drivers/usb/core/devices.c

   1 /*
   2  * devices.c
   3  * (C) Copyright 1999 Randy Dunlap.
   4  * (C) Copyright 1999,2000 Thomas Sailer <sailer@ife.ee.ethz.ch>. (proc file per device)
   5  * (C) Copyright 1999 Deti Fliegl (new USB architecture)
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  *************************************************************
  22  *
  23  * <mountpoint>/devices contains USB topology, device, config, class,
  24  * interface, & endpoint data.
  25  *
  26  * I considered using /proc/bus/usb/devices/device# for each device
  27  * as it is attached or detached, but I didn't like this for some
  28  * reason -- maybe it's just too deep of a directory structure.
  29  * I also don't like looking in multiple places to gather and view
  30  * the data.  Having only one file for ./devices also prevents race
  31  * conditions that could arise if a program was reading device info
  32  * for devices that are being removed (unplugged).  (That is, the
  33  * program may find a directory for devnum_12 then try to open it,
  34  * but it was just unplugged, so the directory is now deleted.
  35  * But programs would just have to be prepared for situations like
  36  * this in any plug-and-play environment.)
  37  *
  38  * 1999-12-16: Thomas Sailer <sailer@ife.ee.ethz.ch>
  39  *   Converted the whole proc stuff to real
  40  *   read methods. Now not the whole device list needs to fit
  41  *   into one page, only the device list for one bus.
  42  *   Added a poll method to /proc/bus/usb/devices, to wake
  43  *   up an eventual usbd
  44  * 2000-01-04: Thomas Sailer <sailer@ife.ee.ethz.ch>
  45  *   Turned into its own filesystem
  46  * 2000-07-05: Ashley Montanaro <ashley@compsoc.man.ac.uk>
  47  *   Converted file reading routine to dump to buffer once
  48  *   per device, not per bus
  49  */
  50
  51 #include <linux/fs.h>
  52 #include <linux/mm.h>
  53 #include <linux/slab.h>
  54 #include <linux/poll.h>
  55 #include <linux/usb.h>
  56 #include <linux/smp_lock.h>
  57 #include <linux/usbdevice_fs.h>
  58 #include <linux/mutex.h>
  59 #include <asm/uaccess.h>
  60
  61 #include "usb.h"
  62 #include "hcd.h"
  63
  64 /* Define ALLOW_SERIAL_NUMBER if you want to see the serial number of devices */
  65 #define ALLOW_SERIAL_NUMBER
  66
  67 static const char *format_topo =
  68 /* T:  Bus=dd Lev=dd Prnt=dd Port=dd Cnt=dd Dev#=ddd Spd=ddd MxCh=dd */
  69 "\nT:  Bus=%2.2d Lev=%2.2d Prnt=%2.2d Port=%2.2d Cnt=%2.2d Dev#=%3d Spd=%3s MxCh=%2d\n";
  70
  71 static const char *format_string_manufacturer =
  72 /* S:  Manufacturer=xxxx */
  73   "S:  Manufacturer=%.100s\n";
  74
  75 static const char *format_string_product =
  76 /* S:  Product=xxxx */
  77   "S:  Product=%.100s\n";
  78
  79 #ifdef ALLOW_SERIAL_NUMBER
  80 static const char *format_string_serialnumber =
  81 /* S:  SerialNumber=xxxx */
  82   "S:  SerialNumber=%.100s\n";
  83 #endif
  84
  85 static const char *format_bandwidth =
  86 /* B:  Alloc=ddd/ddd us (xx%), #Int=ddd, #Iso=ddd */
  87   "B:  Alloc=%3d/%3d us (%2d%%), #Int=%3d, #Iso=%3d\n";
  88
  89 static const char *format_device1 =
  90 /* D:  Ver=xx.xx Cls=xx(sssss) Sub=xx Prot=xx MxPS=dd #Cfgs=dd */
  91   "D:  Ver=%2x.%02x Cls=%02x(%-5s) Sub=%02x Prot=%02x MxPS=%2d #Cfgs=%3d\n";
  92
  93 static const char *format_device2 =
  94 /* P:  Vendor=xxxx ProdID=xxxx Rev=xx.xx */
  95   "P:  Vendor=%04x ProdID=%04x Rev=%2x.%02x\n";
  96
  97 static const char *format_config =
  98 /* C:  #Ifs=dd Cfg#=dd Atr=xx MPwr=dddmA */
  99   "C:%c #Ifs=%2d Cfg#=%2d Atr=%02x MxPwr=%3dmA\n";
 100
 101 static const char *format_iad =
 102 /* A:  FirstIf#=dd IfCount=dd Cls=xx(sssss) Sub=xx Prot=xx */
 103   "A:  FirstIf#=%2d IfCount=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x\n";
 104
 105 static const char *format_iface =
 106 /* I:  If#=dd Alt=dd #EPs=dd Cls=xx(sssss) Sub=xx Prot=xx Driver=xxxx*/
 107   "I:%c If#=%2d Alt=%2d #EPs=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x Driver=%s\n";
 108
 109 static const char *format_endpt =
 110 /* E:  Ad=xx(s) Atr=xx(ssss) MxPS=dddd Ivl=D?s */
 111   "E:  Ad=%02x(%c) Atr=%02x(%-4s) MxPS=%4d Ivl=%d%cs\n";
 112
 113
 114 /*
 115  * Need access to the driver and USB bus lists.
