)                    /* Active */
                return USB_ST_NOERROR;

        return USB_ST_INTERNALERROR;
}
/*
 * Return the result of a TD..
 */
static int uhci_td_result(struct uhci_device *dev, struct uhci_td *td, unsigned long *rval, int debug)
{
        unsigned int status;
        struct uhci_td *tmp;
        int count = 1000;

        if (rval)
                *rval = 0;

        /* Start at the TD first in the chain, if possible */
        if (td->qh && td->qh->first)
                tmp = td->qh->first;
        else
                tmp = td;

        if (!tmp)
                return USB_ST_INTERNALERROR;

        /* Locate the first failing td, if any */
        do {
                status = uhci_status_bits(tmp->status);

                if (status) {
                        if (debug) {
                                /* Must reset the toggle on first error */
                                if (uhci_debug) {
                                        printk(KERN_DEBUG "Set toggle from %x rval %ld\n",
                                                (unsigned int)tmp, rval ? *rval : 0);
                                }

                                usb_settoggle(dev->usb, uhci_endpoint(tmp->info),
                                        uhci_packetout(tmp->info) ^ 1,
                                        uhci_toggle(tmp->info));
                                break;
                        }
                } else {
                        if (rval && ((tmp->info & 0xFF) == USB_PID_IN))
                                *rval += uhci_actual_length(tmp->status);
                }

                if ((tmp->link & UHCI_PTR_TERM) ||
                    (tmp->link & UHCI_PTR_QH))
                        break;

                tmp = uhci_ptr_to_virt(tmp->link);
        } while (--count);

        if (!count) {
                printk(KERN_ERR "runaway td's in uhci_td_result!\n");
                /* Force debugging on */
                debug = 1;
        } else if (!status)
                return USB_ST_NOERROR;

        /* Some debugging code */
        if (debug && uhci_debug) {
                printk(KERN_DEBUG "uhci_td_result() failed with status %x\n",
                        status);

                /* Print the chain for debugging purposes */
                if (td->qh)
                        uhci_show_queue(td->qh);
                else
                        uhci_show_td(td);
        }

        if (status & TD_CTRL_STALLED) {
                /* endpoint has stalled - mark it halted */
                usb_endpoint_halt(dev->usb, uhci_endpoint(tmp->info),
                                uhci_packetout(tmp->info));
                return USB_ST_STALL;
        }

        if ((status == TD_CTRL_ACTIVE) && (!rval))
                return USB_ST_DATAUNDERRUN;

        return uhci_map_status(status, uhci_packetout(tmp->info));
}

/*
 * Inserts a td into qh list at the top.
 *
 * Careful about atomicity: even on UP this
 * requires a locked access due to the concurrent
 * DMA engine.
 *
 * NOTE! This assumes that first->last is a valid
 * list of TD's with the proper backpointers set
 * up and all..
 */
static void uhci_insert_tds_in_qh(struct uhci_qh *qh, struct uhci_td *first, struct uhci_td *last)
{
        unsigned int link = qh->element;
        unsigned int new = virt_to_bus(first) | UHCI_PTR_DEPTH;

        for (;;) {
                unsigned char success;

                last->link = link;
                first->backptr = &qh->element;
                asm volatile("lock ; cmpxchg %4,%2 ; sete %0"
                        :"=q" (success), "=a" (link)
                        :"m" (qh->element), "1" (link), "r" (new)
                        :"memory");

                if (success) {
                        /* Was there a successor entry? Fix it's backpointer */
                        if ((link & UHCI_PTR_TERM) == 0) {
                                struct uhci_td *next = uhci_ptr_to_virt(link);
                                next->backptr = &last->link;
                        }
                        break;
                }
        }

        qh->first = first;
        first->qh = qh;
        last->qh = qh;
}

static inline void uhci_insert_td_in_qh(struct uhci_qh *qh, struct uhci_td *td)
{
        uhci_insert_tds_in_qh(qh, td, td);
}

static void uhci_insert_qh(struct uhci_qh *qh, struct uhci_qh *newqh)
{
        newqh->link = qh->link;
        qh->link = virt_to_bus(newqh) | UHCI_PTR_QH;
}

static void uhci_remove_qh(struct uhci_qh *qh, struct uhci_qh *remqh)
{
        struct uhci_qh *lqh = qh;

        while (uhci_ptr_to_virt(lqh->link) != remqh) {
                if (lqh->link & UHCI_PTR_TERM)
                        break;

                lqh = uhci_ptr_to_virt(lqh->link);
        }

        if (lqh->link & UHCI_PTR_TERM) {
                printk(KERN_DEBUG "couldn't find qh in chain!\n");
                return;
        }

        lqh->link = remqh->link;
}

/*
 * Removes td from qh if present.
 *
 * NOTE! We keep track of both forward and back-pointers,
 * so this should be trivial, right?
 *
 * Wrong. While all TD insert/remove operations are synchronous
 * on the CPU, the UHCI controller can (and does) play with the
 * very first forward pointer. So we need to validate the backptr
 * before we change it, so that we don't by mistake reset the QH
 * head to something old.
 */
static void uhci_remove_td(struct uhci_td *td)
{
        unsigned int *backptr = td->backptr;
        unsigned int link = td->link;
        unsigned int me;

        if (!backptr)
                return;

        td->backptr = NULL;

        /*
         * This is the easy case: the UHCI will never change "td->link",
         * so we can always just look at that and fix up the backpointer
         * of any next element..
         */
        if (!(link & UHCI_PTR_TERM)) {
                struct uhci_td *next = uhci_ptr_to_virt(link);
                next->backptr = backptr;
        }

        /*
         * The nasty case is "backptr->next", which we need to
         * update to "link" _only_ if "backptr" still points
         * to us (it may not: maybe backptr is a QH->element
         * pointer and the UHCI has changed the value).
         */
        me = virt_to_bus(td) | (0xe & *backptr);
        asm volatile("lock ; cmpxchg %0,%1"
                :
                :"r" (link), "m" (*backptr), "a" (me)
                :"memory");

        /* Reset it just in case */
        td->link = UHCI_PTR_TERM;
}

/*
 * Only the USB core should call uhci_alloc_dev and uhci_free_dev
 */
static int uhci_alloc_dev(struct usb_device *usb_dev)
{
        struct uhci_device *dev;

        /* Allocate the UHCI device private data */
        dev = kmalloc(sizeof(*dev), GFP_KERNEL);
        if (!dev)
                return -1;

        /* Initialize "dev" */
        memset(dev, 0, sizeof(*dev));

        usb_dev->hcpriv = dev;
        dev->usb = usb_dev;
        atomic_set(&dev->refcnt, 1);

        if (usb_dev->parent)
                dev->uhci = usb_to_uhci(usb_dev->parent)->uhci;

        return 0;
}

static int uhci_free_dev(struct usb_device *usb_dev)
{
        struct uhci_device *dev = usb_to_uhci(usb_dev);

        if (atomic_dec_and_test(&dev->refcnt))
                kfree(dev);

        return 0;
}

static void uhci_inc_dev_use(struct uhci_device *dev)
{
        atomic_inc(&dev->refcnt);
}

static void uhci_dec_dev_use(struct uhci_device *dev)
{
        uhci_free_dev(dev->usb);
}

static struct uhci_td *uhci_td_alloc(struct uhci_device *dev)
{
        struct uhci_td *td;

        td = kmem_cache_alloc(uhci_td_cachep, SLAB_KERNEL);
        if (!td)
                return NULL;

#ifdef UHCI_DEBUG
        if ((__u32)td & UHCI_PTR_BITS)
                printk("qh not 16 byte aligned!\n");
#endif

        td->link = UHCI_PTR_TERM;
        td->buffer = 0;

        td->backptr = NULL;
        td->qh = NULL;
        td->dev_id = NULL;
        td->dev = dev;
        td->flags = 0;
        INIT_LIST_HEAD(&td->irq_list);
        atomic_set(&td->refcnt, 1);

        uhci_inc_dev_use(dev);

        return td;
}

static void uhci_td_free(struct uhci_td *td)
{
        if (atomic_dec_and_test(&td->refcnt)) {
                kmem_cache_free(uhci_td_cachep, td);

                if (td->dev)
                        uhci_dec_dev_use(td->dev);
        }
}

static struct uhci_qh *uhci_qh_alloc(struct uhci_device *dev)
{
        struct uhci_qh *qh;

        qh = kmem_cache_alloc(uhci_qh_cachep, SLAB_KERNEL);
        if (!qh)
                return NULL;

