[deliverable/linux.git] / drivers / usb / host / ehci-hcd.c

/*
 * Enhanced Host Controller Interface (EHCI) driver for USB.
 *
 * Maintainer: Alan Stern <stern@rowland.harvard.edu>
 *
 * Copyright (c) 2000-2004 by David Brownell
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

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

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

#if defined(CONFIG_PPC_PS3)
#include <asm/firmware.h>
#endif

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

/*
 * EHCI hc_driver implementation ... experimental, incomplete.
 * Based on the final 1.0 register interface specification.
 *
 * USB 2.0 shows up in upcoming www.pcmcia.org technology.
 * First was PCMCIA, like ISA; then CardBus, which is PCI.
 * Next comes "CardBay", using USB 2.0 signals.
 *
 * Contains additional contributions by Brad Hards, Rory Bolt, and others.
 * Special thanks to Intel and VIA for providing host controllers to
 * test this driver on, and Cypress (including In-System Design) for
 * providing early devices for those host controllers to talk to!
 */

#define DRIVER_AUTHOR "David Brownell"
#define DRIVER_DESC "USB 2.0 'Enhanced' Host Controller (EHCI) Driver"

static const char       hcd_name [] = "ehci_hcd";


#undef EHCI_URB_TRACE

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

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

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

/* for flakey hardware, ignore overcurrent indicators */
static bool ignore_oc = 0;
module_param (ignore_oc, bool, S_IRUGO);
MODULE_PARM_DESC (ignore_oc, "ignore bogus hardware overcurrent indications");

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

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

#include "ehci.h"
#include "pci-quirks.h"

static void compute_tt_budget(u8 budget_table[EHCI_BANDWIDTH_SIZE],
                struct ehci_tt *tt);

/*
 * The MosChip MCS9990 controller updates its microframe counter
 * a little before the frame counter, and occasionally we will read
 * the invalid intermediate value.  Avoid problems by checking the
 * microframe number (the low-order 3 bits); if they are 0 then
 * re-read the register to get the correct value.
 */
static unsigned ehci_moschip_read_frame_index(struct ehci_hcd *ehci)
{
        unsigned uf;

        uf = ehci_readl(ehci, &ehci->regs->frame_index);
        if (unlikely((uf & 7) == 0))
                uf = ehci_readl(ehci, &ehci->regs->frame_index);
        return uf;
}

static inline unsigned ehci_read_frame_index(struct ehci_hcd *ehci)
{
        if (ehci->frame_index_bug)
                return ehci_moschip_read_frame_index(ehci);
        return ehci_readl(ehci, &ehci->regs->frame_index);
}

#include "ehci-dbg.c"

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

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

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

/* check TDI/ARC silicon is in host mode */
static int tdi_in_host_mode (struct ehci_hcd *ehci)
{
        u32             tmp;

        tmp = ehci_readl(ehci, &ehci->regs->usbmode);
        return (tmp & 3) == USBMODE_CM_HC;
}

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

        spin_lock_irq(&ehci->lock);

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

        if (ehci_is_TDI(ehci) && !tdi_in_host_mode(ehci)) {
                spin_unlock_irq(&ehci->lock);
                return 0;
        }

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

        spin_unlock_irq(&ehci->lock);
        synchronize_irq(ehci_to_hcd(ehci)->irq);

        return ehci_handshake(ehci, &ehci->regs->status,
                          STS_HALT, STS_HALT, 16 * 125);
}

/* put TDI/ARC silicon into EHCI mode */
static void tdi_reset (struct ehci_hcd *ehci)
{
        u32             tmp;

        tmp = ehci_readl(ehci, &ehci->regs->usbmode);
        tmp |= USBMODE_CM_HC;
        /* The default byte access to MMR space is LE after
         * controller reset. Set the required endian mode
         * for transfer buffers to match the host microprocessor
         */
        if (ehci_big_endian_mmio(ehci))
                tmp |= USBMODE_BE;
        ehci_writel(ehci, tmp, &ehci->regs->usbmode);
}

