USB: Support for bandwidth allocation.

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

/*
 * (C) Copyright Linus Torvalds 1999
 * (C) Copyright Johannes Erdfelt 1999-2001
 * (C) Copyright Andreas Gal 1999
 * (C) Copyright Gregory P. Smith 1999
 * (C) Copyright Deti Fliegl 1999
 * (C) Copyright Randy Dunlap 2000
 * (C) Copyright David Brownell 2000-2002
 * 
 * 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/version.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/completion.h>
#include <linux/utsname.h>
#include <linux/mm.h>
#include <asm/io.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/mutex.h>
#include <asm/irq.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>

#include <linux/usb.h>

#include "usb.h"
#include "hcd.h"
#include "hub.h"


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

/*
 * USB Host Controller Driver framework
 *
 * Plugs into usbcore (usb_bus) and lets HCDs share code, minimizing
 * HCD-specific behaviors/bugs.
 *
 * This does error checks, tracks devices and urbs, and delegates to a
 * "hc_driver" only for code (and data) that really needs to know about
 * hardware differences.  That includes root hub registers, i/o queues,
 * and so on ... but as little else as possible.
 *
 * Shared code includes most of the "root hub" code (these are emulated,
 * though each HC's hardware works differently) and PCI glue, plus request
 * tracking overhead.  The HCD code should only block on spinlocks or on
 * hardware handshaking; blocking on software events (such as other kernel
 * threads releasing resources, or completing actions) is all generic.
 *
 * Happens the USB 2.0 spec says this would be invisible inside the "USBD",
 * and includes mostly a "HCDI" (HCD Interface) along with some APIs used
 * only by the hub driver ... and that neither should be seen or used by
 * usb client device drivers.
 *
 * Contributors of ideas or unattributed patches include: David Brownell,
 * Roman Weissgaerber, Rory Bolt, Greg Kroah-Hartman, ...
 *
 * HISTORY:
 * 2002-02-21   Pull in most of the usb_bus support from usb.c; some
 *              associated cleanup.  "usb_hcd" still != "usb_bus".
 * 2001-12-12   Initial patch version for Linux 2.5.1 kernel.
 */

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

/* Keep track of which host controller drivers are loaded */
unsigned long usb_hcds_loaded;
EXPORT_SYMBOL_GPL(usb_hcds_loaded);

/* host controllers we manage */
LIST_HEAD (usb_bus_list);
EXPORT_SYMBOL_GPL (usb_bus_list);

/* used when allocating bus numbers */
#define USB_MAXBUS              64
struct usb_busmap {
        unsigned long busmap [USB_MAXBUS / (8*sizeof (unsigned long))];
};
static struct usb_busmap busmap;

/* used when updating list of hcds */
DEFINE_MUTEX(usb_bus_list_lock);        /* exported only for usbfs */
EXPORT_SYMBOL_GPL (usb_bus_list_lock);

/* used for controlling access to virtual root hubs */
static DEFINE_SPINLOCK(hcd_root_hub_lock);

/* used when updating an endpoint's URB list */
static DEFINE_SPINLOCK(hcd_urb_list_lock);

/* used to protect against unlinking URBs after the device is gone */
static DEFINE_SPINLOCK(hcd_urb_unlink_lock);

/* wait queue for synchronous unlinks */
DECLARE_WAIT_QUEUE_HEAD(usb_kill_urb_queue);

static inline int is_root_hub(struct usb_device *udev)
{
        return (udev->parent == NULL);
}

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

/*
 * Sharable chunks of root hub code.
 */

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

#define KERNEL_REL      ((LINUX_VERSION_CODE >> 16) & 0x0ff)
#define KERNEL_VER      ((LINUX_VERSION_CODE >> 8) & 0x0ff)

/* usb 3.0 root hub device descriptor */
static const u8 usb3_rh_dev_descriptor[18] = {
        0x12,       /*  __u8  bLength; */
        0x01,       /*  __u8  bDescriptorType; Device */
        0x00, 0x03, /*  __le16 bcdUSB; v3.0 */

        0x09,       /*  __u8  bDeviceClass; HUB_CLASSCODE */
        0x00,       /*  __u8  bDeviceSubClass; */
        0x03,       /*  __u8  bDeviceProtocol; USB 3.0 hub */
        0x09,       /*  __u8  bMaxPacketSize0; 2^9 = 512 Bytes */

        0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
        0x02, 0x00, /*  __le16 idProduct; device 0x0002 */
        KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */

        0x03,       /*  __u8  iManufacturer; */
        0x02,       /*  __u8  iProduct; */
        0x01,       /*  __u8  iSerialNumber; */
        0x01        /*  __u8  bNumConfigurations; */
};

/* usb 2.0 root hub device descriptor */
static const u8 usb2_rh_dev_descriptor [18] = {
        0x12,       /*  __u8  bLength; */
        0x01,       /*  __u8  bDescriptorType; Device */
        0x00, 0x02, /*  __le16 bcdUSB; v2.0 */

        0x09,       /*  __u8  bDeviceClass; HUB_CLASSCODE */
        0x00,       /*  __u8  bDeviceSubClass; */
        0x00,       /*  __u8  bDeviceProtocol; [ usb 2.0 no TT ] */
        0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */

        0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
        0x02, 0x00, /*  __le16 idProduct; device 0x0002 */
        KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */

        0x03,       /*  __u8  iManufacturer; */
        0x02,       /*  __u8  iProduct; */
        0x01,       /*  __u8  iSerialNumber; */
        0x01        /*  __u8  bNumConfigurations; */
};

/* no usb 2.0 root hub "device qualifier" descriptor: one speed only */

/* usb 1.1 root hub device descriptor */
static const u8 usb11_rh_dev_descriptor [18] = {
        0x12,       /*  __u8  bLength; */
        0x01,       /*  __u8  bDescriptorType; Device */
        0x10, 0x01, /*  __le16 bcdUSB; v1.1 */

        0x09,       /*  __u8  bDeviceClass; HUB_CLASSCODE */
        0x00,       /*  __u8  bDeviceSubClass; */
        0x00,       /*  __u8  bDeviceProtocol; [ low/full speeds only ] */
        0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */

        0x6b, 0x1d, /*  __le16 idVendor; Linux Foundation */
        0x01, 0x00, /*  __le16 idProduct; device 0x0001 */
        KERNEL_VER, KERNEL_REL, /*  __le16 bcdDevice */

        0x03,       /*  __u8  iManufacturer; */
        0x02,       /*  __u8  iProduct; */
        0x01,       /*  __u8  iSerialNumber; */
        0x01        /*  __u8  bNumConfigurations; */
};


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

/* Configuration descriptors for our root hubs */

static const u8 fs_rh_config_descriptor [] = {

        /* one configuration */
        0x09,       /*  __u8  bLength; */
        0x02,       /*  __u8  bDescriptorType; Configuration */
        0x19, 0x00, /*  __le16 wTotalLength; */
        0x01,       /*  __u8  bNumInterfaces; (1) */
        0x01,       /*  __u8  bConfigurationValue; */
        0x00,       /*  __u8  iConfiguration; */
        0xc0,       /*  __u8  bmAttributes; 
                                 Bit 7: must be set,
                                     6: Self-powered,
                                     5: Remote wakeup,
                                     4..0: resvd */
        0x00,       /*  __u8  MaxPower; */
      
        /* USB 1.1:
         * USB 2.0, single TT organization (mandatory):
         *      one interface, protocol 0
         *
         * USB 2.0, multiple TT organization (optional):
         *      two interfaces, protocols 1 (like single TT)
         *      and 2 (multiple TT mode) ... config is
         *      sometimes settable
         *      NOT IMPLEMENTED
         */

        /* one interface */
        0x09,       /*  __u8  if_bLength; */
        0x04,       /*  __u8  if_bDescriptorType; Interface */
        0x00,       /*  __u8  if_bInterfaceNumber; */
        0x00,       /*  __u8  if_bAlternateSetting; */
        0x01,       /*  __u8  if_bNumEndpoints; */
        0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
        0x00,       /*  __u8  if_bInterfaceSubClass; */
        0x00,       /*  __u8  if_bInterfaceProtocol; [usb1.1 or single tt] */
        0x00,       /*  __u8  if_iInterface; */
     
        /* one endpoint (status change endpoint) */
        0x07,       /*  __u8  ep_bLength; */
        0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
        0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
        0x03,       /*  __u8  ep_bmAttributes; Interrupt */
        0x02, 0x00, /*  __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8) */
        0xff        /*  __u8  ep_bInterval; (255ms -- usb 2.0 spec) */
};

static const u8 hs_rh_config_descriptor [] = {

        /* one configuration */
        0x09,       /*  __u8  bLength; */
        0x02,       /*  __u8  bDescriptorType; Configuration */
        0x19, 0x00, /*  __le16 wTotalLength; */
        0x01,       /*  __u8  bNumInterfaces; (1) */
        0x01,       /*  __u8  bConfigurationValue; */
        0x00,       /*  __u8  iConfiguration; */
        0xc0,       /*  __u8  bmAttributes; 
                                 Bit 7: must be set,
                                     6: Self-powered,
                                     5: Remote wakeup,
                                     4..0: resvd */
        0x00,       /*  __u8  MaxPower; */
      
        /* USB 1.1:
         * USB 2.0, single TT organization (mandatory):
         *      one interface, protocol 0
         *
         * USB 2.0, multiple TT organization (optional):
         *      two interfaces, protocols 1 (like single TT)
         *      and 2 (multiple TT mode) ... config is
         *      sometimes settable
         *      NOT IMPLEMENTED
         */

