Import 2.3.7pre8

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

/*
 * Open Host Controller Interface driver for USB.
 *
 * (C) Copyright 1999 Gregory P. Smith <greg@electricrain.com>
 *
 * This is the "other" host controller interface for USB.  You will
 * find this on many non-Intel based motherboards, and of course the
 * Mac.  As Linus hacked his UHCI driver together first, I modeled
 * this after his.. (it should be obvious)
 *
 * From the programming standpoint the OHCI interface seems a little
 * prettier and potentially less CPU intensive.  This remains to be
 * proven.  In reality, I don't believe it'll make one darn bit of
 * difference.  USB v1.1 is a slow bus by today's standards.
 *
 * OHCI hardware takes care of most of the scheduling of different
 * transfer types with the correct prioritization for us.
 *
 * To get started in USB, I used the "Universal Serial Bus System
 * Architecture" book by Mindshare, Inc.  It was a reasonable introduction
 * and overview of USB and the two dominant host controller interfaces
 * however you're better off just reading the real specs available
 * from www.usb.org as you'll need them to get enough detailt to
 * actually implement a HCD.  The book has many typos and omissions
 * Beware, the specs are the victim of a committee.
 *
 * This code was written with Guinness on the brain, xsnow on the desktop
 * and Orbital, Orb, Enya & Massive Attack on the CD player.  What a life!  ;) 
 *
 * No filesystems were harmed in the development of this code.
 *
 * $Id: ohci.c,v 1.43 1999/05/16 22:35:24 greg Exp $
 */

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

#include "ohci.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 DECLARE_WAIT_QUEUE_HEAD(ohci_configure);

#ifdef CONFIG_USB_OHCI_DEBUG
#define OHCI_DEBUG    /* to make typing it easier.. */
#endif

int MegaDebug = 0;      /* SIGUSR2 to the control thread toggles this */


#ifdef OHCI_TIMER
static struct timer_list ohci_timer;    /* timer for root hub polling */
#endif

static spinlock_t ohci_edtd_lock = SPIN_LOCK_UNLOCKED;

#define FIELDS_OF_ED(e) le32_to_cpup(&e->status), le32_to_cpup(&e->tail_td), \
                        le32_to_cpup(&e->_head_td), le32_to_cpup(&e->next_ed)
#define FIELDS_OF_TD(t) le32_to_cpup(&t->info), le32_to_cpup(&t->cur_buf), \
                        le32_to_cpup(&t->next_td), le32_to_cpup(&t->buf_end)

static const char *cc_names[16] = {
        "no error",
        "CRC error",
        "bit stuff error",
        "data toggle mismatch",
        "stall",
        "device not responding",
        "PID check failed",
        "unexpected PID",
        "data overrun",
        "data underrun",
        "reserved (10)",
        "reserved (11)",
        "buffer overrun",
        "buffer underrun",
        "not accessed (14)",
        "not accessed"
};

/*
 * Add a chain of TDs to the end of the TD list on a given ED.
 *
 * This function uses the first TD of the chain as the new dummy TD
 * for the ED, and uses the old dummy TD instead of the first TD
 * of the chain.  The reason for this is that this makes it possible
 * to update the TD chain without needing any locking between the
 * CPU and the OHCI controller.
 *
 * The return value is the pointer to the new first TD (the old
 * dummy TD).
 *
 * Important!  This function is not re-entrant w.r.t. each ED.
 * Locking ohci_edtd_lock while using the function is a must
 * if there is any possibility of another CPU or an interrupt routine
 * calling this function with the same ED.
 *
 * This function can be called by the interrupt handler.
 */
static struct ohci_td *ohci_add_td_to_ed(struct ohci_td *td,
                                struct ohci_td *last_td, struct ohci_ed *ed)
{
        struct ohci_td *t, *dummy_td;
        u32 new_dummy;

        if (ed->tail_td == 0) {
                printk(KERN_ERR "eek! an ED without a dummy_td\n");
                return td;
        }

        /* Get a pointer to the current dummy TD. */
        dummy_td = bus_to_virt(ed_tail_td(ed));

        for (t = td; ; t = bus_to_virt(le32_to_cpup(&t->next_td))) {
                t->ed = ed;
                if (t == last_td)
                        break;
        }

        /* Make the last TD point back to the first, since it
         * will become the new dummy TD. */
        new_dummy = cpu_to_le32(virt_to_bus(td));
        last_td->next_td = new_dummy;

        /* Copy the contents of the first TD into the dummy */
        *dummy_td = *td;

        /* Turn the first TD into a dummy */
        make_dumb_td(td);

        /* Set the HC's tail pointer to the new dummy */
        ed->tail_td = new_dummy;

        return dummy_td;        /* replacement head of chain */
} /* ohci_add_td_to_ed() */


inline void ohci_start_control(struct ohci *ohci)
{
        /* tell the HC to start processing the control list */
        writel_set(OHCI_USB_CLE, &ohci->regs->control);
        writel_set(OHCI_CMDSTAT_CLF, &ohci->regs->cmdstatus);
}

inline void ohci_start_bulk(struct ohci *ohci)
{
        /* tell the HC to start processing the bulk list */
        writel_set(OHCI_USB_BLE, &ohci->regs->control);
        writel_set(OHCI_CMDSTAT_BLF, &ohci->regs->cmdstatus);
}

inline void ohci_start_periodic(struct ohci *ohci)
{
        /* enable processing periodic (intr) transfers starting next frame */
        writel_set(OHCI_USB_PLE, &ohci->regs->control);
}

inline void ohci_start_isoc(struct ohci *ohci)
{
        /* enable processing isoc. transfers starting next frame */
        writel_set(OHCI_USB_IE, &ohci->regs->control);
}

/*
 * Add an ED to the hardware register ED list pointed to by hw_listhead_p
 * This function only makes sense for Control and Bulk EDs.
 */
static void ohci_add_ed_to_hw(struct ohci_ed *ed, void* hw_listhead_p)
{
        __u32 listhead;
        unsigned long flags;

        spin_lock_irqsave(&ohci_edtd_lock, flags);
        
        listhead = readl(hw_listhead_p);

        /* if the list is not empty, insert this ED at the front */
        /* XXX should they go on the end? */
        ed->next_ed = cpu_to_le32(listhead);

        /* update the hardware listhead pointer */
        writel(virt_to_bus(ed), hw_listhead_p);

        spin_unlock_irqrestore(&ohci_edtd_lock, flags);
} /* ohci_add_ed_to_hw() */


/*
 *  Put a control ED on the controller's list
 */
void ohci_add_control_ed(struct ohci *ohci, struct ohci_ed *ed)
{
        ohci_add_ed_to_hw(ed, &ohci->regs->ed_controlhead);
        ohci_start_control(ohci);
} /* ohci_add_control_ed() */

/*
 *  Put a bulk ED on the controller's list
 */
void ohci_add_bulk_ed(struct ohci *ohci, struct ohci_ed *ed)
{
        ohci_add_ed_to_hw(ed, &ohci->regs->ed_bulkhead);
        ohci_start_bulk(ohci);
} /* ohci_add_bulk_ed() */

/*
 *  Put a periodic ED on the appropriate list given the period.
 */
void ohci_add_periodic_ed(struct ohci *ohci, struct ohci_ed *ed, int period)
{
        struct ohci_ed *int_ed;
        struct ohci_device *root_hub=usb_to_ohci(ohci->bus->root_hub);
        unsigned long flags;

        /*
         * Pick a good frequency endpoint based on the requested period
         */
        int_ed = &root_hub->ed[ms_to_ed_int(period)];
#ifdef OHCI_DEBUG
        printk(KERN_DEBUG "usb-ohci: Using INT ED queue %d for %dms period\n",
               ms_to_ed_int(period), period);
#endif

        spin_lock_irqsave(&ohci_edtd_lock, flags);
        /*
         * Insert this ED at the front of the list.
         */
        ed->next_ed = int_ed->next_ed;
        int_ed->next_ed = cpu_to_le32(virt_to_bus(ed));

        spin_unlock_irqrestore(&ohci_edtd_lock, flags);

        ohci_start_periodic(ohci);
} /* ohci_add_periodic_ed() */

/*
 *  Put an isochronous ED on the controller's list
 */
inline void ohci_add_isoc_ed(struct ohci *ohci, struct ohci_ed *ed)
{
        ohci_add_periodic_ed(ohci, ed, 1);
}


