[PATCH] I2C: i2c-algo-pca -- gracefully handle a busy bus

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

/*
 * Universal Host Controller Interface driver for USB.
 *
 * Maintainer: Alan Stern <stern@rowland.harvard.edu>
 *
 * (C) Copyright 1999 Linus Torvalds
 * (C) Copyright 1999-2002 Johannes Erdfelt, johannes@erdfelt.com
 * (C) Copyright 1999 Randy Dunlap
 * (C) Copyright 1999 Georg Acher, acher@in.tum.de
 * (C) Copyright 1999 Deti Fliegl, deti@fliegl.de
 * (C) Copyright 1999 Thomas Sailer, sailer@ife.ee.ethz.ch
 * (C) Copyright 1999 Roman Weissgaerber, weissg@vienna.at
 * (C) Copyright 2000 Yggdrasil Computing, Inc. (port of new PCI interface
 *               support from usb-ohci.c by Adam Richter, adam@yggdrasil.com).
 * (C) Copyright 1999 Gregory P. Smith (from usb-ohci.c)
 * (C) Copyright 2004-2005 Alan Stern, stern@rowland.harvard.edu
 *
 * Intel documents this fairly well, and as far as I know there
 * are no royalties or anything like that, but even so there are
 * people who decided that they want to do the same thing in a
 * completely different way.
 *
 */

#include <linux/config.h>
#ifdef CONFIG_USB_DEBUG
#define DEBUG
#else
#undef DEBUG
#endif
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/pm.h>
#include <linux/dmapool.h>
#include <linux/dma-mapping.h>
#include <linux/usb.h>
#include <linux/bitops.h>

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

#include "../core/hcd.h"
#include "uhci-hcd.h"

/*
 * Version Information
 */
#define DRIVER_VERSION "v2.3"
#define DRIVER_AUTHOR "Linus 'Frodo Rabbit' Torvalds, Johannes Erdfelt, \
Randy Dunlap, Georg Acher, Deti Fliegl, Thomas Sailer, Roman Weissgaerber, \
Alan Stern"
#define DRIVER_DESC "USB Universal Host Controller Interface driver"

/*
 * debug = 0, no debugging messages
 * debug = 1, dump failed URB's except for stalls
 * debug = 2, dump all failed URB's (including stalls)
 *            show all queues in /debug/uhci/[pci_addr]
 * debug = 3, show all TD's in URB's when dumping
 */
#ifdef DEBUG
static int debug = 1;
#else
static int debug = 0;
#endif
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug level");
static char *errbuf;
#define ERRBUF_LEN    (32 * 1024)

static kmem_cache_t *uhci_up_cachep;    /* urb_priv */

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

/* If a transfer is still active after this much time, turn off FSBR */
#define IDLE_TIMEOUT    msecs_to_jiffies(50)
#define FSBR_DELAY      msecs_to_jiffies(50)

/* When we timeout an idle transfer for FSBR, we'll switch it over to */
/* depth first traversal. We'll do it in groups of this number of TD's */
/* to make sure it doesn't hog all of the bandwidth */
#define DEPTH_INTERVAL 5

static inline void restart_timer(struct uhci_hcd *uhci)
{
        mod_timer(&uhci->stall_timer, jiffies + msecs_to_jiffies(100));
}

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

/*
 * Make sure the controller is completely inactive, unable to
 * generate interrupts or do DMA.
 */
static void reset_hc(struct uhci_hcd *uhci)
{
        int port;

        /* Turn off PIRQ enable and SMI enable.  (This also turns off the
         * BIOS's USB Legacy Support.)  Turn off all the R/WC bits too.
         */
        pci_write_config_word(to_pci_dev(uhci_dev(uhci)), USBLEGSUP,
                        USBLEGSUP_RWC);

        /* 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, uhci->io_addr + USBCMD);
        mb();
        udelay(5);
        if (inw(uhci->io_addr + USBCMD) & USBCMD_HCRESET)
                dev_warn(uhci_dev(uhci), "HCRESET not completed yet!\n");

