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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 <asm/scatterlist.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/mutex.h>
#include <asm/irq.h>
#include <asm/byteorder.h>

#include <linux/usb.h>

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


// #define USB_BANDWIDTH_MESSAGES

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

/*
 * 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.
 */

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

/* 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 hcd data */
static DEFINE_SPINLOCK(hcd_data_lock);

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

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

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

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

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

/* 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; */
      0x01,       /*  __u8  bDeviceProtocol; [ usb 2.0 single TT ]*/
      0x40,       /*  __u8  bMaxPacketSize0; 64 Bytes */

      0x00, 0x00, /*  __le16 idVendor; */
      0x00, 0x00, /*  __le16 idProduct; */
      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 */

      0x00, 0x00, /*  __le16 idVendor; */
      0x00, 0x00, /*  __le16 idProduct; */
      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 */
      0x02, 0x00, /*  __le16 ep_wMaxPacketSize; 1 + (MAX_ROOT_PORTS / 8) */
      0x0c        /*  __u8  ep_bInterval; (256ms -- usb 2.0 spec) */
};

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

/*
 * helper routine for returning string descriptors in UTF-16LE
 * input can actually be ISO-8859-1; ASCII is its 7-bit subset
 */
static int ascii2utf (char *s, u8 *utf, int utfmax)
{
      int 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
 * @type: string describing our driver 
 * @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 int rh_string (
      int         id,
      struct usb_hcd    *hcd,
      u8          *data,
      int         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 (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", system_utsname.sysname,
                  system_utsname.release, hcd->driver->description);

      // unsupported IDs --> "protocol stall"
      } else
            return -EPIPE;

      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)];
      const u8    *bufp = tbuf;
      int         len = 0;
      int         patch_wakeup = 0;
      unsigned long     flags;
      int         status = 0;
      int         n;

      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_USB2)
                        bufp = usb2_rh_dev_descriptor;
                  else if (hcd->driver->flags & HCD_USB11)
                        bufp = usb11_rh_dev_descriptor;
                  else
                        goto error;
                  len = 18;
                  break;
            case USB_DT_CONFIG << 8:
                  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:
                  n = rh_string (wValue & 0xff, hcd, ubuf, wLength);
                  if (n < 0)
                        goto error;
                  urb->actual_length = n;
                  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;
      }

      /* any errors get returned through the urb completion */
      local_irq_save (flags);
      spin_lock (&urb->lock);
      if (urb->status == -EINPROGRESS)
            urb->status = status;
      spin_unlock (&urb->lock);
      usb_hcd_giveback_urb (hcd, urb, NULL);
      local_irq_restore (flags);
      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 (!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 */
            local_irq_save (flags);
            spin_lock(&hcd_root_hub_lock);
            urb = hcd->status_urb;
            if (urb) {
                  spin_lock(&urb->lock);
                  if (urb->status == -EINPROGRESS) {
                        hcd->poll_pending = 0;
                        hcd->status_urb = NULL;
                        urb->status = 0;
                        urb->hcpriv = NULL;
                        urb->actual_length = length;
                        memcpy(urb->transfer_buffer, buffer, length);
                  } else            /* urb has been unlinked */
                        length = 0;
                  spin_unlock(&urb->lock);
            } else
                  length = 0;
            spin_unlock(&hcd_root_hub_lock);

            /* local irqs are always blocked in completions */
            if (length > 0)
                  usb_hcd_giveback_urb (hcd, urb, NULL);
            else
                  hcd->poll_pending = 1;
            local_irq_restore (flags);
      }