/*
 * This will be used for the interrupt to wake us up on the next SOF
 */
DECLARE_WAIT_QUEUE_HEAD(start_of_frame_wakeup);

static void ohci_wait_sof(struct ohci_regs *regs)
{
        DECLARE_WAITQUEUE(wait, current);

        add_wait_queue(&start_of_frame_wakeup, &wait);

        /* clear the SOF interrupt status and enable it */
        writel(OHCI_INTR_SF, &regs->intrstatus);
        writel(OHCI_INTR_SF, &regs->intrenable);

        schedule_timeout(HZ/10);

        remove_wait_queue(&start_of_frame_wakeup, &wait);
}

/*
 * Guarantee that an ED is safe to be modified by the HCD (us).
 *
 * This function can NOT be called from an interrupt.
 */
void ohci_wait_for_ed_safe(struct ohci_regs *regs, struct ohci_ed *ed, int ed_type)
{
        __u32 *hw_listcurrent;

        /* tell the controller to skip this ED */
        ed->status |= cpu_to_le32(OHCI_ED_SKIP);

        switch (ed_type) {
        case HCD_ED_CONTROL:
                hw_listcurrent = &regs->ed_controlcurrent;
                break;
        case HCD_ED_BULK:
                hw_listcurrent = &regs->ed_bulkcurrent;
                break;
        case HCD_ED_ISOC:
        case HCD_ED_INT:
                hw_listcurrent = &regs->ed_periodcurrent;
                break;
        default:
                return;
        }

        /* 
         * If the HC is processing this ED we need to wait until the
         * at least the next frame.
         */
        if (virt_to_bus(ed) == readl(hw_listcurrent)) {
#ifdef OHCI_DEBUG
                printk(KERN_INFO "Waiting a frame for OHC to finish with ED %p [%x %x %x %x]\n", ed, FIELDS_OF_ED(ed));
#endif
                ohci_wait_sof(regs);

        }

        return; /* The ED is now safe */
} /* ohci_wait_for_ed_safe() */


/*
 *  Remove an ED from the HC's list.
 *  This function can ONLY be used for Control or Bulk EDs.
 *  
 *  Note that the SKIP bit is left on in the removed ED.
 */
void ohci_remove_norm_ed_from_hw(struct ohci *ohci, struct ohci_ed *ed, int ed_type)
{
        unsigned long flags;
        struct ohci_regs *regs = ohci->regs;
        struct ohci_ed *cur;
        __u32 bus_ed = virt_to_bus(ed);
        __u32 bus_cur;
        __u32 *hw_listhead_p;

        if (ed == NULL || !bus_ed)
                return;
        ed->status |= cpu_to_le32(OHCI_ED_SKIP);

        switch (ed_type) {
        case HCD_ED_CONTROL:
                hw_listhead_p = &regs->ed_controlhead;
                break;
        case HCD_ED_BULK:
                hw_listhead_p = &regs->ed_bulkhead;
                break;
        default:
                printk(KERN_ERR "Unknown HCD ED type %d.\n", ed_type);
                return;
        }

        bus_cur = readl(hw_listhead_p);

        if (bus_cur == 0)
                return;   /* the list is already empty */

        cur = bus_to_virt(bus_cur);

        spin_lock_irqsave(&ohci_edtd_lock, flags);

        /* if its the head ED, move the head */
        if (bus_cur == bus_ed) {
                writel(le32_to_cpup(&cur->next_ed), hw_listhead_p);
        } else if (cur->next_ed != 0) {
                struct ohci_ed *prev;

                /* walk the list and unlink the ED if found */
                do {
                        prev = cur;
                        cur = bus_to_virt(le32_to_cpup(&cur->next_ed));

                        if (cur == ed) {
                                /* unlink from the list */
                                prev->next_ed = cur->next_ed;
                                break;
                        }
                } while (cur->next_ed != 0);
        }

        /*
         * Make sure this ED is not being accessed by the HC as we speak.
         */
        ohci_wait_for_ed_safe(regs, ed, ed_type);

        /* clear any links from the ED for safety */
        ed->next_ed = 0;

        spin_unlock_irqrestore(&ohci_edtd_lock, flags);
} /* ohci_remove_norm_ed_from_hw() */

/*
 *  Remove an ED from the controller's control list.  Note that the SKIP bit
 *  is left on in the removed ED.
 */
inline void ohci_remove_control_ed(struct ohci *ohci, struct ohci_ed *ed)
{
        ohci_remove_norm_ed_from_hw(ohci, ed, HCD_ED_CONTROL);
}

/*
 *  Remove an ED from the controller's bulk list.  Note that the SKIP bit
 *  is left on in the removed ED.
 */
inline void ohci_remove_bulk_ed(struct ohci *ohci, struct ohci_ed *ed)
{
        ohci_remove_norm_ed_from_hw(ohci, ed, HCD_ED_BULK);
}

/*
 * Remove all the EDs which have a given device address from a list.
 * Used when the device is unplugged.
 * Returns 1 if anything was changed.
 */
static int ohci_remove_device_list(__u32 *headp, int devnum)
{
        struct ohci_ed *ed;
        __u32 *prevp = headp;
        int removed = 0;

        while (*prevp != 0) {
                ed = bus_to_virt(le32_to_cpup(prevp));
                if ((le32_to_cpup(&ed->status) & OHCI_ED_FA) == devnum) {
                        /* set the controller to skip this one
                           and remove it from the list */
                        ed->status |= cpu_to_le32(OHCI_ED_SKIP);
                        *prevp = ed->next_ed;
                        removed = 1;
                } else {
                        prevp = &ed->next_ed;
                }
        }
        wmb();

        return removed;
}

/*
 * Remove all the EDs for a given device from all lists.
 */
void ohci_remove_device(struct ohci *ohci, int devnum)
{
        unsigned long flags;
        __u32 head;
        struct ohci_regs *regs = ohci->regs;
        struct ohci_device *root_hub=usb_to_ohci(ohci->bus->root_hub);

        spin_lock_irqsave(&ohci_edtd_lock, flags);

        /* Control list */
        head = cpu_to_le32(readl(&regs->ed_controlhead));
        if (ohci_remove_device_list(&head, devnum))
                writel(le32_to_cpup(&head), &regs->ed_controlhead);

        /* Bulk list */
        head = cpu_to_le32(readl(&regs->ed_bulkhead));
        if (ohci_remove_device_list(&head, devnum))
                writel(le32_to_cpup(&head), &regs->ed_bulkhead);

        /* Interrupt/iso list */
        head = cpu_to_le32(virt_to_bus(&root_hub->ed[ED_INT_32]));
        ohci_remove_device_list(&head, devnum);

        /*
         * Wait until the start of the next frame to ensure
         * that the HC has seen any changes.
         */
        ohci_wait_sof(ohci->regs);

        spin_unlock_irqrestore(&ohci_edtd_lock, flags);
}

/*
 *  Remove a TD from the given EDs TD list.
 */
static void ohci_remove_td_from_ed(struct ohci_td *td, struct ohci_ed *ed)
{
        unsigned long flags;
        struct ohci_td *head_td;

        if ((td == NULL) || (ed == NULL))
                return;

        spin_lock_irqsave(&ohci_edtd_lock, flags);

        if (ed_head_td(ed) == 0)
                return;

        /* set the "skip me bit" in this ED */
        ed->status |= cpu_to_le32(OHCI_ED_SKIP);

        /* XXX Assuming this list will never be circular */

        head_td = bus_to_virt(ed_head_td(ed));
        if (virt_to_bus(td) == ed_head_td(ed)) {
                /* It's the first TD, remove it. */
                set_ed_head_td(ed, head_td->next_td);
        } else {
                struct ohci_td *prev_td, *cur_td;

                /* FIXME: collapse this into a nice simple loop :) */
                if (head_td->next_td != 0) {
                        prev_td = head_td;
                        cur_td = bus_to_virt(le32_to_cpup(&head_td->next_td));
                        for (;;) {
                                if (td == cur_td) {
                                        /* remove it */
                                        prev_td->next_td = cur_td->next_td;
                                        break;
                                }
                                if (cur_td->next_td == 0)
                                        break;
                                prev_td = cur_td;
                                cur_td = bus_to_virt(le32_to_cpup(&cur_td->next_td));
                        }
                }
        }

        td->next_td = 0;  /* remove the TDs links */
        td->ed = NULL;

        /* return this TD to the pool of free TDs */
        ohci_free_td(td);