        /* Just to be safe, disable interrupt requests and
         * make sure the controller is stopped.
         */
        outw(0, uhci->io_addr + USBINTR);
        outw(0, uhci->io_addr + USBCMD);

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

        uhci->port_c_suspend = uhci->suspended_ports =
                        uhci->resuming_ports = 0;
        uhci->rh_state = UHCI_RH_RESET;
        uhci->is_stopped = UHCI_IS_STOPPED;
        uhci_to_hcd(uhci)->state = HC_STATE_HALT;
        uhci_to_hcd(uhci)->poll_rh = 0;
}

/*
 * Last rites for a defunct/nonfunctional controller
 * or one we don't want to use any more.
 */
static void hc_died(struct uhci_hcd *uhci)
{
        reset_hc(uhci);
        uhci->hc_inaccessible = 1;
        del_timer(&uhci->stall_timer);
}

/*
 * Initialize a controller that was newly discovered or has just been
 * resumed.  In either case we can't be sure of its previous state.
 */
static void check_and_reset_hc(struct uhci_hcd *uhci)
{
        u16 legsup;
        unsigned int cmd, intr;

        /*
         * When restarting a suspended controller, we expect all the
         * settings to be the same as we left them:
         *
         *      PIRQ and SMI disabled, no R/W bits set in USBLEGSUP;
         *      Controller is stopped and configured with EGSM set;
         *      No interrupts enabled except possibly Resume Detect.
         *
         * If any of these conditions are violated we do a complete reset.
         */
        pci_read_config_word(to_pci_dev(uhci_dev(uhci)), USBLEGSUP, &legsup);
        if (legsup & ~(USBLEGSUP_RO | USBLEGSUP_RWC)) {
                dev_dbg(uhci_dev(uhci), "%s: legsup = 0x%04x\n",
                                __FUNCTION__, legsup);
                goto reset_needed;
        }

        cmd = inw(uhci->io_addr + USBCMD);
        if ((cmd & USBCMD_RS) || !(cmd & USBCMD_CF) || !(cmd & USBCMD_EGSM)) {
                dev_dbg(uhci_dev(uhci), "%s: cmd = 0x%04x\n",
                                __FUNCTION__, cmd);
                goto reset_needed;
        }

        intr = inw(uhci->io_addr + USBINTR);
        if (intr & (~USBINTR_RESUME)) {
                dev_dbg(uhci_dev(uhci), "%s: intr = 0x%04x\n",
                                __FUNCTION__, intr);
                goto reset_needed;
        }
        return;

reset_needed:
        dev_dbg(uhci_dev(uhci), "Performing full reset\n");
        reset_hc(uhci);
}

/*
 * Store the basic register settings needed by the controller.
 */
static void configure_hc(struct uhci_hcd *uhci)
{
        /* Set the frame length to the default: 1 ms exactly */
        outb(USBSOF_DEFAULT, uhci->io_addr + USBSOF);

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

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

        /* Mark controller as running before we enable interrupts */
        uhci_to_hcd(uhci)->state = HC_STATE_RUNNING;
        mb();

        /* Enable PIRQ */
        pci_write_config_word(to_pci_dev(uhci_dev(uhci)), USBLEGSUP,
                        USBLEGSUP_DEFAULT);
}


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

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

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

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

static void suspend_rh(struct uhci_hcd *uhci, enum uhci_rh_state new_state)
__releases(uhci->lock)
__acquires(uhci->lock)
{
        int auto_stop;
        int int_enable;

        auto_stop = (new_state == UHCI_RH_AUTO_STOPPED);
        dev_dbg(uhci_dev(uhci), "%s%s\n", __FUNCTION__,
                        (auto_stop ? " (auto-stop)" : ""));

        /* If we get a suspend request when we're already auto-stopped
         * then there's nothing to do.
         */
        if (uhci->rh_state == UHCI_RH_AUTO_STOPPED) {
                uhci->rh_state = new_state;
                return;
        }

