drivers/usb/core/config.c

   1 #include <linux/usb.h>
   2 #include <linux/usb/ch9.h>
   3 #include <linux/module.h>
   4 #include <linux/init.h>
   5 #include <linux/slab.h>
   6 #include <linux/device.h>
   7 #include <asm/byteorder.h>
   8 #include "usb.h"
   9 #include "hcd.h"
  10
  11 #define USB_MAXALTSETTING               128     /* Hard limit */
  12 #define USB_MAXENDPOINTS                30      /* Hard limit */
  13
  14 #define USB_MAXCONFIG                   8       /* Arbitrary limit */
  15
  16
  17 static inline const char *plural(int n)
  18 {
  19         return (n == 1 ? "" : "s");
  20 }
  21
  22 static int find_next_descriptor(unsigned char *buffer, int size,
  23     int dt1, int dt2, int *num_skipped)
  24 {
  25         struct usb_descriptor_header *h;
  26         int n = 0;
  27         unsigned char *buffer0 = buffer;
  28
  29         /* Find the next descriptor of type dt1 or dt2 */
  30         while (size > 0) {
  31                 h = (struct usb_descriptor_header *) buffer;
  32                 if (h->bDescriptorType == dt1 || h->bDescriptorType == dt2)
  33                         break;
  34                 buffer += h->bLength;
  35                 size -= h->bLength;
  36                 ++n;
  37         }
  38
  39         /* Store the number of descriptors skipped and return the
  40          * number of bytes skipped */
  41         if (num_skipped)
  42                 *num_skipped = n;
  43         return buffer - buffer0;
  44 }
  45
  46 static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
  47     int asnum, struct usb_host_interface *ifp, int num_ep,
  48     unsigned char *buffer, int size)
  49 {
  50         unsigned char *buffer0 = buffer;
  51         struct usb_endpoint_descriptor *d;
  52         struct usb_host_endpoint *endpoint;
  53         int n, i, j;
  54
  55         d = (struct usb_endpoint_descriptor *) buffer;
  56         buffer += d->bLength;
  57         size -= d->bLength;
  58
  59         if (d->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE)
  60                 n = USB_DT_ENDPOINT_AUDIO_SIZE;
  61         else if (d->bLength >= USB_DT_ENDPOINT_SIZE)
  62                 n = USB_DT_ENDPOINT_SIZE;
  63         else {
  64                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
  65                     "invalid endpoint descriptor of length %d, skipping\n",
  66                     cfgno, inum, asnum, d->bLength);
  67                 goto skip_to_next_endpoint_or_interface_descriptor;
  68         }
  69
  70         i = d->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
  71         if (i >= 16 || i == 0) {
  72                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
  73                     "invalid endpoint with address 0x%X, skipping\n",
  74                     cfgno, inum, asnum, d->bEndpointAddress);
  75                 goto skip_to_next_endpoint_or_interface_descriptor;
  76         }
  77
  78         /* Only store as many endpoints as we have room for */
  79         if (ifp->desc.bNumEndpoints >= num_ep)
  80                 goto skip_to_next_endpoint_or_interface_descriptor;
  81
  82         endpoint = &ifp->endpoint[ifp->desc.bNumEndpoints];
  83         ++ifp->desc.bNumEndpoints;
  84
  85         memcpy(&endpoint->desc, d, n);
  86         INIT_LIST_HEAD(&endpoint->urb_list);
  87
  88         /* Fix up bInterval values outside the legal range. Use 32 ms if no
  89          * proper value can be guessed. */
  90         i = 0;          /* i = min, j = max, n = default */
  91         j = 255;
  92         if (usb_endpoint_xfer_int(d)) {
  93                 i = 1;
  94                 switch (to_usb_device(ddev)->speed) {
  95                 case USB_SPEED_HIGH:
  96                         /* Many device manufacturers are using full-speed
  97                          * bInterval values in high-speed interrupt endpoint
  98                          * descriptors. Try to fix those and fall back to a
  99                          * 32 ms default value otherwise. */
 100                         n = fls(d->bInterval*8);
 101                         if (n == 0)
 102                                 n = 9;  /* 32 ms = 2^(9-1) uframes */
 103                         j = 16;
 104                         break;
 105                 default:                /* USB_SPEED_FULL or _LOW */
 106                         /* For low-speed, 10 ms is the official minimum.
 107                          * But some "overclocked" devices might want faster
 108                          * polling so we'll allow it. */
 109                         n = 32;
 110                         break;
 111                 }
 112         } else if (usb_endpoint_xfer_isoc(d)) {
 113                 i = 1;
 114                 j = 16;
 115                 switch (to_usb_device(ddev)->speed) {
 116                 case USB_SPEED_HIGH:
 117                         n = 9;          /* 32 ms = 2^(9-1) uframes */
 118                         break;
 119                 default:                /* USB_SPEED_FULL */
 120                         n = 6;          /* 32 ms = 2^(6-1) frames */
 121                         break;
 122                 }
 123         }
 124         if (d->bInterval < i || d->bInterval > j) {
 125                 dev_warn(ddev, "config %d interface %d altsetting %d "
 126                     "endpoint 0x%X has an invalid bInterval %d, "
 127                     "changing to %d\n",
 128                     cfgno, inum, asnum,
 129                     d->bEndpointAddress, d->bInterval, n);
 130                 endpoint->desc.bInterval = n;
 131         }
 132
 133         /* Some buggy low-speed devices have Bulk endpoints, which is
 134          * explicitly forbidden by the USB spec.  In an attempt to make
 135          * them usable, we will try treating them as Interrupt endpoints.