      /* The USB 2.0 spec says 256 ms.  This is close enough and won't
       * exceed that limit if HZ is 100. */
      if (hcd->uses_new_polling ? hcd->poll_rh :
                  (length == 0 && hcd->status_urb != NULL))
            mod_timer (&hcd->rh_timer, jiffies + msecs_to_jiffies(250));
}
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;
      int         len = 1 + (urb->dev->maxchild / 8);

      spin_lock_irqsave (&hcd_root_hub_lock, flags);
      if (urb->status != -EINPROGRESS)    /* already unlinked */
            retval = urb->status;
      else if (hcd->status_urb || urb->transfer_buffer_length < len) {
            dev_dbg (hcd->self.controller, "not queuing rh status urb\n");
            retval = -EINVAL;
      } else {
            hcd->status_urb = urb;
            urb->hcpriv = hcd;      /* indicate it's queued */

            if (!hcd->uses_new_polling)
                  mod_timer (&hcd->rh_timer, jiffies +
                              msecs_to_jiffies(250));

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

static int rh_urb_enqueue (struct usb_hcd *hcd, struct urb *urb)
{
      if (usb_pipeint (urb->pipe))
            return rh_queue_status (hcd, urb);
      if (usb_pipecontrol (urb->pipe))
            return rh_call_control (hcd, urb);
      return -EINVAL;
}

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

/* Asynchronous unlinks of root-hub control URBs are legal, but they
 * don't do anything.  Status URB unlinks must be made in process context
 * with interrupts enabled.
 */
static int usb_rh_urb_dequeue (struct usb_hcd *hcd, struct urb *urb)
{
      if (usb_pipeendpoint(urb->pipe) == 0) {   /* Control URB */
            if (in_interrupt())
                  return 0;         /* nothing to do */

            spin_lock_irq(&urb->lock);    /* from usb_kill_urb */
            ++urb->reject;
            spin_unlock_irq(&urb->lock);

            wait_event(usb_kill_urb_queue,
                        atomic_read(&urb->use_count) == 0);

            spin_lock_irq(&urb->lock);
            --urb->reject;
            spin_unlock_irq(&urb->lock);

      } else {                      /* Status URB */
            if (!hcd->uses_new_polling)
                  del_timer_sync (&hcd->rh_timer);
            local_irq_disable ();
            spin_lock (&hcd_root_hub_lock);
            if (urb == hcd->status_urb) {
                  hcd->status_urb = NULL;
                  urb->hcpriv = NULL;
            } else
                  urb = NULL;       /* wasn't fully queued */
            spin_unlock (&hcd_root_hub_lock);
            if (urb)
                  usb_hcd_giveback_urb (hcd, urb, NULL);
            local_irq_enable ();
      }

      return 0;
}

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

/* exported only within usbcore */
struct usb_bus *usb_bus_get(struct usb_bus *bus)
{
      if (bus)
            kref_get(&bus->kref);
      return bus;
}

static void usb_host_release(struct kref *kref)
{
      struct usb_bus *bus = container_of(kref, struct usb_bus, kref);

      if (bus->release)
            bus->release(bus);
}

/* exported only within usbcore */
void usb_bus_put(struct usb_bus *bus)
{
      if (bus)
            kref_put(&bus->kref, usb_host_release);
}

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

static struct class *usb_host_class;

int usb_host_init(void)
{
      int retval = 0;

      usb_host_class = class_create(THIS_MODULE, "usb_host");
      if (IS_ERR(usb_host_class))
            retval = PTR_ERR(usb_host_class);
      return retval;
}

void usb_host_cleanup(void)
{
      class_destroy(usb_host_class);
}

/**
 * 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->hcpriv = NULL;
      bus->busnum = -1;
      bus->bandwidth_allocated = 0;
      bus->bandwidth_int_reqs  = 0;
      bus->bandwidth_isoc_reqs = 0;

      INIT_LIST_HEAD (&bus->bus_list);

      kref_init(&bus->kref);
}

/**
 * usb_alloc_bus - creates a new USB host controller structure
 * @op: pointer to a struct usb_operations that this bus structure should use
 * Context: !in_interrupt()
 *
 * Creates a USB host controller bus structure with the specified 
 * usb_operations and initializes all the necessary internal objects.
 *
 * If no memory is available, NULL is returned.
 *
 * The caller should call usb_put_bus() when it is finished with the structure.
 */
struct usb_bus *usb_alloc_bus (struct usb_operations *op)
{
      struct usb_bus *bus;

      bus = kzalloc (sizeof *bus, GFP_KERNEL);
      if (!bus)
            return NULL;
      usb_bus_init (bus);
      bus->op = op;
      return bus;
}