        /* unset the "skip me bit" in this ED */
        ed->status &= cpu_to_le32(~OHCI_ED_SKIP);

        spin_unlock_irqrestore(&ohci_edtd_lock, flags);
} /* ohci_remove_td_from_ed() */


/*
 * Get a pointer (virtual) to an available TD from the given device's
 * pool.  Return NULL if none are left.
 */
static struct ohci_td *ohci_get_free_td(struct ohci_device *dev)
{
        int idx;

#if 0
        printk(KERN_DEBUG "in ohci_get_free_td()\n");
#endif

        /* FIXME: this is horribly inefficient */
        for (idx=0; idx < NUM_TDS; idx++) {
#if 0
                show_ohci_td(&dev->td[idx]);
#endif
                if (!td_allocated(dev->td[idx])) {
                        struct ohci_td *new_td = &dev->td[idx];
                        /* zero out the TD */
                        memset(new_td, 0, sizeof(*new_td));
                        /* mark the new TDs as unaccessed */
                        new_td->info = cpu_to_le32(OHCI_TD_CC_NEW);
                        /* mark it as allocated */
                        allocate_td(new_td);
                        return new_td;
                }
        }

        printk(KERN_ERR "usb-ohci: unable to allocate a TD\n");
        return NULL;
} /* ohci_get_free_td() */


/*
 * Get a pointer (virtual) to an available TD from the given device's
 * pool.  Return NULL if none are left.
 */
static struct ohci_ed *ohci_get_free_ed(struct ohci_device *dev)
{
        int idx;

        /* FIXME: this is horribly inefficient */
        for (idx=0; idx < NUM_EDS; idx++) {
                if (!ed_allocated(dev->ed[idx])) {
                        struct ohci_ed *new_ed = &dev->ed[idx];
                        /* zero out the ED */
                        memset(new_ed, 0, sizeof(*new_ed));
                        /* all new EDs start with the SKIP bit set */
                        new_ed->status |= cpu_to_le32(OHCI_ED_SKIP);
                        /* mark it as allocated */
                        allocate_ed(new_ed);
                        return new_ed;
                }
        }

        printk(KERN_ERR "usb-ohci: unable to allocate an ED\n");
        return NULL;
} /* ohci_get_free_ed() */


void ohci_free_ed(struct ohci_ed *ed)
{
        if (!ed)
                return;

        if (ed_head_td(ed) != 0) {
                struct ohci_td *td, *tail_td, *next_td;

                td = bus_to_virt(ed_head_td(ed));
                tail_td = bus_to_virt(ed_tail_td(ed));
                for (;;) {
                        next_td = bus_to_virt(le32_to_cpup(&td->next_td));
                        ohci_free_td(td);
                        if (td == tail_td)
                                break;
                        td = next_td;
                }
        }

        ed->status &= cpu_to_le32(~(__u32)ED_ALLOCATED);
} /* ohci_free_ed() */


/*
 *  Initialize a TD
 *
 *      dir = OHCI_TD_D_IN, OHCI_TD_D_OUT, or OHCI_TD_D_SETUP
 *      toggle = TOGGLE_AUTO, TOGGLE_DATA0, TOGGLE_DATA1
 */
inline struct ohci_td *ohci_fill_new_td(struct ohci_td *td, int dir, int toggle, __u32 flags, void *data, __u32 len, void *dev_id, usb_device_irq completed)
{
        /* hardware fields */
        td->info = cpu_to_le32(OHCI_TD_CC_NEW |
                               (dir & OHCI_TD_D) |
                               (toggle & OHCI_TD_DT) |
                               flags);
        td->cur_buf = (data == NULL) ? 0 : cpu_to_le32(virt_to_bus(data));
        td->buf_end = (len == 0) ? 0 :
                cpu_to_le32(le32_to_cpup(&td->cur_buf) + len - 1);

        /* driver fields */
        td->data = data;
        td->dev_id = dev_id;
        td->completed = completed;

#if 0
        printk(KERN_DEBUG "ohci_fill_new_td created:\n");
        show_ohci_td(td);
#endif

        return td;
} /* ohci_fill_new_td() */


/*
 *  Initialize a new ED on device dev, including allocating and putting the
 *  dummy tail_td on its queue if it doesn't already have one.  Any
 *  TDs on this ED other than the dummy will be lost (so there better
 *  not be any!).  This assumes that the ED is Allocated and will
 *  force the Allocated bit on.
 */
struct ohci_ed *ohci_fill_ed(struct ohci_device *dev, struct ohci_ed *ed,
                             int maxpacketsize, int lowspeed, int endp_id,
                             int isoc_tds)
{
        struct ohci_td *dummy_td;

        if (ed_head_td(ed) != ed_tail_td(ed))
                printk(KERN_ERR "Reusing a non-empty ED %p!\n", ed);

        if (!ed->tail_td) {
                dummy_td = ohci_get_free_td(dev);
                if (dummy_td == NULL) {
                        printk(KERN_ERR "Error allocating dummy TD for ED %p\n", ed);
                        return NULL;    /* no dummy available! */
                }
                make_dumb_td(dummy_td); /* flag it as a dummy */
                ed->tail_td = cpu_to_le32(virt_to_bus(dummy_td));
        } else {
                dummy_td = bus_to_virt(ed_tail_td(ed));
                if (!td_dummy(*dummy_td))
                        printk(KERN_ERR "ED %p's dummy %p is screwy\n", ed, dummy_td);
        }

        /* set the head TD to the dummy and clear the Carry & Halted bits */
        ed->_head_td = ed->tail_td;

        ed->status = cpu_to_le32(
                ed_set_maxpacket(maxpacketsize) |
                ed_set_speed(lowspeed) |
                (endp_id & 0x7ff) |
                ((isoc_tds == 0) ? OHCI_ED_F_NORM : OHCI_ED_F_ISOC));
        allocate_ed(ed);
        ed->next_ed = 0;

        return ed;
} /* ohci_fill_ed() */


/**********************************
 * OHCI interrupt list operations *
 **********************************/

/*
 * Request an interrupt handler for one "pipe" of a USB device.
 * (this function is pretty minimal right now)
 *
 * At the moment this is only good for input interrupts. (ie: for a
 * mouse or keyboard)
 *
 * Period is desired polling interval in ms.  The closest, shorter
 * match will be used.  Powers of two from 1-32 are supported by OHCI.
 */
static int ohci_request_irq(struct usb_device *usb, unsigned int pipe,
        usb_device_irq handler, int period, void *dev_id)
{
        struct ohci_device *dev = usb_to_ohci(usb);
        struct ohci_td *td;
        struct ohci_ed *interrupt_ed;   /* endpoint descriptor for this irq */
        int maxps = usb_maxpacket(usb, pipe);

        /* Get an ED and TD */
        interrupt_ed = ohci_get_free_ed(dev);
        if (!interrupt_ed) {
                printk(KERN_ERR "Out of EDs on device %p in ohci_request_irq\n", dev);
                return -1;
        }

        td = ohci_get_free_td(dev);
        if (!td) {
                printk(KERN_ERR "Out of TDs in ohci_request_irq\n");
                ohci_free_ed(interrupt_ed);
                return -1;
        }

        /*
         * Set the max packet size, device speed, endpoint number, usb
         * device number (function address), and type of TD.
         */
        ohci_fill_ed(dev, interrupt_ed, maxps, usb_pipeslow(pipe),
                     usb_pipe_endpdev(pipe), 0 /* normal TDs */);

        /* Fill in the TD */
        if (maxps > sizeof(dev->data))
                maxps = sizeof(dev->data);
        ohci_fill_new_td(td, td_set_dir_out(usb_pipeout(pipe)),
                        TOGGLE_AUTO,
                        OHCI_TD_ROUND,
                        dev->data, maxps,
                        dev_id, handler);
        /*
         * TODO: be aware of how the OHCI controller deals with DMA
         * spanning more than one page.
         */

        /*
         *  Put the TD onto our ED and make sure its ready to run
         */
        td = ohci_add_td_to_ed(td, td, interrupt_ed);
        interrupt_ed->status &= cpu_to_le32(~OHCI_ED_SKIP);
        ohci_unhalt_ed(interrupt_ed);

        /* Make sure all the stores above get done before
         * the store which tells the OHCI about the new ed. */
        wmb();

        /* Assimilate the new ED into the collective */
        ohci_add_periodic_ed(dev->ohci, interrupt_ed, period);

        return 0;
} /* ohci_request_irq() */


/*
 * Control thread operations:
 */
static DECLARE_WAIT_QUEUE_HEAD(control_wakeup);