#ifdef UHCI_DEBUG
        if ((__u32)qh & UHCI_PTR_BITS)
                printk("qh not 16 byte aligned!\n");
#endif

        qh->element = UHCI_PTR_TERM;
        qh->link = UHCI_PTR_TERM;

        qh->dev = dev;
        qh->skel = NULL;
        qh->first = NULL;
        init_waitqueue_head(&qh->wakeup);
        atomic_set(&qh->refcnt, 1);

        uhci_inc_dev_use(dev);

        return qh;
}

static void uhci_qh_free(struct uhci_qh *qh)
{
        if (atomic_dec_and_test(&qh->refcnt)) {
                kmem_cache_free(uhci_qh_cachep, qh);

                if (qh->dev)
                        uhci_dec_dev_use(qh->dev);
        }
}

/*
 * UHCI interrupt list operations..
 */
static spinlock_t irqlist_lock = SPIN_LOCK_UNLOCKED;

static void uhci_add_irq_list(struct uhci *uhci, struct uhci_td *td, usb_device_irq completed, void *dev_id)
{
        unsigned long flags;

        td->completed = completed;
        td->dev_id = dev_id;

        spin_lock_irqsave(&irqlist_lock, flags);
        list_add(&td->irq_list, &uhci->interrupt_list);
        spin_unlock_irqrestore(&irqlist_lock, flags);
}

static void uhci_remove_irq_list(struct uhci_td *td)
{
        unsigned long flags;

        spin_lock_irqsave(&irqlist_lock, flags);
        list_del(&td->irq_list);
        spin_unlock_irqrestore(&irqlist_lock, flags);
}

/*
 * frame list manipulation. Used for Isochronous transfers.
 * the list of (iso) TD's enqueued in a frame list entry
 * is basically a doubly linked list with link being
 * the forward pointer and backptr the backward ptr.
 * the frame list entry itself doesn't have a back ptr
 * (therefore the list is not circular), and the forward pointer
 * stops at link entries having the UHCI_PTR_TERM or the UHCI_PTR_QH
 * bit set. Maybe it could be extended to handle the QH's also,
 * but it doesn't seem necessary right now.
 * The layout looks as follows:
 * frame list pointer -> iso td's (if any) -> 
 * periodic interrupt td (if framelist 0) -> irq qh -> control qh -> bulk qh
 */

static spinlock_t framelist_lock = SPIN_LOCK_UNLOCKED;

static void uhci_add_frame_list(struct uhci *uhci, struct uhci_td *td, unsigned framenum)
{
        unsigned long flags;
        struct uhci_td *nexttd;

        framenum %= UHCI_NUMFRAMES;
        spin_lock_irqsave(&framelist_lock, flags);
        td->backptr = &uhci->fl->frame[framenum];
        td->link = uhci->fl->frame[framenum];
        if (!(td->link & (UHCI_PTR_TERM | UHCI_PTR_QH))) {
                nexttd = (struct uhci_td *)bus_to_virt(td->link & ~15);
                nexttd->backptr = &td->link;
        }
        wmb();
        uhci->fl->frame[framenum] = virt_to_bus(td);
        spin_unlock_irqrestore(&framelist_lock, flags);
}

static void uhci_remove_frame_list(struct uhci *uhci, struct uhci_td *td)
{
        unsigned long flags;
        struct uhci_td *nexttd;

        if (!td->backptr)
                return;
        spin_lock_irqsave(&framelist_lock, flags);
        *(td->backptr) = td->link;
        if (!(td->link & (UHCI_PTR_TERM | UHCI_PTR_QH))) {
                nexttd = (struct uhci_td *)bus_to_virt(td->link & ~15);
                nexttd->backptr = td->backptr;
        }
        spin_unlock_irqrestore(&framelist_lock, flags);
        td->backptr = NULL;
        /*
         * attention: td->link might still be in use by the
         * hardware if the td is still active and the hardware
         * was processing it. So td->link should be preserved
         * until the frame number changes. Don't know what to do...
         * udelay(1000) doesn't sound nice, and schedule()
         * can't be used as this is called from within interrupt context.
         */
        /* for now warn if there's a possible problem */
        if (td->status & TD_CTRL_ACTIVE) {
                unsigned frn = inw(uhci->io_addr + USBFRNUM);
                __u32 link = uhci->fl->frame[frn % UHCI_NUMFRAMES];
                if (!(link & (UHCI_PTR_TERM | UHCI_PTR_QH))) {
                        struct uhci_td *tdl = (struct uhci_td *)bus_to_virt(link & ~15);
                        for (;;) {
                                if (tdl == td) {
                                        printk(KERN_WARNING "uhci_remove_frame_list: td possibly still in use!!\n");
                                        break;
                                }
                                if (tdl->link & (UHCI_PTR_TERM | UHCI_PTR_QH))
                                        break;
                                tdl = (struct uhci_td *)bus_to_virt(tdl->link & ~15);
                        }
                }       
        }
}


/*
 * This function removes and disallocates all structures set up for a transfer.
 * It takes the qh out of the skeleton, removes the tq and the td's.
 * It only removes the associated interrupt handler if removeirq is set.
 * The *td argument is any td in the list of td's.
 */
static void uhci_remove_transfer(struct uhci_td *td, char removeirq)
{
        int maxcount = 1000;
        struct uhci_td *curtd;
        unsigned int nextlink;

        if (td->qh && td->qh->first)
                curtd = td->qh->first;
        else
                curtd = td;

        /* Remove it from the skeleton */
        uhci_remove_qh(td->qh->skel, td->qh);
        uhci_qh_free(td->qh);
        do {
                nextlink = curtd->link;

                /* IOC? => remove handler */
                if (removeirq && (td->status & TD_CTRL_IOC))
                        uhci_remove_irq_list(td);

                uhci_remove_td(curtd);
                uhci_td_free(curtd);
                if (nextlink & UHCI_PTR_TERM)   /* Tail? */
                        break;

                curtd = bus_to_virt(nextlink & ~UHCI_PTR_BITS);
                if (!--maxcount) {
                        printk(KERN_ERR "runaway td's!?\n");
                        break;
                }
        } while (1);
}

/*
 * Request a interrupt handler..
 *
 * Returns: a "handle pointer" that release_irq can use to stop this
 * interrupt.  (It's really a pointer to the TD).
 */
static void *uhci_request_irq(struct usb_device *usb_dev, unsigned int pipe, usb_device_irq handler, int period, void *dev_id)
{
        struct uhci_device *dev = usb_to_uhci(usb_dev);
        struct uhci_td *td = uhci_td_alloc(dev);
        struct uhci_qh *qh = uhci_qh_alloc(dev);
        unsigned int destination, status;

        if (!td || !qh)
                return NULL;

        /* Destination: pipe destination with INPUT */
        destination = (pipe & PIPE_DEVEP_MASK) | usb_packetid(pipe);

        /* Infinite errors is 0, so no bits */
        status = (pipe & TD_CTRL_LS) | TD_CTRL_IOC | TD_CTRL_ACTIVE |
                        TD_CTRL_SPD;

        td->link = UHCI_PTR_TERM;               /* Terminate */
        td->status = status;                    /* In */
        td->info = destination | ((usb_maxpacket(usb_dev, pipe, usb_pipeout(pipe)) - 1) << 21) |
                (usb_gettoggle(usb_dev, usb_pipeendpoint(pipe), usb_pipeout(pipe)) << TD_TOKEN_TOGGLE);

        td->buffer = virt_to_bus(dev->data);
        td->qh = qh;
        td->dev = dev;

        /* if period 0, insert into fast q */
        if (period == 0) {
                td->flags |= UHCI_TD_REMOVE;
                qh->skel = &dev->uhci->skel_int2_qh;
        } else
                qh->skel = &dev->uhci->skel_int8_qh;

        uhci_add_irq_list(dev->uhci, td, handler, dev_id);

        uhci_insert_td_in_qh(qh, td);

        /* Add it into the skeleton */
        uhci_insert_qh(qh->skel, qh);

        return (void *)td;
}

/*
 * Release an interrupt handler previously allocated using
 * uhci_request_irq.  This function does no validity checking, so make
 * sure you're not releasing an already released handle as it may be
 * in use by something else..
 *
 * This function can NOT be called from an interrupt.
 */
int uhci_release_irq(struct usb_device *usb, void *handle)
{
        struct uhci_td *td;
        struct uhci_qh *qh;

        td = (struct uhci_td *)handle;
        if (!td)
                return USB_ST_INTERNALERROR;

        /* Remove it from the internal irq_list */
        uhci_remove_irq_list(td);

        /* Remove the interrupt TD and QH */
        uhci_remove_td(td);
        qh = td->qh;
        uhci_remove_qh(qh->skel, qh);

        if (td->completed != NULL)
                td->completed(USB_ST_REMOVED, NULL, 0, td->dev_id);

