Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / usb / core / devices.c
diff --git a/kernel/drivers/usb/core/devices.c b/kernel/drivers/usb/core/devices.c
new file mode 100644 (file)
index 0000000..2a3bbdf
--- /dev/null
@@ -0,0 +1,692 @@
+/*
+ * devices.c
+ * (C) Copyright 1999 Randy Dunlap.
+ * (C) Copyright 1999,2000 Thomas Sailer <sailer@ife.ee.ethz.ch>.
+ *     (proc file per device)
+ * (C) Copyright 1999 Deti Fliegl (new USB architecture)
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *************************************************************
+ *
+ * <mountpoint>/devices contains USB topology, device, config, class,
+ * interface, & endpoint data.
+ *
+ * I considered using /proc/bus/usb/devices/device# for each device
+ * as it is attached or detached, but I didn't like this for some
+ * reason -- maybe it's just too deep of a directory structure.
+ * I also don't like looking in multiple places to gather and view
+ * the data.  Having only one file for ./devices also prevents race
+ * conditions that could arise if a program was reading device info
+ * for devices that are being removed (unplugged).  (That is, the
+ * program may find a directory for devnum_12 then try to open it,
+ * but it was just unplugged, so the directory is now deleted.
+ * But programs would just have to be prepared for situations like
+ * this in any plug-and-play environment.)
+ *
+ * 1999-12-16: Thomas Sailer <sailer@ife.ee.ethz.ch>
+ *   Converted the whole proc stuff to real
+ *   read methods. Now not the whole device list needs to fit
+ *   into one page, only the device list for one bus.
+ *   Added a poll method to /proc/bus/usb/devices, to wake
+ *   up an eventual usbd
+ * 2000-01-04: Thomas Sailer <sailer@ife.ee.ethz.ch>
+ *   Turned into its own filesystem
+ * 2000-07-05: Ashley Montanaro <ashley@compsoc.man.ac.uk>
+ *   Converted file reading routine to dump to buffer once
+ *   per device, not per bus
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/gfp.h>
+#include <linux/poll.h>
+#include <linux/usb.h>
+#include <linux/usbdevice_fs.h>
+#include <linux/usb/hcd.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+
+#include "usb.h"
+
+/* Define ALLOW_SERIAL_NUMBER if you want to see the serial number of devices */
+#define ALLOW_SERIAL_NUMBER
+
+static const char format_topo[] =
+/* T:  Bus=dd Lev=dd Prnt=dd Port=dd Cnt=dd Dev#=ddd Spd=dddd MxCh=dd */
+"\nT:  Bus=%2.2d Lev=%2.2d Prnt=%2.2d Port=%2.2d Cnt=%2.2d Dev#=%3d Spd=%-4s MxCh=%2d\n";
+
+static const char format_string_manufacturer[] =
+/* S:  Manufacturer=xxxx */
+  "S:  Manufacturer=%.100s\n";
+
+static const char format_string_product[] =
+/* S:  Product=xxxx */
+  "S:  Product=%.100s\n";
+
+#ifdef ALLOW_SERIAL_NUMBER
+static const char format_string_serialnumber[] =
+/* S:  SerialNumber=xxxx */
+  "S:  SerialNumber=%.100s\n";
+#endif
+
+static const char format_bandwidth[] =
+/* B:  Alloc=ddd/ddd us (xx%), #Int=ddd, #Iso=ddd */
+  "B:  Alloc=%3d/%3d us (%2d%%), #Int=%3d, #Iso=%3d\n";
+
+static const char format_device1[] =
+/* D:  Ver=xx.xx Cls=xx(sssss) Sub=xx Prot=xx MxPS=dd #Cfgs=dd */
+  "D:  Ver=%2x.%02x Cls=%02x(%-5s) Sub=%02x Prot=%02x MxPS=%2d #Cfgs=%3d\n";
+
+static const char format_device2[] =
+/* P:  Vendor=xxxx ProdID=xxxx Rev=xx.xx */
+  "P:  Vendor=%04x ProdID=%04x Rev=%2x.%02x\n";
+
+static const char format_config[] =
+/* C:  #Ifs=dd Cfg#=dd Atr=xx MPwr=dddmA */
+  "C:%c #Ifs=%2d Cfg#=%2d Atr=%02x MxPwr=%3dmA\n";
+
+static const char format_iad[] =
+/* A:  FirstIf#=dd IfCount=dd Cls=xx(sssss) Sub=xx Prot=xx */
+  "A:  FirstIf#=%2d IfCount=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x\n";
+
+static const char format_iface[] =
+/* I:  If#=dd Alt=dd #EPs=dd Cls=xx(sssss) Sub=xx Prot=xx Driver=xxxx*/
+  "I:%c If#=%2d Alt=%2d #EPs=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x Driver=%s\n";
+
+static const char format_endpt[] =
+/* E:  Ad=xx(s) Atr=xx(ssss) MxPS=dddd Ivl=D?s */
+  "E:  Ad=%02x(%c) Atr=%02x(%-4s) MxPS=%4d Ivl=%d%cs\n";
+
+
+/*
+ * Need access to the driver and USB bus lists.