/*
 *  This is the handler that gets called when a control transaction
 *  completes.
 *
 *  This function is called from the interrupt handler.
 */
static int ohci_control_completed(int stats, void *buffer, void *dev_id)
{
        /* pass the TDs completion status back to control_msg */
        if (dev_id) {
                int *completion_status = (int *)dev_id;
                *completion_status = stats;
        }

        wake_up(&control_wakeup);
        return 0;
} /* ohci_control_completed() */


/*
 * Send or receive a control message on a "pipe"
 *
 * The cmd parameter is a pointer to the 8 byte setup command to be
 * sent.  FIXME:  This is a devrequest in usb.h.  The function
 * should be updated to accept a devrequest* instead of void*..
 *
 * A control message contains:
 *   - The command itself
 *   - An optional data phase (if len > 0)
 *   - Status complete phase
 *
 * This function can NOT be called from an interrupt.
 */
static int ohci_control_msg(struct usb_device *usb, unsigned int pipe,
                            devrequest *cmd, void *data, int len)
{
        struct ohci_device *dev = usb_to_ohci(usb);
        struct ohci_ed *control_ed = ohci_get_free_ed(dev);
        struct ohci_td *setup_td, *data_td, *status_td;
        DECLARE_WAITQUEUE(wait, current);
        unsigned long flags;
        int completion_status = -1;
        devrequest our_cmd;

        /* byte-swap fields of cmd if necessary */
        our_cmd = *cmd;
        cpu_to_le16s(&our_cmd.value);
        cpu_to_le16s(&our_cmd.index);
        cpu_to_le16s(&our_cmd.length);

#ifdef OHCI_DEBUG
        if (MegaDebug)
        printk(KERN_DEBUG "ohci_control_msg %p (ohci_dev: %p) pipe %x, cmd %p, data %p, len %d\n", usb, dev, pipe, cmd, data, len);
#endif
        if (!control_ed) {
                printk(KERN_ERR "usb-ohci: couldn't get ED for dev %p\n", dev);
                return -1;
        }

        /* get a TD to send this control message with */
        setup_td = ohci_get_free_td(dev);
        if (!setup_td) {
                printk(KERN_ERR "usb-ohci: couldn't get TD for dev %p [cntl setup]\n", dev);
                ohci_free_ed(control_ed);
                return -1;
        }

        /*
         * Set the max packet size, device speed, endpoint number, usb
         * device number (function address), and type of TD.
         *
         */
        ohci_fill_ed(dev, control_ed, usb_maxpacket(usb,pipe), usb_pipeslow(pipe),
                usb_pipe_endpdev(pipe), 0 /* normal TDs */);

        /*
         * Build the control TD
         */

        /*
         * Set the not accessed condition code, allow odd sized data,
         * and set the data transfer type to SETUP.  Setup DATA always
         * uses a DATA0 packet.
         *
         * The setup packet contains a devrequest (usb.h) which
         * will always be 8 bytes long.
         */
        ohci_fill_new_td(setup_td, OHCI_TD_D_SETUP, TOGGLE_DATA0,
                        OHCI_TD_IOC_OFF,
                        &our_cmd, 8,    /* cmd is always 8 bytes long */
                        NULL, NULL);

        /* allocate the next TD */
        data_td = ohci_get_free_td(dev);
        if (!data_td) {
                printk(KERN_ERR "usb-ohci: couldn't get TD for dev %p [cntl data]\n", dev);
                ohci_free_td(setup_td);
                ohci_free_ed(control_ed);
                return -1;
        }

        /* link to the next TD */
        setup_td->next_td = cpu_to_le32(virt_to_bus(data_td));

        if (len > 0) {

                /* build the Control DATA TD, it starts with a DATA1. */
                ohci_fill_new_td(data_td, td_set_dir_out(usb_pipeout(pipe)),
                                TOGGLE_DATA1,
                                OHCI_TD_ROUND | OHCI_TD_IOC_OFF,
                                data, len,
                                NULL, NULL);

                /*
                 * TODO: Normal TDs can transfer up to 8192 bytes on OHCI.
                 * However, for that to happen, the data must -start-
                 * on a nice 4kb page.  We need to check for data
                 * sizes > 4096 and, if they cross more than two 4096
                 * byte pages of memory one or more additional TDs
                 * will need to be created.  (repeat doing this in a
                 * loop until all of the DATA is on a TD)
                 *
                 * Control transfers are -highly unlikely- to need to
                 * transfer this much data.. but who knows.. sadistic
                 * hardware is sure to exist.
                 */

                status_td = ohci_get_free_td(dev);  /* TODO check for NULL */
                if (!status_td) {
                        printk(KERN_ERR "usb-ohci: couldn't get TD for dev %p [cntl status]\n", dev);
                        ohci_free_td(setup_td);
                        ohci_free_td(data_td);
                        ohci_free_ed(control_ed);
                        return -1;
                }

                data_td->next_td = cpu_to_le32(virt_to_bus(status_td));
        } else {
                status_td = data_td; /* no data_td, use it for status */
        }

        /* The control status packet always uses a DATA1
         * Give "dev_id" the address of completion_status so that the
         * TDs status can be passed back to us from the IRQ. */
        ohci_fill_new_td(status_td,
                        td_set_dir_in(usb_pipeout(pipe) | (len == 0)),
                        TOGGLE_DATA1,
                        0 /* flags */,
                        NULL /* data */, 0 /* data len */,
                        &completion_status, ohci_control_completed);
        status_td->next_td = 0; /* end of TDs */

        /*
         * Add the chain of 2-3 control TDs to the control ED's TD list
         */
        spin_lock_irqsave(&ohci_edtd_lock, flags);
        setup_td = ohci_add_td_to_ed(setup_td, status_td, control_ed);
        spin_unlock_irqrestore(&ohci_edtd_lock, flags);

#ifdef OHCI_DEBUG
        if (MegaDebug) {
        /* complete transaction debugging output (before) */
        printk(KERN_DEBUG " Control ED %lx:\n", virt_to_bus(control_ed));
        show_ohci_ed(control_ed);
        printk(KERN_DEBUG " Setup TD %lx:\n", virt_to_bus(setup_td));
        show_ohci_td(setup_td);
        if (data_td != status_td) {
                printk(KERN_DEBUG " Data TD %lx:\n", virt_to_bus(data_td));
                show_ohci_td(data_td);
        }
        printk(KERN_DEBUG " Status TD %lx:\n", virt_to_bus(status_td));
        show_ohci_td(status_td);
        printk(KERN_DEBUG " Controller Status:\n");
        show_ohci_status(dev->ohci);
        }
#endif

        /*
         * Start the control transaction..
         */
        current->state = TASK_UNINTERRUPTIBLE;
        add_wait_queue(&control_wakeup, &wait);

        /* Give the ED to the HC */
        ohci_add_control_ed(dev->ohci, control_ed);

        schedule_timeout(HZ/10);

        remove_wait_queue(&control_wakeup, &wait);

#ifdef OHCI_DEBUG
        if (MegaDebug) {
        /* complete transaction debugging output (after) */
        printk(KERN_DEBUG " *after* Control ED %lx:\n", virt_to_bus(control_ed));
        show_ohci_ed(control_ed);
        printk(KERN_DEBUG " *after* Setup TD %lx:\n", virt_to_bus(setup_td));
        show_ohci_td(setup_td);
        if (data_td != status_td) {
                printk(KERN_DEBUG " *after* Data TD %lx:\n", virt_to_bus(data_td));
                show_ohci_td(data_td);
        }
        printk(KERN_DEBUG " *after* Status TD %lx:\n", virt_to_bus(status_td));
        show_ohci_td(status_td);
        printk(KERN_DEBUG " *after* Controller Status:\n");
        show_ohci_status(dev->ohci);
        }
#endif

        /* remove the control ED from the HC */
        ohci_remove_control_ed(dev->ohci, control_ed);
        ohci_free_ed(control_ed);        /* return it to the pool */

#ifdef OHCI_DEBUG
        if (completion_status != 0) {
                char *what = (completion_status < 0)? "timed out":
                        cc_names[completion_status & 0xf];
                printk(KERN_ERR "ohci_control_msg: %s on pipe %x cmd %x %x %x %x %x\n",
                       what, pipe, cmd->requesttype, cmd->request,
                       cmd->value, cmd->index, cmd->length);
        } else if (!usb_pipeout(pipe)) {
                unsigned char *q = data;
                int i;
                printk(KERN_DEBUG "ctrl msg %x %x %x %x %x on pipe %x returned:",
                       cmd->requesttype, cmd->request, cmd->value, cmd->index,
                       cmd->length, pipe);
                for (i = 0; i < len; ++i) {
                        if (i % 16 == 0)
                                printk("\n" KERN_DEBUG);
                        printk(" %x", q[i]);
                }
                printk("\n");
        }
#endif
        return completion_status;
} /* ohci_control_msg() */