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

/**
 * 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 busnum;

      mutex_lock(&usb_bus_list_lock);
      busnum = find_next_zero_bit (busmap.busmap, USB_MAXBUS, 1);
      if (busnum < USB_MAXBUS) {
            set_bit (busnum, busmap.busmap);
            bus->busnum = busnum;
      } else {
            printk (KERN_ERR "%s: too many buses\n", usbcore_name);
            mutex_unlock(&usb_bus_list_lock);
            return -E2BIG;
      }

      bus->class_dev = class_device_create(usb_host_class, NULL, MKDEV(0,0),
                                   bus->controller, "usb_host%d", busnum);
      if (IS_ERR(bus->class_dev)) {
            clear_bit(busnum, busmap.busmap);
            mutex_unlock(&usb_bus_list_lock);
            return PTR_ERR(bus->class_dev);
      }

      class_set_devdata(bus->class_dev, bus);

      /* 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;
}

/**
 * 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);

      class_device_unregister(bus->class_dev);
}

/**
 * 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 = __constant_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",
                        usb_dev->dev.bus_id, 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",
                        usb_dev->dev.bus_id, 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;
}

void usb_enable_root_hub_irq (struct usb_bus *bus)
{
      struct usb_hcd *hcd;

      hcd = container_of (bus, struct usb_hcd, self);
      if (hcd->driver->hub_irq_enable && !hcd->poll_rh &&
                  hcd->state != HC_STATE_HALT)
            hcd->driver->hub_irq_enable (hcd);
}


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

/**
 * 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 (usb_calc_bus_time);

/*
 * usb_check_bandwidth():
 *
 * old_alloc is from host_controller->bandwidth_allocated in microseconds;
 * bustime is from calc_bus_time(), but converted to microseconds.
 *
 * returns <bustime in us> if successful,
 * or -ENOSPC if bandwidth request fails.
 *
 * FIXME:
 * This initial implementation does not use Endpoint.bInterval
 * in managing bandwidth allocation.
 * It probably needs to be expanded to use Endpoint.bInterval.
 * This can be done as a later enhancement (correction).
 *
 * This will also probably require some kind of
 * frame allocation tracking...meaning, for example,
 * that if multiple drivers request interrupts every 10 USB frames,
 * they don't all have to be allocated at
 * frame numbers N, N+10, N+20, etc.  Some of them could be at
 * N+11, N+21, N+31, etc., and others at
 * N+12, N+22, N+32, etc.
 *
 * Similarly for isochronous transfers...
 *
 * Individual HCDs can schedule more directly ... this logic
 * is not correct for high speed transfers.
 */
int usb_check_bandwidth (struct usb_device *dev, struct urb *urb)
{
      unsigned int      pipe = urb->pipe;
      long        bustime;
      int         is_in = usb_pipein (pipe);
      int         is_iso = usb_pipeisoc (pipe);
      int         old_alloc = dev->bus->bandwidth_allocated;
      int         new_alloc;


      bustime = NS_TO_US (usb_calc_bus_time (dev->speed, is_in, is_iso,
                  usb_maxpacket (dev, pipe, !is_in)));
      if (is_iso)
            bustime /= urb->number_of_packets;

      new_alloc = old_alloc + (int) bustime;
      if (new_alloc > FRAME_TIME_MAX_USECS_ALLOC) {
#ifdef      DEBUG
            char  *mode = 
#ifdef CONFIG_USB_BANDWIDTH
                  "";
#else
                  "would have ";
#endif
            dev_dbg (&dev->dev, "usb_check_bandwidth %sFAILED: %d + %ld = %d usec\n",
                  mode, old_alloc, bustime, new_alloc);
#endif
#ifdef CONFIG_USB_BANDWIDTH
            bustime = -ENOSPC;      /* report error */
#endif
      }

      return bustime;
}
EXPORT_SYMBOL (usb_check_bandwidth);