        /* one interface */
        0x09,       /*  __u8  if_bLength; */
        0x04,       /*  __u8  if_bDescriptorType; Interface */
        0x00,       /*  __u8  if_bInterfaceNumber; */
        0x00,       /*  __u8  if_bAlternateSetting; */
        0x01,       /*  __u8  if_bNumEndpoints; */
        0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
        0x00,       /*  __u8  if_bInterfaceSubClass; */
        0x00,       /*  __u8  if_bInterfaceProtocol; [usb1.1 or single tt] */
        0x00,       /*  __u8  if_iInterface; */
     
        /* one endpoint (status change endpoint) */
        0x07,       /*  __u8  ep_bLength; */
        0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
        0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
        0x03,       /*  __u8  ep_bmAttributes; Interrupt */
                    /* __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8)
                     * see hub.c:hub_configure() for details. */
        (USB_MAXCHILDREN + 1 + 7) / 8, 0x00,
        0x0c        /*  __u8  ep_bInterval; (256ms -- usb 2.0 spec) */
};

static const u8 ss_rh_config_descriptor[] = {
        /* one configuration */
        0x09,       /*  __u8  bLength; */
        0x02,       /*  __u8  bDescriptorType; Configuration */
        0x19, 0x00, /*  __le16 wTotalLength; FIXME */
        0x01,       /*  __u8  bNumInterfaces; (1) */
        0x01,       /*  __u8  bConfigurationValue; */
        0x00,       /*  __u8  iConfiguration; */
        0xc0,       /*  __u8  bmAttributes;
                                 Bit 7: must be set,
                                     6: Self-powered,
                                     5: Remote wakeup,
                                     4..0: resvd */
        0x00,       /*  __u8  MaxPower; */

        /* one interface */
        0x09,       /*  __u8  if_bLength; */
        0x04,       /*  __u8  if_bDescriptorType; Interface */
        0x00,       /*  __u8  if_bInterfaceNumber; */
        0x00,       /*  __u8  if_bAlternateSetting; */
        0x01,       /*  __u8  if_bNumEndpoints; */
        0x09,       /*  __u8  if_bInterfaceClass; HUB_CLASSCODE */
        0x00,       /*  __u8  if_bInterfaceSubClass; */
        0x00,       /*  __u8  if_bInterfaceProtocol; */
        0x00,       /*  __u8  if_iInterface; */

        /* one endpoint (status change endpoint) */
        0x07,       /*  __u8  ep_bLength; */
        0x05,       /*  __u8  ep_bDescriptorType; Endpoint */
        0x81,       /*  __u8  ep_bEndpointAddress; IN Endpoint 1 */
        0x03,       /*  __u8  ep_bmAttributes; Interrupt */
                    /* __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8)
                     * see hub.c:hub_configure() for details. */
        (USB_MAXCHILDREN + 1 + 7) / 8, 0x00,
        0x0c        /*  __u8  ep_bInterval; (256ms -- usb 2.0 spec) */
        /*
         * All 3.0 hubs should have an endpoint companion descriptor,
         * but we're ignoring that for now.  FIXME?
         */
};

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

/*
 * helper routine for returning string descriptors in UTF-16LE
 * input can actually be ISO-8859-1; ASCII is its 7-bit subset
 */
static unsigned ascii2utf(char *s, u8 *utf, int utfmax)
{
        unsigned retval;

        for (retval = 0; *s && utfmax > 1; utfmax -= 2, retval += 2) {
                *utf++ = *s++;
                *utf++ = 0;
        }
        if (utfmax > 0) {
                *utf = *s;
                ++retval;
        }
        return retval;
}

/*
 * rh_string - provides manufacturer, product and serial strings for root hub
 * @id: the string ID number (1: serial number, 2: product, 3: vendor)
 * @hcd: the host controller for this root hub
 * @data: return packet in UTF-16 LE
 * @len: length of the return packet
 *
 * Produces either a manufacturer, product or serial number string for the
 * virtual root hub device.
 */
static unsigned rh_string(int id, struct usb_hcd *hcd, u8 *data, unsigned len)
{
        char buf [100];

        // language ids
        if (id == 0) {
                buf[0] = 4;    buf[1] = 3;      /* 4 bytes string data */
                buf[2] = 0x09; buf[3] = 0x04;   /* MSFT-speak for "en-us" */
                len = min_t(unsigned, len, 4);
                memcpy (data, buf, len);
                return len;

        // serial number
        } else if (id == 1) {
                strlcpy (buf, hcd->self.bus_name, sizeof buf);

        // product description
        } else if (id == 2) {
                strlcpy (buf, hcd->product_desc, sizeof buf);

        // id 3 == vendor description
        } else if (id == 3) {
                snprintf (buf, sizeof buf, "%s %s %s", init_utsname()->sysname,
                        init_utsname()->release, hcd->driver->description);
        }

        switch (len) {          /* All cases fall through */
        default:
                len = 2 + ascii2utf (buf, data + 2, len - 2);
        case 2:
                data [1] = 3;   /* type == string */
        case 1:
                data [0] = 2 * (strlen (buf) + 1);
        case 0:
                ;               /* Compiler wants a statement here */
        }
        return len;
}


/* Root hub control transfers execute synchronously */
static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
{
        struct usb_ctrlrequest *cmd;
        u16             typeReq, wValue, wIndex, wLength;
        u8              *ubuf = urb->transfer_buffer;
        u8              tbuf [sizeof (struct usb_hub_descriptor)]
                __attribute__((aligned(4)));
        const u8        *bufp = tbuf;
        unsigned        len = 0;
        int             status;
        u8              patch_wakeup = 0;
        u8              patch_protocol = 0;

        might_sleep();

        spin_lock_irq(&hcd_root_hub_lock);
        status = usb_hcd_link_urb_to_ep(hcd, urb);
        spin_unlock_irq(&hcd_root_hub_lock);
        if (status)
                return status;
        urb->hcpriv = hcd;      /* Indicate it's queued */

        cmd = (struct usb_ctrlrequest *) urb->setup_packet;
        typeReq  = (cmd->bRequestType << 8) | cmd->bRequest;
        wValue   = le16_to_cpu (cmd->wValue);
        wIndex   = le16_to_cpu (cmd->wIndex);
        wLength  = le16_to_cpu (cmd->wLength);

        if (wLength > urb->transfer_buffer_length)
                goto error;

        urb->actual_length = 0;
        switch (typeReq) {

        /* DEVICE REQUESTS */

        /* The root hub's remote wakeup enable bit is implemented using
         * driver model wakeup flags.  If this system supports wakeup
         * through USB, userspace may change the default "allow wakeup"
         * policy through sysfs or these calls.
         *
         * Most root hubs support wakeup from downstream devices, for
         * runtime power management (disabling USB clocks and reducing
         * VBUS power usage).  However, not all of them do so; silicon,
         * board, and BIOS bugs here are not uncommon, so these can't
         * be treated quite like external hubs.
         *
         * Likewise, not all root hubs will pass wakeup events upstream,
         * to wake up the whole system.  So don't assume root hub and
         * controller capabilities are identical.
         */

        case DeviceRequest | USB_REQ_GET_STATUS:
                tbuf [0] = (device_may_wakeup(&hcd->self.root_hub->dev)
                                        << USB_DEVICE_REMOTE_WAKEUP)
                                | (1 << USB_DEVICE_SELF_POWERED);
                tbuf [1] = 0;
                len = 2;
                break;
        case DeviceOutRequest | USB_REQ_CLEAR_FEATURE:
                if (wValue == USB_DEVICE_REMOTE_WAKEUP)
                        device_set_wakeup_enable(&hcd->self.root_hub->dev, 0);
                else
                        goto error;
                break;
        case DeviceOutRequest | USB_REQ_SET_FEATURE:
                if (device_can_wakeup(&hcd->self.root_hub->dev)
                                && wValue == USB_DEVICE_REMOTE_WAKEUP)
                        device_set_wakeup_enable(&hcd->self.root_hub->dev, 1);
                else
                        goto error;
                break;
        case DeviceRequest | USB_REQ_GET_CONFIGURATION:
                tbuf [0] = 1;
                len = 1;
                        /* FALLTHROUGH */
        case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
                break;
        case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
                switch (wValue & 0xff00) {
                case USB_DT_DEVICE << 8:
                        if (hcd->driver->flags & HCD_USB3)
                                bufp = usb3_rh_dev_descriptor;
                        else if (hcd->driver->flags & HCD_USB2)
                                bufp = usb2_rh_dev_descriptor;
                        else if (hcd->driver->flags & HCD_USB11)
                                bufp = usb11_rh_dev_descriptor;
                        else
                                goto error;
                        len = 18;
                        if (hcd->has_tt)
                                patch_protocol = 1;
                        break;
                case USB_DT_CONFIG << 8:
                        if (hcd->driver->flags & HCD_USB3) {
                                bufp = ss_rh_config_descriptor;
                                len = sizeof ss_rh_config_descriptor;
                        } else if (hcd->driver->flags & HCD_USB2) {
                                bufp = hs_rh_config_descriptor;
                                len = sizeof hs_rh_config_descriptor;
                        } else {
                                bufp = fs_rh_config_descriptor;
                                len = sizeof fs_rh_config_descriptor;
                        }
                        if (device_can_wakeup(&hcd->self.root_hub->dev))
                                patch_wakeup = 1;
                        break;
                case USB_DT_STRING << 8:
                        if ((wValue & 0xff) < 4)
                                urb->actual_length = rh_string(wValue & 0xff,
                                                hcd, ubuf, wLength);
                        else /* unsupported IDs --> "protocol stall" */
                                goto error;
                        break;
                default:
                        goto error;
                }
                break;
        case DeviceRequest | USB_REQ_GET_INTERFACE:
                tbuf [0] = 0;
                len = 1;
                        /* FALLTHROUGH */
        case DeviceOutRequest | USB_REQ_SET_INTERFACE:
                break;
        case DeviceOutRequest | USB_REQ_SET_ADDRESS:
                // wValue == urb->dev->devaddr
                dev_dbg (hcd->self.controller, "root hub device address %d\n",
                        wValue);
                break;