/*
 * Allocate a new USB device to be attached to an OHCI controller
 */
static struct usb_device *ohci_usb_allocate(struct usb_device *parent)
{
        struct usb_device *usb_dev;
        struct ohci_device *dev;
        int idx;

        /*
         * Allocate the generic USB device
         */
        usb_dev = kmalloc(sizeof(*usb_dev), GFP_KERNEL);
        if (!usb_dev)
                return NULL;

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

        /*
         * Allocate an OHCI device (EDs and TDs for this device)
         */
        dev = kmalloc(sizeof(*dev), GFP_KERNEL);
        if (!dev) {
                kfree(usb_dev);
                return NULL;
        }

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

        /* Initialize all EDs in a new device with the skip flag so that
         * they are ignored by the controller until set otherwise. */
        for (idx = 0; idx < NUM_EDS; ++idx) {
                dev->ed[idx].status = cpu_to_le32(OHCI_ED_SKIP);
        }

        /*
         * Link them together
         */
        usb_dev->hcpriv = dev;
        dev->usb = usb_dev;

        /*
         * Link the device to its parent (hub, etc..) if any.
         */
        usb_dev->parent = parent;

        if (parent) {
                usb_dev->bus = parent->bus;
                dev->ohci = usb_to_ohci(parent)->ohci;
        }

        return usb_dev;
} /* ohci_usb_allocate() */


/*
 * Free a usb device.
 *
 * TODO This function needs to take better care of the EDs and TDs, etc.
 */
static int ohci_usb_deallocate(struct usb_device *usb_dev)
{
        struct ohci_device *dev = usb_to_ohci(usb_dev);

        ohci_remove_device(dev->ohci, usb_dev->devnum);

        /* kfree(usb_to_ohci(usb_dev)); */
        /* kfree(usb_dev); */
        return 0;
}

/* FIXME! */
#define ohci_bulk_msg NULL

/*
 * functions for the generic USB driver
 */
struct usb_operations ohci_device_operations = {
        ohci_usb_allocate,
        ohci_usb_deallocate,
        ohci_control_msg,
        ohci_bulk_msg,
        ohci_request_irq,
};


/*
 * Reset an OHCI controller.  Returns >= 0 on success.
 *
 * Afterwards the HC will be in the "suspend" state which prevents you
 * from writing to some registers.  Bring it to the operational state
 * ASAP.
 */
static int reset_hc(struct ohci *ohci)
{
        int timeout = 10000;  /* prevent an infinite loop */

#if 0
        printk(KERN_INFO "usb-ohci: resetting HC %p\n", ohci);
#endif

        writel(~0x0, &ohci->regs->intrdisable);    /* Disable HC interrupts */
        writel(1, &ohci->regs->cmdstatus);         /* HC Reset */
        writel_mask(0x3f, &ohci->regs->control);   /* move to UsbReset state */

        while ((readl(&ohci->regs->cmdstatus) & OHCI_CMDSTAT_HCR) != 0) {
                if (!--timeout) {
                        printk(KERN_ERR "usb-ohci: USB HC reset timed out!\n");
                        return -1;
                }
                udelay(1);
        }

        printk(KERN_DEBUG "usb-ohci: HC %p reset.\n", ohci);

        return 0;
} /* reset_hc() */


/*
 * Reset and start an OHCI controller.  Returns >= 0 on success.
 */
static int start_hc(struct ohci *ohci)
{
        int ret = 0;
        int fminterval;
        __u32 what_to_enable;

        struct ohci_device *root_hub=usb_to_ohci(ohci->bus->root_hub);

        fminterval = readl(&ohci->regs->fminterval) & 0x3fff;
#if 0
        printk(KERN_DEBUG "entering start_hc %p\n", ohci);
#endif

        if (reset_hc(ohci) < 0)
                return -1;

        /* restore registers cleared by the reset */
        writel(virt_to_bus(root_hub->hcca), &ohci->regs->hcca);

        /*
         * XXX Should fminterval also be set here?
         * The spec suggests 0x2edf [11,999]. (FIXME: make this a constant)
         */
        /* fminterval |= (0x2edf << 16); */
        fminterval = (10240 << 16) | 11999;
        writel(fminterval, &ohci->regs->fminterval);
        /* Start periodic transfers at 90% of fminterval (fmremaining
         * counts down; this will put them in the first 10% of the
         * frame). */
        writel((0x2edf*9)/10, &ohci->regs->periodicstart);

        /*
         * FNO (frame number overflow) could be enabled...  they
         * occur every 32768 frames (every 32-33 seconds).  This is
         * useful for debugging and as a bus heartbeat. -greg
         */
        /* Choose the interrupts we care about */
        what_to_enable = OHCI_INTR_MIE |
#ifdef OHCI_RHSC_INT
                        OHCI_INTR_RHSC |
#endif
                        /* | OHCI_INTR_FNO */
                        OHCI_INTR_WDH;
        writel( what_to_enable, &ohci->regs->intrenable);

        /* Enter the USB Operational state & start the frames a flowing.. */
        writel_set(OHCI_USB_OPER, &ohci->regs->control);
        
        /* Enable control lists */
        writel_set(OHCI_USB_IE | OHCI_USB_CLE | OHCI_USB_BLE, &ohci->regs->control);

        /* Force global power enable -gal@cs.uni-magdeburg.de */
        /* 
         * This turns on global power switching for all the ports
         * and tells the HC that all of the ports should be powered on
         * all of the time.
         *
         * TODO: This could be battery draining for laptops.. We
         *       should implement power switching.
         */
        writel_set( OHCI_ROOT_A_NPS, &ohci->regs->roothub.a );
        writel_mask( ~((__u32)OHCI_ROOT_A_PSM), &ohci->regs->roothub.a );

        /* Turn on power to the root hub ports (thanks Roman!) */
        writel( OHCI_ROOT_LPSC, &ohci->regs->roothub.status );

        printk(KERN_INFO "usb-ohci: host controller operational\n");

        return ret;
} /* start_hc() */


/*
 * Reset a root hub port
 */
static void ohci_reset_port(struct ohci *ohci, unsigned int port)
{
        int status;

        /* Don't allow overflows. */
        if (port >= MAX_ROOT_PORTS) {
                printk(KERN_ERR "usb-ohci: bad port #%d in ohci_reset_port\n", port);
                port = MAX_ROOT_PORTS-1;
        }

        writel(PORT_PRS, &ohci->regs->roothub.portstatus[port]);  /* Reset */

        /*
         * Wait for the reset to complete.
         */
        wait_ms(20);

        /* check port status to see that the reset completed */
        status = readl(&ohci->regs->roothub.portstatus[port]);
        if (status & PORT_PRS) {
                /* reset failed, try harder? */
                printk(KERN_ERR "usb-ohci: port %d reset failed, retrying\n", port);
                writel(PORT_PRS, &ohci->regs->roothub.portstatus[port]);
                wait_ms(50);
        }

        /* TODO we might need to re-enable the port here or is that
         * done elsewhere? */

} /* ohci_reset_port */


/*
 * This gets called if the connect status on the root hub changes.
 */
static void ohci_connect_change(struct ohci * ohci, int port)
{
        struct usb_device *usb_dev;
        struct ohci_device *dev;
        struct ohci_device *root_hub=usb_to_ohci(ohci->bus->root_hub);
        /* memory I/O address of the port status register */
        __u32 *portaddr = &ohci->regs->roothub.portstatus[port];
        int portstatus; 

#ifdef OHCI_DEBUG
        printk(KERN_DEBUG "ohci_connect_change on port %d\n", port);
#endif

        /*
         * Because of the status change we have to forget
         * everything we think we know about the device
         * on this root hub port.  It may have changed.
         */
        usb_disconnect(root_hub->usb->children + port);

        portstatus = readl(portaddr);

        /* disable the port if nothing is connected */
        if (!(portstatus & PORT_CCS)) {
                writel(PORT_CCS, portaddr);
                /* We need to reset the CSC bit -after- disabling the
                 * port because it causes the CSC bit to come on
                 * again... */
                wait_ms(20);
                writel(PORT_CSC, portaddr);
#ifdef OHCI_DEBUG
                printk(KERN_DEBUG "ohci port %d disabled, nothing connected.\n", port);
#endif
                return;
        }