 116  * extern struct list_head usb_bus_list;
 117  * However, these will come from functions that return ptrs to each of them.
 118  */
 119
 120 /*
 121  * Wait for an connect/disconnect event to happen. We initialize
 122  * the event counter with an odd number, and each event will increment
 123  * the event counter by two, so it will always _stay_ odd. That means
 124  * that it will never be zero, so "event 0" will never match a current
 125  * event, and thus 'poll' will always trigger as readable for the first
 126  * time it gets called.
 127  */
 128 static struct device_connect_event {
 129         atomic_t count;
 130         wait_queue_head_t wait;
 131 } device_event = {
 132         .count = ATOMIC_INIT(1),
 133         .wait = __WAIT_QUEUE_HEAD_INITIALIZER(device_event.wait)
 134 };
 135
 136 struct class_info {
 137         int class;
 138         char *class_name;
 139 };
 140
 141 static const struct class_info clas_info[] =
 142 {                                       /* max. 5 chars. per name string */
 143         {USB_CLASS_PER_INTERFACE,       ">ifc"},
 144         {USB_CLASS_AUDIO,               "audio"},
 145         {USB_CLASS_COMM,                "comm."},
 146         {USB_CLASS_HID,                 "HID"},
 147         {USB_CLASS_PHYSICAL,            "PID"},
 148         {USB_CLASS_STILL_IMAGE,         "still"},
 149         {USB_CLASS_PRINTER,             "print"},
 150         {USB_CLASS_MASS_STORAGE,        "stor."},
 151         {USB_CLASS_HUB,                 "hub"},
 152         {USB_CLASS_CDC_DATA,            "data"},
 153         {USB_CLASS_CSCID,               "scard"},
 154         {USB_CLASS_CONTENT_SEC,         "c-sec"},
 155         {USB_CLASS_VIDEO,               "video"},
 156         {USB_CLASS_WIRELESS_CONTROLLER, "wlcon"},
 157         {USB_CLASS_MISC,                "misc"},
 158         {USB_CLASS_APP_SPEC,            "app."},
 159         {USB_CLASS_VENDOR_SPEC,         "vend."},
 160         {-1,                            "unk."}         /* leave as last */
 161 };
 162
 163 /*****************************************************************/
 164
 165 void usbfs_conn_disc_event(void)
 166 {
 167         atomic_add(2, &device_event.count);
 168         wake_up(&device_event.wait);
 169 }
 170
 171 static const char *class_decode(const int class)
 172 {
 173         int ix;
 174
 175         for (ix = 0; clas_info[ix].class != -1; ix++)
 176                 if (clas_info[ix].class == class)
 177                         break;
 178         return clas_info[ix].class_name;
 179 }
 180
 181 static char *usb_dump_endpoint_descriptor(int speed, char *start, char *end,
 182                                 const struct usb_endpoint_descriptor *desc)
 183 {
 184         char dir, unit, *type;
 185         unsigned interval, bandwidth = 1;
 186
 187         if (start > end)
 188                 return start;
 189
 190         dir = usb_endpoint_dir_in(desc) ? 'I' : 'O';
 191
 192         if (speed == USB_SPEED_HIGH) {
 193                 switch (le16_to_cpu(desc->wMaxPacketSize) & (0x03 << 11)) {
 194                 case 1 << 11:   bandwidth = 2; break;
 195                 case 2 << 11:   bandwidth = 3; break;
 196                 }
 197         }
 198
 199         /* this isn't checking for illegal values */
 200         switch (usb_endpoint_type(desc)) {
 201         case USB_ENDPOINT_XFER_CONTROL:
 202                 type = "Ctrl";
 203                 if (speed == USB_SPEED_HIGH)    /* uframes per NAK */
 204                         interval = desc->bInterval;
 205                 else
 206                         interval = 0;
 207                 dir = 'B';                      /* ctrl is bidirectional */
 208                 break;
 209         case USB_ENDPOINT_XFER_ISOC:
 210                 type = "Isoc";
 211                 interval = 1 << (desc->bInterval - 1);
 212                 break;
 213         case USB_ENDPOINT_XFER_BULK:
 214                 type = "Bulk";
 215                 if (speed == USB_SPEED_HIGH && dir == 'O') /* uframes per NAK */
 216                         interval = desc->bInterval;
 217                 else
 218                         interval = 0;
 219                 break;
 220         case USB_ENDPOINT_XFER_INT:
 221                 type = "Int.";
 222                 if (speed == USB_SPEED_HIGH)
 223                         interval = 1 << (desc->bInterval - 1);
 224                 else