        /* INTERFACE REQUESTS (no defined feature/status flags) */

        /* ENDPOINT REQUESTS */

        case EndpointRequest | USB_REQ_GET_STATUS:
                // ENDPOINT_HALT flag
                tbuf [0] = 0;
                tbuf [1] = 0;
                len = 2;
                        /* FALLTHROUGH */
        case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
        case EndpointOutRequest | USB_REQ_SET_FEATURE:
                dev_dbg (hcd->self.controller, "no endpoint features yet\n");
                break;

        /* CLASS REQUESTS (and errors) */

        default:
                /* non-generic request */
                switch (typeReq) {
                case GetHubStatus:
                case GetPortStatus:
                        len = 4;
                        break;
                case GetHubDescriptor:
                        len = sizeof (struct usb_hub_descriptor);
                        break;
                }
                status = hcd->driver->hub_control (hcd,
                        typeReq, wValue, wIndex,
                        tbuf, wLength);
                break;
error:
                /* "protocol stall" on error */
                status = -EPIPE;
        }

        if (status) {
                len = 0;
                if (status != -EPIPE) {
                        dev_dbg (hcd->self.controller,
                                "CTRL: TypeReq=0x%x val=0x%x "
                                "idx=0x%x len=%d ==> %d\n",
                                typeReq, wValue, wIndex,
                                wLength, status);
                }
        }
        if (len) {
                if (urb->transfer_buffer_length < len)
                        len = urb->transfer_buffer_length;
                urb->actual_length = len;
                // always USB_DIR_IN, toward host
                memcpy (ubuf, bufp, len);

                /* report whether RH hardware supports remote wakeup */
                if (patch_wakeup &&
                                len > offsetof (struct usb_config_descriptor,
                                                bmAttributes))
                        ((struct usb_config_descriptor *)ubuf)->bmAttributes
                                |= USB_CONFIG_ATT_WAKEUP;

                /* report whether RH hardware has an integrated TT */
                if (patch_protocol &&
                                len > offsetof(struct usb_device_descriptor,
                                                bDeviceProtocol))
                        ((struct usb_device_descriptor *) ubuf)->
                                        bDeviceProtocol = 1;
        }

        /* any errors get returned through the urb completion */
        spin_lock_irq(&hcd_root_hub_lock);
        usb_hcd_unlink_urb_from_ep(hcd, urb);

        /* This peculiar use of spinlocks echoes what real HC drivers do.
         * Avoiding calls to local_irq_disable/enable makes the code
         * RT-friendly.
         */
        spin_unlock(&hcd_root_hub_lock);
        usb_hcd_giveback_urb(hcd, urb, status);
        spin_lock(&hcd_root_hub_lock);

        spin_unlock_irq(&hcd_root_hub_lock);
        return 0;
}

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

/*
 * Root Hub interrupt transfers are polled using a timer if the
 * driver requests it; otherwise the driver is responsible for
 * calling usb_hcd_poll_rh_status() when an event occurs.
 *
 * Completions are called in_interrupt(), but they may or may not
 * be in_irq().
 */
void usb_hcd_poll_rh_status(struct usb_hcd *hcd)
{
        struct urb      *urb;
        int             length;
        unsigned long   flags;
        char            buffer[4];      /* Any root hubs with > 31 ports? */

        if (unlikely(!hcd->rh_registered))
                return;
        if (!hcd->uses_new_polling && !hcd->status_urb)
                return;

        length = hcd->driver->hub_status_data(hcd, buffer);
        if (length > 0) {

                /* try to complete the status urb */
                spin_lock_irqsave(&hcd_root_hub_lock, flags);
                urb = hcd->status_urb;
                if (urb) {
                        hcd->poll_pending = 0;
                        hcd->status_urb = NULL;
                        urb->actual_length = length;
                        memcpy(urb->transfer_buffer, buffer, length);

                        usb_hcd_unlink_urb_from_ep(hcd, urb);
                        spin_unlock(&hcd_root_hub_lock);
                        usb_hcd_giveback_urb(hcd, urb, 0);
                        spin_lock(&hcd_root_hub_lock);
                } else {
                        length = 0;
                        hcd->poll_pending = 1;
                }
                spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
        }

        /* The USB 2.0 spec says 256 ms.  This is close enough and won't
         * exceed that limit if HZ is 100. The math is more clunky than
         * maybe expected, this is to make sure that all timers for USB devices
         * fire at the same time to give the CPU a break inbetween */
        if (hcd->uses_new_polling ? hcd->poll_rh :
                        (length == 0 && hcd->status_urb != NULL))
                mod_timer (&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));
}
EXPORT_SYMBOL_GPL(usb_hcd_poll_rh_status);

/* timer callback */
static void rh_timer_func (unsigned long _hcd)
{
        usb_hcd_poll_rh_status((struct usb_hcd *) _hcd);
}

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

static int rh_queue_status (struct usb_hcd *hcd, struct urb *urb)
{
        int             retval;
        unsigned long   flags;
        unsigned        len = 1 + (urb->dev->maxchild / 8);

        spin_lock_irqsave (&hcd_root_hub_lock, flags);
        if (hcd->status_urb || urb->transfer_buffer_length < len) {
                dev_dbg (hcd->self.controller, "not queuing rh status urb\n");
                retval = -EINVAL;
                goto done;
        }

        retval = usb_hcd_link_urb_to_ep(hcd, urb);
        if (retval)
                goto done;

        hcd->status_urb = urb;
        urb->hcpriv = hcd;      /* indicate it's queued */
        if (!hcd->uses_new_polling)
                mod_timer(&hcd->rh_timer, (jiffies/(HZ/4) + 1) * (HZ/4));

        /* If a status change has already occurred, report it ASAP */
        else if (hcd->poll_pending)
                mod_timer(&hcd->rh_timer, jiffies);
        retval = 0;
 done:
        spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
        return retval;
}

static int rh_urb_enqueue (struct usb_hcd *hcd, struct urb *urb)
{
        if (usb_endpoint_xfer_int(&urb->ep->desc))
                return rh_queue_status (hcd, urb);
        if (usb_endpoint_xfer_control(&urb->ep->desc))
                return rh_call_control (hcd, urb);
        return -EINVAL;
}

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

/* Unlinks of root-hub control URBs are legal, but they don't do anything
 * since these URBs always execute synchronously.
 */
static int usb_rh_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
{
        unsigned long   flags;
        int             rc;

        spin_lock_irqsave(&hcd_root_hub_lock, flags);
        rc = usb_hcd_check_unlink_urb(hcd, urb, status);
        if (rc)
                goto done;

        if (usb_endpoint_num(&urb->ep->desc) == 0) {    /* Control URB */
                ;       /* Do nothing */

        } else {                                /* Status URB */
                if (!hcd->uses_new_polling)
                        del_timer (&hcd->rh_timer);
                if (urb == hcd->status_urb) {
                        hcd->status_urb = NULL;
                        usb_hcd_unlink_urb_from_ep(hcd, urb);

                        spin_unlock(&hcd_root_hub_lock);
                        usb_hcd_giveback_urb(hcd, urb, status);
                        spin_lock(&hcd_root_hub_lock);
                }
        }
 done:
        spin_unlock_irqrestore(&hcd_root_hub_lock, flags);
        return rc;
}



/*
 * Show & store the current value of authorized_default
 */
static ssize_t usb_host_authorized_default_show(struct device *dev,
                                                struct device_attribute *attr,
                                                char *buf)
{
        struct usb_device *rh_usb_dev = to_usb_device(dev);
        struct usb_bus *usb_bus = rh_usb_dev->bus;
        struct usb_hcd *usb_hcd;

        if (usb_bus == NULL)    /* FIXME: not sure if this case is possible */
                return -ENODEV;
        usb_hcd = bus_to_hcd(usb_bus);
        return snprintf(buf, PAGE_SIZE, "%u\n", usb_hcd->authorized_default);
}

static ssize_t usb_host_authorized_default_store(struct device *dev,
                                                 struct device_attribute *attr,
                                                 const char *buf, size_t size)
{
        ssize_t result;
        unsigned val;
        struct usb_device *rh_usb_dev = to_usb_device(dev);
        struct usb_bus *usb_bus = rh_usb_dev->bus;
        struct usb_hcd *usb_hcd;

        if (usb_bus == NULL)    /* FIXME: not sure if this case is possible */
                return -ENODEV;
        usb_hcd = bus_to_hcd(usb_bus);
        result = sscanf(buf, "%u\n", &val);
        if (result == 1) {
                usb_hcd->authorized_default = val? 1 : 0;
                result = size;
        }
        else
                result = -EINVAL;
        return result;
}

static DEVICE_ATTR(authorized_default, 0644,
            usb_host_authorized_default_show,
            usb_host_authorized_default_store);