        /* Enable resume-detect interrupts if they work.
         * Then enter Global Suspend mode, still configured.
         */
        int_enable = (resume_detect_interrupts_are_broken(uhci) ?
                        0 : USBINTR_RESUME);
        outw(int_enable, uhci->io_addr + USBINTR);
        outw(USBCMD_EGSM | USBCMD_CF, uhci->io_addr + USBCMD);
        mb();
        udelay(5);

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

        uhci_get_current_frame_number(uhci);
        smp_wmb();

        uhci->rh_state = new_state;
        uhci->is_stopped = UHCI_IS_STOPPED;
        del_timer(&uhci->stall_timer);
        uhci_to_hcd(uhci)->poll_rh = !int_enable;

        uhci_scan_schedule(uhci, NULL);
}

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

        /* Mark it configured and running with a 64-byte max packet.
         * All interrupts are enabled, even though RESUME won't do anything.
         */
        outw(USBCMD_RS | USBCMD_CF | USBCMD_MAXP, uhci->io_addr + USBCMD);
        outw(USBINTR_TIMEOUT | USBINTR_RESUME | USBINTR_IOC | USBINTR_SP,
                        uhci->io_addr + USBINTR);
        mb();
        uhci->rh_state = UHCI_RH_RUNNING;
        uhci_to_hcd(uhci)->poll_rh = 1;
        restart_timer(uhci);
}

static void wakeup_rh(struct uhci_hcd *uhci)
__releases(uhci->lock)
__acquires(uhci->lock)
{
        dev_dbg(uhci_dev(uhci), "%s%s\n", __FUNCTION__,
                        uhci->rh_state == UHCI_RH_AUTO_STOPPED ?
                                " (auto-start)" : "");

        /* If we are auto-stopped then no devices are attached so there's
         * no need for wakeup signals.  Otherwise we send Global Resume
         * for 20 ms.
         */
        if (uhci->rh_state == UHCI_RH_SUSPENDED) {
                uhci->rh_state = UHCI_RH_RESUMING;
                outw(USBCMD_FGR | USBCMD_EGSM | USBCMD_CF,
                                uhci->io_addr + USBCMD);
                spin_unlock_irq(&uhci->lock);
                msleep(20);
                spin_lock_irq(&uhci->lock);
                if (uhci->hc_inaccessible)      /* Died */
                        return;

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

        start_rh(uhci);

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

static void stall_callback(unsigned long _uhci)
{
        struct uhci_hcd *uhci = (struct uhci_hcd *) _uhci;
        unsigned long flags;

        spin_lock_irqsave(&uhci->lock, flags);
        uhci_scan_schedule(uhci, NULL);
        check_fsbr(uhci);

        if (!uhci->is_stopped)
                restart_timer(uhci);
        spin_unlock_irqrestore(&uhci->lock, flags);
}

static irqreturn_t uhci_irq(struct usb_hcd *hcd, struct pt_regs *regs)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        unsigned short status;
        unsigned long flags;

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

        if (status & ~(USBSTS_USBINT | USBSTS_ERROR | USBSTS_RD)) {
                if (status & USBSTS_HSE)
                        dev_err(uhci_dev(uhci), "host system error, "
                                        "PCI problems?\n");
                if (status & USBSTS_HCPE)
                        dev_err(uhci_dev(uhci), "host controller process "
                                        "error, something bad happened!\n");
                if (status & USBSTS_HCH) {
                        spin_lock_irqsave(&uhci->lock, flags);
                        if (uhci->rh_state >= UHCI_RH_RUNNING) {
                                dev_err(uhci_dev(uhci),
                                        "host controller halted, "
                                        "very bad!\n");
                                hc_died(uhci);
                                spin_unlock_irqrestore(&uhci->lock, flags);
                                return IRQ_HANDLED;
                        }
                        spin_unlock_irqrestore(&uhci->lock, flags);
                }
        }

        if (status & USBSTS_RD)
                usb_hcd_poll_rh_status(hcd);

        spin_lock_irqsave(&uhci->lock, flags);
        uhci_scan_schedule(uhci, regs);
        spin_unlock_irqrestore(&uhci->lock, flags);

        return IRQ_HANDLED;
}

/*
 * Store the current frame number in uhci->frame_number if the controller
 * is runnning
 */
static void uhci_get_current_frame_number(struct uhci_hcd *uhci)
{
        if (!uhci->is_stopped)
                uhci->frame_number = inw(uhci->io_addr + USBFRNUM);
}