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

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

        command |= CMD_RESET;
        dbg_cmd (ehci, "reset", command);
        ehci_writel(ehci, command, &ehci->regs->command);
        ehci->rh_state = EHCI_RH_HALTED;
        ehci->next_statechange = jiffies;
        retval = ehci_handshake(ehci, &ehci->regs->command,
                            CMD_RESET, 0, 250 * 1000);

        if (ehci->has_hostpc) {
                ehci_writel(ehci, USBMODE_EX_HC | USBMODE_EX_VBPS,
                                &ehci->regs->usbmode_ex);
                ehci_writel(ehci, TXFIFO_DEFAULT, &ehci->regs->txfill_tuning);
        }
        if (retval)
                return retval;

        if (ehci_is_TDI(ehci))
                tdi_reset (ehci);

        if (ehci->debug)
                dbgp_external_startup(ehci_to_hcd(ehci));

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

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

        if (ehci->rh_state != EHCI_RH_RUNNING)
                return;

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

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

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

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

static void end_unlink_async(struct ehci_hcd *ehci);
static void unlink_empty_async(struct ehci_hcd *ehci);
static void unlink_empty_async_suspended(struct ehci_hcd *ehci);
static void ehci_work(struct ehci_hcd *ehci);
static void start_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh);
static void end_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh);

#include "ehci-timer.c"
#include "ehci-hub.c"
#include "ehci-mem.c"
#include "ehci-q.c"
#include "ehci-sched.c"
#include "ehci-sysfs.c"

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

/* On some systems, leaving remote wakeup enabled prevents system shutdown.
 * The firmware seems to think that powering off is a wakeup event!
 * This routine turns off remote wakeup and everything else, on all ports.
 */
static void ehci_turn_off_all_ports(struct ehci_hcd *ehci)
{
        int     port = HCS_N_PORTS(ehci->hcs_params);

        while (port--)
                ehci_writel(ehci, PORT_RWC_BITS,
                                &ehci->regs->port_status[port]);
}

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

        spin_lock_irq(&ehci->lock);
        ehci->rh_state = EHCI_RH_HALTED;
        ehci_turn_off_all_ports(ehci);

        /* make BIOS/etc use companion controller during reboot */
        ehci_writel(ehci, 0, &ehci->regs->configured_flag);

        /* unblock posted writes */
        ehci_readl(ehci, &ehci->regs->configured_flag);
        spin_unlock_irq(&ehci->lock);
}

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

        spin_lock_irq(&ehci->lock);
        ehci->shutdown = true;
        ehci->rh_state = EHCI_RH_STOPPING;
        ehci->enabled_hrtimer_events = 0;
        spin_unlock_irq(&ehci->lock);

        ehci_silence_controller(ehci);

        hrtimer_cancel(&ehci->hrtimer);
}

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

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

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

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

/*
 * Called when the ehci_hcd module is removed.
 */
static void ehci_stop (struct usb_hcd *hcd)
{
        struct ehci_hcd         *ehci = hcd_to_ehci (hcd);

        ehci_dbg (ehci, "stop\n");

        /* no more interrupts ... */

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

        ehci_quiesce(ehci);
        ehci_silence_controller(ehci);
        ehci_reset (ehci);

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

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

        if (ehci->amd_pll_fix == 1)
                usb_amd_dev_put();

        dbg_status (ehci, "ehci_stop completed",
                    ehci_readl(ehci, &ehci->regs->status));
}

/* one-time init, only for memory state */
static int ehci_init(struct usb_hcd *hcd)
{
        struct ehci_hcd         *ehci = hcd_to_ehci(hcd);
        u32                     temp;
        int                     retval;
        u32                     hcc_params;
        struct ehci_qh_hw       *hw;

        spin_lock_init(&ehci->lock);

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

        hrtimer_init(&ehci->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
        ehci->hrtimer.function = ehci_hrtimer_func;
        ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;

        hcc_params = ehci_readl(ehci, &ehci->caps->hcc_params);

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

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

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

        /* controllers may cache some of the periodic schedule ... */
        if (HCC_ISOC_CACHE(hcc_params))         // full frame cache
                ehci->i_thresh = 0;
        else                                    // N microframes cached
                ehci->i_thresh = 2 + HCC_ISOC_THRES(hcc_params);