/* Group all the USB bus attributes */
static struct attribute *usb_bus_attrs[] = {
                &dev_attr_authorized_default.attr,
                NULL,
};

static struct attribute_group usb_bus_attr_group = {
        .name = NULL,   /* we want them in the same directory */
        .attrs = usb_bus_attrs,
};



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

/**
 * usb_bus_init - shared initialization code
 * @bus: the bus structure being initialized
 *
 * This code is used to initialize a usb_bus structure, memory for which is
 * separately managed.
 */
static void usb_bus_init (struct usb_bus *bus)
{
        memset (&bus->devmap, 0, sizeof(struct usb_devmap));

        bus->devnum_next = 1;

        bus->root_hub = NULL;
        bus->busnum = -1;
        bus->bandwidth_allocated = 0;
        bus->bandwidth_int_reqs  = 0;
        bus->bandwidth_isoc_reqs = 0;

        INIT_LIST_HEAD (&bus->bus_list);
}

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

/**
 * usb_register_bus - registers the USB host controller with the usb core
 * @bus: pointer to the bus to register
 * Context: !in_interrupt()
 *
 * Assigns a bus number, and links the controller into usbcore data
 * structures so that it can be seen by scanning the bus list.
 */
static int usb_register_bus(struct usb_bus *bus)
{
        int result = -E2BIG;
        int busnum;

        mutex_lock(&usb_bus_list_lock);
        busnum = find_next_zero_bit (busmap.busmap, USB_MAXBUS, 1);
        if (busnum >= USB_MAXBUS) {
                printk (KERN_ERR "%s: too many buses\n", usbcore_name);
                goto error_find_busnum;
        }
        set_bit (busnum, busmap.busmap);
        bus->busnum = busnum;

        /* Add it to the local list of buses */
        list_add (&bus->bus_list, &usb_bus_list);
        mutex_unlock(&usb_bus_list_lock);

        usb_notify_add_bus(bus);

        dev_info (bus->controller, "new USB bus registered, assigned bus "
                  "number %d\n", bus->busnum);
        return 0;

error_find_busnum:
        mutex_unlock(&usb_bus_list_lock);
        return result;
}

/**
 * usb_deregister_bus - deregisters the USB host controller
 * @bus: pointer to the bus to deregister
 * Context: !in_interrupt()
 *
 * Recycles the bus number, and unlinks the controller from usbcore data
 * structures so that it won't be seen by scanning the bus list.
 */
static void usb_deregister_bus (struct usb_bus *bus)
{
        dev_info (bus->controller, "USB bus %d deregistered\n", bus->busnum);

        /*
         * NOTE: make sure that all the devices are removed by the
         * controller code, as well as having it call this when cleaning
         * itself up
         */
        mutex_lock(&usb_bus_list_lock);
        list_del (&bus->bus_list);
        mutex_unlock(&usb_bus_list_lock);

        usb_notify_remove_bus(bus);

        clear_bit (bus->busnum, busmap.busmap);
}

/**
 * register_root_hub - called by usb_add_hcd() to register a root hub
 * @hcd: host controller for this root hub
 *
 * This function registers the root hub with the USB subsystem.  It sets up
 * the device properly in the device tree and then calls usb_new_device()
 * to register the usb device.  It also assigns the root hub's USB address
 * (always 1).
 */
static int register_root_hub(struct usb_hcd *hcd)
{
        struct device *parent_dev = hcd->self.controller;
        struct usb_device *usb_dev = hcd->self.root_hub;
        const int devnum = 1;
        int retval;

        usb_dev->devnum = devnum;
        usb_dev->bus->devnum_next = devnum + 1;
        memset (&usb_dev->bus->devmap.devicemap, 0,
                        sizeof usb_dev->bus->devmap.devicemap);
        set_bit (devnum, usb_dev->bus->devmap.devicemap);
        usb_set_device_state(usb_dev, USB_STATE_ADDRESS);

        mutex_lock(&usb_bus_list_lock);

        usb_dev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
        retval = usb_get_device_descriptor(usb_dev, USB_DT_DEVICE_SIZE);
        if (retval != sizeof usb_dev->descriptor) {
                mutex_unlock(&usb_bus_list_lock);
                dev_dbg (parent_dev, "can't read %s device descriptor %d\n",
                                dev_name(&usb_dev->dev), retval);
                return (retval < 0) ? retval : -EMSGSIZE;
        }

        retval = usb_new_device (usb_dev);
        if (retval) {
                dev_err (parent_dev, "can't register root hub for %s, %d\n",
                                dev_name(&usb_dev->dev), retval);
        }
        mutex_unlock(&usb_bus_list_lock);

        if (retval == 0) {
                spin_lock_irq (&hcd_root_hub_lock);
                hcd->rh_registered = 1;
                spin_unlock_irq (&hcd_root_hub_lock);

                /* Did the HC die before the root hub was registered? */
                if (hcd->state == HC_STATE_HALT)
                        usb_hc_died (hcd);      /* This time clean up */
        }

        return retval;
}


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

/**
 * usb_calc_bus_time - approximate periodic transaction time in nanoseconds
 * @speed: from dev->speed; USB_SPEED_{LOW,FULL,HIGH}
 * @is_input: true iff the transaction sends data to the host
 * @isoc: true for isochronous transactions, false for interrupt ones
 * @bytecount: how many bytes in the transaction.
 *
 * Returns approximate bus time in nanoseconds for a periodic transaction.
 * See USB 2.0 spec section 5.11.3; only periodic transfers need to be
 * scheduled in software, this function is only used for such scheduling.
 */
long usb_calc_bus_time (int speed, int is_input, int isoc, int bytecount)
{
        unsigned long   tmp;

        switch (speed) {
        case USB_SPEED_LOW:     /* INTR only */
                if (is_input) {
                        tmp = (67667L * (31L + 10L * BitTime (bytecount))) / 1000L;
                        return (64060L + (2 * BW_HUB_LS_SETUP) + BW_HOST_DELAY + tmp);
                } else {
                        tmp = (66700L * (31L + 10L * BitTime (bytecount))) / 1000L;
                        return (64107L + (2 * BW_HUB_LS_SETUP) + BW_HOST_DELAY + tmp);
                }
        case USB_SPEED_FULL:    /* ISOC or INTR */
                if (isoc) {
                        tmp = (8354L * (31L + 10L * BitTime (bytecount))) / 1000L;
                        return (((is_input) ? 7268L : 6265L) + BW_HOST_DELAY + tmp);
                } else {
                        tmp = (8354L * (31L + 10L * BitTime (bytecount))) / 1000L;
                        return (9107L + BW_HOST_DELAY + tmp);
                }
        case USB_SPEED_HIGH:    /* ISOC or INTR */
                // FIXME adjust for input vs output
                if (isoc)
                        tmp = HS_NSECS_ISO (bytecount);
                else
                        tmp = HS_NSECS (bytecount);
                return tmp;
        default:
                pr_debug ("%s: bogus device speed!\n", usbcore_name);
                return -1;
        }
}
EXPORT_SYMBOL_GPL(usb_calc_bus_time);


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

/*
 * Generic HC operations.
 */

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

/**
 * usb_hcd_link_urb_to_ep - add an URB to its endpoint queue
 * @hcd: host controller to which @urb was submitted
 * @urb: URB being submitted
 *
 * Host controller drivers should call this routine in their enqueue()
 * method.  The HCD's private spinlock must be held and interrupts must
 * be disabled.  The actions carried out here are required for URB
 * submission, as well as for endpoint shutdown and for usb_kill_urb.
 *
 * Returns 0 for no error, otherwise a negative error code (in which case
 * the enqueue() method must fail).  If no error occurs but enqueue() fails
 * anyway, it must call usb_hcd_unlink_urb_from_ep() before releasing
 * the private spinlock and returning.
 */
int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb)
{
        int             rc = 0;

        spin_lock(&hcd_urb_list_lock);

        /* Check that the URB isn't being killed */
        if (unlikely(atomic_read(&urb->reject))) {
                rc = -EPERM;
                goto done;
        }

        if (unlikely(!urb->ep->enabled)) {
                rc = -ENOENT;
                goto done;
        }

        if (unlikely(!urb->dev->can_submit)) {
                rc = -EHOSTUNREACH;
                goto done;
        }

        /*
         * Check the host controller's state and add the URB to the
         * endpoint's queue.
         */
        switch (hcd->state) {
        case HC_STATE_RUNNING:
        case HC_STATE_RESUMING:
                urb->unlinked = 0;
                list_add_tail(&urb->urb_list, &urb->ep->urb_list);
                break;
        default:
                rc = -ESHUTDOWN;
                goto done;
        }
 done:
        spin_unlock(&hcd_urb_list_lock);
        return rc;
}
EXPORT_SYMBOL_GPL(usb_hcd_link_urb_to_ep);

/**
 * usb_hcd_check_unlink_urb - check whether an URB may be unlinked
 * @hcd: host controller to which @urb was submitted
 * @urb: URB being checked for unlinkability
 * @status: error code to store in @urb if the unlink succeeds
 *
 * Host controller drivers should call this routine in their dequeue()
 * method.  The HCD's private spinlock must be held and interrupts must
 * be disabled.  The actions carried out here are required for making
 * sure than an unlink is valid.
 *
 * Returns 0 for no error, otherwise a negative error code (in which case
 * the dequeue() method must fail).  The possible error codes are:
 *
 *      -EIDRM: @urb was not submitted or has already completed.
 *              The completion function may not have been called yet.
 *
 *      -EBUSY: @urb has already been unlinked.
 */
int usb_hcd_check_unlink_urb(struct usb_hcd *hcd, struct urb *urb,
                int status)
{
        struct list_head        *tmp;