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

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

        if (uhci->term_td) {
                uhci_free_td(uhci, uhci->term_td);
                uhci->term_td = NULL;
        }

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

        if (uhci->td_pool) {
                dma_pool_destroy(uhci->td_pool);
                uhci->td_pool = NULL;
        }

        if (uhci->fl) {
                dma_free_coherent(uhci_dev(uhci), sizeof(*uhci->fl),
                                uhci->fl, uhci->fl->dma_handle);
                uhci->fl = NULL;
        }

        if (uhci->dentry) {
                debugfs_remove(uhci->dentry);
                uhci->dentry = NULL;
        }
}

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

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

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

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

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

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

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

        hc_died(hcd_to_uhci(hcd));
}

/*
 * Allocate a frame list, and then setup the skeleton
 *
 * The hardware doesn't really know any difference
 * in the queues, but the order does matter for the
 * protocols higher up. The order 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, split into low- and full-speed
 *  - The third queue is bulk queue.
 *  - The fourth queue is the bandwidth reclamation queue, which loops back
 *    to the full-speed control queue.
 */
static int uhci_start(struct usb_hcd *hcd)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        int retval = -EBUSY;
        int i;
        dma_addr_t dma_handle;
        struct dentry *dentry;

        hcd->uses_new_polling = 1;
        if (pci_find_capability(to_pci_dev(uhci_dev(uhci)), PCI_CAP_ID_PM))
                hcd->can_wakeup = 1;            /* Assume it supports PME# */

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

        uhci->fsbr = 0;
        uhci->fsbrtimeout = 0;

        spin_lock_init(&uhci->lock);
        INIT_LIST_HEAD(&uhci->qh_remove_list);

        INIT_LIST_HEAD(&uhci->td_remove_list);

        INIT_LIST_HEAD(&uhci->urb_remove_list);

        INIT_LIST_HEAD(&uhci->urb_list);

        INIT_LIST_HEAD(&uhci->complete_list);

        init_waitqueue_head(&uhci->waitqh);

        init_timer(&uhci->stall_timer);
        uhci->stall_timer.function = stall_callback;
        uhci->stall_timer.data = (unsigned long) uhci;

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

        memset((void *)uhci->fl, 0, sizeof(*uhci->fl));

        uhci->fl->dma_handle = dma_handle;

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

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

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

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

        /*
         * 8 Interrupt queues; link all higher int queues to int1,
         * then link int1 to control and control to bulk
         */
        uhci->skel_int128_qh->link =
                        uhci->skel_int64_qh->link =
                        uhci->skel_int32_qh->link =
                        uhci->skel_int16_qh->link =
                        uhci->skel_int8_qh->link =
                        uhci->skel_int4_qh->link =
                        uhci->skel_int2_qh->link =
                        cpu_to_le32(uhci->skel_int1_qh->dma_handle) | UHCI_PTR_QH;
        uhci->skel_int1_qh->link = cpu_to_le32(uhci->skel_ls_control_qh->dma_handle) | UHCI_PTR_QH;

        uhci->skel_ls_control_qh->link = cpu_to_le32(uhci->skel_fs_control_qh->dma_handle) | UHCI_PTR_QH;
        uhci->skel_fs_control_qh->link = cpu_to_le32(uhci->skel_bulk_qh->dma_handle) | UHCI_PTR_QH;
        uhci->skel_bulk_qh->link = cpu_to_le32(uhci->skel_term_qh->dma_handle) | UHCI_PTR_QH;

        /* This dummy TD is to work around a bug in Intel PIIX controllers */
        uhci_fill_td(uhci->term_td, 0, (UHCI_NULL_DATA_SIZE << 21) |
                (0x7f << TD_TOKEN_DEVADDR_SHIFT) | USB_PID_IN, 0);
        uhci->term_td->link = cpu_to_le32(uhci->term_td->dma_handle);

        uhci->skel_term_qh->link = UHCI_PTR_TERM;
        uhci->skel_term_qh->element = cpu_to_le32(uhci->term_td->dma_handle);