/**
 * usb_claim_bandwidth - records bandwidth for a periodic transfer
 * @dev: source/target of request
 * @urb: request (urb->dev == dev)
 * @bustime: bandwidth consumed, in (average) microseconds per frame
 * @isoc: true iff the request is isochronous
 *
 * Bus bandwidth reservations are recorded purely for diagnostic purposes.
 * HCDs are expected not to overcommit periodic bandwidth, and to record such
 * reservations whenever endpoints are added to the periodic schedule.
 *
 * FIXME averaging per-frame is suboptimal.  Better to sum over the HCD's
 * entire periodic schedule ... 32 frames for OHCI, 1024 for UHCI, settable
 * for EHCI (256/512/1024 frames, default 1024) and have the bus expose how
 * large its periodic schedule is.
 */
void usb_claim_bandwidth (struct usb_device *dev, struct urb *urb, int bustime, int isoc)
{
      dev->bus->bandwidth_allocated += bustime;
      if (isoc)
            dev->bus->bandwidth_isoc_reqs++;
      else
            dev->bus->bandwidth_int_reqs++;
      urb->bandwidth = bustime;

#ifdef USB_BANDWIDTH_MESSAGES
      dev_dbg (&dev->dev, "bandwidth alloc increased by %d (%s) to %d for %d requesters\n",
            bustime,
            isoc ? "ISOC" : "INTR",
            dev->bus->bandwidth_allocated,
            dev->bus->bandwidth_int_reqs + dev->bus->bandwidth_isoc_reqs);
#endif
}
EXPORT_SYMBOL (usb_claim_bandwidth);


/**
 * usb_release_bandwidth - reverses effect of usb_claim_bandwidth()
 * @dev: source/target of request
 * @urb: request (urb->dev == dev)
 * @isoc: true iff the request is isochronous
 *
 * This records that previously allocated bandwidth has been released.
 * Bandwidth is released when endpoints are removed from the host controller's
 * periodic schedule.
 */
void usb_release_bandwidth (struct usb_device *dev, struct urb *urb, int isoc)
{
      dev->bus->bandwidth_allocated -= urb->bandwidth;
      if (isoc)
            dev->bus->bandwidth_isoc_reqs--;
      else
            dev->bus->bandwidth_int_reqs--;

#ifdef USB_BANDWIDTH_MESSAGES
      dev_dbg (&dev->dev, "bandwidth alloc reduced by %d (%s) to %d for %d requesters\n",
            urb->bandwidth,
            isoc ? "ISOC" : "INTR",
            dev->bus->bandwidth_allocated,
            dev->bus->bandwidth_int_reqs + dev->bus->bandwidth_isoc_reqs);
#endif
      urb->bandwidth = 0;
}
EXPORT_SYMBOL (usb_release_bandwidth);


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

/*
 * Generic HC operations.
 */

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

static void urb_unlink (struct urb *urb)
{
      unsigned long           flags;

      /* Release any periodic transfer bandwidth */
      if (urb->bandwidth)
            usb_release_bandwidth (urb->dev, urb,
                  usb_pipeisoc (urb->pipe));

      /* clear all state linking urb to this dev (and hcd) */

      spin_lock_irqsave (&hcd_data_lock, flags);
      list_del_init (&urb->urb_list);
      spin_unlock_irqrestore (&hcd_data_lock, flags);
}


/* 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
 */
static int hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
{
      int               status;
      struct usb_hcd          *hcd = urb->dev->bus->hcpriv;
      struct usb_host_endpoint *ep;
      unsigned long           flags;

      if (!hcd)
            return -ENODEV;

      usbmon_urb_submit(&hcd->self, urb);