+ * extern struct list_head usb_bus_list;
+ * However, these will come from functions that return ptrs to each of them.
+ */
+
+/*
+ * Wait for an connect/disconnect event to happen. We initialize
+ * the event counter with an odd number, and each event will increment
+ * the event counter by two, so it will always _stay_ odd. That means
+ * that it will never be zero, so "event 0" will never match a current
+ * event, and thus 'poll' will always trigger as readable for the first
+ * time it gets called.
+ */
+static struct device_connect_event {
+       atomic_t count;
+       wait_queue_head_t wait;
+} device_event = {
+       .count = ATOMIC_INIT(1),
+       .wait = __WAIT_QUEUE_HEAD_INITIALIZER(device_event.wait)
+};
+
+struct class_info {
+       int class;
+       char *class_name;
+};
+
+static const struct class_info clas_info[] = {
+       /* max. 5 chars. per name string */
+       {USB_CLASS_PER_INTERFACE,       ">ifc"},
+       {USB_CLASS_AUDIO,               "audio"},
+       {USB_CLASS_COMM,                "comm."},
+       {USB_CLASS_HID,                 "HID"},
+       {USB_CLASS_PHYSICAL,            "PID"},
+       {USB_CLASS_STILL_IMAGE,         "still"},
+       {USB_CLASS_PRINTER,             "print"},
+       {USB_CLASS_MASS_STORAGE,        "stor."},
+       {USB_CLASS_HUB,                 "hub"},
+       {USB_CLASS_CDC_DATA,            "data"},
+       {USB_CLASS_CSCID,               "scard"},
+       {USB_CLASS_CONTENT_SEC,         "c-sec"},
+       {USB_CLASS_VIDEO,               "video"},
+       {USB_CLASS_WIRELESS_CONTROLLER, "wlcon"},
+       {USB_CLASS_MISC,                "misc"},
+       {USB_CLASS_APP_SPEC,            "app."},
+       {USB_CLASS_VENDOR_SPEC,         "vend."},
+       {-1,                            "unk."}         /* leave as last */
+};
+
+/*****************************************************************/
+
+void usbfs_conn_disc_event(void)
+{
+       atomic_add(2, &device_event.count);
+       wake_up(&device_event.wait);
+}
+
+static const char *class_decode(const int class)
+{
+       int ix;
+
+       for (ix = 0; clas_info[ix].class != -1; ix++)
+               if (clas_info[ix].class == class)
+                       break;
+       return clas_info[ix].class_name;
+}
+
+static char *usb_dump_endpoint_descriptor(int speed, char *start, char *end,
+                               const struct usb_endpoint_descriptor *desc)
+{
+       char dir, unit, *type;
+       unsigned interval, bandwidth = 1;
+
+       if (start > end)
+               return start;
+
+       dir = usb_endpoint_dir_in(desc) ? 'I' : 'O';
+
+       if (speed == USB_SPEED_HIGH) {
+               switch (usb_endpoint_maxp(desc) & (0x03 << 11)) {
+               case 1 << 11:
+                       bandwidth = 2; break;
+               case 2 << 11:
+                       bandwidth = 3; break;
+               }
+       }
+
+       /* this isn't checking for illegal values */
+       switch (usb_endpoint_type(desc)) {
+       case USB_ENDPOINT_XFER_CONTROL:
+               type = "Ctrl";
+               if (speed == USB_SPEED_HIGH)    /* uframes per NAK */
+                       interval = desc->bInterval;
+               else
+                       interval = 0;
+               dir = 'B';                      /* ctrl is bidirectional */
+               break;
+       case USB_ENDPOINT_XFER_ISOC:
+               type = "Isoc";
+               interval = 1 << (desc->bInterval - 1);
+               break;
+       case USB_ENDPOINT_XFER_BULK:
+               type = "Bulk";
+               if (speed == USB_SPEED_HIGH && dir == 'O') /* uframes per NAK */
+                       interval = desc->bInterval;
+               else
+                       interval = 0;
+               break;
+       case USB_ENDPOINT_XFER_INT:
+               type = "Int.";
+               if (speed == USB_SPEED_HIGH || speed == USB_SPEED_SUPER)
+                       interval = 1 << (desc->bInterval - 1);
+               else
+                       interval = desc->bInterval;
+               break;
