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 static DECLARE_WAIT_QUEUE_HEAD(deviceconndiscwq);
 121 /* guarded by usbfs_mutex */
 122 static unsigned int conndiscevcnt;
 123
 124 /* this struct stores the poll state for <mountpoint>/devices pollers */
 125 struct usb_device_status {
 126         unsigned int lastev;
 127 };
 128
 129 struct class_info {
 130         int class;
 131         char *class_name;
 132 };
 133
 134 static const struct class_info clas_info[] =
 135 {                                       /* max. 5 chars. per name string */
 136         {USB_CLASS_PER_INTERFACE,       ">ifc"},
 137         {USB_CLASS_AUDIO,               "audio"},
 138         {USB_CLASS_COMM,                "comm."},
 139         {USB_CLASS_HID,                 "HID"},
 140         {USB_CLASS_PHYSICAL,            "PID"},
 141         {USB_CLASS_STILL_IMAGE,         "still"},
 142         {USB_CLASS_PRINTER,             "print"},
 143         {USB_CLASS_MASS_STORAGE,        "stor."},
 144         {USB_CLASS_HUB,                 "hub"},
 145         {USB_CLASS_CDC_DATA,            "data"},
 146         {USB_CLASS_CSCID,               "scard"},
 147         {USB_CLASS_CONTENT_SEC,         "c-sec"},
 148         {USB_CLASS_VIDEO,               "video"},
 149         {USB_CLASS_WIRELESS_CONTROLLER, "wlcon"},
 150         {USB_CLASS_MISC,                "misc"},
 151         {USB_CLASS_APP_SPEC,            "app."},
 152         {USB_CLASS_VENDOR_SPEC,         "vend."},
 153         {-1,                            "unk."}         /* leave as last */
 154 };
 155
 156 /*****************************************************************/
 157
 158 void usbfs_conn_disc_event(void)
 159 {
 160         mutex_lock(&usbfs_mutex);
 161         conndiscevcnt++;
 162         mutex_unlock(&usbfs_mutex);
 163         wake_up(&deviceconndiscwq);
 164 }
 165
 166 static const char *class_decode(const int class)
 167 {
 168         int ix;
 169
 170         for (ix = 0; clas_info[ix].class != -1; ix++)
 171                 if (clas_info[ix].class == class)
 172                         break;
 173         return clas_info[ix].class_name;
 174 }
 175
 176 static char *usb_dump_endpoint_descriptor(int speed, char *start, char *end,
 177                                 const struct usb_endpoint_descriptor *desc)
 178 {
 179         char dir, unit, *type;
 180         unsigned interval, bandwidth = 1;
 181
 182         if (start > end)
 183                 return start;
 184
 185         dir = usb_endpoint_dir_in(desc) ? 'I' : 'O';
 186
 187         if (speed == USB_SPEED_HIGH) {
 188                 switch (le16_to_cpu(desc->wMaxPacketSize) & (0x03 << 11)) {
 189                 case 1 << 11:   bandwidth = 2; break;
 190                 case 2 << 11:   bandwidth = 3; break;
 191                 }
 192         }
 193
 194         /* this isn't checking for illegal values */
 195         switch (usb_endpoint_type(desc)) {
 196         case USB_ENDPOINT_XFER_CONTROL:
 197                 type = "Ctrl";
 198                 if (speed == USB_SPEED_HIGH)    /* uframes per NAK */
 199                         interval = desc->bInterval;
 200                 else
 201                         interval = 0;
 202                 dir = 'B';                      /* ctrl is bidirectional */
 203                 break;
 204         case USB_ENDPOINT_XFER_ISOC:
 205                 type = "Isoc";
 206                 interval = 1 << (desc->bInterval - 1);
 207                 break;
 208         case USB_ENDPOINT_XFER_BULK:
 209                 type = "Bulk";
 210                 if (speed == USB_SPEED_HIGH && dir == 'O') /* uframes per NAK */
 211                         interval = desc->bInterval;
 212                 else
 213                         interval = 0;
 214                 break;
 215         case USB_ENDPOINT_XFER_INT:
 216                 type = "Int.";
 217                 if (speed == USB_SPEED_HIGH)
 218                         interval = 1 << (desc->bInterval - 1);
 219                 else
 220                         interval = desc->bInterval;
 221                 break;
 222         default:        /* "can't happen" */
 223                 return start;
 224         }
 225         interval *= (speed == USB_SPEED_HIGH) ? 125 : 1000;
 226         if (interval % 1000)
 227                 unit = 'u';
 228         else {
 229                 unit = 'm';
 230                 interval /= 1000;
 231         }
 232
 233         start += sprintf(start, format_endpt, desc->bEndpointAddress, dir,
 234                          desc->bmAttributes, type,
 235                          (le16_to_cpu(desc->wMaxPacketSize) & 0x07ff) *
 236                          bandwidth,
 237                          interval, unit);
 238         return start;
 239 }
 240
 241 static char *usb_dump_interface_descriptor(char *start, char *end,
 242                                         const struct usb_interface_cache *intfc,