        /* Free the TD and QH */
        uhci_td_free(td);
        uhci_qh_free(qh);

        return USB_ST_NOERROR;
} /* uhci_release_irq() */

/*
 * uhci_get_current_frame_number()
 *
 * returns the current frame number for a USB bus/controller.
 */
static int uhci_get_current_frame_number(struct usb_device *usb_dev)
{
       return inw (usb_to_uhci(usb_dev)->uhci->io_addr + USBFRNUM);
}


/*
 * uhci_init_isoc()
 *
 * Checks bus bandwidth allocation for this USB bus.
 * Allocates some data structures.
 * Initializes parts of them from the function parameters.
 *
 * It does not associate any data/buffer pointers or
 * driver (caller) callback functions with the allocated
 * data structures.  Such associations are left until
 * uhci_run_isoc().
 *
 * Returns 0 for success or negative value for error.
 * Sets isocdesc before successful return.
 */
static int uhci_init_isoc (struct usb_device *usb_dev,
                                unsigned int pipe,
                                int frame_count,        /* bandwidth % = 100 * this / 1000 */
                                void *context,
                                struct usb_isoc_desc **isocdesc)
{
        struct usb_isoc_desc *id;
        int i;

#ifdef BANDWIDTH_ALLOCATION
        /* TBD: add bandwidth allocation/checking/management HERE. */
        /* TBD: some way to factor in frame_spacing ??? */
#endif

        *isocdesc = NULL;

        /* Check some parameters. */
        if ((frame_count <= 0) || (frame_count > UHCI_NUMFRAMES)) {
#ifdef CONFIG_USB_DEBUG_ISOC
                printk (KERN_DEBUG "uhci_init_isoc: invalid frame_count (%d)\n",
                        frame_count);
#endif
                return -EINVAL;
        }

        if (!usb_pipeisoc (pipe)) {
#ifdef CONFIG_USB_DEBUG_ISOC
                printk (KERN_DEBUG "uhci_init_isoc: NOT an Isoc. pipe\n");
#endif
                return -EINVAL;
        }

        id = kmalloc (sizeof (*id) +
                (sizeof (struct isoc_frame_desc) * frame_count), GFP_KERNEL);
        if (!id)
                return -ENOMEM;

        memset (id, 0, sizeof (*id) +
                (sizeof (struct isoc_frame_desc) * frame_count));

        id->td = kmalloc (sizeof (struct uhci_td) * frame_count, GFP_KERNEL);
        if (!id->td) {
                kfree (id);
                return -ENOMEM;
        }

        memset (id->td, 0, sizeof (struct uhci_td) * frame_count);

        for (i = 0; i < frame_count; i++)
                INIT_LIST_HEAD(&((struct uhci_td *)(id->td))[i].irq_list);

        id->frame_count = frame_count;
        id->frame_size  = usb_maxpacket (usb_dev, pipe, usb_pipeout(pipe));
                /* TBD: or make this a parameter to allow for frame_size
                that is less than maxpacketsize */
        id->start_frame = -1;
        id->end_frame   = -1;
        id->usb_dev     = usb_dev;
        id->pipe        = pipe;
        id->context     = context;

        *isocdesc = id;
        return 0;
} /* end uhci_init_isoc */

/*
 * uhci_run_isoc()
 *
 * Associates data/buffer pointers/lengths and
 * driver (caller) callback functions with the
 * allocated Isoc. data structures and TDs.
 *
 * Then inserts the TDs into the USB controller frame list
 * for its processing.
 * And inserts the callback function into its TD.
 *
 * pr_isocdesc (previous Isoc. desc.) may be NULL.
 * It is used only for chaining one list of TDs onto the
 * end of the previous list of TDs.
 *
 * Returns 0 (success) or error code (negative value).
 */
static int uhci_run_isoc (struct usb_isoc_desc *isocdesc,
                                struct usb_isoc_desc *pr_isocdesc)
{
        struct uhci_device *dev = usb_to_uhci (isocdesc->usb_dev);
        struct uhci *uhci = dev->uhci;
        unsigned long   destination, status;
        struct uhci_td  *td;
        int             ix, cur_frame, pipeinput, frlen;
        int             cb_frames = 0;
        struct isoc_frame_desc *fd;
        unsigned char   *bufptr;

        if (!isocdesc->callback_fn) {
#ifdef CONFIG_USB_DEBUG_ISOC
                printk (KERN_DEBUG "uhci_run_isoc: caller must have a callback function\n");
#endif
                return -EINVAL;
        }

        /* Check buffer size large enough for maxpacketsize * frame_count. */
        if (isocdesc->buf_size < (isocdesc->frame_count * isocdesc->frame_size)) {
#ifdef CONFIG_USB_DEBUG_ISOC
                printk (KERN_DEBUG "uhci_init_isoc: buf_size too small (%d < %d)\n",
                        isocdesc->buf_size, isocdesc->frame_count * isocdesc->frame_size);
#endif
                return -EINVAL;
        }

        /* Check buffer ptr for Null. */
        if (!isocdesc->data) {
#ifdef CONFIG_USB_DEBUG_ISOC
                printk (KERN_DEBUG "uhci_init_isoc: data ptr is null\n");
#endif
                return -EINVAL;
        }

#ifdef NEED_ALIGNMENT
        /* Check data page alignment. */
        if (((int)(isocdesc->data) & (PAGE_SIZE - 1)) != 0) {
#ifdef CONFIG_USB_DEBUG_ISOC
                printk (KERN_DEBUG "uhci_init_isoc: buffer must be page-aligned (%p)\n",
                        isocdesc->data);
#endif
                return -EINVAL;
        }
#endif /* NEED_ALIGNMENT */

        /*
         * Check start_type unless pr_isocdesc is used.
         */
        if (!pr_isocdesc && (isocdesc->start_type > START_TYPE_MAX)) {
#ifdef CONFIG_USB_DEBUG_ISOC
                printk (KERN_DEBUG "uhci_run_isoc: invalid start_type (%d)\n",
                        isocdesc->start_type);
#endif
                return -EINVAL;
        }

        /*
         * Check start_frame for inside a valid range.
         * Only allow transfer requests to be made 1.000 second
         * into the future.
         */
        cur_frame = uhci_get_current_frame_number (isocdesc->usb_dev);

        /* if not START_ASAP (i.e., RELATIVE or ABSOLUTE): */
        if (!pr_isocdesc) {
                if (isocdesc->start_type == START_RELATIVE) {
                        if ((isocdesc->start_frame < 0) || (isocdesc->start_frame > CAN_SCHEDULE_FRAMES)) {
#ifdef CONFIG_USB_DEBUG_ISOC
                                printk (KERN_DEBUG "uhci_init_isoc: bad start_frame value (%d)\n",
                                        isocdesc->start_frame);
#endif
                                return -EINVAL;
                        }
                } /* end START_RELATIVE */
                else
                if (isocdesc->start_type == START_ABSOLUTE) { /* within the scope of cur_frame */
                        ix = USB_WRAP_FRAMENR(isocdesc->start_frame - cur_frame);
                        if (ix < START_FRAME_FUDGE || /* too small */
                            ix > CAN_SCHEDULE_FRAMES) { /* too large */
#ifdef CONFIG_USB_DEBUG_ISOC
                                        printk (KERN_DEBUG "uhci_init_isoc: bad start_frame value (%d,%d)\n",
                                                isocdesc->start_frame, cur_frame);
#endif
                                        return -EINVAL;
                        }
                } /* end START_ABSOLUTE */
        }

        /*
         * Set the start/end frame numbers.
         */
        if (pr_isocdesc) {
                isocdesc->start_frame = pr_isocdesc->end_frame + 1;
        } else if (isocdesc->start_type == START_RELATIVE) {
                if (isocdesc->start_frame < START_FRAME_FUDGE)
                        isocdesc->start_frame = START_FRAME_FUDGE;
                isocdesc->start_frame += cur_frame;
        } else if (isocdesc->start_type == START_ASAP) {
                isocdesc->start_frame = cur_frame + START_FRAME_FUDGE;
        }

        /* and see if start_frame needs any correction */
        /* only wrap to USB frame numbers, the frame_list insertion routine
           takes care of the wrapping to the frame_list size */
        isocdesc->start_frame = USB_WRAP_FRAMENR(isocdesc->start_frame);