        /*
         * dedicate a qh for the async ring head, since we couldn't unlink
         * a 'real' qh without stopping the async schedule [4.8].  use it
         * as the 'reclamation list head' too.
         * its dummy is used in hw_alt_next of many tds, to prevent the qh
         * from automatically advancing to the next td after short reads.
         */
        ehci->async->qh_next.qh = NULL;
        hw = ehci->async->hw;
        hw->hw_next = QH_NEXT(ehci, ehci->async->qh_dma);
        hw->hw_info1 = cpu_to_hc32(ehci, QH_HEAD);
#if defined(CONFIG_PPC_PS3)
        hw->hw_info1 |= cpu_to_hc32(ehci, QH_INACTIVATE);
#endif
        hw->hw_token = cpu_to_hc32(ehci, QTD_STS_HALT);
        hw->hw_qtd_next = EHCI_LIST_END(ehci);
        ehci->async->qh_state = QH_STATE_LINKED;
        hw->hw_alt_next = QTD_NEXT(ehci, ehci->async->dummy->qtd_dma);

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

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

/* start HC running; it's halted, ehci_init() has been run (once) */
static int ehci_run (struct usb_hcd *hcd)
{
        struct ehci_hcd         *ehci = hcd_to_ehci (hcd);
        u32                     temp;
        u32                     hcc_params;

        hcd->uses_new_polling = 1;

        /* EHCI spec section 4.1 */

        ehci_writel(ehci, ehci->periodic_dma, &ehci->regs->frame_list);
        ehci_writel(ehci, (u32)ehci->async->qh_dma, &ehci->regs->async_next);

        /*
         * hcc_params controls whether ehci->regs->segment must (!!!)
         * be used; it constrains QH/ITD/SITD and QTD locations.
         * pci_pool consistent memory always uses segment zero.
         * streaming mappings for I/O buffers, like pci_map_single(),
         * can return segments above 4GB, if the device allows.
         *
         * NOTE:  the dma mask is visible through dma_supported(), so
         * drivers can pass this info along ... like NETIF_F_HIGHDMA,
         * Scsi_Host.highmem_io, and so forth.  It's readonly to all
         * host side drivers though.
         */
        hcc_params = ehci_readl(ehci, &ehci->caps->hcc_params);
        if (HCC_64BIT_ADDR(hcc_params)) {
                ehci_writel(ehci, 0, &ehci->regs->segment);
#if 0
// this is deeply broken on almost all architectures
                if (!dma_set_mask(hcd->self.controller, DMA_BIT_MASK(64)))
                        ehci_info(ehci, "enabled 64bit DMA\n");
#endif
        }


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

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

        temp = HC_VERSION(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));
        ehci_info (ehci,
                "USB %x.%x started, EHCI %x.%02x%s\n",
                ((ehci->sbrn & 0xf0)>>4), (ehci->sbrn & 0x0f),
                temp >> 8, temp & 0xff,
                ignore_oc ? ", overcurrent ignored" : "");

        ehci_writel(ehci, INTR_MASK,
                    &ehci->regs->intr_enable); /* Turn On Interrupts */

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

        return 0;
}

int ehci_setup(struct usb_hcd *hcd)
{
        struct ehci_hcd *ehci = hcd_to_ehci(hcd);
        int retval;

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

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

        ehci->sbrn = HCD_USB2;

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

        retval = ehci_halt(ehci);
        if (retval)
                return retval;

        ehci_reset(ehci);

        return 0;
}
EXPORT_SYMBOL_GPL(ehci_setup);

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

static irqreturn_t ehci_irq (struct usb_hcd *hcd)
{
        struct ehci_hcd         *ehci = hcd_to_ehci (hcd);
        u32                     status, masked_status, pcd_status = 0, cmd;
        int                     bh;
        unsigned long           flags;

        /*
         * For threadirqs option we use spin_lock_irqsave() variant to prevent
         * deadlock with ehci hrtimer callback, because hrtimer callbacks run
         * in interrupt context even when threadirqs is specified. We can go
         * back to spin_lock() variant when hrtimer callbacks become threaded.
         */
        spin_lock_irqsave(&ehci->lock, flags);

        status = ehci_readl(ehci, &ehci->regs->status);

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

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

        /* Shared IRQ? */
        if (!masked_status || unlikely(ehci->rh_state == EHCI_RH_HALTED)) {
                spin_unlock_irqrestore(&ehci->lock, flags);
                return IRQ_NONE;
        }

        /* clear (just) interrupts */
        ehci_writel(ehci, masked_status, &ehci->regs->status);
        cmd = ehci_readl(ehci, &ehci->regs->command);
        bh = 0;

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

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

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

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

                /* guard against (alleged) silicon errata */
                if (cmd & CMD_IAAD)
                        ehci_dbg(ehci, "IAA with IAAD still set?\n");
                if (ehci->iaa_in_progress)
                        COUNT(ehci->stats.iaa);
                end_unlink_async(ehci);
        }