        /* insist the urb is still queued */
        list_for_each(tmp, &urb->ep->urb_list) {
                if (tmp == &urb->urb_list)
                        break;
        }
        if (tmp != &urb->urb_list)
                return -EIDRM;

        /* Any status except -EINPROGRESS means something already started to
         * unlink this URB from the hardware.  So there's no more work to do.
         */
        if (urb->unlinked)
                return -EBUSY;
        urb->unlinked = status;

        /* IRQ setup can easily be broken so that USB controllers
         * never get completion IRQs ... maybe even the ones we need to
         * finish unlinking the initial failed usb_set_address()
         * or device descriptor fetch.
         */
        if (!test_bit(HCD_FLAG_SAW_IRQ, &hcd->flags) &&
                        !is_root_hub(urb->dev)) {
                dev_warn(hcd->self.controller, "Unlink after no-IRQ?  "
                        "Controller is probably using the wrong IRQ.\n");
                set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
        }

        return 0;
}
EXPORT_SYMBOL_GPL(usb_hcd_check_unlink_urb);

/**
 * usb_hcd_unlink_urb_from_ep - remove an URB from its endpoint queue
 * @hcd: host controller to which @urb was submitted
 * @urb: URB being unlinked
 *
 * Host controller drivers should call this routine before calling
 * usb_hcd_giveback_urb().  The HCD's private spinlock must be held and
 * interrupts must be disabled.  The actions carried out here are required
 * for URB completion.
 */
void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb)
{
        /* clear all state linking urb to this dev (and hcd) */
        spin_lock(&hcd_urb_list_lock);
        list_del_init(&urb->urb_list);
        spin_unlock(&hcd_urb_list_lock);
}
EXPORT_SYMBOL_GPL(usb_hcd_unlink_urb_from_ep);

/*
 * Some usb host controllers can only perform dma using a small SRAM area.
 * The usb core itself is however optimized for host controllers that can dma
 * using regular system memory - like pci devices doing bus mastering.
 *
 * To support host controllers with limited dma capabilites we provide dma
 * bounce buffers. This feature can be enabled using the HCD_LOCAL_MEM flag.
 * For this to work properly the host controller code must first use the
 * function dma_declare_coherent_memory() to point out which memory area
 * that should be used for dma allocations.
 *
 * The HCD_LOCAL_MEM flag then tells the usb code to allocate all data for
 * dma using dma_alloc_coherent() which in turn allocates from the memory
 * area pointed out with dma_declare_coherent_memory().
 *
 * So, to summarize...
 *
 * - We need "local" memory, canonical example being
 *   a small SRAM on a discrete controller being the
 *   only memory that the controller can read ...
 *   (a) "normal" kernel memory is no good, and
 *   (b) there's not enough to share
 *
 * - The only *portable* hook for such stuff in the
 *   DMA framework is dma_declare_coherent_memory()
 *
 * - So we use that, even though the primary requirement
 *   is that the memory be "local" (hence addressible
 *   by that device), not "coherent".
 *
 */

static int hcd_alloc_coherent(struct usb_bus *bus,
                              gfp_t mem_flags, dma_addr_t *dma_handle,
                              void **vaddr_handle, size_t size,
                              enum dma_data_direction dir)
{
        unsigned char *vaddr;

        vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
                                 mem_flags, dma_handle);
        if (!vaddr)
                return -ENOMEM;

        /*
         * Store the virtual address of the buffer at the end
         * of the allocated dma buffer. The size of the buffer
         * may be uneven so use unaligned functions instead
         * of just rounding up. It makes sense to optimize for
         * memory footprint over access speed since the amount
         * of memory available for dma may be limited.
         */
        put_unaligned((unsigned long)*vaddr_handle,
                      (unsigned long *)(vaddr + size));

        if (dir == DMA_TO_DEVICE)
                memcpy(vaddr, *vaddr_handle, size);

        *vaddr_handle = vaddr;
        return 0;
}

static void hcd_free_coherent(struct usb_bus *bus, dma_addr_t *dma_handle,
                              void **vaddr_handle, size_t size,
                              enum dma_data_direction dir)
{
        unsigned char *vaddr = *vaddr_handle;

        vaddr = (void *)get_unaligned((unsigned long *)(vaddr + size));

        if (dir == DMA_FROM_DEVICE)
                memcpy(vaddr, *vaddr_handle, size);

        hcd_buffer_free(bus, size + sizeof(vaddr), *vaddr_handle, *dma_handle);

        *vaddr_handle = vaddr;
        *dma_handle = 0;
}

static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
                           gfp_t mem_flags)
{
        enum dma_data_direction dir;
        int ret = 0;

        /* Map the URB's buffers for DMA access.
         * Lower level HCD code should use *_dma exclusively,
         * unless it uses pio or talks to another transport.
         */
        if (is_root_hub(urb->dev))
                return 0;

        if (usb_endpoint_xfer_control(&urb->ep->desc)
            && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) {
                if (hcd->self.uses_dma)
                        urb->setup_dma = dma_map_single(
                                        hcd->self.controller,
                                        urb->setup_packet,
                                        sizeof(struct usb_ctrlrequest),
                                        DMA_TO_DEVICE);
                else if (hcd->driver->flags & HCD_LOCAL_MEM)
                        ret = hcd_alloc_coherent(
                                        urb->dev->bus, mem_flags,
                                        &urb->setup_dma,
                                        (void **)&urb->setup_packet,
                                        sizeof(struct usb_ctrlrequest),
                                        DMA_TO_DEVICE);
        }

        dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
        if (ret == 0 && urb->transfer_buffer_length != 0
            && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
                if (hcd->self.uses_dma)
                        urb->transfer_dma = dma_map_single (
                                        hcd->self.controller,
                                        urb->transfer_buffer,
                                        urb->transfer_buffer_length,
                                        dir);
                else if (hcd->driver->flags & HCD_LOCAL_MEM) {
                        ret = hcd_alloc_coherent(
                                        urb->dev->bus, mem_flags,
                                        &urb->transfer_dma,
                                        &urb->transfer_buffer,
                                        urb->transfer_buffer_length,
                                        dir);

                        if (ret && usb_endpoint_xfer_control(&urb->ep->desc)
                            && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP))
                                hcd_free_coherent(urb->dev->bus,
                                        &urb->setup_dma,
                                        (void **)&urb->setup_packet,
                                        sizeof(struct usb_ctrlrequest),
                                        DMA_TO_DEVICE);
                }
        }
        return ret;
}

static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
{
        enum dma_data_direction dir;

        if (is_root_hub(urb->dev))
                return;

        if (usb_endpoint_xfer_control(&urb->ep->desc)
            && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) {
                if (hcd->self.uses_dma)
                        dma_unmap_single(hcd->self.controller, urb->setup_dma,
                                        sizeof(struct usb_ctrlrequest),
                                        DMA_TO_DEVICE);
                else if (hcd->driver->flags & HCD_LOCAL_MEM)
                        hcd_free_coherent(urb->dev->bus, &urb->setup_dma,
                                        (void **)&urb->setup_packet,
                                        sizeof(struct usb_ctrlrequest),
                                        DMA_TO_DEVICE);
        }

        dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
        if (urb->transfer_buffer_length != 0
            && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
                if (hcd->self.uses_dma)
                        dma_unmap_single(hcd->self.controller,
                                        urb->transfer_dma,
                                        urb->transfer_buffer_length,
                                        dir);
                else if (hcd->driver->flags & HCD_LOCAL_MEM)
                        hcd_free_coherent(urb->dev->bus, &urb->transfer_dma,
                                        &urb->transfer_buffer,
                                        urb->transfer_buffer_length,
                                        dir);
        }
}

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

/* may be called in any context with a valid urb->dev usecount
 * caller surrenders "ownership" of urb
 * expects usb_submit_urb() to have sanity checked and conditioned all
 * inputs in the urb
 */
int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
{
        int                     status;
        struct usb_hcd          *hcd = bus_to_hcd(urb->dev->bus);

        /* increment urb's reference count as part of giving it to the HCD
         * (which will control it).  HCD guarantees that it either returns
         * an error or calls giveback(), but not both.
         */
        usb_get_urb(urb);
        atomic_inc(&urb->use_count);
        atomic_inc(&urb->dev->urbnum);
        usbmon_urb_submit(&hcd->self, urb);

        /* NOTE requirements on root-hub callers (usbfs and the hub
         * driver, for now):  URBs' urb->transfer_buffer must be
         * valid and usb_buffer_{sync,unmap}() not be needed, since
         * they could clobber root hub response data.  Also, control
         * URBs must be submitted in process context with interrupts
         * enabled.
         */
        status = map_urb_for_dma(hcd, urb, mem_flags);
        if (unlikely(status)) {
                usbmon_urb_submit_error(&hcd->self, urb, status);
                goto error;
        }

        if (is_root_hub(urb->dev))
                status = rh_urb_enqueue(hcd, urb);
        else
                status = hcd->driver->urb_enqueue(hcd, urb, mem_flags);

        if (unlikely(status)) {
                usbmon_urb_submit_error(&hcd->self, urb, status);
                unmap_urb_for_dma(hcd, urb);
 error:
                urb->hcpriv = NULL;
                INIT_LIST_HEAD(&urb->urb_list);
                atomic_dec(&urb->use_count);
                atomic_dec(&urb->dev->urbnum);
                if (atomic_read(&urb->reject))
                        wake_up(&usb_kill_urb_queue);
                usb_put_urb(urb);
        }
        return status;
}