 243                                         const struct usb_interface *iface,
 244                                         int setno)
 245 {
 246         const struct usb_interface_descriptor *desc;
 247         const char *driver_name = "";
 248         int active = 0;
 249
 250         if (start > end)
 251                 return start;
 252         desc = &intfc->altsetting[setno].desc;
 253         if (iface) {
 254                 driver_name = (iface->dev.driver
 255                                 ? iface->dev.driver->name
 256                                 : "(none)");
 257                 active = (desc == &iface->cur_altsetting->desc);
 258         }
 259         start += sprintf(start, format_iface,
 260                          active ? '*' : ' ',    /* mark active altsetting */
 261                          desc->bInterfaceNumber,
 262                          desc->bAlternateSetting,
 263                          desc->bNumEndpoints,
 264                          desc->bInterfaceClass,
 265                          class_decode(desc->bInterfaceClass),
 266                          desc->bInterfaceSubClass,
 267                          desc->bInterfaceProtocol,
 268                          driver_name);
 269         return start;
 270 }
 271
 272 static char *usb_dump_interface(int speed, char *start, char *end,
 273                                 const struct usb_interface_cache *intfc,
 274                                 const struct usb_interface *iface, int setno)
 275 {
 276         const struct usb_host_interface *desc = &intfc->altsetting[setno];
 277         int i;
 278
 279         start = usb_dump_interface_descriptor(start, end, intfc, iface, setno);
 280         for (i = 0; i < desc->desc.bNumEndpoints; i++) {
 281                 if (start > end)
 282                         return start;
 283                 start = usb_dump_endpoint_descriptor(speed,
 284                                 start, end, &desc->endpoint[i].desc);
 285         }
 286         return start;
 287 }
 288
 289 static char *usb_dump_iad_descriptor(char *start, char *end,
 290                         const struct usb_interface_assoc_descriptor *iad)
 291 {
 292         if (start > end)
 293                 return start;
 294         start += sprintf(start, format_iad,
 295                          iad->bFirstInterface,
 296                          iad->bInterfaceCount,
 297                          iad->bFunctionClass,
 298                          class_decode(iad->bFunctionClass),
 299                          iad->bFunctionSubClass,
 300                          iad->bFunctionProtocol);
 301         return start;
 302 }
 303
 304 /* TBD:
 305  * 0. TBDs
 306  * 1. marking active interface altsettings (code lists all, but should mark
 307  *    which ones are active, if any)
 308  */
 309 static char *usb_dump_config_descriptor(char *start, char *end,
 310                                 const struct usb_config_descriptor *desc,
 311                                 int active)
 312 {
 313         if (start > end)
 314                 return start;
 315         start += sprintf(start, format_config,
 316                          /* mark active/actual/current cfg. */
 317                          active ? '*' : ' ',
 318                          desc->bNumInterfaces,
 319                          desc->bConfigurationValue,
 320                          desc->bmAttributes,
 321                          desc->bMaxPower * 2);
 322         return start;
 323 }
 324
 325 static char *usb_dump_config(int speed, char *start, char *end,
 326                              const struct usb_host_config *config, int active)
 327 {
 328         int i, j;
 329         struct usb_interface_cache *intfc;
 330         struct usb_interface *interface;
 331
 332         if (start > end)
 333                 return start;
 334         if (!config)
 335                 /* getting these some in 2.3.7; none in 2.3.6 */
 336                 return start + sprintf(start, "(null Cfg. desc.)\n");
 337         start = usb_dump_config_descriptor(start, end, &config->desc, active);
 338         for (i = 0; i < USB_MAXIADS; i++) {
 339                 if (config->intf_assoc[i] == NULL)
 340                         break;
 341                 start = usb_dump_iad_descriptor(start, end,
 342                                         config->intf_assoc[i]);
 343         }
 344         for (i = 0; i < config->desc.bNumInterfaces; i++) {
 345                 intfc = config->intf_cache[i];
 346                 interface = config->interface[i];
 347                 for (j = 0; j < intfc->num_altsetting; j++) {
 348                         if (start > end)
 349                                 return start;
 350                         start = usb_dump_interface(speed,
 351                                 start, end, intfc, interface, j);
 352                 }
 353         }
 354         return start;
 355 }
 356
 357 /*
 358  * Dump the different USB descriptors.