 225                         interval = desc->bInterval;
 226                 break;
 227         default:        /* "can't happen" */
 228                 return start;
 229         }
 230         interval *= (speed == USB_SPEED_HIGH) ? 125 : 1000;
 231         if (interval % 1000)
 232                 unit = 'u';
 233         else {
 234                 unit = 'm';
 235                 interval /= 1000;
 236         }
 237
 238         start += sprintf(start, format_endpt, desc->bEndpointAddress, dir,
 239                          desc->bmAttributes, type,
 240                          (le16_to_cpu(desc->wMaxPacketSize) & 0x07ff) *
 241                          bandwidth,
 242                          interval, unit);
 243         return start;
 244 }
 245
 246 static char *usb_dump_interface_descriptor(char *start, char *end,
 247                                         const struct usb_interface_cache *intfc,
 248                                         const struct usb_interface *iface,
 249                                         int setno)
 250 {
 251         const struct usb_interface_descriptor *desc;
 252         const char *driver_name = "";
 253         int active = 0;
 254
 255         if (start > end)
 256                 return start;
 257         desc = &intfc->altsetting[setno].desc;
 258         if (iface) {
 259                 driver_name = (iface->dev.driver
 260                                 ? iface->dev.driver->name
 261                                 : "(none)");
 262                 active = (desc == &iface->cur_altsetting->desc);
 263         }
 264         start += sprintf(start, format_iface,
 265                          active ? '*' : ' ',    /* mark active altsetting */
 266                          desc->bInterfaceNumber,
 267                          desc->bAlternateSetting,
 268                          desc->bNumEndpoints,
 269                          desc->bInterfaceClass,
 270                          class_decode(desc->bInterfaceClass),
 271                          desc->bInterfaceSubClass,
 272                          desc->bInterfaceProtocol,
 273                          driver_name);
 274         return start;
 275 }
 276
 277 static char *usb_dump_interface(int speed, char *start, char *end,
 278                                 const struct usb_interface_cache *intfc,
 279                                 const struct usb_interface *iface, int setno)
 280 {
 281         const struct usb_host_interface *desc = &intfc->altsetting[setno];
 282         int i;
 283
 284         start = usb_dump_interface_descriptor(start, end, intfc, iface, setno);
 285         for (i = 0; i < desc->desc.bNumEndpoints; i++) {
 286                 if (start > end)
 287                         return start;
 288                 start = usb_dump_endpoint_descriptor(speed,
 289                                 start, end, &desc->endpoint[i].desc);
 290         }
 291         return start;
 292 }
 293
 294 static char *usb_dump_iad_descriptor(char *start, char *end,
 295                         const struct usb_interface_assoc_descriptor *iad)
 296 {
 297         if (start > end)
 298                 return start;
 299         start += sprintf(start, format_iad,
 300                          iad->bFirstInterface,
 301                          iad->bInterfaceCount,
 302                          iad->bFunctionClass,
 303                          class_decode(iad->bFunctionClass),
 304                          iad->bFunctionSubClass,
 305                          iad->bFunctionProtocol);
 306         return start;
 307 }
 308
 309 /* TBD:
 310  * 0. TBDs
 311  * 1. marking active interface altsettings (code lists all, but should mark
 312  *    which ones are active, if any)
 313  */
 314 static char *usb_dump_config_descriptor(char *start, char *end,
 315                                 const struct usb_config_descriptor *desc,
 316                                 int active)
 317 {
 318         if (start > end)
 319                 return start;
 320         start += sprintf(start, format_config,
 321                          /* mark active/actual/current cfg. */
 322                          active ? '*' : ' ',
 323                          desc->bNumInterfaces,
 324                          desc->bConfigurationValue,
 325                          desc->bmAttributes,
 326                          desc->bMaxPower * 2);
 327         return start;
 328 }
 329