        /*
         * Allocate a device for the new thingy that's been attached
         */
        usb_dev = ohci_usb_allocate(root_hub->usb);
        dev = usb_dev->hcpriv;

        dev->ohci = ohci;

        usb_connect(dev->usb);

        /* link it into the bus's device tree */
        root_hub->usb->children[port] = usb_dev;

        wait_ms(200); /* wait for powerup; XXX is this needed? */
        ohci_reset_port(ohci, port);

        /* Get information on speed by using LSD */
        usb_dev->slow = readl(portaddr) & PORT_LSDA ? 1 : 0;

        /*
         * Do generic USB device tree processing on the new device.
         */
        usb_new_device(usb_dev);

} /* ohci_connect_change() */


/*
 * This gets called when the root hub configuration
 * has changed.  Just go through each port, seeing if
 * there is something interesting happening.
 */
static void ohci_check_configuration(struct ohci *ohci)
{
        struct ohci_regs *regs = ohci->regs;
        int num = 0;
        int maxport = readl(&ohci->regs->roothub) & 0xff;
        __u32 rh_change_flags = PORT_CSC | PORT_PESC;   /* root hub status changes */

#ifdef OHCI_DEBUG
        printk(KERN_DEBUG "entering ohci_check_configuration %p\n", ohci);
#endif

        do {
                __u32 *portstatus_p = &regs->roothub.portstatus[num];
                if (readl(portstatus_p) & rh_change_flags) {
                        /* acknowledge the root hub status changes */
                        writel_set(rh_change_flags, portstatus_p);
                        /* disable the port if nothing is on it */
                        /* check the port for a nifty device */
                        ohci_connect_change(ohci, num);
                }
        } while (++num < maxport);

#if 0
        printk(KERN_DEBUG "leaving ohci_check_configuration %p\n", ohci);
#endif
} /* ohci_check_configuration() */



/*
 * Check root hub port status and wake the control thread up if
 * anything has changed.
 *
 * This function is called from the interrupt handler.
 */
static void ohci_root_hub_events(struct ohci *ohci)
{
        int num = 0;
        struct ohci_device *root_hub=usb_to_ohci(ohci->bus->root_hub);
        int maxport = root_hub->usb->maxchild;

        if (!waitqueue_active(&ohci_configure))
                return;
        do {
                __u32 *portstatus_p = &ohci->regs->roothub.portstatus[num];
                if (readl(portstatus_p) & PORT_CSC) {
                        if (waitqueue_active(&ohci_configure))
                                wake_up(&ohci_configure);
                        return;
                }
        } while (++num < maxport);
        
} /* ohci_root_hub_events() */


/*
 * The done list is in reverse order; we need to process TDs in the
 * order they were finished (FIFO).  This function builds the FIFO
 * list using the next_dl_td pointer.
 *
 * This function originally by Roman Weissgaerber (weissg@vienna.at)
 *
 * This function is called from the interrupt handler.
 */
static struct ohci_td * ohci_reverse_donelist(struct ohci * ohci)
{
        __u32 td_list_hc;
        struct ohci_device *root_hub=usb_to_ohci(ohci->bus->root_hub);
        struct ohci_hcca *hcca = root_hub->hcca;
        struct ohci_td *td_list = NULL;
        struct ohci_td *td_rev = NULL;

        td_list_hc = le32_to_cpup(&hcca->donehead) & 0xfffffff0;
        hcca->donehead = 0;

        while(td_list_hc) {
                td_list = (struct ohci_td *) bus_to_virt(td_list_hc);
                td_list->next_dl_td = td_rev;
                td_rev = td_list;
                td_list_hc = le32_to_cpup(&td_list->next_td) & 0xfffffff0;
        }

        return td_list;
} /* ohci_reverse_donelist() */


/*
 * Collect this interrupt's goodies off of the list of finished TDs
 * that the OHCI controller is kind enough to setup for us.
 *
 * This function is called from the interrupt handler.
 */
static void ohci_reap_donelist(struct ohci *ohci)
{
        struct ohci_td *td;             /* used for walking the list */

        spin_lock(&ohci_edtd_lock);

        /* create the FIFO ordered donelist */
        td = ohci_reverse_donelist(ohci);

        while (td != NULL) {
                struct ohci_td *next_td = td->next_dl_td;
                int cc = OHCI_TD_CC_GET(le32_to_cpup(&td->info));

                if (td_dummy(*td))
                        printk(KERN_ERR "yikes! reaping a dummy TD\n");

                /* FIXME: munge td->info into a future standard status format */

                if (cc != 0 && ohci_ed_halted(td->ed) && td->completed == 0) {
                        /*
                         * There was an error on this TD and the ED
                         * is halted, and this was not the last TD
                         * of the transaction, so there will be TDs
                         * to clean off the ED.
                         * (We assume that a TD with a non-NULL completed
                         * field is the last one of a transaction.
                         * Ultimately we should have a flag in the TD
                         * to say that it is the last one.)
                         */
                        struct ohci_ed *ed = td->ed;
                        struct ohci_td *tail_td = bus_to_virt(ed_tail_td(ed));
                        struct ohci_td *ntd;

                        ohci_free_td(td);
                        td = ntd = bus_to_virt(ed_head_td(ed));
                        while (td != tail_td) {
                                ntd = bus_to_virt(le32_to_cpup(&td->next_td));
                                if (td->completed != 0)
                                        break;
                                ohci_free_td(td);
                                td = ntd;
                        }
                        /* Set the ED head past the ones we cleaned
                           off, and clear the halted flag */
                        set_ed_head_td(ed, virt_to_bus(ntd));
                        ohci_unhalt_ed(ed);
                        /* If we didn't find a TD with a completion
                           routine, give up */
                        if (td == tail_td) {
                                td = next_td;
                                continue;
                        }
                }

                /* Check if TD should be re-queued */
                if ((td->completed != NULL) &&
                    (td->completed(cc, td->data, td->dev_id))) {
                        /* Mark the TD as active again:
                         * Set the not accessed condition code
                         * Reset the Error count
                         */
                        td->info |= cpu_to_le32(OHCI_TD_CC_NEW);
                        clear_td_errorcount(td);
                        /* reset the toggle field to TOGGLE_AUTO (0) */
                        td->info &= cpu_to_le32(~OHCI_TD_DT);

                        /* point it back to the start of the data buffer */
                        td->cur_buf = cpu_to_le32(virt_to_bus(td->data));

                        /* insert it back on its ED */
                        ohci_add_td_to_ed(td, td, td->ed);
                } else {
                        /* return it to the pool of free TDs */
                        ohci_free_td(td);
                }

                td = next_td;
        }

        spin_unlock(&ohci_edtd_lock);
} /* ohci_reap_donelist() */


/*
 * Get annoyed at the controller for bothering us.
 * This pretty much follows the OHCI v1.0a spec, section 5.3.
 */
static void ohci_interrupt(int irq, void *__ohci, struct pt_regs *r)
{
        struct ohci *ohci = __ohci;
        struct ohci_regs *regs = ohci->regs;
        struct ohci_device *root_hub=usb_to_ohci(ohci->bus->root_hub);
        struct ohci_hcca *hcca = root_hub->hcca;
        __u32 status, context;

        /* Save the status of the interrupts that are enabled */
        status = readl(&regs->intrstatus);
        status &= readl(&regs->intrenable);

        /* make context = the interrupt status bits that we care about */
        if (hcca->donehead != 0) {
                context = OHCI_INTR_WDH;   /* hcca donehead needs processing */
                if (hcca->donehead & cpu_to_le32(1)) {
                        context |= status;  /* other status change to check */
                }
        } else {
                context = status;
                if (!context) {
                        /* TODO increment a useless interrupt counter here */
                        return;
                }
        }

        /* Disable HC interrupts */ /* why? - paulus */
        writel(OHCI_INTR_MIE, &regs->intrdisable);

        /* Process the done list */
        if (context & OHCI_INTR_WDH) {
                /* See which TD's completed.. */
                ohci_reap_donelist(ohci);