 359  */
 360 static char *usb_dump_device_descriptor(char *start, char *end,
 361                                 const struct usb_device_descriptor *desc)
 362 {
 363         u16 bcdUSB = le16_to_cpu(desc->bcdUSB);
 364         u16 bcdDevice = le16_to_cpu(desc->bcdDevice);
 365
 366         if (start > end)
 367                 return start;
 368         start += sprintf(start, format_device1,
 369                           bcdUSB >> 8, bcdUSB & 0xff,
 370                           desc->bDeviceClass,
 371                           class_decode(desc->bDeviceClass),
 372                           desc->bDeviceSubClass,
 373                           desc->bDeviceProtocol,
 374                           desc->bMaxPacketSize0,
 375                           desc->bNumConfigurations);
 376         if (start > end)
 377                 return start;
 378         start += sprintf(start, format_device2,
 379                          le16_to_cpu(desc->idVendor),
 380                          le16_to_cpu(desc->idProduct),
 381                          bcdDevice >> 8, bcdDevice & 0xff);
 382         return start;
 383 }
 384
 385 /*
 386  * Dump the different strings that this device holds.
 387  */
 388 static char *usb_dump_device_strings(char *start, char *end,
 389                                      struct usb_device *dev)
 390 {
 391         if (start > end)
 392                 return start;
 393         if (dev->manufacturer)
 394                 start += sprintf(start, format_string_manufacturer,
 395                                  dev->manufacturer);
 396         if (start > end)
 397                 goto out;
 398         if (dev->product)
 399                 start += sprintf(start, format_string_product, dev->product);
 400         if (start > end)
 401                 goto out;
 402 #ifdef ALLOW_SERIAL_NUMBER
 403         if (dev->serial)
 404                 start += sprintf(start, format_string_serialnumber,
 405                                  dev->serial);
 406 #endif
 407  out:
 408         return start;
 409 }
 410
 411 static char *usb_dump_desc(char *start, char *end, struct usb_device *dev)
 412 {
 413         int i;
 414
 415         if (start > end)
 416                 return start;
 417
 418         start = usb_dump_device_descriptor(start, end, &dev->descriptor);
 419
 420         if (start > end)
 421                 return start;
 422
 423         start = usb_dump_device_strings(start, end, dev);
 424
 425         for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
 426                 if (start > end)
 427                         return start;
 428                 start = usb_dump_config(dev->speed,
 429                                 start, end, dev->config + i,
 430                                 /* active ? */
 431                                 (dev->config + i) == dev->actconfig);
 432         }
 433         return start;
 434 }
 435
 436
 437 #ifdef PROC_EXTRA /* TBD: may want to add this code later */
 438
 439 static char *usb_dump_hub_descriptor(char *start, char *end,
 440                                      const struct usb_hub_descriptor *desc)
 441 {
 442         int leng = USB_DT_HUB_NONVAR_SIZE;
 443         unsigned char *ptr = (unsigned char *)desc;
 444
 445         if (start > end)
 446                 return start;
 447         start += sprintf(start, "Interface:");
 448         while (leng && start <= end) {
 449                 start += sprintf(start, " %02x", *ptr);
 450                 ptr++; leng--;
 451         }
 452         *start++ = '\n';
 453         return start;
 454 }
 455
 456 static char *usb_dump_string(char *start, char *end,
 457                              const struct usb_device *dev, char *id, int index)
 458 {
 459         if (start > end)
 460                 return start;
 461         start += sprintf(start, "Interface:");
 462         if (index <= dev->maxstring && dev->stringindex &&
 463             dev->stringindex[index])
 464                 start += sprintf(start, "%s: %.100s ", id,
 465                                  dev->stringindex[index]);
 466         return start;
 467 }
 468
 469 #endif /* PROC_EXTRA */
 470
 471 /*****************************************************************/
 472
 473 /* This is a recursive function. Parameters:
 474  * buffer - the user-space buffer to write data into
 475  * nbytes - the maximum number of bytes to write
 476  * skip_bytes - the number of bytes to skip before writing anything
 477  * file_offset - the offset into the devices file on completion
 478  * The caller must own the device lock.