        /* and fix the end_frame value */
        isocdesc->end_frame = USB_WRAP_FRAMENR(isocdesc->start_frame + isocdesc->frame_count - 1);

        isocdesc->prev_completed_frame = -1;
        isocdesc->cur_completed_frame  = -1;

        destination = (isocdesc->pipe & PIPE_DEVEP_MASK) |
                usb_packetid (isocdesc->pipe);
        status = TD_CTRL_ACTIVE | TD_CTRL_IOS;  /* mark Isoc.; can't be low speed */
        pipeinput = usb_pipein (isocdesc->pipe);
        cur_frame = isocdesc->start_frame;
        bufptr = isocdesc->data;

        /*
         * Build the Data TDs.
         * TBD: Not using frame_spacing (Yet).  Defaults to 1 (every frame).
         * (frame_spacing is a way to request less bandwidth.)
         * This can also be done by using frame_length = 0 in the
         * frame_desc array, but this way won't take less bandwidth
         * allocation into account.
         */

        if (isocdesc->frame_spacing <= 0)
                isocdesc->frame_spacing = 1;

        for (ix = 0, td = isocdesc->td, fd = isocdesc->frames;
             ix < isocdesc->frame_count; ix++, td++, fd++) {
                frlen = fd->frame_length;
                if (frlen > isocdesc->frame_size)
                        frlen = isocdesc->frame_size;

#ifdef NOTDEF
                td->info = destination |  /* use Actual len on OUT; max. on IN */
                        (pipeinput ? ((isocdesc->frame_size - 1) << 21)
                        : ((frlen - 1) << 21));
#endif

                td->dev_id = isocdesc;  /* can get dev_id or context from isocdesc */
                td->status = status;
                td->info   = destination | ((frlen - 1) << 21);
                td->buffer = virt_to_bus (bufptr);
                td->dev    = dev;
                td->isoc_td_number = ix;        /* 0-based; does not wrap/overflow back to 0 */

                if (isocdesc->callback_frames &&
                    (++cb_frames >= isocdesc->callback_frames)) {
                        td->status |= TD_CTRL_IOC;
                        td->completed = isocdesc->callback_fn;
                        cb_frames = 0;
                        uhci_add_irq_list (dev->uhci, td, isocdesc->callback_fn, isocdesc->context);
                }

                bufptr += fd->frame_length;  /* or isocdesc->frame_size; */

                /*
                 * Insert the TD in the frame list.
                 */
                uhci_add_frame_list(uhci, td, cur_frame);

                cur_frame = USB_WRAP_FRAMENR(cur_frame+1);
        } /* end for ix */

        /*
         * Add IOC on the last TD.
         */
        td--;
        if (!(td->status & TD_CTRL_IOC)) {
                td->status |= TD_CTRL_IOC;
                td->completed = isocdesc->callback_fn;
                uhci_add_irq_list(dev->uhci, td, isocdesc->callback_fn, isocdesc->context); /* TBD: D.K. ??? */
        }
        return 0;
} /* end uhci_run_isoc */

/*
 * uhci_kill_isoc()
 *
 * Marks a TD list as Inactive and removes it from the Isoc.
 * TD frame list.
 *
 * Does not free any memory resources.
 *
 * Returns 0 for success or negative value for error.
 */
static int uhci_kill_isoc (struct usb_isoc_desc *isocdesc)
{
        struct uhci_device *dev = usb_to_uhci (isocdesc->usb_dev);
        struct uhci     *uhci = dev->uhci;
        struct uhci_td  *td;
        int             ix;

        if (USB_WRAP_FRAMENR(isocdesc->start_frame) != isocdesc->start_frame) {
#ifdef CONFIG_USB_DEBUG_ISOC
                printk (KERN_DEBUG "uhci_kill_isoc: invalid start_frame (%d)\n",
                        isocdesc->start_frame);
#endif
                return -EINVAL;
        }

        for (ix = 0, td = isocdesc->td; ix < isocdesc->frame_count; ix++, td++) {
                uhci_remove_frame_list(uhci, td);
                td->status &= ~(TD_CTRL_ACTIVE | TD_CTRL_IOC);
        } /* end for ix */

        isocdesc->start_frame = -1;
        return 0;
} /* end uhci_kill_isoc */

static void uhci_free_isoc (struct usb_isoc_desc *isocdesc)
{
        int i;

        /* If still Active, kill it. */
        if (isocdesc->start_frame >= 0)
                uhci_kill_isoc(isocdesc);

        /* Remove all td's from the IRQ list. */
        for(i = 0; i < isocdesc->frame_count; i++)
                uhci_remove_irq_list(((struct uhci_td *)(isocdesc->td))+i);

        /* Free the associate memory. */
        if (isocdesc->td)
                kfree(isocdesc->td);

        kfree(isocdesc);
} /* end uhci_free_isoc */

/*
 * Control thread operations: we just mark the last TD
 * in a control thread as an interrupt TD, and wake up
 * the front-end on completion.
 *
 * We need to remove the TD from the lists (both interrupt
 * list and TD lists) by hand if something bad happens!
 */

static int uhci_generic_completed(int status, void *buffer, int len, void *dev_id)
{
        wait_queue_head_t *wakeup = (wait_queue_head_t *)dev_id;

        if (waitqueue_active(wakeup))
                wake_up(wakeup);
        else
                printk("waitqueue empty!\n");

        return 0;                       /* Don't re-instate */
}

/* td points to the last td in the list, which interrupts on completion */
static int uhci_run_control(struct uhci_device *dev, struct uhci_td *first, struct uhci_td *last)
{
        DECLARE_WAITQUEUE(wait, current);
        struct uhci_qh *qh = uhci_qh_alloc(dev);

        if (!qh)
                return -1;

        current->state = TASK_UNINTERRUPTIBLE;
        add_wait_queue(&qh->wakeup, &wait);

        uhci_add_irq_list(dev->uhci, last, uhci_generic_completed, &qh->wakeup);
        
        uhci_insert_tds_in_qh(qh, first, last);

        /* Add it into the skeleton */
        uhci_insert_qh(&dev->uhci->skel_control_qh, qh);

        schedule_timeout(HZ * 5);       /* 5 seconds */

        remove_wait_queue(&qh->wakeup, &wait);

        /* Clean up in case it failed.. */
        uhci_remove_irq_list(last);

        /* Remove it from the skeleton */
        uhci_remove_qh(&dev->uhci->skel_control_qh, qh);

        uhci_qh_free(qh);

        return uhci_td_result(dev, last, NULL, 1);
}

/*
 * Send or receive a control message on a pipe.
 *
 * Note that the "pipe" structure is set up to map
 * easily to the uhci destination fields.
 *
 * A control message is built up from three parts:
 *  - The command itself
 *  - [ optional ] data phase
 *  - Status complete phase
 *
 * The data phase can be an arbitrary number of TD's
 * although we currently had better not have more than
 * 29 TD's here (we have 31 TD's allocated for control
 * operations, and two of them are used for command and
 * status).
 *
 * 29 TD's is a minimum of 232 bytes worth of control
 * information, that's just ridiculously high. Most
 * control messages have just a few bytes of data.
 *
 * 232 is not ridiculously high with many of the
 * configurations on audio devices, etc. anyway,
 * there is no restriction on length of transfers
 * anymore
 */
static int uhci_control_msg(struct usb_device *usb_dev, unsigned int pipe, devrequest *cmd, void *data, int len)
{
        struct uhci_device *dev = usb_to_uhci(usb_dev);
        struct uhci_td *first, *td, *prevtd;
        unsigned long destination, status;
        int ret, count;
        int maxsze = usb_maxpacket(usb_dev, pipe, usb_pipeout(pipe));
        __u32 nextlink;
        unsigned long bytesrequested = len;
        unsigned long bytesread = 0;

        first = td = uhci_td_alloc(dev);
        if (!td)
                return -ENOMEM;

        /* The "pipe" thing contains the destination in bits 8--18 */
        destination = (pipe & PIPE_DEVEP_MASK) | USB_PID_SETUP;

        /* 3 errors */
        status = (pipe & TD_CTRL_LS) | TD_CTRL_ACTIVE | TD_CTRL_SPD | (3 << 27);

        /*
         * Build the TD for the control request
         */
        td->status = status;                            /* Try forever */
        td->info = destination | (7 << 21);             /* 8 bytes of data */
        td->buffer = virt_to_bus(cmd);

        /*
         * If direction is "send", change the frame from SETUP (0x2D)
         * to OUT (0xE1). Else change it from SETUP to IN (0x69).
         */
        destination ^= (USB_PID_SETUP ^ USB_PID_IN);            /* SETUP -> IN */
        if (usb_pipeout(pipe))
                destination ^= (USB_PID_IN ^ USB_PID_OUT);      /* IN -> OUT */

        prevtd = td;
        td = uhci_td_alloc(dev);
        if (!td)
                return -ENOMEM;

        prevtd->link = virt_to_bus(td) | UHCI_PTR_DEPTH;