+       default:        /* "can't happen" */
+               return start;
+       }
+       interval *= (speed == USB_SPEED_HIGH ||
+                    speed == USB_SPEED_SUPER) ? 125 : 1000;
+       if (interval % 1000)
+               unit = 'u';
+       else {
+               unit = 'm';
+               interval /= 1000;
+       }
+
+       start += sprintf(start, format_endpt, desc->bEndpointAddress, dir,
+                        desc->bmAttributes, type,
+                        (usb_endpoint_maxp(desc) & 0x07ff) *
+                        bandwidth,
+                        interval, unit);
+       return start;
+}
+
+static char *usb_dump_interface_descriptor(char *start, char *end,
+                                       const struct usb_interface_cache *intfc,
+                                       const struct usb_interface *iface,
+                                       int setno)
+{
+       const struct usb_interface_descriptor *desc;
+       const char *driver_name = "";
+       int active = 0;
+
+       if (start > end)
+               return start;
+       desc = &intfc->altsetting[setno].desc;
+       if (iface) {
+               driver_name = (iface->dev.driver
+                               ? iface->dev.driver->name
+                               : "(none)");
+               active = (desc == &iface->cur_altsetting->desc);
+       }
+       start += sprintf(start, format_iface,
+                        active ? '*' : ' ',    /* mark active altsetting */
+                        desc->bInterfaceNumber,
+                        desc->bAlternateSetting,
+                        desc->bNumEndpoints,
+                        desc->bInterfaceClass,
+                        class_decode(desc->bInterfaceClass),
+                        desc->bInterfaceSubClass,
+                        desc->bInterfaceProtocol,
+                        driver_name);
+       return start;
+}
+
+static char *usb_dump_interface(int speed, char *start, char *end,
+                               const struct usb_interface_cache *intfc,
+                               const struct usb_interface *iface, int setno)
+{
+       const struct usb_host_interface *desc = &intfc->altsetting[setno];
+       int i;
+
+       start = usb_dump_interface_descriptor(start, end, intfc, iface, setno);
+       for (i = 0; i < desc->desc.bNumEndpoints; i++) {
+               if (start > end)
+                       return start;
+               start = usb_dump_endpoint_descriptor(speed,
+                               start, end, &desc->endpoint[i].desc);
+       }
+       return start;
+}
+
+static char *usb_dump_iad_descriptor(char *start, char *end,
+                       const struct usb_interface_assoc_descriptor *iad)
+{
+       if (start > end)
+               return start;
+       start += sprintf(start, format_iad,
+                        iad->bFirstInterface,
+                        iad->bInterfaceCount,
+                        iad->bFunctionClass,
+                        class_decode(iad->bFunctionClass),
+                        iad->bFunctionSubClass,
+                        iad->bFunctionProtocol);
+       return start;
+}
+
+/* TBD:
+ * 0. TBDs
+ * 1. marking active interface altsettings (code lists all, but should mark
+ *    which ones are active, if any)
+ */
+static char *usb_dump_config_descriptor(char *start, char *end,
+                               const struct usb_config_descriptor *desc,
+                               int active, int speed)
+{
+       int mul;
+
+       if (start > end)
+               return start;
+       if (speed == USB_SPEED_SUPER)
+               mul = 8;
+       else
+               mul = 2;
+       start += sprintf(start, format_config,
+                        /* mark active/actual/current cfg. */
+                        active ? '*' : ' ',
+                        desc->bNumInterfaces,
+                        desc->bConfigurationValue,
+                        desc->bmAttributes,
+                        desc->bMaxPower * mul);
+       return start;
+}
+
+static char *usb_dump_config(int speed, char *start, char *end,