 330 static char *usb_dump_config(int speed, char *start, char *end,
 331                              const struct usb_host_config *config, int active)
 332 {
 333         int i, j;
 334         struct usb_interface_cache *intfc;
 335         struct usb_interface *interface;
 336
 337         if (start > end)
 338                 return start;
 339         if (!config)
 340                 /* getting these some in 2.3.7; none in 2.3.6 */
 341                 return start + sprintf(start, "(null Cfg. desc.)\n");
 342         start = usb_dump_config_descriptor(start, end, &config->desc, active);
 343         for (i = 0; i < USB_MAXIADS; i++) {
 344                 if (config->intf_assoc[i] == NULL)
 345                         break;
 346                 start = usb_dump_iad_descriptor(start, end,
 347                                         config->intf_assoc[i]);
 348         }
 349         for (i = 0; i < config->desc.bNumInterfaces; i++) {
 350                 intfc = config->intf_cache[i];
 351                 interface = config->interface[i];
 352                 for (j = 0; j < intfc->num_altsetting; j++) {
 353                         if (start > end)
 354                                 return start;
 355                         start = usb_dump_interface(speed,
 356                                 start, end, intfc, interface, j);
 357                 }
 358         }
 359         return start;
 360 }
 361
 362 /*
 363  * Dump the different USB descriptors.
 364  */
 365 static char *usb_dump_device_descriptor(char *start, char *end,
 366                                 const struct usb_device_descriptor *desc)
 367 {
 368         u16 bcdUSB = le16_to_cpu(desc->bcdUSB);
 369         u16 bcdDevice = le16_to_cpu(desc->bcdDevice);
 370
 371         if (start > end)
 372                 return start;
 373         start += sprintf(start, format_device1,
 374                           bcdUSB >> 8, bcdUSB & 0xff,
 375                           desc->bDeviceClass,
 376                           class_decode(desc->bDeviceClass),
 377                           desc->bDeviceSubClass,
 378                           desc->bDeviceProtocol,
 379                           desc->bMaxPacketSize0,
 380                           desc->bNumConfigurations);
 381         if (start > end)
 382                 return start;
 383         start += sprintf(start, format_device2,
 384                          le16_to_cpu(desc->idVendor),
 385                          le16_to_cpu(desc->idProduct),
 386                          bcdDevice >> 8, bcdDevice & 0xff);
 387         return start;
 388 }
 389
 390 /*
 391  * Dump the different strings that this device holds.
 392  */
 393 static char *usb_dump_device_strings(char *start, char *end,
 394                                      struct usb_device *dev)
 395 {
 396         if (start > end)
 397                 return start;
 398         if (dev->manufacturer)
 399                 start += sprintf(start, format_string_manufacturer,
 400                                  dev->manufacturer);
 401         if (start > end)
 402                 goto out;
 403         if (dev->product)
 404                 start += sprintf(start, format_string_product, dev->product);
 405         if (start > end)
 406                 goto out;
 407 #ifdef ALLOW_SERIAL_NUMBER
 408         if (dev->serial)
 409                 start += sprintf(start, format_string_serialnumber,
 410                                  dev->serial);
 411 #endif
 412  out:
 413         return start;
 414 }
 415
 416 static char *usb_dump_desc(char *start, char *end, struct usb_device *dev)
 417 {
 418         int i;
 419
 420         if (start > end)
 421                 return start;
 422
 423         start = usb_dump_device_descriptor(start, end, &dev->descriptor);
 424
 425         if (start > end)
 426                 return start;
 427
 428         start = usb_dump_device_strings(start, end, dev);
 429
 430         for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
 431                 if (start > end)
 432                         return start;
 433                 start = usb_dump_config(dev->speed,
 434                                 start, end, dev->config + i,
 435                                 /* active ? */
 436                                 (dev->config + i) == dev->actconfig);
 437         }
 438         return start;
 439 }
 440
 441
 442 #ifdef PROC_EXTRA /* TBD: may want to add this code later */