        /*
         * Build the DATA TD's
         */
        while (len > 0) {
                /* Build the TD for control status */
                int pktsze = len;

                if (pktsze > maxsze)
                        pktsze = maxsze;

                /* Alternate Data0/1 (start with Data1) */
                destination ^= 1 << TD_TOKEN_TOGGLE;
        
                td->status = status;                                    /* Status */
                td->info = destination | ((pktsze - 1) << 21);          /* pktsze bytes of data */
                td->buffer = virt_to_bus(data);
                td->backptr = &prevtd->link;

                data += pktsze;
                len -= pktsze;

                prevtd = td;
                td = uhci_td_alloc(dev);
                if (!td)
                        return -ENOMEM;
                prevtd->link = virt_to_bus(td) | UHCI_PTR_DEPTH;        /* Update previous TD */
        }

        /*
         * Build the final TD for control status 
         */
        /* It's only IN if the pipe is out AND we aren't expecting data */
        destination &= ~0xFF;
        if (usb_pipeout(pipe) | (bytesrequested == 0))
                destination |= USB_PID_IN;
        else
                destination |= USB_PID_OUT;

        destination |= 1 << TD_TOKEN_TOGGLE;            /* End in Data1 */

        td->status = status | TD_CTRL_IOC;                      /* no limit on errors on final packet */
        td->info = destination | (UHCI_NULL_DATA_SIZE << 21);   /* 0 bytes of data */
        td->buffer = 0;
        td->backptr = &prevtd->link;
        td->link = UHCI_PTR_TERM;                       /* Terminate */

        /* Start it up.. */
        ret = uhci_run_control(dev, first, td);

        count = 1000;
        td = first;
        do {
                if (!uhci_status_bits(td->status) && ((td->info & 0xFF) ==
                    USB_PID_IN))
                        bytesread += uhci_actual_length(td->status);

                nextlink = td->link;
                uhci_remove_td(td);
                uhci_td_free(td);

                if (nextlink & UHCI_PTR_TERM)   /* Tail? */
                        break;

                td = uhci_ptr_to_virt(nextlink);
        } while (--count);

        if (!count)
                printk(KERN_ERR "runaway td's!?\n");

        if (ret && (bytesread >= bytesrequested)) {
                printk(KERN_DEBUG "Recovered sufficient data (asked for %ld, got %ld) from failed cmd\n",
                        bytesrequested, bytesread);
                ret = 0;
        }

        if (uhci_debug && ret) {
                __u8 *p = (__u8 *)cmd;

                printk(KERN_DEBUG "Failed cmd - %02X %02X %02X %02X %02X %02X %02X %02X\n",
                       p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
        }
        return ret;
}

/*
 * Bulk thread operations: we just mark the last TD
 * in a bulk thread as an interrupt TD, and wake up
 * the front-end on completion.
 *
 * We need to remove the TD from the lists (both interrupt
 * list and TD lists) by hand if something bad happens!
 */

/* td points to the last td in the list, which interrupts on completion */
static int uhci_run_bulk(struct uhci_device *dev, struct uhci_td *first, struct uhci_td *last, unsigned long *rval)
{
        DECLARE_WAITQUEUE(wait, current);
        struct uhci_qh *qh = uhci_qh_alloc(dev);

        if (!qh)
                return -ENOMEM;

        current->state = TASK_UNINTERRUPTIBLE;
        add_wait_queue(&qh->wakeup, &wait);

        uhci_add_irq_list(dev->uhci, last, uhci_generic_completed, &qh->wakeup);
        
        uhci_insert_tds_in_qh(qh, first, last);

        /* Add it into the skeleton */
        uhci_insert_qh(&dev->uhci->skel_bulk_qh, qh);

        schedule_timeout(HZ * 5);       /* 5 seconds */

        remove_wait_queue(&qh->wakeup, &wait);

        /* Clean up in case it failed.. */
        uhci_remove_irq_list(last);

        uhci_remove_qh(&dev->uhci->skel_bulk_qh, qh);

        uhci_qh_free(qh);

        return uhci_td_result(dev, last, rval, 1);
}

/*
 * Send or receive a bulk message on a pipe.
 *
 * Note that the "pipe" structure is set up to map
 * easily to the uhci destination fields.
 *
 * A bulk message is only built up from
 * the data phase
 */
static int uhci_bulk_msg(struct usb_device *usb_dev, unsigned int pipe, void *data, int len, unsigned long *rval)
{
        struct uhci_device *dev = usb_to_uhci(usb_dev);
        struct uhci_td *first, *td, *prevtd;
        unsigned long destination, status;
        int ret;
        int maxsze = usb_maxpacket(usb_dev, pipe, usb_pipeout(pipe));

        if (usb_endpoint_halted(usb_dev, usb_pipeendpoint(pipe), usb_pipeout(pipe)) &&
            usb_clear_halt(usb_dev, usb_pipeendpoint(pipe) | (pipe & USB_DIR_IN)))
                return USB_ST_STALL;

        /* The "pipe" thing contains the destination in bits 8--18. */
        destination = (pipe & PIPE_DEVEP_MASK) | usb_packetid (pipe);

        /* 3 errors */
        status = (pipe & TD_CTRL_LS) | TD_CTRL_ACTIVE | TD_CTRL_SPD | (3 << 27);

        /*
         * Build the TDs for the bulk request
         */
        first = td = uhci_td_alloc(dev);
        if (!td)
                return -ENOMEM;

        prevtd = first; //This is fake, but at least it's not NULL
        while (len > 0) {
                /* Build the TD for control status */
                int pktsze = len;

                if (pktsze > maxsze)
                        pktsze = maxsze;

                td->status = status;                                    /* Status */
                td->info = destination | ((pktsze-1) << 21) |
                        (usb_gettoggle(usb_dev, usb_pipeendpoint(pipe),
                                usb_pipeout(pipe)) << TD_TOKEN_TOGGLE); /* pktsze bytes of data */
                td->buffer = virt_to_bus(data);
                td->backptr = &prevtd->link;

                data += maxsze;
                len -= maxsze;

                if (len > 0) {
                        prevtd = td;
                        td = uhci_td_alloc(dev);
                        if (!td)
                                return -ENOMEM;

                        prevtd->link = virt_to_bus(td) | UHCI_PTR_DEPTH;/* Update previous TD */
                }

                /* Alternate Data0/1 (start with Data0) */
                usb_dotoggle(usb_dev, usb_pipeendpoint(pipe), usb_pipeout(pipe));
        }

        td->link = 1;                           /* Terminate */
        td->status |= TD_CTRL_IOC;

        /* CHANGE DIRECTION HERE! SAVE IT SOMEWHERE IN THE ENDPOINT!!! */

        /* Start it up.. */
        ret = uhci_run_bulk(dev, first, td, rval);

        {
                int count = 100;
                struct uhci_td *curtd = first;
                unsigned int nextlink;

                do {
                        nextlink = curtd->link;
                        uhci_remove_td(curtd);
                        uhci_td_free(curtd);

                        if (nextlink & UHCI_PTR_TERM)   /* Tail? */
                                break;

                        curtd = uhci_ptr_to_virt(nextlink);
                } while (--count);

                if (!count)
                        printk(KERN_DEBUG "runaway td's!?\n");
        }

        return ret;
}

static void * uhci_request_bulk(struct usb_device *usb_dev, unsigned int pipe, usb_device_irq handler, void *data, int len, void *dev_id)
{
        struct uhci_device *dev = usb_to_uhci(usb_dev);
        struct uhci *uhci = dev->uhci;
        struct uhci_td *first, *td, *prevtd;
        struct uhci_qh *bulk_qh = uhci_qh_alloc(dev);
        unsigned long destination, status;
        int maxsze = usb_maxpacket(usb_dev, pipe, usb_pipeout(pipe));

        /* The "pipe" thing contains the destination in bits 8--18. */
        destination = (pipe & PIPE_DEVEP_MASK) | usb_packetid(pipe);

        /* Infinite errors is 0 */
        status = (pipe & TD_CTRL_LS) | TD_CTRL_ACTIVE | TD_CTRL_SPD;