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

/* this makes the hcd giveback() the urb more quickly, by kicking it
 * off hardware queues (which may take a while) and returning it as
 * soon as practical.  we've already set up the urb's return status,
 * but we can't know if the callback completed already.
 */
static int unlink1(struct usb_hcd *hcd, struct urb *urb, int status)
{
        int             value;

        if (is_root_hub(urb->dev))
                value = usb_rh_urb_dequeue(hcd, urb, status);
        else {

                /* The only reason an HCD might fail this call is if
                 * it has not yet fully queued the urb to begin with.
                 * Such failures should be harmless. */
                value = hcd->driver->urb_dequeue(hcd, urb, status);
        }
        return value;
}

/*
 * called in any context
 *
 * caller guarantees urb won't be recycled till both unlink()
 * and the urb's completion function return
 */
int usb_hcd_unlink_urb (struct urb *urb, int status)
{
        struct usb_hcd          *hcd;
        int                     retval = -EIDRM;
        unsigned long           flags;

        /* Prevent the device and bus from going away while
         * the unlink is carried out.  If they are already gone
         * then urb->use_count must be 0, since disconnected
         * devices can't have any active URBs.
         */
        spin_lock_irqsave(&hcd_urb_unlink_lock, flags);
        if (atomic_read(&urb->use_count) > 0) {
                retval = 0;
                usb_get_dev(urb->dev);
        }
        spin_unlock_irqrestore(&hcd_urb_unlink_lock, flags);
        if (retval == 0) {
                hcd = bus_to_hcd(urb->dev->bus);
                retval = unlink1(hcd, urb, status);
                usb_put_dev(urb->dev);
        }

        if (retval == 0)
                retval = -EINPROGRESS;
        else if (retval != -EIDRM && retval != -EBUSY)
                dev_dbg(&urb->dev->dev, "hcd_unlink_urb %p fail %d\n",
                                urb, retval);
        return retval;
}

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

/**
 * usb_hcd_giveback_urb - return URB from HCD to device driver
 * @hcd: host controller returning the URB
 * @urb: urb being returned to the USB device driver.
 * @status: completion status code for the URB.
 * Context: in_interrupt()
 *
 * This hands the URB from HCD to its USB device driver, using its
 * completion function.  The HCD has freed all per-urb resources
 * (and is done using urb->hcpriv).  It also released all HCD locks;
 * the device driver won't cause problems if it frees, modifies,
 * or resubmits this URB.
 *
 * If @urb was unlinked, the value of @status will be overridden by
 * @urb->unlinked.  Erroneous short transfers are detected in case
 * the HCD hasn't checked for them.
 */
void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
{
        urb->hcpriv = NULL;
        if (unlikely(urb->unlinked))
                status = urb->unlinked;
        else if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) &&
                        urb->actual_length < urb->transfer_buffer_length &&
                        !status))
                status = -EREMOTEIO;

        unmap_urb_for_dma(hcd, urb);
        usbmon_urb_complete(&hcd->self, urb, status);
        usb_unanchor_urb(urb);

        /* pass ownership to the completion handler */
        urb->status = status;
        urb->complete (urb);
        atomic_dec (&urb->use_count);
        if (unlikely(atomic_read(&urb->reject)))
                wake_up (&usb_kill_urb_queue);
        usb_put_urb (urb);
}
EXPORT_SYMBOL_GPL(usb_hcd_giveback_urb);

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

/* Cancel all URBs pending on this endpoint and wait for the endpoint's
 * queue to drain completely.  The caller must first insure that no more
 * URBs can be submitted for this endpoint.
 */
void usb_hcd_flush_endpoint(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        struct usb_hcd          *hcd;
        struct urb              *urb;

        if (!ep)
                return;
        might_sleep();
        hcd = bus_to_hcd(udev->bus);

        /* No more submits can occur */
        spin_lock_irq(&hcd_urb_list_lock);
rescan:
        list_for_each_entry (urb, &ep->urb_list, urb_list) {
                int     is_in;

                if (urb->unlinked)
                        continue;
                usb_get_urb (urb);
                is_in = usb_urb_dir_in(urb);
                spin_unlock(&hcd_urb_list_lock);

                /* kick hcd */
                unlink1(hcd, urb, -ESHUTDOWN);
                dev_dbg (hcd->self.controller,
                        "shutdown urb %p ep%d%s%s\n",
                        urb, usb_endpoint_num(&ep->desc),
                        is_in ? "in" : "out",
                        ({      char *s;

                                 switch (usb_endpoint_type(&ep->desc)) {
                                 case USB_ENDPOINT_XFER_CONTROL:
                                        s = ""; break;
                                 case USB_ENDPOINT_XFER_BULK:
                                        s = "-bulk"; break;
                                 case USB_ENDPOINT_XFER_INT:
                                        s = "-intr"; break;
                                 default:
                                        s = "-iso"; break;
                                };
                                s;
                        }));
                usb_put_urb (urb);

                /* list contents may have changed */
                spin_lock(&hcd_urb_list_lock);
                goto rescan;
        }
        spin_unlock_irq(&hcd_urb_list_lock);

        /* Wait until the endpoint queue is completely empty */
        while (!list_empty (&ep->urb_list)) {
                spin_lock_irq(&hcd_urb_list_lock);

                /* The list may have changed while we acquired the spinlock */
                urb = NULL;
                if (!list_empty (&ep->urb_list)) {
                        urb = list_entry (ep->urb_list.prev, struct urb,
                                        urb_list);
                        usb_get_urb (urb);
                }
                spin_unlock_irq(&hcd_urb_list_lock);

                if (urb) {
                        usb_kill_urb (urb);
                        usb_put_urb (urb);
                }
        }
}

/* Check whether a new configuration or alt setting for an interface
 * will exceed the bandwidth for the bus (or the host controller resources).
 * Only pass in a non-NULL config or interface, not both!
 * Passing NULL for both new_config and new_intf means the device will be
 * de-configured by issuing a set configuration 0 command.
 */
int usb_hcd_check_bandwidth(struct usb_device *udev,
                struct usb_host_config *new_config,
                struct usb_interface *new_intf)
{
        int num_intfs, i, j;
        struct usb_interface_cache *intf_cache;
        struct usb_host_interface *alt = 0;
        int ret = 0;
        struct usb_hcd *hcd;
        struct usb_host_endpoint *ep;

        hcd = bus_to_hcd(udev->bus);
        if (!hcd->driver->check_bandwidth)
                return 0;

        /* Configuration is being removed - set configuration 0 */
        if (!new_config && !new_intf) {
                for (i = 1; i < 16; ++i) {
                        ep = udev->ep_out[i];
                        if (ep)
                                hcd->driver->drop_endpoint(hcd, udev, ep);
                        ep = udev->ep_in[i];
                        if (ep)
                                hcd->driver->drop_endpoint(hcd, udev, ep);
                }
                hcd->driver->check_bandwidth(hcd, udev);
                return 0;
        }
        /* Check if the HCD says there's enough bandwidth.  Enable all endpoints
         * each interface's alt setting 0 and ask the HCD to check the bandwidth
         * of the bus.  There will always be bandwidth for endpoint 0, so it's
         * ok to exclude it.
         */
        if (new_config) {
                num_intfs = new_config->desc.bNumInterfaces;
                /* Remove endpoints (except endpoint 0, which is always on the
                 * schedule) from the old config from the schedule
                 */
                for (i = 1; i < 16; ++i) {
                        ep = udev->ep_out[i];
                        if (ep) {
                                ret = hcd->driver->drop_endpoint(hcd, udev, ep);
                                if (ret < 0)
                                        goto reset;
                        }
                        ep = udev->ep_in[i];
                        if (ep) {
                                ret = hcd->driver->drop_endpoint(hcd, udev, ep);
                                if (ret < 0)
                                        goto reset;
                        }
                }
                for (i = 0; i < num_intfs; ++i) {

                        /* Dig the endpoints for alt setting 0 out of the
                         * interface cache for this interface
                         */
                        intf_cache = new_config->intf_cache[i];
                        for (j = 0; j < intf_cache->num_altsetting; j++) {
                                if (intf_cache->altsetting[j].desc.bAlternateSetting == 0)
                                        alt = &intf_cache->altsetting[j];
                        }
                        if (!alt) {
                                printk(KERN_DEBUG "Did not find alt setting 0 for intf %d\n", i);
                                continue;
                        }
                        for (j = 0; j < alt->desc.bNumEndpoints; j++) {
                                ret = hcd->driver->add_endpoint(hcd, udev, &alt->endpoint[j]);
                                if (ret < 0)
                                        goto reset;
                        }
                }
        }
        ret = hcd->driver->check_bandwidth(hcd, udev);
reset:
        if (ret < 0)
                hcd->driver->reset_bandwidth(hcd, udev);
        return ret;
}

/* Disables the endpoint: synchronizes with the hcd to make sure all
 * endpoint state is gone from hardware.  usb_hcd_flush_endpoint() must
 * have been called previously.  Use for set_configuration, set_interface,
 * driver removal, physical disconnect.
 *
 * example:  a qh stored in ep->hcpriv, holding state related to endpoint
 * type, maxpacket size, toggle, halt status, and scheduling.
 */
void usb_hcd_disable_endpoint(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        struct usb_hcd          *hcd;

        might_sleep();
        hcd = bus_to_hcd(udev->bus);
        if (hcd->driver->endpoint_disable)
                hcd->driver->endpoint_disable(hcd, ep);
}