 136          */
 137         if (to_usb_device(ddev)->speed == USB_SPEED_LOW &&
 138                         usb_endpoint_xfer_bulk(d)) {
 139                 dev_warn(ddev, "config %d interface %d altsetting %d "
 140                     "endpoint 0x%X is Bulk; changing to Interrupt\n",
 141                     cfgno, inum, asnum, d->bEndpointAddress);
 142                 endpoint->desc.bmAttributes = USB_ENDPOINT_XFER_INT;
 143                 endpoint->desc.bInterval = 1;
 144                 if (le16_to_cpu(endpoint->desc.wMaxPacketSize) > 8)
 145                         endpoint->desc.wMaxPacketSize = cpu_to_le16(8);
 146         }
 147
 148         /* Skip over any Class Specific or Vendor Specific descriptors;
 149          * find the next endpoint or interface descriptor */
 150         endpoint->extra = buffer;
 151         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 152             USB_DT_INTERFACE, &n);
 153         endpoint->extralen = i;
 154         if (n > 0)
 155                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 156                     n, plural(n), "endpoint");
 157         return buffer - buffer0 + i;
 158
 159 skip_to_next_endpoint_or_interface_descriptor:
 160         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 161             USB_DT_INTERFACE, NULL);
 162         return buffer - buffer0 + i;
 163 }
 164
 165 void usb_release_interface_cache(struct kref *ref)
 166 {
 167         struct usb_interface_cache *intfc = ref_to_usb_interface_cache(ref);
 168         int j;
 169
 170         for (j = 0; j < intfc->num_altsetting; j++) {
 171                 struct usb_host_interface *alt = &intfc->altsetting[j];
 172
 173                 kfree(alt->endpoint);
 174                 kfree(alt->string);
 175         }
 176         kfree(intfc);
 177 }
 178
 179 static int usb_parse_interface(struct device *ddev, int cfgno,
 180     struct usb_host_config *config, unsigned char *buffer, int size,
 181     u8 inums[], u8 nalts[])
 182 {
 183         unsigned char *buffer0 = buffer;
 184         struct usb_interface_descriptor *d;
 185         int inum, asnum;
 186         struct usb_interface_cache *intfc;
 187         struct usb_host_interface *alt;
 188         int i, n;
 189         int len, retval;
 190         int num_ep, num_ep_orig;
 191
 192         d = (struct usb_interface_descriptor *) buffer;
 193         buffer += d->bLength;
 194         size -= d->bLength;
 195
 196         if (d->bLength < USB_DT_INTERFACE_SIZE)
 197                 goto skip_to_next_interface_descriptor;
 198
 199         /* Which interface entry is this? */
 200         intfc = NULL;
 201         inum = d->bInterfaceNumber;
 202         for (i = 0; i < config->desc.bNumInterfaces; ++i) {
 203                 if (inums[i] == inum) {
 204                         intfc = config->intf_cache[i];
 205                         break;
 206                 }
 207         }
 208         if (!intfc || intfc->num_altsetting >= nalts[i])
 209                 goto skip_to_next_interface_descriptor;
 210
 211         /* Check for duplicate altsetting entries */
 212         asnum = d->bAlternateSetting;
 213         for ((i = 0, alt = &intfc->altsetting[0]);
 214               i < intfc->num_altsetting;
 215              (++i, ++alt)) {
 216                 if (alt->desc.bAlternateSetting == asnum) {
 217                         dev_warn(ddev, "Duplicate descriptor for config %d "
 218                             "interface %d altsetting %d, skipping\n",
 219                             cfgno, inum, asnum);
 220                         goto skip_to_next_interface_descriptor;
 221                 }
 222         }
 223
 224         ++intfc->num_altsetting;
 225         memcpy(&alt->desc, d, USB_DT_INTERFACE_SIZE);
 226
 227         /* Skip over any Class Specific or Vendor Specific descriptors;
 228          * find the first endpoint or interface descriptor */
 229         alt->extra = buffer;
 230         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 231             USB_DT_INTERFACE, &n);
 232         alt->extralen = i;
 233         if (n > 0)
 234                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 235                     n, plural(n), "interface");
 236         buffer += i;
 237         size -= i;
 238
 239         /* Allocate space for the right(?) number of endpoints */
 240         num_ep = num_ep_orig = alt->desc.bNumEndpoints;
 241         alt->desc.bNumEndpoints = 0;            // Use as a counter
 242         if (num_ep > USB_MAXENDPOINTS) {
 243                 dev_warn(ddev, "too many endpoints for config %d interface %d "
 244                     "altsetting %d: %d, using maximum allowed: %d\n",
 245                     cfgno, inum, asnum, num_ep, USB_MAXENDPOINTS);
 246                 num_ep = USB_MAXENDPOINTS;
 247         }
 248
 249         if (num_ep > 0) {       /* Can't allocate 0 bytes */
 250                 len = sizeof(struct usb_host_endpoint) * num_ep;
 251                 alt->endpoint = kzalloc(len, GFP_KERNEL);