        /* remote wakeup [4.3.1] */
        if (status & STS_PCD) {
                unsigned        i = HCS_N_PORTS (ehci->hcs_params);
                u32             ppcd = ~0;

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

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

                /* get per-port change detect bits */
                if (ehci->has_ppcd)
                        ppcd = status >> 16;

                while (i--) {
                        int pstatus;

                        /* leverage per-port change bits feature */
                        if (!(ppcd & (1 << i)))
                                continue;
                        pstatus = ehci_readl(ehci,
                                         &ehci->regs->port_status[i]);

                        if (pstatus & PORT_OWNER)
                                continue;
                        if (!(test_bit(i, &ehci->suspended_ports) &&
                                        ((pstatus & PORT_RESUME) ||
                                                !(pstatus & PORT_SUSPEND)) &&
                                        (pstatus & PORT_PE) &&
                                        ehci->reset_done[i] == 0))
                                continue;

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

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

                /* Don't let the controller do anything more */
                ehci->shutdown = true;
                ehci->rh_state = EHCI_RH_STOPPING;
                ehci->command &= ~(CMD_RUN | CMD_ASE | CMD_PSE);
                ehci_writel(ehci, ehci->command, &ehci->regs->command);
                ehci_writel(ehci, 0, &ehci->regs->intr_enable);
                ehci_handle_controller_death(ehci);

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

        if (bh)
                ehci_work (ehci);
        spin_unlock_irqrestore(&ehci->lock, flags);
        if (pcd_status)
                usb_hcd_poll_rh_status(hcd);
        return IRQ_HANDLED;
}

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

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

        INIT_LIST_HEAD (&qtd_list);

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

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

        case PIPE_ISOCHRONOUS:
                if (urb->dev->speed == USB_SPEED_HIGH)
                        return itd_submit (ehci, urb, mem_flags);
                else
                        return sitd_submit (ehci, urb, mem_flags);
        }
}

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

static int ehci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
{
        struct ehci_hcd         *ehci = hcd_to_ehci (hcd);
        struct ehci_qh          *qh;
        unsigned long           flags;
        int                     rc;

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

        if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
                /*
                 * We don't expedite dequeue for isochronous URBs.
                 * Just wait until they complete normally or their
                 * time slot expires.
                 */
        } else {
                qh = (struct ehci_qh *) urb->hcpriv;
                qh->exception = 1;
                switch (qh->qh_state) {
                case QH_STATE_LINKED:
                        if (usb_pipetype(urb->pipe) == PIPE_INTERRUPT)
                                start_unlink_intr(ehci, qh);
                        else
                                start_unlink_async(ehci, qh);
                        break;
                case QH_STATE_COMPLETING:
                        qh->dequeue_during_giveback = 1;
                        break;
                case QH_STATE_UNLINK:
                case QH_STATE_UNLINK_WAIT:
                        /* already started */
                        break;
                case QH_STATE_IDLE:
                        /* QH might be waiting for a Clear-TT-Buffer */
                        qh_completions(ehci, qh);
                        break;
                }
        }
done:
        spin_unlock_irqrestore (&ehci->lock, flags);
        return rc;
}

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

// bulk qh holds the data toggle

static void
ehci_endpoint_disable (struct usb_hcd *hcd, struct usb_host_endpoint *ep)
{
        struct ehci_hcd         *ehci = hcd_to_ehci (hcd);
        unsigned long           flags;
        struct ehci_qh          *qh;

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

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

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

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

                /* BUG_ON(!list_empty(&stream->free_list)); */
                reserve_release_iso_bandwidth(ehci, stream, -1);
                kfree(stream);
                goto done;
        }