        /*
         * Fill the frame list: make all entries point to the proper
         * interrupt queue.
         *
         * The interrupt queues will be interleaved as evenly as possible.
         * There's not much to be done about period-1 interrupts; they have
         * to occur in every frame.  But we can schedule period-2 interrupts
         * in odd-numbered frames, period-4 interrupts in frames congruent
         * to 2 (mod 4), and so on.  This way each frame only has two
         * interrupt QHs, which will help spread out bandwidth utilization.
         */
        for (i = 0; i < UHCI_NUMFRAMES; i++) {
                int irq;

                /*
                 * ffs (Find First bit Set) does exactly what we need:
                 * 1,3,5,...  => ffs = 0 => use skel_int2_qh = skelqh[6],
                 * 2,6,10,... => ffs = 1 => use skel_int4_qh = skelqh[5], etc.
                 * ffs > 6 => not on any high-period queue, so use
                 *      skel_int1_qh = skelqh[7].
                 * Add UHCI_NUMFRAMES to insure at least one bit is set.
                 */
                irq = 6 - (int) __ffs(i + UHCI_NUMFRAMES);
                if (irq < 0)
                        irq = 7;

                /* Only place we don't use the frame list routines */
                uhci->fl->frame[i] = UHCI_PTR_QH |
                                cpu_to_le32(uhci->skelqh[irq]->dma_handle);
        }

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

        configure_hc(uhci);
        start_rh(uhci);
        return 0;

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

        uhci_free_td(uhci, uhci->term_td);
        uhci->term_td = NULL;

err_alloc_term_td:
        dma_pool_destroy(uhci->qh_pool);
        uhci->qh_pool = NULL;

err_create_qh_pool:
        dma_pool_destroy(uhci->td_pool);
        uhci->td_pool = NULL;

err_create_td_pool:
        dma_free_coherent(uhci_dev(uhci), sizeof(*uhci->fl),
                        uhci->fl, uhci->fl->dma_handle);
        uhci->fl = NULL;

err_alloc_fl:
        debugfs_remove(uhci->dentry);
        uhci->dentry = NULL;

err_create_debug_entry:
        return retval;
}

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

        spin_lock_irq(&uhci->lock);
        reset_hc(uhci);
        uhci_scan_schedule(uhci, NULL);
        spin_unlock_irq(&uhci->lock);

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

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

        spin_lock_irq(&uhci->lock);
        if (!uhci->hc_inaccessible)             /* Not dead */
                suspend_rh(uhci, UHCI_RH_SUSPENDED);
        spin_unlock_irq(&uhci->lock);
        return 0;
}

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

        spin_lock_irq(&uhci->lock);
        if (uhci->hc_inaccessible) {
                if (uhci->rh_state == UHCI_RH_SUSPENDED) {
                        dev_warn(uhci_dev(uhci), "HC isn't running!\n");
                        rc = -ENODEV;
                }
                /* Otherwise the HC is dead */
        } else
                wakeup_rh(uhci);
        spin_unlock_irq(&uhci->lock);
        return rc;
}

static int uhci_suspend(struct usb_hcd *hcd, pm_message_t message)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        int rc = 0;

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

        spin_lock_irq(&uhci->lock);
        if (uhci->hc_inaccessible)      /* Dead or already suspended */
                goto done;

#ifndef CONFIG_USB_SUSPEND
        /* Otherwise this would never happen */
        suspend_rh(uhci, UHCI_RH_SUSPENDED);
#endif

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

        /* All PCI host controllers are required to disable IRQ generation
         * at the source, so we must turn off PIRQ.
         */
        pci_write_config_word(to_pci_dev(uhci_dev(uhci)), USBLEGSUP, 0);
        uhci->hc_inaccessible = 1;