/**
 * usb_hcd_reset_endpoint - reset host endpoint state
 * @udev: USB device.
 * @ep:   the endpoint to reset.
 *
 * Resets any host endpoint state such as the toggle bit, sequence
 * number and current window.
 */
void usb_hcd_reset_endpoint(struct usb_device *udev,
                            struct usb_host_endpoint *ep)
{
        struct usb_hcd *hcd = bus_to_hcd(udev->bus);

        if (hcd->driver->endpoint_reset)
                hcd->driver->endpoint_reset(hcd, ep);
        else {
                int epnum = usb_endpoint_num(&ep->desc);
                int is_out = usb_endpoint_dir_out(&ep->desc);
                int is_control = usb_endpoint_xfer_control(&ep->desc);

                usb_settoggle(udev, epnum, is_out, 0);
                if (is_control)
                        usb_settoggle(udev, epnum, !is_out, 0);
        }
}

/* Protect against drivers that try to unlink URBs after the device
 * is gone, by waiting until all unlinks for @udev are finished.
 * Since we don't currently track URBs by device, simply wait until
 * nothing is running in the locked region of usb_hcd_unlink_urb().
 */
void usb_hcd_synchronize_unlinks(struct usb_device *udev)
{
        spin_lock_irq(&hcd_urb_unlink_lock);
        spin_unlock_irq(&hcd_urb_unlink_lock);
}

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

/* called in any context */
int usb_hcd_get_frame_number (struct usb_device *udev)
{
        struct usb_hcd  *hcd = bus_to_hcd(udev->bus);

        if (!HC_IS_RUNNING (hcd->state))
                return -ESHUTDOWN;
        return hcd->driver->get_frame_number (hcd);
}

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

#ifdef  CONFIG_PM

int hcd_bus_suspend(struct usb_device *rhdev, pm_message_t msg)
{
        struct usb_hcd  *hcd = container_of(rhdev->bus, struct usb_hcd, self);
        int             status;
        int             old_state = hcd->state;

        dev_dbg(&rhdev->dev, "bus %s%s\n",
                        (msg.event & PM_EVENT_AUTO ? "auto-" : ""), "suspend");
        if (!hcd->driver->bus_suspend) {
                status = -ENOENT;
        } else {
                hcd->state = HC_STATE_QUIESCING;
                status = hcd->driver->bus_suspend(hcd);
        }
        if (status == 0) {
                usb_set_device_state(rhdev, USB_STATE_SUSPENDED);
                hcd->state = HC_STATE_SUSPENDED;
        } else {
                hcd->state = old_state;
                dev_dbg(&rhdev->dev, "bus %s fail, err %d\n",
                                "suspend", status);
        }
        return status;
}

int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg)
{
        struct usb_hcd  *hcd = container_of(rhdev->bus, struct usb_hcd, self);
        int             status;
        int             old_state = hcd->state;

        dev_dbg(&rhdev->dev, "usb %s%s\n",
                        (msg.event & PM_EVENT_AUTO ? "auto-" : ""), "resume");
        if (!hcd->driver->bus_resume)
                return -ENOENT;
        if (hcd->state == HC_STATE_RUNNING)
                return 0;

        hcd->state = HC_STATE_RESUMING;
        status = hcd->driver->bus_resume(hcd);
        if (status == 0) {
                /* TRSMRCY = 10 msec */
                msleep(10);
                usb_set_device_state(rhdev, rhdev->actconfig
                                ? USB_STATE_CONFIGURED
                                : USB_STATE_ADDRESS);
                hcd->state = HC_STATE_RUNNING;
        } else {
                hcd->state = old_state;
                dev_dbg(&rhdev->dev, "bus %s fail, err %d\n",
                                "resume", status);
                if (status != -ESHUTDOWN)
                        usb_hc_died(hcd);
        }
        return status;
}

/* Workqueue routine for root-hub remote wakeup */
static void hcd_resume_work(struct work_struct *work)
{
        struct usb_hcd *hcd = container_of(work, struct usb_hcd, wakeup_work);
        struct usb_device *udev = hcd->self.root_hub;

        usb_lock_device(udev);
        usb_mark_last_busy(udev);
        usb_external_resume_device(udev, PMSG_REMOTE_RESUME);
        usb_unlock_device(udev);
}

/**
 * usb_hcd_resume_root_hub - called by HCD to resume its root hub 
 * @hcd: host controller for this root hub
 *
 * The USB host controller calls this function when its root hub is
 * suspended (with the remote wakeup feature enabled) and a remote
 * wakeup request is received.  The routine submits a workqueue request
 * to resume the root hub (that is, manage its downstream ports again).
 */
void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
{
        unsigned long flags;

        spin_lock_irqsave (&hcd_root_hub_lock, flags);
        if (hcd->rh_registered)
                queue_work(ksuspend_usb_wq, &hcd->wakeup_work);
        spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
}
EXPORT_SYMBOL_GPL(usb_hcd_resume_root_hub);

#endif

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

#ifdef  CONFIG_USB_OTG

/**
 * usb_bus_start_enum - start immediate enumeration (for OTG)
 * @bus: the bus (must use hcd framework)
 * @port_num: 1-based number of port; usually bus->otg_port
 * Context: in_interrupt()
 *
 * Starts enumeration, with an immediate reset followed later by
 * khubd identifying and possibly configuring the device.
 * This is needed by OTG controller drivers, where it helps meet
 * HNP protocol timing requirements for starting a port reset.
 */
int usb_bus_start_enum(struct usb_bus *bus, unsigned port_num)
{
        struct usb_hcd          *hcd;
        int                     status = -EOPNOTSUPP;

        /* NOTE: since HNP can't start by grabbing the bus's address0_sem,
         * boards with root hubs hooked up to internal devices (instead of
         * just the OTG port) may need more attention to resetting...
         */
        hcd = container_of (bus, struct usb_hcd, self);
        if (port_num && hcd->driver->start_port_reset)
                status = hcd->driver->start_port_reset(hcd, port_num);

        /* run khubd shortly after (first) root port reset finishes;
         * it may issue others, until at least 50 msecs have passed.
         */
        if (status == 0)
                mod_timer(&hcd->rh_timer, jiffies + msecs_to_jiffies(10));
        return status;
}
EXPORT_SYMBOL_GPL(usb_bus_start_enum);

#endif

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

/**
 * usb_hcd_irq - hook IRQs to HCD framework (bus glue)
 * @irq: the IRQ being raised
 * @__hcd: pointer to the HCD whose IRQ is being signaled
 *
 * If the controller isn't HALTed, calls the driver's irq handler.
 * Checks whether the controller is now dead.
 */
irqreturn_t usb_hcd_irq (int irq, void *__hcd)
{
        struct usb_hcd          *hcd = __hcd;
        unsigned long           flags;
        irqreturn_t             rc;

        /* IRQF_DISABLED doesn't work correctly with shared IRQs
         * when the first handler doesn't use it.  So let's just
         * assume it's never used.
         */
        local_irq_save(flags);

        if (unlikely(hcd->state == HC_STATE_HALT ||
                     !test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags))) {
                rc = IRQ_NONE;
        } else if (hcd->driver->irq(hcd) == IRQ_NONE) {
                rc = IRQ_NONE;
        } else {
                set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);

                if (unlikely(hcd->state == HC_STATE_HALT))
                        usb_hc_died(hcd);
                rc = IRQ_HANDLED;
        }

        local_irq_restore(flags);
        return rc;
}

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

/**
 * usb_hc_died - report abnormal shutdown of a host controller (bus glue)
 * @hcd: pointer to the HCD representing the controller
 *
 * This is called by bus glue to report a USB host controller that died
 * while operations may still have been pending.  It's called automatically
 * by the PCI glue, so only glue for non-PCI busses should need to call it. 
 */
void usb_hc_died (struct usb_hcd *hcd)
{
        unsigned long flags;

        dev_err (hcd->self.controller, "HC died; cleaning up\n");

        spin_lock_irqsave (&hcd_root_hub_lock, flags);
        if (hcd->rh_registered) {
                hcd->poll_rh = 0;

                /* make khubd clean up old urbs and devices */
                usb_set_device_state (hcd->self.root_hub,
                                USB_STATE_NOTATTACHED);
                usb_kick_khubd (hcd->self.root_hub);
        }
        spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
}
EXPORT_SYMBOL_GPL (usb_hc_died);