+                            const struct usb_host_config *config, int active)
+{
+       int i, j;
+       struct usb_interface_cache *intfc;
+       struct usb_interface *interface;
+
+       if (start > end)
+               return start;
+       if (!config)
+               /* getting these some in 2.3.7; none in 2.3.6 */
+               return start + sprintf(start, "(null Cfg. desc.)\n");
+       start = usb_dump_config_descriptor(start, end, &config->desc, active,
+                       speed);
+       for (i = 0; i < USB_MAXIADS; i++) {
+               if (config->intf_assoc[i] == NULL)
+                       break;
+               start = usb_dump_iad_descriptor(start, end,
+                                       config->intf_assoc[i]);
+       }
+       for (i = 0; i < config->desc.bNumInterfaces; i++) {
+               intfc = config->intf_cache[i];
+               interface = config->interface[i];
+               for (j = 0; j < intfc->num_altsetting; j++) {
+                       if (start > end)
+                               return start;
+                       start = usb_dump_interface(speed,
+                               start, end, intfc, interface, j);
+               }
+       }
+       return start;
+}
+
+/*
+ * Dump the different USB descriptors.
+ */
+static char *usb_dump_device_descriptor(char *start, char *end,
+                               const struct usb_device_descriptor *desc)
+{
+       u16 bcdUSB = le16_to_cpu(desc->bcdUSB);
+       u16 bcdDevice = le16_to_cpu(desc->bcdDevice);
+
+       if (start > end)
+               return start;
+       start += sprintf(start, format_device1,
+                         bcdUSB >> 8, bcdUSB & 0xff,
+                         desc->bDeviceClass,
+                         class_decode(desc->bDeviceClass),
+                         desc->bDeviceSubClass,
+                         desc->bDeviceProtocol,
+                         desc->bMaxPacketSize0,
+                         desc->bNumConfigurations);
+       if (start > end)
+               return start;
+       start += sprintf(start, format_device2,
+                        le16_to_cpu(desc->idVendor),
+                        le16_to_cpu(desc->idProduct),
+                        bcdDevice >> 8, bcdDevice & 0xff);
+       return start;
+}
+
+/*
+ * Dump the different strings that this device holds.
+ */
+static char *usb_dump_device_strings(char *start, char *end,
+                                    struct usb_device *dev)
+{
+       if (start > end)
+               return start;
+       if (dev->manufacturer)
+               start += sprintf(start, format_string_manufacturer,
+                                dev->manufacturer);
+       if (start > end)
+               goto out;
+       if (dev->product)
+               start += sprintf(start, format_string_product, dev->product);
+       if (start > end)
+               goto out;
+#ifdef ALLOW_SERIAL_NUMBER
+       if (dev->serial)
+               start += sprintf(start, format_string_serialnumber,
+                                dev->serial);
+#endif
+ out:
+       return start;
+}
+
+static char *usb_dump_desc(char *start, char *end, struct usb_device *dev)
+{
+       int i;
+
+       if (start > end)
+               return start;
+
+       start = usb_dump_device_descriptor(start, end, &dev->descriptor);
+
+       if (start > end)
+               return start;
+
+       start = usb_dump_device_strings(start, end, dev);
+
+       for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
+               if (start > end)
+                       return start;
+               start = usb_dump_config(dev->speed,
+                               start, end, dev->config + i,
+                               /* active ? */
+                               (dev->config + i) == dev->actconfig);
+       }
+       return start;
+}
+
+
+#ifdef PROC_EXTRA /* TBD: may want to add this code later */
+
+static char *usb_dump_hub_descriptor(char *start, char *end,
+                                    const struct usb_hub_descriptor *desc)