        /* FIXME: Enable non-PME# remote wakeup? */

done:
        spin_unlock_irq(&uhci->lock);
        if (rc == 0)
                del_timer_sync(&hcd->rh_timer);
        return rc;
}

static int uhci_resume(struct usb_hcd *hcd)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);

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

        if (uhci->rh_state == UHCI_RH_RESET)    /* Dead */
                return 0;
        spin_lock_irq(&uhci->lock);

        /* FIXME: Disable non-PME# remote wakeup? */

        uhci->hc_inaccessible = 0;

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

#ifndef CONFIG_USB_SUSPEND
        /* Otherwise this would never happen */
        wakeup_rh(uhci);
#endif
        if (uhci->rh_state == UHCI_RH_RESET)
                suspend_rh(uhci, UHCI_RH_SUSPENDED);

        spin_unlock_irq(&uhci->lock);

        if (hcd->poll_rh)
                usb_hcd_poll_rh_status(hcd);
        return 0;
}
#endif

/* Wait until all the URBs for a particular device/endpoint are gone */
static void uhci_hcd_endpoint_disable(struct usb_hcd *hcd,
                struct usb_host_endpoint *ep)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);

        wait_event_interruptible(uhci->waitqh, list_empty(&ep->urb_list));
}

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

        /* Minimize latency by avoiding the spinlock */
        local_irq_save(flags);
        is_stopped = uhci->is_stopped;
        smp_rmb();
        frame_number = (is_stopped ? uhci->frame_number :
                        inw(uhci->io_addr + USBFRNUM));
        local_irq_restore(flags);
        return frame_number;
}

static const char hcd_name[] = "uhci_hcd";

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

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

        /* Basic lifecycle operations */
        .reset =                uhci_reset,
        .start =                uhci_start,
#ifdef CONFIG_PM
        .suspend =              uhci_suspend,
        .resume =               uhci_resume,
        .hub_suspend =          uhci_rh_suspend,
        .hub_resume =           uhci_rh_resume,
#endif
        .stop =                 uhci_stop,

        .urb_enqueue =          uhci_urb_enqueue,
        .urb_dequeue =          uhci_urb_dequeue,

        .endpoint_disable =     uhci_hcd_endpoint_disable,
        .get_frame_number =     uhci_hcd_get_frame_number,

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

static const struct pci_device_id uhci_pci_ids[] = { {
        /* handle any USB UHCI controller */
        PCI_DEVICE_CLASS(((PCI_CLASS_SERIAL_USB << 8) | 0x00), ~0),
        .driver_data =  (unsigned long) &uhci_driver,
        }, { /* end: all zeroes */ }
};

MODULE_DEVICE_TABLE(pci, uhci_pci_ids);

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

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

#ifdef  CONFIG_PM
        .suspend =      usb_hcd_pci_suspend,
        .resume =       usb_hcd_pci_resume,
#endif  /* PM */
};
 
static int __init uhci_hcd_init(void)
{
        int retval = -ENOMEM;

        printk(KERN_INFO DRIVER_DESC " " DRIVER_VERSION "\n");

        if (usb_disabled())
                return -ENODEV;

        if (debug) {
                errbuf = kmalloc(ERRBUF_LEN, GFP_KERNEL);
                if (!errbuf)
                        goto errbuf_failed;
        }

        uhci_debugfs_root = debugfs_create_dir("uhci", NULL);
        if (!uhci_debugfs_root)
                goto debug_failed;

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

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

        return 0;

init_failed:
        if (kmem_cache_destroy(uhci_up_cachep))
                warn("not all urb_priv's were freed!");

up_failed:
        debugfs_remove(uhci_debugfs_root);

debug_failed:
        kfree(errbuf);

errbuf_failed:

        return retval;
}

static void __exit uhci_hcd_cleanup(void) 
{
        pci_unregister_driver(&uhci_pci_driver);
        
        if (kmem_cache_destroy(uhci_up_cachep))
                warn("not all urb_priv's were freed!");

        debugfs_remove(uhci_debugfs_root);
        kfree(errbuf);
}

module_init(uhci_hcd_init);
module_exit(uhci_hcd_cleanup);

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