 479  */
 480 static ssize_t usb_device_dump(char __user **buffer, size_t *nbytes,
 481                                loff_t *skip_bytes, loff_t *file_offset,
 482                                struct usb_device *usbdev, struct usb_bus *bus,
 483                                int level, int index, int count)
 484 {
 485         int chix;
 486         int ret, cnt = 0;
 487         int parent_devnum = 0;
 488         char *pages_start, *data_end, *speed;
 489         unsigned int length;
 490         ssize_t total_written = 0;
 491
 492         /* don't bother with anything else if we're not writing any data */
 493         if (*nbytes <= 0)
 494                 return 0;
 495
 496         if (level > MAX_TOPO_LEVEL)
 497                 return 0;
 498         /* allocate 2^1 pages = 8K (on i386);
 499          * should be more than enough for one device */
 500         pages_start = (char *)__get_free_pages(GFP_NOIO, 1);
 501         if (!pages_start)
 502                 return -ENOMEM;
 503
 504         if (usbdev->parent && usbdev->parent->devnum != -1)
 505                 parent_devnum = usbdev->parent->devnum;
 506         /*
 507          * So the root hub's parent is 0 and any device that is
 508          * plugged into the root hub has a parent of 0.
 509          */
 510         switch (usbdev->speed) {
 511         case USB_SPEED_LOW:
 512                 speed = "1.5"; break;
 513         case USB_SPEED_UNKNOWN:         /* usb 1.1 root hub code */
 514         case USB_SPEED_FULL:
 515                 speed = "12 "; break;
 516         case USB_SPEED_HIGH:
 517                 speed = "480"; break;
 518         default:
 519                 speed = "?? ";
 520         }
 521         data_end = pages_start + sprintf(pages_start, format_topo,
 522                         bus->busnum, level, parent_devnum,
 523                         index, count, usbdev->devnum,
 524                         speed, usbdev->maxchild);
 525         /*
 526          * level = topology-tier level;
 527          * parent_devnum = parent device number;
 528          * index = parent's connector number;
 529          * count = device count at this level
 530          */
 531         /* If this is the root hub, display the bandwidth information */
 532         if (level == 0) {
 533                 int     max;
 534
 535                 /* high speed reserves 80%, full/low reserves 90% */
 536                 if (usbdev->speed == USB_SPEED_HIGH)
 537                         max = 800;
 538                 else
 539                         max = FRAME_TIME_MAX_USECS_ALLOC;
 540
 541                 /* report "average" periodic allocation over a microsecond.
 542                  * the schedules are actually bursty, HCDs need to deal with
 543                  * that and just compute/report this average.
 544                  */
 545                 data_end += sprintf(data_end, format_bandwidth,
 546                                 bus->bandwidth_allocated, max,
 547                                 (100 * bus->bandwidth_allocated + max / 2)
 548                                         / max,
 549                                 bus->bandwidth_int_reqs,
 550                                 bus->bandwidth_isoc_reqs);
 551
 552         }
 553         data_end = usb_dump_desc(data_end, pages_start + (2 * PAGE_SIZE) - 256,
 554                                  usbdev);
 555
 556         if (data_end > (pages_start + (2 * PAGE_SIZE) - 256))
 557                 data_end += sprintf(data_end, "(truncated)\n");
 558
 559         length = data_end - pages_start;
 560         /* if we can start copying some data to the user */
 561         if (length > *skip_bytes) {
 562                 length -= *skip_bytes;
 563                 if (length > *nbytes)
 564                         length = *nbytes;
 565                 if (copy_to_user(*buffer, pages_start + *skip_bytes, length)) {
 566                         free_pages((unsigned long)pages_start, 1);
 567                         return -EFAULT;
 568                 }
 569                 *nbytes -= length;
 570                 *file_offset += length;
 571                 total_written += length;
 572                 *buffer += length;
 573                 *skip_bytes = 0;
 574         } else
 575                 *skip_bytes -= length;
 576
 577         free_pages((unsigned long)pages_start, 1);
 578
 579         /* Now look at all of this device's children. */
 580         for (chix = 0; chix < usbdev->maxchild; chix++) {