        qh->exception = 1;
        switch (qh->qh_state) {
        case QH_STATE_LINKED:
                WARN_ON(!list_empty(&qh->qtd_list));
                if (usb_endpoint_type(&ep->desc) != USB_ENDPOINT_XFER_INT)
                        start_unlink_async(ehci, qh);
                else
                        start_unlink_intr(ehci, qh);
                /* FALL THROUGH */
        case QH_STATE_COMPLETING:       /* already in unlinking */
        case QH_STATE_UNLINK:           /* wait for hw to finish? */
        case QH_STATE_UNLINK_WAIT:
idle_timeout:
                spin_unlock_irqrestore (&ehci->lock, flags);
                schedule_timeout_uninterruptible(1);
                goto rescan;
        case QH_STATE_IDLE:             /* fully unlinked */
                if (qh->clearing_tt)
                        goto idle_timeout;
                if (list_empty (&qh->qtd_list)) {
                        if (qh->ps.bw_uperiod)
                                reserve_release_intr_bandwidth(ehci, qh, -1);
                        qh_destroy(ehci, qh);
                        break;
                }
                /* else FALL THROUGH */
        default:
                /* caller was supposed to have unlinked any requests;
                 * that's not our job.  just leak this memory.
                 */
                ehci_err (ehci, "qh %p (#%02x) state %d%s\n",
                        qh, ep->desc.bEndpointAddress, qh->qh_state,
                        list_empty (&qh->qtd_list) ? "" : "(has tds)");
                break;
        }
 done:
        ep->hcpriv = NULL;
        spin_unlock_irqrestore (&ehci->lock, flags);
}

static void
ehci_endpoint_reset(struct usb_hcd *hcd, struct usb_host_endpoint *ep)
{
        struct ehci_hcd         *ehci = hcd_to_ehci(hcd);
        struct ehci_qh          *qh;
        int                     eptype = usb_endpoint_type(&ep->desc);
        int                     epnum = usb_endpoint_num(&ep->desc);
        int                     is_out = usb_endpoint_dir_out(&ep->desc);
        unsigned long           flags;

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

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

        /* For Bulk and Interrupt endpoints we maintain the toggle state
         * in the hardware; the toggle bits in udev aren't used at all.
         * When an endpoint is reset by usb_clear_halt() we must reset
         * the toggle bit in the QH.
         */
        if (qh) {
                if (!list_empty(&qh->qtd_list)) {
                        WARN_ONCE(1, "clear_halt for a busy endpoint\n");
                } else {
                        /* The toggle value in the QH can't be updated
                         * while the QH is active.  Unlink it now;
                         * re-linking will call qh_refresh().
                         */
                        usb_settoggle(qh->ps.udev, epnum, is_out, 0);
                        qh->exception = 1;
                        if (eptype == USB_ENDPOINT_XFER_BULK)
                                start_unlink_async(ehci, qh);
                        else
                                start_unlink_intr(ehci, qh);
                }
        }
        spin_unlock_irqrestore(&ehci->lock, flags);
}

static int ehci_get_frame (struct usb_hcd *hcd)
{
        struct ehci_hcd         *ehci = hcd_to_ehci (hcd);
        return (ehci_read_frame_index(ehci) >> 3) % ehci->periodic_size;
}

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

/* Device addition and removal */

static void ehci_remove_device(struct usb_hcd *hcd, struct usb_device *udev)
{
        struct ehci_hcd         *ehci = hcd_to_ehci(hcd);

        spin_lock_irq(&ehci->lock);
        drop_tt(udev);
        spin_unlock_irq(&ehci->lock);
}

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

#ifdef  CONFIG_PM

/* suspend/resume, section 4.3 */

/* These routines handle the generic parts of controller suspend/resume */

int ehci_suspend(struct usb_hcd *hcd, bool do_wakeup)
{
        struct ehci_hcd         *ehci = hcd_to_ehci(hcd);

        if (time_before(jiffies, ehci->next_statechange))
                msleep(10);

        /*
         * Root hub was already suspended.  Disable IRQ emission and
         * mark HW unaccessible.  The PM and USB cores make sure that
         * the root hub is either suspended or stopped.
         */
        ehci_prepare_ports_for_controller_suspend(ehci, do_wakeup);

        spin_lock_irq(&ehci->lock);
        ehci_writel(ehci, 0, &ehci->regs->intr_enable);
        (void) ehci_readl(ehci, &ehci->regs->intr_enable);

        clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
        spin_unlock_irq(&ehci->lock);

        synchronize_irq(hcd->irq);

        /* Check for race with a wakeup request */
        if (do_wakeup && HCD_WAKEUP_PENDING(hcd)) {
                ehci_resume(hcd, false);
                return -EBUSY;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(ehci_suspend);

/* Returns 0 if power was preserved, 1 if power was lost */
int ehci_resume(struct usb_hcd *hcd, bool hibernated)
{
        struct ehci_hcd         *ehci = hcd_to_ehci(hcd);

        if (time_before(jiffies, ehci->next_statechange))
                msleep(100);