 443
 444 static char *usb_dump_hub_descriptor(char *start, char *end,
 445                                      const struct usb_hub_descriptor *desc)
 446 {
 447         int leng = USB_DT_HUB_NONVAR_SIZE;
 448         unsigned char *ptr = (unsigned char *)desc;
 449
 450         if (start > end)
 451                 return start;
 452         start += sprintf(start, "Interface:");
 453         while (leng && start <= end) {
 454                 start += sprintf(start, " %02x", *ptr);
 455                 ptr++; leng--;
 456         }
 457         *start++ = '\n';
 458         return start;
 459 }
 460
 461 static char *usb_dump_string(char *start, char *end,
 462                              const struct usb_device *dev, char *id, int index)
 463 {
 464         if (start > end)
 465                 return start;
 466         start += sprintf(start, "Interface:");
 467         if (index <= dev->maxstring && dev->stringindex &&
 468             dev->stringindex[index])
 469                 start += sprintf(start, "%s: %.100s ", id,
 470                                  dev->stringindex[index]);
 471         return start;
 472 }
 473
 474 #endif /* PROC_EXTRA */
 475
 476 /*****************************************************************/
 477
 478 /* This is a recursive function. Parameters:
 479  * buffer - the user-space buffer to write data into
 480  * nbytes - the maximum number of bytes to write
 481  * skip_bytes - the number of bytes to skip before writing anything
 482  * file_offset - the offset into the devices file on completion
 483  * The caller must own the device lock.
 484  */
 485 static ssize_t usb_device_dump(char __user **buffer, size_t *nbytes,
 486                                loff_t *skip_bytes, loff_t *file_offset,
 487                                struct usb_device *usbdev, struct usb_bus *bus,
 488                                int level, int index, int count)
 489 {
 490         int chix;
 491         int ret, cnt = 0;
 492         int parent_devnum = 0;
 493         char *pages_start, *data_end, *speed;
 494         unsigned int length;
 495         ssize_t total_written = 0;
 496
 497         /* don't bother with anything else if we're not writing any data */
 498         if (*nbytes <= 0)
 499                 return 0;
 500
 501         if (level > MAX_TOPO_LEVEL)
 502                 return 0;
 503         /* allocate 2^1 pages = 8K (on i386);
 504          * should be more than enough for one device */
 505         pages_start = (char *)__get_free_pages(GFP_NOIO, 1);
 506         if (!pages_start)
 507                 return -ENOMEM;
 508
 509         if (usbdev->parent && usbdev->parent->devnum != -1)
 510                 parent_devnum = usbdev->parent->devnum;
 511         /*
 512          * So the root hub's parent is 0 and any device that is
 513          * plugged into the root hub has a parent of 0.
 514          */
 515         switch (usbdev->speed) {
 516         case USB_SPEED_LOW:
 517                 speed = "1.5"; break;
 518         case USB_SPEED_UNKNOWN:         /* usb 1.1 root hub code */
 519         case USB_SPEED_FULL:
 520                 speed = "12 "; break;
 521         case USB_SPEED_HIGH:
 522                 speed = "480"; break;
 523         default:
 524                 speed = "?? ";
 525         }
 526         data_end = pages_start + sprintf(pages_start, format_topo,
 527                         bus->busnum, level, parent_devnum,
 528                         index, count, usbdev->devnum,
 529                         speed, usbdev->maxchild);
 530         /*
 531          * level = topology-tier level;
 532          * parent_devnum = parent device number;
 533          * index = parent's connector number;
 534          * count = device count at this level
 535          */
 536         /* If this is the root hub, display the bandwidth information */
 537         if (level == 0) {
 538                 int     max;
 539
 540                 /* high speed reserves 80%, full/low reserves 90% */
 541                 if (usbdev->speed == USB_SPEED_HIGH)
 542                         max = 800;
 543                 else
 544                         max = FRAME_TIME_MAX_USECS_ALLOC;
 545
 546                 /* report "average" periodic allocation over a microsecond.
 547                  * the schedules are actually bursty, HCDs need to deal with
 548                  * that and just compute/report this average.