      /*
       * Atomically queue the urb,  first to our records, then to the HCD.
       * Access to urb->status is controlled by urb->lock ... changes on
       * i/o completion (normal or fault) or unlinking.
       */

      // FIXME:  verify that quiescing hc works right (RH cleans up)

      spin_lock_irqsave (&hcd_data_lock, flags);
      ep = (usb_pipein(urb->pipe) ? urb->dev->ep_in : urb->dev->ep_out)
                  [usb_pipeendpoint(urb->pipe)];
      if (unlikely (!ep))
            status = -ENOENT;
      else if (unlikely (urb->reject))
            status = -EPERM;
      else switch (hcd->state) {
      case HC_STATE_RUNNING:
      case HC_STATE_RESUMING:
doit:
            list_add_tail (&urb->urb_list, &ep->urb_list);
            status = 0;
            break;
      case HC_STATE_SUSPENDED:
            /* HC upstream links (register access, wakeup signaling) can work
             * even when the downstream links (and DMA etc) are quiesced; let
             * usbcore talk to the root hub.
             */
            if (hcd->self.controller->power.power_state.event == PM_EVENT_ON
                        && urb->dev->parent == NULL)
                  goto doit;
            /* FALL THROUGH */
      default:
            status = -ESHUTDOWN;
            break;
      }
      spin_unlock_irqrestore (&hcd_data_lock, flags);
      if (status) {
            INIT_LIST_HEAD (&urb->urb_list);
            usbmon_urb_submit_error(&hcd->self, urb, status);
            return status;
      }

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

      if (urb->dev == hcd->self.root_hub) {
            /* NOTE:  requirement on hub callers (usbfs and the hub
             * driver, for now) that URBs' urb->transfer_buffer be
             * valid and usb_buffer_{sync,unmap}() not be needed, since
             * they could clobber root hub response data.
             */
            status = rh_urb_enqueue (hcd, urb);
            goto done;
      }

      /* lower level hcd code should use *_dma exclusively,
       * unless it uses pio or talks to another transport.
       */
      if (hcd->self.controller->dma_mask) {
            if (usb_pipecontrol (urb->pipe)
                  && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP))
                  urb->setup_dma = dma_map_single (
                              hcd->self.controller,
                              urb->setup_packet,
                              sizeof (struct usb_ctrlrequest),
                              DMA_TO_DEVICE);
            if (urb->transfer_buffer_length != 0
                  && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP))
                  urb->transfer_dma = dma_map_single (
                              hcd->self.controller,
                              urb->transfer_buffer,
                              urb->transfer_buffer_length,
                              usb_pipein (urb->pipe)
                                  ? DMA_FROM_DEVICE
                                  : DMA_TO_DEVICE);
      }

      status = hcd->driver->urb_enqueue (hcd, ep, urb, mem_flags);
done:
      if (unlikely (status)) {
            urb_unlink (urb);
            atomic_dec (&urb->use_count);
            if (urb->reject)
                  wake_up (&usb_kill_urb_queue);
            usb_put_urb (urb);
            usbmon_urb_submit_error(&hcd->self, urb, status);
      }
      return status;
}

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

/* called in any context */
static int hcd_get_frame_number (struct usb_device *udev)
{
      struct usb_hcd    *hcd = (struct usb_hcd *)udev->bus->hcpriv;
      if (!HC_IS_RUNNING (hcd->state))
            return -ESHUTDOWN;
      return hcd->driver->get_frame_number (hcd);
}

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

/* 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         value;

      if (urb->dev == hcd->self.root_hub)
            value = usb_rh_urb_dequeue (hcd, urb);
      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);
      }

      if (value != 0)
            dev_dbg (hcd->self.controller, "dequeue %p --> %d\n",
                        urb, value);
      return value;
}