        /* Mark hardware accessible again as we are back to full power by now */
        set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);

        if (ehci->shutdown)
                return 0;               /* Controller is dead */

        /*
         * If CF is still set and we aren't resuming from hibernation
         * then we maintained suspend power.
         * Just undo the effect of ehci_suspend().
         */
        if (ehci_readl(ehci, &ehci->regs->configured_flag) == FLAG_CF &&
                        !hibernated) {
                int     mask = INTR_MASK;

                ehci_prepare_ports_for_controller_resume(ehci);

                spin_lock_irq(&ehci->lock);
                if (ehci->shutdown)
                        goto skip;

                if (!hcd->self.root_hub->do_remote_wakeup)
                        mask &= ~STS_PCD;
                ehci_writel(ehci, mask, &ehci->regs->intr_enable);
                ehci_readl(ehci, &ehci->regs->intr_enable);
 skip:
                spin_unlock_irq(&ehci->lock);
                return 0;
        }

        /*
         * Else reset, to cope with power loss or resume from hibernation
         * having let the firmware kick in during reboot.
         */
        usb_root_hub_lost_power(hcd->self.root_hub);
        (void) ehci_halt(ehci);
        (void) ehci_reset(ehci);

        spin_lock_irq(&ehci->lock);
        if (ehci->shutdown)
                goto skip;

        ehci_writel(ehci, ehci->command, &ehci->regs->command);
        ehci_writel(ehci, FLAG_CF, &ehci->regs->configured_flag);
        ehci_readl(ehci, &ehci->regs->command); /* unblock posted writes */

        ehci->rh_state = EHCI_RH_SUSPENDED;
        spin_unlock_irq(&ehci->lock);

        return 1;
}
EXPORT_SYMBOL_GPL(ehci_resume);

#endif

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

/*
 * Generic structure: This gets copied for platform drivers so that
 * individual entries can be overridden as needed.
 */

static const struct hc_driver ehci_hc_driver = {
        .description =          hcd_name,
        .product_desc =         "EHCI Host Controller",
        .hcd_priv_size =        sizeof(struct ehci_hcd),

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

        /*
         * basic lifecycle operations
         */
        .reset =                ehci_setup,
        .start =                ehci_run,
        .stop =                 ehci_stop,
        .shutdown =             ehci_shutdown,

        /*
         * managing i/o requests and associated device resources
         */
        .urb_enqueue =          ehci_urb_enqueue,
        .urb_dequeue =          ehci_urb_dequeue,
        .endpoint_disable =     ehci_endpoint_disable,
        .endpoint_reset =       ehci_endpoint_reset,
        .clear_tt_buffer_complete =     ehci_clear_tt_buffer_complete,

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

        /*
         * root hub support
         */
        .hub_status_data =      ehci_hub_status_data,
        .hub_control =          ehci_hub_control,
        .bus_suspend =          ehci_bus_suspend,
        .bus_resume =           ehci_bus_resume,
        .relinquish_port =      ehci_relinquish_port,
        .port_handed_over =     ehci_port_handed_over,

        /*
         * device support
         */
        .free_dev =             ehci_remove_device,
};

void ehci_init_driver(struct hc_driver *drv,
                const struct ehci_driver_overrides *over)
{
        /* Copy the generic table to drv and then apply the overrides */
        *drv = ehci_hc_driver;

        if (over) {
                drv->hcd_priv_size += over->extra_priv_size;
                if (over->reset)
                        drv->reset = over->reset;
        }
}
EXPORT_SYMBOL_GPL(ehci_init_driver);

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

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

#ifdef CONFIG_USB_EHCI_FSL
#include "ehci-fsl.c"
#define PLATFORM_DRIVER         ehci_fsl_driver
#endif

#ifdef CONFIG_USB_EHCI_SH
#include "ehci-sh.c"
#define PLATFORM_DRIVER         ehci_hcd_sh_driver
#endif

#ifdef CONFIG_PPC_PS3
#include "ehci-ps3.c"
#define PS3_SYSTEM_BUS_DRIVER   ps3_ehci_driver
#endif

#ifdef CONFIG_USB_EHCI_HCD_PPC_OF
#include "ehci-ppc-of.c"
#define OF_PLATFORM_DRIVER      ehci_hcd_ppc_of_driver
#endif

#ifdef CONFIG_XPS_USB_HCD_XILINX
#include "ehci-xilinx-of.c"
#define XILINX_OF_PLATFORM_DRIVER       ehci_hcd_xilinx_of_driver
#endif