                /* reset the done queue and tell the controller */
                hcca->donehead = 0;     /* XXX already done in ohci_reverse_donelist */
                writel(OHCI_INTR_WDH, &regs->intrstatus);

                context &= ~OHCI_INTR_WDH;  /* mark this as checked */
        }

#ifdef OHCI_RHSC_INT
        /* NOTE: this is very funky on some USB controllers (ie: it
         * doesn't work right).  Using the ohci_timer instead to poll
         * the root hub is a much better choice. */
        /* Process any root hub status changes */
        if (context & OHCI_INTR_RHSC) {
                /* Wake the thread to process root hub events */
                if (waitqueue_active(&ohci_configure))
                        wake_up(&ohci_configure);

                writel(OHCI_INTR_RHSC, &regs->intrstatus);
                /* 
                 * Don't unset RHSC in context; it should be disabled.
                 * The control thread will re-enable it after it has
                 * checked the root hub status.
                 */
        }
#endif

        /* Start of Frame interrupts, used during safe ED removal */
        if (context & (OHCI_INTR_SF)) {
                writel(OHCI_INTR_SF, &regs->intrstatus);
                if (waitqueue_active(&start_of_frame_wakeup))
                        wake_up(&start_of_frame_wakeup);
                /* Do NOT mark the frame start interrupt as checked
                 * as we don't want to receive any more of them until
                 * asked. */
        }

        /* Check those "other" pesky bits */
        if (context & (OHCI_INTR_FNO)) {
                writel(OHCI_INTR_FNO, &regs->intrstatus);
                context &= ~OHCI_INTR_FNO;  /* mark this as checked */
        }
        if (context & OHCI_INTR_SO) {
                writel(OHCI_INTR_SO, &regs->intrstatus);
                context &= ~OHCI_INTR_SO;  /* mark this as checked */
        }
        if (context & OHCI_INTR_RD) {
                writel(OHCI_INTR_RD, &regs->intrstatus);
                context &= ~OHCI_INTR_RD;  /* mark this as checked */
        }
        if (context & OHCI_INTR_UE) {
                /* FIXME: need to have the control thread reset the
                 * controller now and keep a count of unrecoverable
                 * errors.  If there are too many, it should just shut
                 * the broken controller down entirely. */
                writel(OHCI_INTR_UE, &regs->intrstatus);
                context &= ~OHCI_INTR_UE;  /* mark this as checked */
        }
        if (context & OHCI_INTR_OC) {
                writel(OHCI_INTR_OC, &regs->intrstatus);
                context &= ~OHCI_INTR_OC;  /* mark this as checked */
        }

        /* Mask out any remaining unprocessed or unmasked interrupts
         * so that we don't get any more of them. */
        if (context & ~OHCI_INTR_MIE) {
                writel(context, &regs->intrdisable);
        }

        /* Re-enable HC interrupts */
        writel(OHCI_INTR_MIE, &regs->intrenable);

} /* ohci_interrupt() */


/*
 * Allocate the resources required for running an OHCI controller.
 * Host controller interrupts must not be running while calling this
 * function or the penguins will get angry.
 *
 * The mem_base parameter must be the usable -virtual- address of the
 * host controller's memory mapped I/O registers.
 */
static struct ohci *alloc_ohci(void* mem_base)
{
        int i;
        struct ohci *ohci;
        struct usb_bus *bus;
        struct ohci_device *dev;
        struct usb_device *usb;

#if 0
        printk(KERN_DEBUG "entering alloc_ohci %p\n", mem_base);
#endif

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

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

        ohci->irq = -1;
        ohci->regs = mem_base;
        INIT_LIST_HEAD(&ohci->interrupt_list);

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

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

        ohci->bus = bus;
        bus->hcpriv = ohci;
        bus->op = &ohci_device_operations;

        /*
         * Allocate the USB device structure and root hub.
         *
         * Here we allocate our own root hub and TDs as well as the
         * OHCI host controller communications area.  The HCCA is just
         * a nice pool of memory with pointers to endpoint descriptors
         * for the different interrupts.
         */
        usb = ohci_usb_allocate(NULL);
        if (!usb)
                return NULL;

        dev = usb_to_ohci(usb);
        ohci->bus->root_hub= ohci_to_usb(dev);
        usb->bus = bus;

        /* Initialize the root hub */
        dev->ohci = ohci;    /* link back to the controller */

        /*
         * Allocate the Host Controller Communications Area on a 256
         * byte boundary.  XXX take the easy way out and just grab a
         * page as that's guaranteed to have a nice boundary.
         */
        dev->hcca = (struct ohci_hcca *) __get_free_page(GFP_KERNEL);
        memset(dev->hcca, 0, sizeof(struct ohci_hcca));
 
        /* Tell the controller where the HCCA is */
        writel(virt_to_bus(dev->hcca), &ohci->regs->hcca);

#if 0
        printk(KERN_DEBUG "usb-ohci: HCCA allocated at %p (bus %p)\n", dev->hcca, (void*)virt_to_bus(dev->hcca));
#endif

        /* Get the number of ports on the root hub */
        usb->maxchild = readl(&ohci->regs->roothub.a) & 0xff;
        if (usb->maxchild > MAX_ROOT_PORTS) {
                printk(KERN_INFO "usb-ohci: Limited to %d ports\n", MAX_ROOT_PORTS);
                usb->maxchild = MAX_ROOT_PORTS;
        }
        if (usb->maxchild < 1) {
                printk(KERN_ERR "usb-ohci: Less than one root hub port? Impossible!\n");
                usb->maxchild = 1;
        }
        printk(KERN_DEBUG "usb-ohci: %d root hub ports found\n", usb->maxchild);

        /*
         * Initialize the ED polling "tree" (for simplicity's sake in
         * this driver many nodes in the tree will be identical)
         */
        dev->ed[ED_INT_32].next_ed = cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_16]));
        dev->ed[ED_INT_16].next_ed = cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_8]));
        dev->ed[ED_INT_8].next_ed = cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_4]));
        dev->ed[ED_INT_4].next_ed = cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_2]));
        dev->ed[ED_INT_2].next_ed = cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_1]));

        /*
         * Initialize the polling table to call interrupts at the
         * intended intervals.  Note that these EDs are just
         * placeholders.  They have their SKIP bit set and are used as
         * list heads to insert real EDs onto.
         */
        dev->hcca->int_table[0] = cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_1]));
        for (i = 1; i < NUM_INTS; i++) {
                if (i & 16)
                        dev->hcca->int_table[i] =
                                cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_32]));
                if (i & 8)
                        dev->hcca->int_table[i] =
                                cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_16]));
                if (i & 4)
                        dev->hcca->int_table[i] =
                                cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_8]));
                if (i & 2)
                        dev->hcca->int_table[i] =
                                cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_4]));
                if (i & 1)
                        dev->hcca->int_table[i] =
                                cpu_to_le32(virt_to_bus(&dev->ed[ED_INT_2]));
        }

        /*
         * Tell the controller where the control and bulk lists are.
         * The lists start out empty.
         */
        writel(0, &ohci->regs->ed_controlhead);
        writel(0, &ohci->regs->ed_bulkhead);

#ifdef OHCI_DEBUG
        printk(KERN_DEBUG "alloc_ohci(): controller\n");
        show_ohci_status(ohci);
#endif

#if 0
        printk(KERN_DEBUG "leaving alloc_ohci %p\n", ohci);
#endif

        return ohci;
} /* alloc_ohci() */


/*
 * De-allocate all resoueces..
 */
static void release_ohci(struct ohci *ohci)
{
        printk(KERN_INFO "Releasing OHCI controller 0x%p\n", ohci);

#ifdef OHCI_TIMER
        /* stop our timer */
        del_timer(&ohci_timer);
#endif
        if (ohci->irq >= 0) {
                free_irq(ohci->irq, ohci);
                ohci->irq = -1;
        }

        /* stop all OHCI interrupts */
        writel(~0x0, &ohci->regs->intrdisable);

        if (ohci->bus->root_hub) {
                struct ohci_device *root_hub=usb_to_ohci(ohci->bus->root_hub);
                /* ensure that HC is stopped before releasing the HCCA */
                writel(OHCI_USB_SUSPEND, &ohci->regs->control);
                free_page((unsigned long) root_hub->hcca);
                kfree(ohci->bus->root_hub);
                root_hub->hcca = NULL;
                ohci->bus->root_hub = NULL;
        }

        /* unmap the IO address space */
        iounmap(ohci->regs);

        kfree(ohci);

        MOD_DEC_USE_COUNT;

        /* If the ohci itself were dynamic we'd free it here */

        printk(KERN_DEBUG "usb-ohci: HC resources released.\n");
} /* release_ohci() */


/*
 * USB OHCI control thread
 */
static int ohci_control_thread(void * __ohci)
{
        struct ohci *ohci = (struct ohci *)__ohci;

        /*
         * I'm unfamiliar with the SMP kernel locking.. where should
         * this be released and what does it do?  -greg
         */
        lock_kernel();