        /* Build the TDs for the bulk request */
        first = td = uhci_td_alloc(dev);
        prevtd = td;
        while (len > 0) {
                /* Build the TD for control status */
                int pktsze = len;

                if (pktsze > maxsze)
                        pktsze = maxsze;

                td->status = status;                                    /* Status */
                td->info = destination | ((pktsze-1) << 21) |
                        (usb_gettoggle(usb_dev, usb_pipeendpoint(pipe), usb_pipeout(pipe)) << TD_TOKEN_TOGGLE); /* pktsze bytes of data */
                td->buffer = virt_to_bus(data);
                td->backptr = &prevtd->link;
                td->qh = bulk_qh;
                td->dev = dev;
                data += pktsze;
                len -= pktsze;

                if (len > 0) {
                        prevtd = td;
                        td = uhci_td_alloc(dev);
                        prevtd->link = virt_to_bus(td) | UHCI_PTR_DEPTH;
                }

                /* Alternate Data0/1 */
                usb_dotoggle(usb_dev, usb_pipeendpoint(pipe), usb_pipeout(pipe));
        }

        first->backptr = NULL;
        td->link = 1;                           /* Terminate */
        td->status = status | TD_CTRL_IOC;      /* IOC */

        uhci_add_irq_list(dev->uhci, td, handler, dev_id);

        uhci_insert_tds_in_qh(bulk_qh, first, td);

        bulk_qh->skel = &uhci->skel_bulk_qh;
        uhci_insert_qh(&uhci->skel_bulk_qh, bulk_qh);

        /* Return last td for removal */
        return td;
}

/*
 * Remove a handler from a pipe. This terminates the transfer.
 * We have some assumptions here:
 * There is only one queue using this pipe. (the one we remove)
 * Any data that is in the queue is useless for us, we throw it away.
 */
static int uhci_terminate_bulk(struct usb_device *dev, void *first)
{
        /* none found? there is nothing to remove! */
        if (!first)
                return 0;

        uhci_remove_transfer(first, 1);

        return 1;
}

struct usb_operations uhci_device_operations = {
        uhci_alloc_dev,
        uhci_free_dev,
        uhci_control_msg,
        uhci_bulk_msg,
        uhci_request_irq,
        uhci_release_irq,
        uhci_request_bulk,
        uhci_terminate_bulk,
        uhci_get_current_frame_number,
        uhci_init_isoc,
        uhci_free_isoc,
        uhci_run_isoc,
        uhci_kill_isoc
};

/*
 * This is just incredibly fragile. The timings must be just
 * right, and they aren't really documented very well.
 *
 * Note the short delay between disabling reset and enabling
 * the port..
 */
static void uhci_reset_port(unsigned int port)
{
        unsigned short status;

        status = inw(port);
        outw(status | USBPORTSC_PR, port);              /* reset port */
        wait_ms(10);
        outw(status & ~USBPORTSC_PR, port);
        udelay(5);

        status = inw(port);
        outw(status | USBPORTSC_PE, port);              /* enable port */
        wait_ms(10);

        status = inw(port);
        if (!(status & USBPORTSC_PE)) {
                outw(status | USBPORTSC_PE, port);      /* one more try at enabling port */
                wait_ms(50);
        }

}

/*
 * This gets called if the connect status on the root
 * hub (and the root hub only) changes.
 */
static void uhci_connect_change(struct uhci *uhci, unsigned int port, unsigned int nr)
{
        struct usb_device *usb_dev;
        struct uhci_device *dev;
        unsigned short status;
        struct uhci_device *root_hub = usb_to_uhci(uhci->bus->root_hub);

#ifdef UHCI_DEBUG
        printk(KERN_INFO "uhci_connect_change: called for %d\n", nr);
#endif

        /*
         * Even if the status says we're connected,
         * the fact that the status bits changed may
         * that we got disconnected and then reconnected.
         *
         * So start off by getting rid of any old devices..
         */
        usb_disconnect(&root_hub->usb->children[nr]);

        status = inw(port);

        /* If we have nothing connected, then clear change status and disable the port */
        status = (status & ~USBPORTSC_PE) | USBPORTSC_PEC;
        if (!(status & USBPORTSC_CCS)) {
                outw(status, port);
                return;
        }

        /*
         * Ok, we got a new connection. Allocate a device to it,
         * and find out what it wants to do..
         */
        usb_dev = usb_alloc_dev(root_hub->usb, root_hub->usb->bus);
        if (!usb_dev)
                return;
        
        dev = usb_dev->hcpriv;

        usb_connect(usb_dev);

        root_hub->usb->children[nr] = usb_dev;

        wait_ms(200); /* wait for powerup */
        uhci_reset_port(port);

        /* Get speed information */
        usb_dev->slow = (inw(port) & USBPORTSC_LSDA) ? 1 : 0;

        /*
         * Ok, all the stuff specific to the root hub has been done.
         * The rest is generic for any new USB attach, regardless of
         * hub type.
         */
        if (usb_new_device(usb_dev)) {
                unsigned short status = inw(port);

                printk(KERN_INFO "uhci: disabling malfunctioning port %d\n",
                        nr + 1);
                outw(status | USBPORTSC_PE, port);
        }
}

/*
 * This gets called when the root hub configuration
 * has changed. Just go through each port, seeing if
 * there is something interesting happening.
 */
static void uhci_check_configuration(struct uhci *uhci)
{
        struct uhci_device *root_hub = usb_to_uhci(uhci->bus->root_hub);
        unsigned int io_addr = uhci->io_addr + USBPORTSC1;
        int maxchild = root_hub->usb->maxchild;
        int nr = 0;

        do {
                unsigned short status = inw(io_addr);

                if (status & USBPORTSC_CSC)
                        uhci_connect_change(uhci, io_addr, nr);

                nr++; io_addr += 2;
        } while (nr < maxchild);
}

static int fixup_isoc_desc (struct uhci_td *td)
{
        struct usb_isoc_desc    *isocdesc = td->dev_id;
        struct uhci_td          *prtd;
        struct isoc_frame_desc  *frm;
        int                     first_comp = isocdesc->cur_completed_frame + 1; /* 0-based */
        int                     cur_comp = td->isoc_td_number;  /* 0-based */
        int                     ix, fx;
        int                     num_comp;

        if (first_comp >= isocdesc->frame_count)
                first_comp = 0;
        num_comp = cur_comp - first_comp + 1;

#ifdef CONFIG_USB_DEBUG_ISOC
        printk ("fixup_isoc_desc.1: td = %p, id = %p, first_comp = %d, cur_comp = %d, num_comp = %d\n",
                        td, isocdesc, first_comp, cur_comp, num_comp);
#endif

        for (ix = 0, fx = first_comp, prtd = ((struct uhci_td *)(isocdesc->td))+first_comp, frm = &isocdesc->frames [first_comp];
            ix < num_comp; ix++) {
                frm->frame_length = uhci_actual_length (prtd->status);
                isocdesc->total_length += frm->frame_length;

                if ((frm->frame_status = uhci_map_status (uhci_status_bits (prtd->status),
                    uhci_packetout (prtd->info))))
                        isocdesc->error_count++;
             
                prtd++;
                frm++;
                if (++fx >= isocdesc->frame_count) {    /* wrap fx, prtd, and frm */
                        fx = 0;
                        prtd = isocdesc->td;
                        frm  = isocdesc->frames;
                } /* end wrap */
        } /* end for */

        /*
         * Update some other fields for drivers.
         */
        isocdesc->prev_completed_frame = isocdesc->cur_completed_frame;
        isocdesc->cur_completed_frame  = cur_comp;
        isocdesc->total_completed_frames += num_comp;   /* 1-based */

#ifdef CONFIG_USB_DEBUG_ISOC
        printk ("fixup_isoc_desc.2: total_comp_frames = %d, total_length = %d, error_count = %d\n",
                isocdesc->total_completed_frames, isocdesc->total_length, isocdesc->error_count);
#endif /* CONFIG_USB_DEBUG_ISOC */

        return 0;
}

static void uhci_interrupt_notify(struct uhci *uhci)
{
        struct list_head *tmp, *head = &uhci->interrupt_list;
        int status;

        spin_lock(&irqlist_lock);
        tmp = head->next;
        while (tmp != head) {
                struct uhci_td *td = list_entry(tmp, struct uhci_td, irq_list);
                unsigned long rval;

                tmp = tmp->next;

                /* We're interested if there was an error or if the chain of */
                /*  TD's completed successfully */
                status = uhci_td_result(td->dev, td, &rval, 0);

                if ((status == USB_ST_NOERROR) && (td->status & TD_CTRL_ACTIVE))
                        continue;

                /* remove from IRQ list */
                list_del(&td->irq_list);
                INIT_LIST_HEAD(&td->irq_list);

                if (td->completed(status, bus_to_virt(td->buffer), rval,
                    td->dev_id)) {
                        struct usb_device *usb_dev = td->dev->usb;