/*
 * called in any context
 *
 * caller guarantees urb won't be recycled till both unlink()
 * and the urb's completion function return
 */
static int hcd_unlink_urb (struct urb *urb, int status)
{
      struct usb_host_endpoint      *ep;
      struct usb_hcd                *hcd = NULL;
      struct device                 *sys = NULL;
      unsigned long                 flags;
      struct list_head        *tmp;
      int                     retval;

      if (!urb)
            return -EINVAL;
      if (!urb->dev || !urb->dev->bus)
            return -ENODEV;
      ep = (usb_pipein(urb->pipe) ? urb->dev->ep_in : urb->dev->ep_out)
                  [usb_pipeendpoint(urb->pipe)];
      if (!ep)
            return -ENODEV;

      /*
       * we contend for urb->status with the hcd core,
       * which changes it while returning the urb.
       *
       * Caller guaranteed that the urb pointer hasn't been freed, and
       * that it was submitted.  But as a rule it can't know whether or
       * not it's already been unlinked ... so we respect the reversed
       * lock sequence needed for the usb_hcd_giveback_urb() code paths
       * (urb lock, then hcd_data_lock) in case some other CPU is now
       * unlinking it.
       */
      spin_lock_irqsave (&urb->lock, flags);
      spin_lock (&hcd_data_lock);

      sys = &urb->dev->dev;
      hcd = urb->dev->bus->hcpriv;
      if (hcd == NULL) {
            retval = -ENODEV;
            goto done;
      }

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

      /* 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->status != -EINPROGRESS) {
            retval = -EBUSY;
            goto done;
      }

      /* 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)
          && hcd->self.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);
      }

      urb->status = status;

      spin_unlock (&hcd_data_lock);
      spin_unlock_irqrestore (&urb->lock, flags);

      retval = unlink1 (hcd, urb);
      if (retval == 0)
            retval = -EINPROGRESS;
      return retval;

done:
      spin_unlock (&hcd_data_lock);
      spin_unlock_irqrestore (&urb->lock, flags);
      if (retval != -EIDRM && sys && sys->driver)
            dev_dbg (sys, "hcd_unlink_urb %p fail %d\n", urb, retval);
      return retval;
}

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

/* disables the endpoint: cancels any pending urbs, then synchronizes with
 * the hcd to make sure all endpoint state is gone from hardware. 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.
 */
static void
hcd_endpoint_disable (struct usb_device *udev, struct usb_host_endpoint *ep)
{
      struct usb_hcd          *hcd;
      struct urb        *urb;

      hcd = udev->bus->hcpriv;

      WARN_ON (!HC_IS_RUNNING (hcd->state) && hcd->state != HC_STATE_HALT &&
                  udev->state != USB_STATE_NOTATTACHED);

      local_irq_disable ();

      /* FIXME move most of this into message.c as part of its
       * endpoint disable logic
       */

      /* ep is already gone from udev->ep_{in,out}[]; no more submits */
rescan:
      spin_lock (&hcd_data_lock);
      list_for_each_entry (urb, &ep->urb_list, urb_list) {
            int   tmp;

            /* another cpu may be in hcd, spinning on hcd_data_lock
             * to giveback() this urb.  the races here should be
             * small, but a full fix needs a new "can't submit"
             * urb state.
             * FIXME urb->reject should allow that...
             */
            if (urb->status != -EINPROGRESS)
                  continue;
            usb_get_urb (urb);
            spin_unlock (&hcd_data_lock);

            spin_lock (&urb->lock);
            tmp = urb->status;
            if (tmp == -EINPROGRESS)
                  urb->status = -ESHUTDOWN;
            spin_unlock (&urb->lock);

