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

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

/* 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);

/* 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 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 */
                /* __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) */
};

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

/*
 * 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", init_utsname()->sysname,
                  init_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)]
            __attribute__((aligned(4)));
      const u8    *bufp = tbuf;
      int         len = 0;
      int         patch_wakeup = 0;
      int         status;
      int         n;

      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_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 */
      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;
      int         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,
};



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

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->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;
      bus->class_dev = class_device_create(usb_host_class, NULL, MKDEV(0,0),
                                   bus->controller, "usb_host%d",
                                   busnum);
      result = PTR_ERR(bus->class_dev);
      if (IS_ERR(bus->class_dev))
            goto error_create_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;

error_create_class_dev:
      clear_bit(busnum, busmap.busmap);
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);

      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->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);


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

/*
 * 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(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);

static void map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
{
      /* 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 (hcd->self.uses_dma && !is_root_hub(urb->dev)) {
            if (usb_endpoint_xfer_control(&urb->ep->desc)
                  && !(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_urb_dir_in(urb)
                                  ? DMA_FROM_DEVICE
                                  : DMA_TO_DEVICE);
      }
}

static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb)
{
      if (hcd->self.uses_dma && !is_root_hub(urb->dev)) {
            if (usb_endpoint_xfer_control(&urb->ep->desc)
                  && !(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_urb_dir_in(urb)
                                  ? DMA_FROM_DEVICE
                                  : DMA_TO_DEVICE);
      }
}

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

/* 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.
       */
      map_urb_for_dma(hcd, urb);
      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);
            urb->hcpriv = NULL;
            INIT_LIST_HEAD(&urb->urb_list);
            atomic_dec(&urb->use_count);
            atomic_dec(&urb->dev->urbnum);
            if (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;

      hcd = bus_to_hcd(urb->dev->bus);
      retval = unlink1(hcd, urb, status);

      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 (urb->reject))
            wake_up (&usb_kill_urb_queue);
      usb_put_urb (urb);
}
EXPORT_SYMBOL (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);
            }
      }
}

/* 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);
}

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

/* 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)
{
      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",
                  rhdev->auto_pm ? "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)
{
      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",
                  rhdev->auto_pm ? "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);
      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 (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
 * @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 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) == 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);

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

/**
 * 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);
      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 (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 (usb_get_hcd);

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

      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;
      }
      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;

      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 (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 (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 (usb_hcd_platform_shutdown);

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

#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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