+{
+       int leng = USB_DT_HUB_NONVAR_SIZE;
+       unsigned char *ptr = (unsigned char *)desc;
+
+       if (start > end)
+               return start;
+       start += sprintf(start, "Interface:");
+       while (leng && start <= end) {
+               start += sprintf(start, " %02x", *ptr);
+               ptr++; leng--;
+       }
+       *start++ = '\n';
+       return start;
+}
+
+static char *usb_dump_string(char *start, char *end,
+                            const struct usb_device *dev, char *id, int index)
+{
+       if (start > end)
+               return start;
+       start += sprintf(start, "Interface:");
+       if (index <= dev->maxstring && dev->stringindex &&
+           dev->stringindex[index])
+               start += sprintf(start, "%s: %.100s ", id,
+                                dev->stringindex[index]);
+       return start;
+}
+
+#endif /* PROC_EXTRA */
+
+/*****************************************************************/
+
+/* This is a recursive function. Parameters:
+ * buffer - the user-space buffer to write data into
+ * nbytes - the maximum number of bytes to write
+ * skip_bytes - the number of bytes to skip before writing anything
+ * file_offset - the offset into the devices file on completion
+ * The caller must own the device lock.
+ */
+static ssize_t usb_device_dump(char __user **buffer, size_t *nbytes,
+                              loff_t *skip_bytes, loff_t *file_offset,
+                              struct usb_device *usbdev, struct usb_bus *bus,
+                              int level, int index, int count)
+{
+       int chix;
+       int ret, cnt = 0;
+       int parent_devnum = 0;
+       char *pages_start, *data_end, *speed;
+       unsigned int length;
+       ssize_t total_written = 0;
+       struct usb_device *childdev = NULL;
+
+       /* don't bother with anything else if we're not writing any data */
+       if (*nbytes <= 0)
+               return 0;
+
+       if (level > MAX_TOPO_LEVEL)
+               return 0;
+       /* allocate 2^1 pages = 8K (on i386);
+        * should be more than enough for one device */
+       pages_start = (char *)__get_free_pages(GFP_NOIO, 1);
+       if (!pages_start)
+               return -ENOMEM;
+
+       if (usbdev->parent && usbdev->parent->devnum != -1)
+               parent_devnum = usbdev->parent->devnum;
+       /*
+        * So the root hub's parent is 0 and any device that is
+        * plugged into the root hub has a parent of 0.
+        */
+       switch (usbdev->speed) {
+       case USB_SPEED_LOW:
+               speed = "1.5"; break;
+       case USB_SPEED_UNKNOWN:         /* usb 1.1 root hub code */
+       case USB_SPEED_FULL:
+               speed = "12"; break;
+       case USB_SPEED_WIRELESS:        /* Wireless has no real fixed speed */
+       case USB_SPEED_HIGH:
+               speed = "480"; break;
+       case USB_SPEED_SUPER:
+               speed = "5000"; break;
+       default:
+               speed = "??";
+       }
+       data_end = pages_start + sprintf(pages_start, format_topo,
+                       bus->busnum, level, parent_devnum,
+                       index, count, usbdev->devnum,
+                       speed, usbdev->maxchild);
+       /*
+        * level = topology-tier level;
+        * parent_devnum = parent device number;
+        * index = parent's connector number;
+        * count = device count at this level
+        */
+       /* If this is the root hub, display the bandwidth information */
+       if (level == 0) {
+               int     max;
+
+               /* super/high speed reserves 80%, full/low reserves 90% */
+               if (usbdev->speed == USB_SPEED_HIGH ||
+                   usbdev->speed == USB_SPEED_SUPER)
+                       max = 800;
+               else
+                       max = FRAME_TIME_MAX_USECS_ALLOC;
+
+               /* report "average" periodic allocation over a microsecond.
+                * the schedules are actually bursty, HCDs need to deal with
+                * that and just compute/report this average.