            /* kick hcd unless it's already returning this */
            if (tmp == -EINPROGRESS) {
                  tmp = urb->pipe;
                  unlink1 (hcd, urb);
                  dev_dbg (hcd->self.controller,
                        "shutdown urb %p pipe %08x ep%d%s%s\n",
                        urb, tmp, usb_pipeendpoint (tmp),
                        (tmp & USB_DIR_IN) ? "in" : "out",
                        ({ char *s; \
                         switch (usb_pipetype (tmp)) { \
                         case PIPE_CONTROL:     s = ""; break; \
                         case PIPE_BULK:  s = "-bulk"; break; \
                         case PIPE_INTERRUPT:   s = "-intr"; break; \
                         default:         s = "-iso"; break; \
                        }; s;}));
            }
            usb_put_urb (urb);

            /* list contents may have changed */
            goto rescan;
      }
      spin_unlock (&hcd_data_lock);
      local_irq_enable ();

      /* synchronize with the hardware, so old configuration state
       * clears out immediately (and will be freed).
       */
      might_sleep ();
      if (hcd->driver->endpoint_disable)
            hcd->driver->endpoint_disable (hcd, ep);
}

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

#ifdef      CONFIG_PM

int hcd_bus_suspend (struct usb_bus *bus)
{
      struct usb_hcd          *hcd;
      int               status;

      hcd = container_of (bus, struct usb_hcd, self);
      if (!hcd->driver->bus_suspend)
            return -ENOENT;
      hcd->state = HC_STATE_QUIESCING;
      status = hcd->driver->bus_suspend (hcd);
      if (status == 0)
            hcd->state = HC_STATE_SUSPENDED;
      else
            dev_dbg(&bus->root_hub->dev, "%s fail, err %d\n",
                        "suspend", status);
      return status;
}

int hcd_bus_resume (struct usb_bus *bus)
{
      struct usb_hcd          *hcd;
      int               status;

      hcd = container_of (bus, struct usb_hcd, self);
      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)
            hcd->state = HC_STATE_RUNNING;
      else {
            dev_dbg(&bus->root_hub->dev, "%s fail, err %d\n",
                        "resume", status);
            usb_hc_died(hcd);
      }
      return status;
}

/*
 * usb_hcd_suspend_root_hub - HCD autosuspends downstream ports
 * @hcd: host controller for this root hub
 *
 * This call arranges that usb_hcd_resume_root_hub() is safe to call later;
 * that the HCD's root hub polling is deactivated; and that the root's hub
 * driver is suspended.  HCDs may call this to autosuspend when their root
 * hub's downstream ports are all inactive:  unpowered, disconnected,
 * disabled, or suspended.
 *
 * The HCD will autoresume on device connect change detection (using SRP
 * or a D+/D- pullup).  The HCD also autoresumes on remote wakeup signaling
 * from any ports that are suspended (if that is enabled).  In most cases,
 * overcurrent signaling (on powered ports) will also start autoresume.
 *
 * Always called with IRQs blocked.
 */
void usb_hcd_suspend_root_hub (struct usb_hcd *hcd)
{
      struct urb  *urb;

      spin_lock (&hcd_root_hub_lock);
      usb_suspend_root_hub (hcd->self.root_hub);

      /* force status urb to complete/unlink while suspended */
      if (hcd->status_urb) {
            urb = hcd->status_urb;
            urb->status = -ECONNRESET;
            urb->hcpriv = NULL;
            urb->actual_length = 0;

            del_timer (&hcd->rh_timer);
            hcd->poll_pending = 0;
            hcd->status_urb = NULL;
      } else
            urb = NULL;
      spin_unlock (&hcd_root_hub_lock);
      hcd->state = HC_STATE_SUSPENDED;

      if (urb)
            usb_hcd_giveback_urb (hcd, urb, NULL);
}
EXPORT_SYMBOL_GPL(usb_hcd_suspend_root_hub);

/**
 * 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.  It queues a request for khubd 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)
            usb_resume_root_hub (hcd->self.root_hub);
      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 (usb_bus_start_enum);