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

/**
 * usb_create_hcd - create and initialize an HCD structure
 * @driver: HC driver that will use this hcd
 * @dev: device for this HC, stored in hcd->self.controller
 * @bus_name: value to store in hcd->self.bus_name
 * Context: !in_interrupt()
 *
 * Allocate a struct usb_hcd, with extra space at the end for the
 * HC driver's private data.  Initialize the generic members of the
 * hcd structure.
 *
 * If memory is unavailable, returns NULL.
 */
struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
                struct device *dev, const char *bus_name)
{
        struct usb_hcd *hcd;

        hcd = kzalloc(sizeof(*hcd) + driver->hcd_priv_size, GFP_KERNEL);
        if (!hcd) {
                dev_dbg (dev, "hcd alloc failed\n");
                return NULL;
        }
        dev_set_drvdata(dev, hcd);
        kref_init(&hcd->kref);

        usb_bus_init(&hcd->self);
        hcd->self.controller = dev;
        hcd->self.bus_name = bus_name;
        hcd->self.uses_dma = (dev->dma_mask != NULL);

        init_timer(&hcd->rh_timer);
        hcd->rh_timer.function = rh_timer_func;
        hcd->rh_timer.data = (unsigned long) hcd;
#ifdef CONFIG_PM
        INIT_WORK(&hcd->wakeup_work, hcd_resume_work);
#endif

        hcd->driver = driver;
        hcd->product_desc = (driver->product_desc) ? driver->product_desc :
                        "USB Host Controller";
        return hcd;
}
EXPORT_SYMBOL_GPL(usb_create_hcd);

static void hcd_release (struct kref *kref)
{
        struct usb_hcd *hcd = container_of (kref, struct usb_hcd, kref);

        kfree(hcd);
}

struct usb_hcd *usb_get_hcd (struct usb_hcd *hcd)
{
        if (hcd)
                kref_get (&hcd->kref);
        return hcd;
}
EXPORT_SYMBOL_GPL(usb_get_hcd);

void usb_put_hcd (struct usb_hcd *hcd)
{
        if (hcd)
                kref_put (&hcd->kref, hcd_release);
}
EXPORT_SYMBOL_GPL(usb_put_hcd);

/**
 * usb_add_hcd - finish generic HCD structure initialization and register
 * @hcd: the usb_hcd structure to initialize
 * @irqnum: Interrupt line to allocate
 * @irqflags: Interrupt type flags
 *
 * Finish the remaining parts of generic HCD initialization: allocate the
 * buffers of consistent memory, register the bus, request the IRQ line,
 * and call the driver's reset() and start() routines.
 */
int usb_add_hcd(struct usb_hcd *hcd,
                unsigned int irqnum, unsigned long irqflags)
{
        int retval;
        struct usb_device *rhdev;

        dev_info(hcd->self.controller, "%s\n", hcd->product_desc);

        hcd->authorized_default = hcd->wireless? 0 : 1;
        set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);

        /* HC is in reset state, but accessible.  Now do the one-time init,
         * bottom up so that hcds can customize the root hubs before khubd
         * starts talking to them.  (Note, bus id is assigned early too.)
         */
        if ((retval = hcd_buffer_create(hcd)) != 0) {
                dev_dbg(hcd->self.controller, "pool alloc failed\n");
                return retval;
        }

        if ((retval = usb_register_bus(&hcd->self)) < 0)
                goto err_register_bus;

        if ((rhdev = usb_alloc_dev(NULL, &hcd->self, 0)) == NULL) {
                dev_err(hcd->self.controller, "unable to allocate root hub\n");
                retval = -ENOMEM;
                goto err_allocate_root_hub;
        }

        switch (hcd->driver->flags & HCD_MASK) {
        case HCD_USB11:
                rhdev->speed = USB_SPEED_FULL;
                break;
        case HCD_USB2:
                rhdev->speed = USB_SPEED_HIGH;
                break;
        case HCD_USB3:
                rhdev->speed = USB_SPEED_SUPER;
                break;
        default:
                goto err_allocate_root_hub;
        }
        hcd->self.root_hub = rhdev;

        /* wakeup flag init defaults to "everything works" for root hubs,
         * but drivers can override it in reset() if needed, along with
         * recording the overall controller's system wakeup capability.
         */
        device_init_wakeup(&rhdev->dev, 1);

        /* "reset" is misnamed; its role is now one-time init. the controller
         * should already have been reset (and boot firmware kicked off etc).
         */
        if (hcd->driver->reset && (retval = hcd->driver->reset(hcd)) < 0) {
                dev_err(hcd->self.controller, "can't setup\n");
                goto err_hcd_driver_setup;
        }

        /* NOTE: root hub and controller capabilities may not be the same */
        if (device_can_wakeup(hcd->self.controller)
                        && device_can_wakeup(&hcd->self.root_hub->dev))
                dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");

        /* enable irqs just before we start the controller */
        if (hcd->driver->irq) {

                /* IRQF_DISABLED doesn't work as advertised when used together
                 * with IRQF_SHARED. As usb_hcd_irq() will always disable
                 * interrupts we can remove it here.
                 */
                if (irqflags & IRQF_SHARED)
                        irqflags &= ~IRQF_DISABLED;

                snprintf(hcd->irq_descr, sizeof(hcd->irq_descr), "%s:usb%d",
                                hcd->driver->description, hcd->self.busnum);
                if ((retval = request_irq(irqnum, &usb_hcd_irq, irqflags,
                                hcd->irq_descr, hcd)) != 0) {
                        dev_err(hcd->self.controller,
                                        "request interrupt %d failed\n", irqnum);
                        goto err_request_irq;
                }
                hcd->irq = irqnum;
                dev_info(hcd->self.controller, "irq %d, %s 0x%08llx\n", irqnum,
                                (hcd->driver->flags & HCD_MEMORY) ?
                                        "io mem" : "io base",
                                        (unsigned long long)hcd->rsrc_start);
        } else {
                hcd->irq = -1;
                if (hcd->rsrc_start)
                        dev_info(hcd->self.controller, "%s 0x%08llx\n",
                                        (hcd->driver->flags & HCD_MEMORY) ?
                                        "io mem" : "io base",
                                        (unsigned long long)hcd->rsrc_start);
        }

        if ((retval = hcd->driver->start(hcd)) < 0) {
                dev_err(hcd->self.controller, "startup error %d\n", retval);
                goto err_hcd_driver_start;
        }

        /* starting here, usbcore will pay attention to this root hub */
        rhdev->bus_mA = min(500u, hcd->power_budget);
        if ((retval = register_root_hub(hcd)) != 0)
                goto err_register_root_hub;

        retval = sysfs_create_group(&rhdev->dev.kobj, &usb_bus_attr_group);
        if (retval < 0) {
                printk(KERN_ERR "Cannot register USB bus sysfs attributes: %d\n",
                       retval);
                goto error_create_attr_group;
        }
        if (hcd->uses_new_polling && hcd->poll_rh)
                usb_hcd_poll_rh_status(hcd);
        return retval;

error_create_attr_group:
        mutex_lock(&usb_bus_list_lock);
        usb_disconnect(&hcd->self.root_hub);
        mutex_unlock(&usb_bus_list_lock);
err_register_root_hub:
        hcd->driver->stop(hcd);
err_hcd_driver_start:
        if (hcd->irq >= 0)
                free_irq(irqnum, hcd);
err_request_irq:
err_hcd_driver_setup:
        hcd->self.root_hub = NULL;
        usb_put_dev(rhdev);
err_allocate_root_hub:
        usb_deregister_bus(&hcd->self);
err_register_bus:
        hcd_buffer_destroy(hcd);
        return retval;
} 
EXPORT_SYMBOL_GPL(usb_add_hcd);

/**
 * usb_remove_hcd - shutdown processing for generic HCDs
 * @hcd: the usb_hcd structure to remove
 * Context: !in_interrupt()
 *
 * Disconnects the root hub, then reverses the effects of usb_add_hcd(),
 * invoking the HCD's stop() method.
 */
void usb_remove_hcd(struct usb_hcd *hcd)
{
        dev_info(hcd->self.controller, "remove, state %x\n", hcd->state);

        if (HC_IS_RUNNING (hcd->state))
                hcd->state = HC_STATE_QUIESCING;

        dev_dbg(hcd->self.controller, "roothub graceful disconnect\n");
        spin_lock_irq (&hcd_root_hub_lock);
        hcd->rh_registered = 0;
        spin_unlock_irq (&hcd_root_hub_lock);

#ifdef CONFIG_PM
        cancel_work_sync(&hcd->wakeup_work);
#endif

        sysfs_remove_group(&hcd->self.root_hub->dev.kobj, &usb_bus_attr_group);
        mutex_lock(&usb_bus_list_lock);
        usb_disconnect(&hcd->self.root_hub);
        mutex_unlock(&usb_bus_list_lock);

        hcd->driver->stop(hcd);
        hcd->state = HC_STATE_HALT;

        hcd->poll_rh = 0;
        del_timer_sync(&hcd->rh_timer);

        if (hcd->irq >= 0)
                free_irq(hcd->irq, hcd);
        usb_deregister_bus(&hcd->self);
        hcd_buffer_destroy(hcd);
}
EXPORT_SYMBOL_GPL(usb_remove_hcd);

void
usb_hcd_platform_shutdown(struct platform_device* dev)
{
        struct usb_hcd *hcd = platform_get_drvdata(dev);

        if (hcd->driver->shutdown)
                hcd->driver->shutdown(hcd);
}
EXPORT_SYMBOL_GPL(usb_hcd_platform_shutdown);

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

#if defined(CONFIG_USB_MON) || defined(CONFIG_USB_MON_MODULE)

struct usb_mon_operations *mon_ops;

/*
 * The registration is unlocked.
 * We do it this way because we do not want to lock in hot paths.
 *
 * Notice that the code is minimally error-proof. Because usbmon needs
 * symbols from usbcore, usbcore gets referenced and cannot be unloaded first.
 */
 
int usb_mon_register (struct usb_mon_operations *ops)
{

        if (mon_ops)
                return -EBUSY;

        mon_ops = ops;
        mb();
        return 0;
}
EXPORT_SYMBOL_GPL (usb_mon_register);

void usb_mon_deregister (void)
{

        if (mon_ops == NULL) {
                printk(KERN_ERR "USB: monitor was not registered\n");
                return;
        }
        mon_ops = NULL;
        mb();
}
EXPORT_SYMBOL_GPL (usb_mon_deregister);

#endif /* CONFIG_USB_MON || CONFIG_USB_MON_MODULE */