 549                  */
 550                 data_end += sprintf(data_end, format_bandwidth,
 551                                 bus->bandwidth_allocated, max,
 552                                 (100 * bus->bandwidth_allocated + max / 2)
 553                                         / max,
 554                                 bus->bandwidth_int_reqs,
 555                                 bus->bandwidth_isoc_reqs);
 556
 557         }
 558         data_end = usb_dump_desc(data_end, pages_start + (2 * PAGE_SIZE) - 256,
 559                                  usbdev);
 560
 561         if (data_end > (pages_start + (2 * PAGE_SIZE) - 256))
 562                 data_end += sprintf(data_end, "(truncated)\n");
 563
 564         length = data_end - pages_start;
 565         /* if we can start copying some data to the user */
 566         if (length > *skip_bytes) {
 567                 length -= *skip_bytes;
 568                 if (length > *nbytes)
 569                         length = *nbytes;
 570                 if (copy_to_user(*buffer, pages_start + *skip_bytes, length)) {
 571                         free_pages((unsigned long)pages_start, 1);
 572                         return -EFAULT;
 573                 }
 574                 *nbytes -= length;
 575                 *file_offset += length;
 576                 total_written += length;
 577                 *buffer += length;
 578                 *skip_bytes = 0;
 579         } else
 580                 *skip_bytes -= length;
 581
 582         free_pages((unsigned long)pages_start, 1);
 583
 584         /* Now look at all of this device's children. */
 585         for (chix = 0; chix < usbdev->maxchild; chix++) {
 586                 struct usb_device *childdev = usbdev->children[chix];
 587
 588                 if (childdev) {
 589                         usb_lock_device(childdev);
 590                         ret = usb_device_dump(buffer, nbytes, skip_bytes,
 591                                               file_offset, childdev, bus,
 592                                               level + 1, chix, ++cnt);
 593                         usb_unlock_device(childdev);
 594                         if (ret == -EFAULT)
 595                                 return total_written;
 596                         total_written += ret;
 597                 }
 598         }
 599         return total_written;
 600 }
 601
 602 static ssize_t usb_device_read(struct file *file, char __user *buf,
 603                                size_t nbytes, loff_t *ppos)
 604 {
 605         struct usb_bus *bus;
 606         ssize_t ret, total_written = 0;
 607         loff_t skip_bytes = *ppos;
 608
 609         if (*ppos < 0)
 610                 return -EINVAL;
 611         if (nbytes <= 0)
 612                 return 0;
 613         if (!access_ok(VERIFY_WRITE, buf, nbytes))
 614                 return -EFAULT;
 615
 616         mutex_lock(&usb_bus_list_lock);
 617         /* print devices for all busses */
 618         list_for_each_entry(bus, &usb_bus_list, bus_list) {
 619                 /* recurse through all children of the root hub */
 620                 if (!bus->root_hub)
 621                         continue;
 622                 usb_lock_device(bus->root_hub);
 623                 ret = usb_device_dump(&buf, &nbytes, &skip_bytes, ppos,
 624                                       bus->root_hub, bus, 0, 0, 0);
 625                 usb_unlock_device(bus->root_hub);
 626                 if (ret < 0) {
 627                         mutex_unlock(&usb_bus_list_lock);
 628                         return ret;
 629                 }
 630                 total_written += ret;
 631         }
 632         mutex_unlock(&usb_bus_list_lock);
 633         return total_written;
 634 }
 635
 636 /* Kernel lock for "lastev" protection */
 637 static unsigned int usb_device_poll(struct file *file,
 638                                     struct poll_table_struct *wait)
 639 {
 640         unsigned int event_count;
 641
 642         poll_wait(file, &device_event.wait, wait);
 643
 644         event_count = atomic_read(&device_event.count);
 645         if (file->f_version != event_count) {
 646                 file->f_version = event_count;
 647                 return POLLIN | POLLRDNORM;
 648         }
 649
 650         return 0;
 651 }
 652
 653 static loff_t usb_device_lseek(struct file *file, loff_t offset, int orig)
 654 {
 655         loff_t ret;
 656
 657         mutex_lock(&file->f_dentry->d_inode->i_mutex);
 658
 659         switch (orig) {
 660         case 0:
 661                 file->f_pos = offset;
 662                 ret = file->f_pos;
 663                 break;
 664         case 1:
 665                 file->f_pos += offset;
 666                 ret = file->f_pos;
 667                 break;
 668         case 2:
 669         default:
 670                 ret = -EINVAL;
 671         }
 672
 673         mutex_unlock(&file->f_dentry->d_inode->i_mutex);
 674         return ret;
 675 }
 676
 677 const struct file_operations usbfs_devices_fops = {
 678         .llseek =       usb_device_lseek,
 679         .read =         usb_device_read,
 680         .poll =         usb_device_poll,
 681 };