+                */
+               data_end += sprintf(data_end, format_bandwidth,
+                               bus->bandwidth_allocated, max,
+                               (100 * bus->bandwidth_allocated + max / 2)
+                                       / max,
+                               bus->bandwidth_int_reqs,
+                               bus->bandwidth_isoc_reqs);
+
+       }
+       data_end = usb_dump_desc(data_end, pages_start + (2 * PAGE_SIZE) - 256,
+                                usbdev);
+
+       if (data_end > (pages_start + (2 * PAGE_SIZE) - 256))
+               data_end += sprintf(data_end, "(truncated)\n");
+
+       length = data_end - pages_start;
+       /* if we can start copying some data to the user */
+       if (length > *skip_bytes) {
+               length -= *skip_bytes;
+               if (length > *nbytes)
+                       length = *nbytes;
+               if (copy_to_user(*buffer, pages_start + *skip_bytes, length)) {
+                       free_pages((unsigned long)pages_start, 1);
+                       return -EFAULT;
+               }
+               *nbytes -= length;
+               *file_offset += length;
+               total_written += length;
+               *buffer += length;
+               *skip_bytes = 0;
+       } else
+               *skip_bytes -= length;
+
+       free_pages((unsigned long)pages_start, 1);
+
+       /* Now look at all of this device's children. */
+       usb_hub_for_each_child(usbdev, chix, childdev) {
+               usb_lock_device(childdev);
+               ret = usb_device_dump(buffer, nbytes, skip_bytes,
+                                     file_offset, childdev, bus,
+                                     level + 1, chix - 1, ++cnt);
+               usb_unlock_device(childdev);
+               if (ret == -EFAULT)
+                       return total_written;
+               total_written += ret;
+       }
+       return total_written;
+}
+
+static ssize_t usb_device_read(struct file *file, char __user *buf,
+                              size_t nbytes, loff_t *ppos)
+{
+       struct usb_bus *bus;
+       ssize_t ret, total_written = 0;
+       loff_t skip_bytes = *ppos;
+
+       if (*ppos < 0)
+               return -EINVAL;
+       if (nbytes <= 0)
+               return 0;
+       if (!access_ok(VERIFY_WRITE, buf, nbytes))
+               return -EFAULT;
+
+       mutex_lock(&usb_bus_list_lock);
+       /* print devices for all busses */
+       list_for_each_entry(bus, &usb_bus_list, bus_list) {
+               /* recurse through all children of the root hub */
+               if (!bus_to_hcd(bus)->rh_registered)
+                       continue;
+               usb_lock_device(bus->root_hub);
+               ret = usb_device_dump(&buf, &nbytes, &skip_bytes, ppos,
+                                     bus->root_hub, bus, 0, 0, 0);
+               usb_unlock_device(bus->root_hub);
+               if (ret < 0) {
+                       mutex_unlock(&usb_bus_list_lock);
+                       return ret;
+               }
+               total_written += ret;
+       }
+       mutex_unlock(&usb_bus_list_lock);
+       return total_written;
+}
+
+/* Kernel lock for "lastev" protection */
+static unsigned int usb_device_poll(struct file *file,
+                                   struct poll_table_struct *wait)
+{
+       unsigned int event_count;
+
+       poll_wait(file, &device_event.wait, wait);
+
+       event_count = atomic_read(&device_event.count);
+       if (file->f_version != event_count) {
+               file->f_version = event_count;
+               return POLLIN | POLLRDNORM;
+       }
+
+       return 0;
+}
+
+static loff_t usb_device_lseek(struct file *file, loff_t offset, int orig)
+{
+       loff_t ret;
+
+       mutex_lock(&file_inode(file)->i_mutex);
+
+       switch (orig) {
+       case 0:
+               file->f_pos = offset;
+               ret = file->f_pos;
+               break;
+       case 1:
+               file->f_pos += offset;
+               ret = file->f_pos;
+               break;
+       case 2:
+       default:
+               ret = -EINVAL;
+       }
+
+       mutex_unlock(&file_inode(file)->i_mutex);
+       return ret;
+}
+
+const struct file_operations usbfs_devices_fops = {
+       .llseek =       usb_device_lseek,
+       .read =         usb_device_read,
+       .poll =         usb_device_poll,
+};