                        list_add(&td->irq_list, &uhci->interrupt_list);

                        usb_dotoggle(usb_dev, usb_pipeendpoint(td->info), usb_pipeout(td->info) ^ 1);
                        td->info &= ~(1 << 19); /* clear data toggle */
                        td->info |= usb_gettoggle(usb_dev, usb_pipeendpoint(td->info),
                                uhci_packetout(td->info)) << 19; /* toggle between data0 and data1 */
                        td->status = (td->status & 0x2F000000) | TD_CTRL_ACTIVE | TD_CTRL_IOC;
                        /* The HC only removes it when it completed */
                        /* successfully, so force remove and readd it */
                        uhci_remove_td(td);
                        uhci_insert_td_in_qh(td->qh, td);
                } else if (td->flags & UHCI_TD_REMOVE) {
                        struct usb_device *usb_dev = td->dev->usb;

                        /* marked for removal */
                        td->flags &= ~UHCI_TD_REMOVE;
                        usb_dotoggle(usb_dev, usb_pipeendpoint(td->info), uhci_packetout(td->info));
                        uhci_remove_qh(td->qh->skel, td->qh);
                        uhci_qh_free(td->qh);
                        uhci_td_free(td);
                }

                /* If completed does not wants to reactivate, then */
                /* it's responsible for free'ing the TD's and QH's */
                /* or another function (such as run_control) */
        }
        spin_unlock(&irqlist_lock);
}

/*
 * Check port status - Connect Status Change - for
 * each of the attached ports (defaults to two ports,
 * but at least in theory there can be more of them).
 *
 * Wake up the configurator if something happened, we
 * can't really do much at interrupt time.
 */
static void uhci_root_hub_events(struct uhci *uhci, unsigned int io_addr)
{
        if (waitqueue_active(&uhci_configure)) {
                struct uhci_device *root_hub = usb_to_uhci(uhci->bus->root_hub);
                int ports = root_hub->usb->maxchild;

                io_addr += USBPORTSC1;
                do {
                        if (inw(io_addr) & USBPORTSC_CSC) {
                                wake_up(&uhci_configure);
                                return;
                        }
                        io_addr += 2;
                } while (--ports > 0);
        }
}

static void uhci_interrupt(int irq, void *__uhci, struct pt_regs *regs)
{
        struct uhci *uhci = __uhci;
        unsigned int io_addr = uhci->io_addr;
        unsigned short status;

        /*
         * Read the interrupt status, and write it back to clear the
         * interrupt cause
         */
        status = inw(io_addr + USBSTS);
        outw(status, io_addr + USBSTS);

        /* Walk the list of pending TD's to see which ones completed.. */
        uhci_interrupt_notify(uhci);

        /* Check if there are any events on the root hub.. */
        uhci_root_hub_events(uhci, io_addr);
}

/*
 * We init one packet, and mark it just IOC and _not_
 * active. Which will result in no actual USB traffic,
 * but _will_ result in an interrupt every second.
 *
 * Which is exactly what we want.
 */
static void uhci_init_ticktd(struct uhci *uhci)
{
        struct uhci_device *dev = usb_to_uhci(uhci->bus->root_hub);
        struct uhci_td *td = uhci_td_alloc(dev);

        if (!td) {
                printk(KERN_ERR "unable to allocate ticktd\n");
                return;
        }

        /* Don't clobber the frame */
        td->link = uhci->fl->frame[0];
        td->backptr = &uhci->fl->frame[0];
        td->status = TD_CTRL_IOC;
        td->info = (15 << 21) | (0x7f << 8) | USB_PID_IN;       /* (ignored) input packet, 16 bytes, device 127 */
        td->buffer = 0;
        td->qh = NULL;

        uhci->fl->frame[0] = virt_to_bus(td);

        uhci->ticktd = td;
}

static void reset_hc(struct uhci *uhci)
{
        unsigned int io_addr = uhci->io_addr;

        /* Global reset for 50ms */
        outw(USBCMD_GRESET, io_addr + USBCMD);
        wait_ms(50);
        outw(0, io_addr + USBCMD);
        wait_ms(10);
}

static void start_hc(struct uhci *uhci)
{
        unsigned int io_addr = uhci->io_addr;
        int timeout = 1000;

        uhci_init_ticktd(uhci);

        /*
         * Reset the HC - this will force us to get a
         * new notification of any already connected
         * ports due to the virtual disconnect that it
         * implies.
         */
        outw(USBCMD_HCRESET, io_addr + USBCMD);
        while (inw(io_addr + USBCMD) & USBCMD_HCRESET) {
                if (!--timeout) {
                        printk(KERN_ERR "USBCMD_HCRESET timed out!\n");
                        break;
                }
        }

        /* Turn on all interrupts */
        outw(USBINTR_TIMEOUT | USBINTR_RESUME | USBINTR_IOC | USBINTR_SP, io_addr + USBINTR);

        /* Start at frame 0 */
        outw(0, io_addr + USBFRNUM);
        outl(virt_to_bus(uhci->fl), io_addr + USBFLBASEADD);

        /* Run and mark it configured with a 64-byte max packet */
        outw(USBCMD_RS | USBCMD_CF | USBCMD_MAXP, io_addr + USBCMD);
}

/*
 * Allocate a frame list, and four regular queues.
 *
 * The hardware doesn't really know any difference
 * in the queues, but the order does matter for the
 * protocols higher up. The order is:
 *
 *  - any isochronous events 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 "interrupt queue".
 *  - The second queue is the "control queue".
 *  - The third queue is "bulk data".
 *
 * We could certainly have multiple queues of the same
 * type, and maybe we should. We could have per-device
 * queues, for example. We begin small.
 *
 * Queues are dynamically allocated for devices now,
 * this code only sets up the skeleton queue
 */
static struct uhci *alloc_uhci(unsigned int io_addr, unsigned int io_size)
{
        int i, port;
        struct uhci *uhci;
        struct usb_bus *bus;
        struct uhci_device *dev;
        struct usb_device *usb;

        uhci = kmalloc(sizeof(*uhci), GFP_KERNEL);
        if (!uhci)
                return NULL;

        memset(uhci, 0, sizeof(*uhci));

        uhci->irq = -1;
        uhci->io_addr = io_addr;
        uhci->io_size = io_size;
        INIT_LIST_HEAD(&uhci->interrupt_list);

        /* We need exactly one page (per UHCI specs), how convenient */
        uhci->fl = (void *)__get_free_page(GFP_KERNEL);
        if (!uhci->fl)
                goto au_free_uhci;

        bus = usb_alloc_bus(&uhci_device_operations);
        if (!bus)
                goto au_free_fl;

        uhci->bus = bus;
        bus->hcpriv = uhci;

        /*
         * Allocate the root_hub
         */
        usb = usb_alloc_dev(NULL, bus);
        if (!usb)
                goto au_free_bus;

        usb->bus = bus;

        dev = usb_to_uhci(usb);
        dev->uhci = uhci;

        uhci->bus->root_hub = uhci_to_usb(dev);

        /* Initialize the root hub */

        /* UHCI specs says devices must have 2 ports, but goes on to say */
        /* they may have more but give no way to determine how many they */
        /* have, so default to 2 */
        /* According to the UHCI spec, Bit 7 is always set to 1. So we try */
        /* to use this to our advantage */
        for (port = 0; port < (io_size - 0x10) / 2; port++) {
                unsigned int portstatus;

                portstatus = inw(io_addr + 0x10 + (port * 2));
                if (!(portstatus & 0x0080))
                        break;
        }
        printk(KERN_DEBUG "Detected %d ports\n", port);

        /* This is experimental so anything less than 2 or greater than 8 is */
        /*  something weird and we'll ignore it */
        if (port < 2 || port > 8) {
                printk(KERN_DEBUG "Port count misdetected, forcing to 2 ports\n");
                port = 2;
        }

        usb->maxchild = port;
        usb_init_root_hub(usb);

        /* 8 Interrupt queues */
        for (i = 0; i < 8; i++) {
                struct uhci_qh *qh = &uhci->skelqh[i];

                qh->link = virt_to_bus(&uhci->skel_control_qh) | UHCI_PTR_QH;
                qh->element = UHCI_PTR_TERM;
        }

        uhci->skel_control_qh.link = virt_to_bus(&uhci->skel_bulk_qh) |
                UHCI_PTR_QH;
        uhci->skel_control_qh.element = UHCI_PTR_TERM;

        uhci->skel_bulk_qh.link = UHCI_PTR_TERM;
        uhci->skel_bulk_qh.element = UHCI_PTR_TERM;