#endif

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

/*
 * usb_hcd_operations - adapts usb_bus framework to HCD framework (bus glue)
 */
static struct usb_operations usb_hcd_operations = {
      .get_frame_number =     hcd_get_frame_number,
      .submit_urb =           hcd_submit_urb,
      .unlink_urb =           hcd_unlink_urb,
      .buffer_alloc =         hcd_buffer_alloc,
      .buffer_free =          hcd_buffer_free,
      .disable =        hcd_endpoint_disable,
};

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

/**
 * 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.
 * @regs: pt_regs, passed down to the URB completion handler
 * 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.
 */
void usb_hcd_giveback_urb (struct usb_hcd *hcd, struct urb *urb, struct pt_regs *regs)
{
      int at_root_hub;

      at_root_hub = (urb->dev == hcd->self.root_hub);
      urb_unlink (urb);

      /* lower level hcd code should use *_dma exclusively */
      if (hcd->self.controller->dma_mask && !at_root_hub) {
            if (usb_pipecontrol (urb->pipe)
                  && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP))
                  dma_unmap_single (hcd->self.controller, urb->setup_dma,
                              sizeof (struct usb_ctrlrequest),
                              DMA_TO_DEVICE);
            if (urb->transfer_buffer_length != 0
                  && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP))
                  dma_unmap_single (hcd->self.controller, 
                              urb->transfer_dma,
                              urb->transfer_buffer_length,
                              usb_pipein (urb->pipe)
                                  ? DMA_FROM_DEVICE
                                  : DMA_TO_DEVICE);
      }

      usbmon_urb_complete (&hcd->self, urb);
      /* pass ownership to the completion handler */
      urb->complete (urb, regs);
      atomic_dec (&urb->use_count);
      if (unlikely (urb->reject))
            wake_up (&usb_kill_urb_queue);
      usb_put_urb (urb);
}
EXPORT_SYMBOL (usb_hcd_giveback_urb);

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

/**
 * 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
 * @r: saved hardware registers
 *
 * 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 pt_regs * r)
{
      struct usb_hcd          *hcd = __hcd;
      int               start = hcd->state;

      if (unlikely(start == HC_STATE_HALT ||
          !test_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags)))
            return IRQ_NONE;
      if (hcd->driver->irq (hcd, r) == IRQ_NONE)
            return IRQ_NONE;

      set_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);

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

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

/**
 * 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);

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

static void hcd_release (struct usb_bus *bus)
{
      struct usb_hcd *hcd;

      hcd = container_of(bus, struct usb_hcd, self);
      kfree(hcd);
}

/**
 * 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, 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);

      usb_bus_init(&hcd->self);
      hcd->self.op = &usb_hcd_operations;
      hcd->self.hcpriv = hcd;
      hcd->self.release = &hcd_release;
      hcd->self.controller = dev;
      hcd->self.bus_name = bus_name;

      init_timer(&hcd->rh_timer);
      hcd->rh_timer.function = rh_timer_func;
      hcd->rh_timer.data = (unsigned long) hcd;

      hcd->driver = driver;
      hcd->product_desc = (driver->product_desc) ? driver->product_desc :
                  "USB Host Controller";

      return hcd;
}
EXPORT_SYMBOL (usb_create_hcd);

void usb_put_hcd (struct usb_hcd *hcd)
{
      dev_set_drvdata(hcd->self.controller, NULL);
      usb_bus_put(&hcd->self);
}
EXPORT_SYMBOL (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);

      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;
      }
      rhdev->speed = (hcd->driver->flags & HCD_USB2) ? USB_SPEED_HIGH :
                  USB_SPEED_FULL;
      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) {
            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;

      if (hcd->uses_new_polling && hcd->poll_rh)
            usb_hcd_poll_rh_status(hcd);
      return retval;

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 (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);

      mutex_lock(&usb_bus_list_lock);
      usb_disconnect(&hcd->self.root_hub);
      mutex_unlock(&usb_bus_list_lock);

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

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

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

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

#if defined(CONFIG_USB_MON)

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 */

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