 581                 struct usb_device *childdev = usbdev->children[chix];
 582
 583                 if (childdev) {
 584                         usb_lock_device(childdev);
 585                         ret = usb_device_dump(buffer, nbytes, skip_bytes,
 586                                               file_offset, childdev, bus,
 587                                               level + 1, chix, ++cnt);
 588                         usb_unlock_device(childdev);
 589                         if (ret == -EFAULT)
 590                                 return total_written;
 591                         total_written += ret;
 592                 }
 593         }
 594         return total_written;
 595 }
 596
 597 static ssize_t usb_device_read(struct file *file, char __user *buf,
 598                                size_t nbytes, loff_t *ppos)
 599 {
 600         struct usb_bus *bus;
 601         ssize_t ret, total_written = 0;
 602         loff_t skip_bytes = *ppos;
 603
 604         if (*ppos < 0)
 605                 return -EINVAL;
 606         if (nbytes <= 0)
 607                 return 0;
 608         if (!access_ok(VERIFY_WRITE, buf, nbytes))
 609                 return -EFAULT;
 610
 611         mutex_lock(&usb_bus_list_lock);
 612         /* print devices for all busses */
 613         list_for_each_entry(bus, &usb_bus_list, bus_list) {
 614                 /* recurse through all children of the root hub */
 615                 if (!bus->root_hub)
 616                         continue;
 617                 usb_lock_device(bus->root_hub);
 618                 ret = usb_device_dump(&buf, &nbytes, &skip_bytes, ppos,
 619                                       bus->root_hub, bus, 0, 0, 0);
 620                 usb_unlock_device(bus->root_hub);
 621                 if (ret < 0) {
 622                         mutex_unlock(&usb_bus_list_lock);
 623                         return ret;
 624                 }
 625                 total_written += ret;
 626         }
 627         mutex_unlock(&usb_bus_list_lock);
 628         return total_written;
 629 }
 630
 631 /* Kernel lock for "lastev" protection */
 632 static unsigned int usb_device_poll(struct file *file,
 633                                     struct poll_table_struct *wait)
 634 {
 635         struct usb_device_status *st;
 636         unsigned int mask = 0;
 637
 638         mutex_lock(&usbfs_mutex);
 639         st = file->private_data;
 640         if (!st) {
 641                 st = kmalloc(sizeof(struct usb_device_status), GFP_KERNEL);
 642                 if (!st) {
 643                         mutex_unlock(&usbfs_mutex);
 644                         return POLLIN;
 645                 }
 646
 647                 st->lastev = conndiscevcnt;
 648                 file->private_data = st;
 649                 mask = POLLIN;
 650         }
 651
 652         if (file->f_mode & FMODE_READ)
 653                 poll_wait(file, &deviceconndiscwq, wait);
 654         if (st->lastev != conndiscevcnt)
 655                 mask |= POLLIN;
 656         st->lastev = conndiscevcnt;
 657         mutex_unlock(&usbfs_mutex);
 658         return mask;
 659 }
 660
 661 static int usb_device_open(struct inode *inode, struct file *file)
 662 {
 663         file->private_data = NULL;
 664         return 0;
 665 }
 666
 667 static int usb_device_release(struct inode *inode, struct file *file)
 668 {
 669         kfree(file->private_data);
 670         file->private_data = NULL;
 671         return 0;
 672 }
 673
 674 static loff_t usb_device_lseek(struct file *file, loff_t offset, int orig)
 675 {
 676         loff_t ret;
 677
 678         mutex_lock(&file->f_dentry->d_inode->i_mutex);
 679
 680         switch (orig) {
 681         case 0:
 682                 file->f_pos = offset;
 683                 ret = file->f_pos;
 684                 break;
 685         case 1:
 686                 file->f_pos += offset;
 687                 ret = file->f_pos;
 688                 break;
 689         case 2:
 690         default:
 691                 ret = -EINVAL;
 692         }
 693
 694         mutex_unlock(&file->f_dentry->d_inode->i_mutex);
 695         return ret;
 696 }
 697
 698 const struct file_operations usbfs_devices_fops = {
 699         .llseek =       usb_device_lseek,
 700         .read =         usb_device_read,
 701         .poll =         usb_device_poll,
 702         .open =         usb_device_open,
 703         .release =      usb_device_release,
 704 };