#ifdef CONFIG_USB_OCTEON_EHCI
#include "ehci-octeon.c"
#define PLATFORM_DRIVER         ehci_octeon_driver
#endif

#ifdef CONFIG_TILE_USB
#include "ehci-tilegx.c"
#define PLATFORM_DRIVER         ehci_hcd_tilegx_driver
#endif

#ifdef CONFIG_USB_EHCI_HCD_PMC_MSP
#include "ehci-pmcmsp.c"
#define PLATFORM_DRIVER         ehci_hcd_msp_driver
#endif

#ifdef CONFIG_SPARC_LEON
#include "ehci-grlib.c"
#define PLATFORM_DRIVER         ehci_grlib_driver
#endif

#ifdef CONFIG_USB_EHCI_MV
#include "ehci-mv.c"
#define        PLATFORM_DRIVER         ehci_mv_driver
#endif

#ifdef CONFIG_MIPS_SEAD3
#include "ehci-sead3.c"
#define PLATFORM_DRIVER         ehci_hcd_sead3_driver
#endif

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

        if (usb_disabled())
                return -ENODEV;

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

        pr_debug("%s: block sizes: qh %Zd qtd %Zd itd %Zd sitd %Zd\n",
                 hcd_name,
                 sizeof(struct ehci_qh), sizeof(struct ehci_qtd),
                 sizeof(struct ehci_itd), sizeof(struct ehci_sitd));

#ifdef CONFIG_DYNAMIC_DEBUG
        ehci_debug_root = debugfs_create_dir("ehci", usb_debug_root);
        if (!ehci_debug_root) {
                retval = -ENOENT;
                goto err_debug;
        }
#endif

#ifdef PLATFORM_DRIVER
        retval = platform_driver_register(&PLATFORM_DRIVER);
        if (retval < 0)
                goto clean0;
#endif

#ifdef PS3_SYSTEM_BUS_DRIVER
        retval = ps3_ehci_driver_register(&PS3_SYSTEM_BUS_DRIVER);
        if (retval < 0)
                goto clean2;
#endif

#ifdef OF_PLATFORM_DRIVER
        retval = platform_driver_register(&OF_PLATFORM_DRIVER);
        if (retval < 0)
                goto clean3;
#endif

#ifdef XILINX_OF_PLATFORM_DRIVER
        retval = platform_driver_register(&XILINX_OF_PLATFORM_DRIVER);
        if (retval < 0)
                goto clean4;
#endif
        return retval;

#ifdef XILINX_OF_PLATFORM_DRIVER
        /* platform_driver_unregister(&XILINX_OF_PLATFORM_DRIVER); */
clean4:
#endif
#ifdef OF_PLATFORM_DRIVER
        platform_driver_unregister(&OF_PLATFORM_DRIVER);
clean3:
#endif
#ifdef PS3_SYSTEM_BUS_DRIVER
        ps3_ehci_driver_unregister(&PS3_SYSTEM_BUS_DRIVER);
clean2:
#endif
#ifdef PLATFORM_DRIVER
        platform_driver_unregister(&PLATFORM_DRIVER);
clean0:
#endif
#ifdef CONFIG_DYNAMIC_DEBUG
        debugfs_remove(ehci_debug_root);
        ehci_debug_root = NULL;
err_debug:
#endif
        clear_bit(USB_EHCI_LOADED, &usb_hcds_loaded);
        return retval;
}
module_init(ehci_hcd_init);

static void __exit ehci_hcd_cleanup(void)
{
#ifdef XILINX_OF_PLATFORM_DRIVER
        platform_driver_unregister(&XILINX_OF_PLATFORM_DRIVER);
#endif
#ifdef OF_PLATFORM_DRIVER
        platform_driver_unregister(&OF_PLATFORM_DRIVER);
#endif
#ifdef PLATFORM_DRIVER
        platform_driver_unregister(&PLATFORM_DRIVER);
#endif
#ifdef PS3_SYSTEM_BUS_DRIVER
        ps3_ehci_driver_unregister(&PS3_SYSTEM_BUS_DRIVER);
#endif
#ifdef CONFIG_DYNAMIC_DEBUG
        debugfs_remove(ehci_debug_root);
#endif
        clear_bit(USB_EHCI_LOADED, &usb_hcds_loaded);
}
module_exit(ehci_hcd_cleanup);