        /*
         * This thread doesn't need any user-level access,
         * so get rid of all of our resources..
         */
        printk(KERN_DEBUG "ohci-control thread code for 0x%p code at 0x%p\n", __ohci, &ohci_control_thread);
        exit_mm(current);
        exit_files(current);
        exit_fs(current);

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

        usb_register_bus(ohci->bus);

        /*
         * Damn the torpedoes, full speed ahead
         */
        if (start_hc(ohci) < 0) {
                printk(KERN_ERR "usb-ohci: failed to start the controller\n");
                release_ohci(ohci);
                usb_deregister_bus(ohci->bus);
                printk(KERN_INFO "leaving ohci_control_thread %p\n", __ohci);
                return 0;
        }

        for(;;) {
                siginfo_t info;
                int unsigned long signr;

                wait_ms(200);

                /* check the root hub configuration for changes. */
                ohci_check_configuration(ohci);

                /* re-enable root hub status change interrupts. */
#ifdef OHCI_RHSC_INT
                writel(OHCI_INTR_RHSC, &ohci->regs->intrenable);
#endif

                printk(KERN_DEBUG "ohci-control thread sleeping\n");
                interruptible_sleep_on(&ohci_configure);
#ifdef CONFIG_APM
                if (apm_resume) {
                        apm_resume = 0;
                        if (start_hc(ohci) < 0)
                                break;
                        continue;
                }
#endif

                /*
                 * If we were woken up by a signal, see if its useful,
                 * otherwise exit.
                 */
                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) {
                                /* TODO: have it do a full ed/td queue dump? */
                                printk(KERN_DEBUG "OHCI status dump:\n");
                                show_ohci_status(ohci);
                        } else if (signr == SIGUSR2) {
                                /* toggle mega TD/ED debugging output */
                                MegaDebug = !MegaDebug;
                                printk(KERN_DEBUG "usb-ohci: Mega debugging %sabled.\n",
                                                MegaDebug ? "en" : "dis");
                        } else {
                                /* unknown signal, exit the thread */
                                break;
                        }
                }
        } /* for (;;) */

        reset_hc(ohci);
        release_ohci(ohci);
        usb_deregister_bus(ohci->bus);
        printk(KERN_DEBUG "ohci-control thread for 0x%p exiting\n", __ohci);

        return 0;
} /* ohci_control_thread() */


#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 "usb-ohci: received extra suspend event\n");
                        break;
                }
                down = 1;
                break;
        case APM_NORMAL_RESUME:
        case APM_CRITICAL_RESUME:
                if (!down) {
                        printk(KERN_DEBUG "usb-ohci: received bogus resume event\n");
                        break;
                }
                down = 0;
                if (waitqueue_active(&ohci_configure)) {
                        apm_resume = 1;
                        wake_up(&ohci_configure);
                }
                break;
        }
        return 0;
} /* handle_apm_event() */
#endif


#ifdef OHCI_TIMER
/*
 * Inspired by Iñaky's driver.  This function is a timer routine that
 * is called every OHCI_TIMER_FREQ ms.  It polls the root hub for
 * status changes as on my system the RHSC interrupt just doesn't
 * play well with others.. (so RHSC is turned off by default in this
 * driver)
 * [my controller is a "SiS 7001 USB (rev 16)"]
 * -greg
 */
static void ohci_timer_func (unsigned long ohci_ptr)
{
        struct ohci *ohci = (struct ohci*)ohci_ptr;

        ohci_root_hub_events(ohci);

        /* set the next timer */
        mod_timer(&ohci_timer, jiffies + ((OHCI_TIMER_FREQ*HZ)/1000));

} /* ohci_timer_func() */
#endif


/*
 * Increment the module usage count, start the control thread and
 * return success if the controller is good.
 */
static int found_ohci(int irq, void* mem_base)
{
        int retval;
        struct ohci *ohci;

#if 0
        printk(KERN_DEBUG "entering found_ohci %d %p\n", irq, mem_base);
#endif

        /* Allocate the running OHCI structures */
        ohci = alloc_ohci(mem_base);
        if (!ohci) {
                return -ENOMEM;
        }

#ifdef OHCI_TIMER
        init_timer(&ohci_timer);
        ohci_timer.expires = jiffies + ((OHCI_TIMER_FREQ*HZ)/1000);
        ohci_timer.data = (unsigned long)ohci;
        ohci_timer.function = ohci_timer_func;
        add_timer(&ohci_timer);
#endif

        retval = -EBUSY;
        if (request_irq(irq, ohci_interrupt, SA_SHIRQ, "usb-ohci", ohci) == 0) {
                int pid;

                ohci->irq = irq;

#ifdef OHCI_DEBUG
                printk(KERN_DEBUG "usb-ohci: forking ohci-control thread for 0x%p\n", ohci);
#endif

                /* fork off the handler */
                pid = kernel_thread(ohci_control_thread, ohci,
                                CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
                if (pid >= 0) {
                        return 0;
                }

                retval = pid;
        } else {
                printk(KERN_ERR "usb-ohci: Couldn't allocate interrupt %d\n", irq);
        }
        release_ohci(ohci);

#ifdef OHCI_DEBUG
        printk(KERN_DEBUG "leaving found_ohci %d %p\n", irq, mem_base);
#endif

        return retval;
} /* found_ohci() */


/*
 * If this controller is for real, map the IO memory and proceed
 */
static int init_ohci(struct pci_dev *dev)
{
        unsigned long mem_base = dev->base_address[0];
        
        /* If its OHCI, its memory */
        if (mem_base & PCI_BASE_ADDRESS_SPACE_IO)
                return -ENODEV;

        /* Get the memory address and map it for IO */
        mem_base &= PCI_BASE_ADDRESS_MEM_MASK;

        /* no interrupt won't work... */
        if (dev->irq == 0) {
                printk(KERN_ERR "usb-ohci: no irq assigned? check your BIOS settings.\n");
                return -ENODEV;
        }

        /* 
         * FIXME ioremap_nocache isn't implemented on all CPUs (such
         * as the Alpha) [?]  What should I use instead...
         *
         * The iounmap() is done on in release_ohci.
         */
        mem_base = (unsigned long) ioremap_nocache(mem_base, 4096);

        if (!mem_base) {
                printk(KERN_ERR "Error mapping OHCI memory\n");
                return -EFAULT;
        }
        MOD_INC_USE_COUNT;

#ifdef OHCI_DEBUG
        printk(KERN_INFO "usb-ohci: Warning! Gobs of debugging output has been enabled.\n");
        printk(KERN_INFO "          Check your kern.debug logs for the bulk of it.\n");
#endif

        if (found_ohci(dev->irq, (void *) mem_base) < 0) {
                MOD_DEC_USE_COUNT;
                return -1;
        }

        return 0;
} /* init_ohci() */

/* TODO this should be named following Linux convention and go in pci.h */
#define PCI_CLASS_SERIAL_USB_OHCI ((PCI_CLASS_SERIAL_USB << 8) | 0x0010)

/*
 * Search the PCI bus for an OHCI USB controller and set it up
 *
 * If anyone wants multiple controllers this will need to be
 * updated..  Right now, it just picks the first one it finds.
 */
int ohci_init(void)
{
        int retval;
        struct pci_dev *dev = NULL;
        /*u8 type;*/

        if (sizeof(struct ohci_device) > 4096) {
                printk(KERN_ERR "usb-ohci: struct ohci_device to large\n");
                return -ENODEV;
        }

        printk(KERN_INFO "OHCI USB Driver loading\n");

        retval = -ENODEV;
        for (;;) {
                /* Find an OHCI USB controller */
                dev = pci_find_class(PCI_CLASS_SERIAL_USB_OHCI, dev);
                if (!dev)
                        break;

                /* Verify that its OpenHCI by checking for MMIO */
                /* pci_read_config_byte(dev, PCI_CLASS_PROG, &type);
                if (!type)
                        continue; */

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

#ifdef CONFIG_APM
                apm_register_callback(&handle_apm_event);
#endif

                return 0; /* no error */
        }
        return retval;
} /* ohci_init */


/* vim:sw=8
 */

#ifdef MODULE
/*
 *  Clean up when unloading the module
 */
void cleanup_module(void){
#       ifdef CONFIG_APM
        apm_unregister_callback(&handle_apm_event);
#       endif
        printk(KERN_ERR "usb-ohci: module unloaded\n");
}

int init_module(void){
        return ohci_init();
}
#endif //MODULE