        /*
         * Fill the frame list: make all entries point to
         * the proper interrupt queue.
         *
         * This is probably silly, but it's a simple way to
         * scatter the interrupt queues in a way that gives
         * us a reasonable dynamic range for irq latencies.
         */
        for (i = 0; i < 1024; i++) {
                struct uhci_qh *irq = &uhci->skel_int2_qh;
                if (i & 1) {
                        irq++;
                        if (i & 2) {
                                irq++;
                                if (i & 4) { 
                                        irq++;
                                        if (i & 8) { 
                                                irq++;
                                                if (i & 16) {
                                                        irq++;
                                                        if (i & 32) {
                                                                irq++;
                                                                if (i & 64) {
                                                                        irq++;
                                                                }
                                                        }
                                                }
                                        }
                                }
                        }
                }
                uhci->fl->frame[i] =  virt_to_bus(irq) | UHCI_PTR_QH;
        }

        return uhci;

/*
 * error exits:
 */

au_free_bus:
        usb_free_bus(bus);
au_free_fl:
        free_page((unsigned long)uhci->fl);
au_free_uhci:
        kfree(uhci);
        return NULL;
}

/*
 * De-allocate all resources..
 */
static void release_uhci(struct uhci *uhci)
{
        if (uhci->irq >= 0) {
                free_irq(uhci->irq, uhci);
                uhci->irq = -1;
        }

        if (uhci->ticktd) {
                uhci_td_free(uhci->ticktd);
                uhci->ticktd = NULL;
        }

        if (uhci->fl) {
                free_page((unsigned long)uhci->fl);
                uhci->fl = NULL;
        }

        usb_free_bus(uhci->bus);
        kfree(uhci);
}

static int uhci_control_thread(void *__uhci)
{
        struct uhci *uhci = (struct uhci *)__uhci;

        uhci->control_running = 1;

        lock_kernel();

        /*
         * This thread doesn't need any user-level access,
         * so get rid of all our resources..
         */
        exit_mm(current);
        exit_files(current);

        strcpy(current->comm, "uhci-control");

        /*
         * Ok, all systems are go..
         */
        do {
                siginfo_t info;
                int unsigned long signr;

#ifdef CONFIG_APM
                if (apm_resume) {
                        apm_resume = 0;
                        start_hc(uhci);
                        continue;
                }
#endif
                uhci_check_configuration(uhci);

                interruptible_sleep_on(&uhci_configure);

                if (signal_pending(current)) {
                        /* sending SIGUSR1 makes us print out some info */
                        spin_lock_irq(&current->sigmask_lock);
                        signr = dequeue_signal(&current->blocked, &info);
                        spin_unlock_irq(&current->sigmask_lock);

                        if (signr == SIGUSR1) {
                                printk(KERN_DEBUG "UHCI queue dump:\n");
                                uhci_show_queues(uhci);
                        } else if (signr == SIGUSR2) {
                                uhci_debug = !uhci_debug;
                                printk(KERN_DEBUG "UHCI debug toggle = %x\n",
                                        uhci_debug);
                        } else
                                break;
                }
        } while (uhci->control_continue);

/*
        MOD_DEC_USE_COUNT;
*/

        uhci->control_running = 0;

        return 0;
}       

/*
 * If we've successfully found a UHCI, now is the time to increment the
 * module usage count, start the control thread, and return success..
 */
static int found_uhci(int irq, unsigned int io_addr, unsigned int io_size)
{
        int retval;
        struct uhci *uhci;

        uhci = alloc_uhci(io_addr, io_size);
        if (!uhci)
                return -ENOMEM;

        INIT_LIST_HEAD(&uhci->uhci_list);
        list_add(&uhci->uhci_list, &uhci_list);

        request_region(uhci->io_addr, io_size, "usb-uhci");

        reset_hc(uhci);

        usb_register_bus(uhci->bus);
        start_hc(uhci);

        uhci->control_continue = 1;

        retval = -EBUSY;
        if (request_irq(irq, uhci_interrupt, SA_SHIRQ, "uhci", uhci) == 0) {
                int pid;

                uhci->irq = irq;
                pid = kernel_thread(uhci_control_thread, uhci,
                        CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
                if (pid >= 0) {
                        uhci->control_pid = pid;

                        return(pid);
                }

                retval = pid;
        }

        reset_hc(uhci);
        release_region(uhci->io_addr, uhci->io_size);

        release_uhci(uhci);
        return retval;
}

static int start_uhci(struct pci_dev *dev)
{
        int i;

        /* Search for the IO base address.. */
        for (i = 0; i < 6; i++) {
                unsigned int io_addr = dev->resource[i].start;
                unsigned int io_size =
                        dev->resource[i].end - dev->resource[i].start;

                /* IO address? */
                if (!(dev->resource[i].flags & 1))
                        continue;

                /* Is it already in use? */
                if (check_region(io_addr, io_size))
                        break;

                return found_uhci(dev->irq, io_addr, io_size);
        }
        return -1;
}

#ifdef CONFIG_APM
static int handle_apm_event(apm_event_t event)
{
        static int down = 0;

        switch (event) {
        case APM_SYS_SUSPEND:
        case APM_USER_SUSPEND:
                if (down) {
                        printk(KERN_DEBUG "uhci: received extra suspend event\n");
                        break;
                }
                down = 1;
                break;
        case APM_NORMAL_RESUME:
        case APM_CRITICAL_RESUME:
                if (!down) {
                        printk(KERN_DEBUG "uhci: received bogus resume event\n");
                        break;
                }
                down = 0;
                if (waitqueue_active(&uhci_configure)) {
                        apm_resume = 1;
                        wake_up(&uhci_configure);
                }
                break;
        }
        return 0;
}
#endif

int uhci_init(void)
{
        int retval;
        struct pci_dev *dev = NULL;
        u8 type;

        uhci_td_cachep = kmem_cache_create("uhci_td",
                sizeof(struct uhci_td), 0,
                SLAB_HWCACHE_ALIGN, NULL, NULL);

        if (!uhci_td_cachep)
                return -ENOMEM;

        uhci_qh_cachep = kmem_cache_create("uhci_qh",
                sizeof(struct uhci_qh), 0,
                SLAB_HWCACHE_ALIGN, NULL, NULL);

        if (!uhci_qh_cachep)
                return -ENOMEM;

        retval = -ENODEV;
        for (;;) {
                dev = pci_find_class(PCI_CLASS_SERIAL_USB << 8, dev);
                if (!dev)
                        break;

                /* Is it UHCI */
                pci_read_config_byte(dev, PCI_CLASS_PROG, &type);
                if (type != 0)
                        continue;

                /* Ok set it up */
                retval = start_uhci(dev);
                if (retval < 0)
                        continue;

#ifdef CONFIG_APM
                apm_register_callback(&handle_apm_event);
#endif
                return 0;
        }
        return retval;
}

void uhci_cleanup(void)
{
        struct list_head *next, *tmp, *head = &uhci_list;
        int ret, i;

        tmp = head->next;
        while (tmp != head) {
                struct uhci *uhci = list_entry(tmp, struct uhci, uhci_list);
                struct uhci_device *root_hub = usb_to_uhci(uhci->bus->root_hub);

                next = tmp->next;

                list_del(&uhci->uhci_list);
                INIT_LIST_HEAD(&uhci->uhci_list);

                /* Check if the process is still running */
                ret = kill_proc(uhci->control_pid, 0, 1);
                if (!ret) {
                        /* Try a maximum of 10 seconds */
                        int count = 10 * 100;

                        uhci->control_continue = 0;
                        wake_up(&uhci_configure);

                        while (uhci->control_running && --count) {
                                current->state = TASK_INTERRUPTIBLE;
                                schedule_timeout(1);
                        }

                        if (!count)
                                printk(KERN_ERR "uhci: giving up on killing uhci-control\n");
                }

                if (root_hub)
                        for (i = 0; i < root_hub->usb->maxchild; i++)
                                usb_disconnect(root_hub->usb->children + i);

                usb_deregister_bus(uhci->bus);

                reset_hc(uhci);
                release_region(uhci->io_addr, uhci->io_size);

                release_uhci(uhci);

                tmp = next;
        }

        if (kmem_cache_destroy(uhci_qh_cachep))
                printk(KERN_INFO "uhci: not all QH's were freed\n");

        if (kmem_cache_destroy(uhci_td_cachep))
                printk(KERN_INFO "uhci: not all TD's were freed\n");
}

#ifdef MODULE
int init_module(void)
{
        return uhci_init();
}

void cleanup_module(void)
{
#ifdef CONFIG_APM
        apm_unregister_callback(&handle_apm_event);
#endif
        uhci_cleanup();
}
#endif //MODULE