 252                 if (!alt->endpoint)
 253                         return -ENOMEM;
 254         }
 255
 256         /* Parse all the endpoint descriptors */
 257         n = 0;
 258         while (size > 0) {
 259                 if (((struct usb_descriptor_header *) buffer)->bDescriptorType
 260                      == USB_DT_INTERFACE)
 261                         break;
 262                 retval = usb_parse_endpoint(ddev, cfgno, inum, asnum, alt,
 263                     num_ep, buffer, size);
 264                 if (retval < 0)
 265                         return retval;
 266                 ++n;
 267
 268                 buffer += retval;
 269                 size -= retval;
 270         }
 271
 272         if (n != num_ep_orig)
 273                 dev_warn(ddev, "config %d interface %d altsetting %d has %d "
 274                     "endpoint descriptor%s, different from the interface "
 275                     "descriptor's value: %d\n",
 276                     cfgno, inum, asnum, n, plural(n), num_ep_orig);
 277         return buffer - buffer0;
 278
 279 skip_to_next_interface_descriptor:
 280         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 281             USB_DT_INTERFACE, NULL);
 282         return buffer - buffer0 + i;
 283 }
 284
 285 static int usb_parse_configuration(struct device *ddev, int cfgidx,
 286     struct usb_host_config *config, unsigned char *buffer, int size)
 287 {
 288         unsigned char *buffer0 = buffer;
 289         int cfgno;
 290         int nintf, nintf_orig;
 291         int i, j, n;
 292         struct usb_interface_cache *intfc;
 293         unsigned char *buffer2;
 294         int size2;
 295         struct usb_descriptor_header *header;
 296         int len, retval;
 297         u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];
 298
 299         memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
 300         if (config->desc.bDescriptorType != USB_DT_CONFIG ||
 301             config->desc.bLength < USB_DT_CONFIG_SIZE) {
 302                 dev_err(ddev, "invalid descriptor for config index %d: "
 303                     "type = 0x%X, length = %d\n", cfgidx,
 304                     config->desc.bDescriptorType, config->desc.bLength);
 305                 return -EINVAL;
 306         }
 307         cfgno = config->desc.bConfigurationValue;
 308
 309         buffer += config->desc.bLength;
 310         size -= config->desc.bLength;
 311
 312         nintf = nintf_orig = config->desc.bNumInterfaces;
 313         if (nintf > USB_MAXINTERFACES) {
 314                 dev_warn(ddev, "config %d has too many interfaces: %d, "
 315                     "using maximum allowed: %d\n",
 316                     cfgno, nintf, USB_MAXINTERFACES);
 317                 nintf = USB_MAXINTERFACES;
 318         }
 319
 320         /* Go through the descriptors, checking their length and counting the
 321          * number of altsettings for each interface */
 322         n = 0;
 323         for ((buffer2 = buffer, size2 = size);
 324               size2 > 0;
 325              (buffer2 += header->bLength, size2 -= header->bLength)) {
 326
 327                 if (size2 < sizeof(struct usb_descriptor_header)) {
 328                         dev_warn(ddev, "config %d descriptor has %d excess "
 329                             "byte%s, ignoring\n",
 330                             cfgno, size2, plural(size2));
 331                         break;
 332                 }
 333
 334                 header = (struct usb_descriptor_header *) buffer2;
 335                 if ((header->bLength > size2) || (header->bLength < 2)) {
 336                         dev_warn(ddev, "config %d has an invalid descriptor "
 337                             "of length %d, skipping remainder of the config\n",
 338                             cfgno, header->bLength);
 339                         break;
 340                 }
 341
 342                 if (header->bDescriptorType == USB_DT_INTERFACE) {
 343                         struct usb_interface_descriptor *d;
 344                         int inum;
 345
 346                         d = (struct usb_interface_descriptor *) header;
 347                         if (d->bLength < USB_DT_INTERFACE_SIZE) {
 348                                 dev_warn(ddev, "config %d has an invalid "
 349                                     "interface descriptor of length %d, "
 350                                     "skipping\n", cfgno, d->bLength);
 351                                 continue;
 352                         }
 353
 354                         inum = d->bInterfaceNumber;
 355                         if (inum >= nintf_orig)
 356                                 dev_warn(ddev, "config %d has an invalid "
 357                                     "interface number: %d but max is %d\n",
 358                                     cfgno, inum, nintf_orig - 1);
 359
 360                         /* Have we already encountered this interface?
 361                          * Count its altsettings */
 362                         for (i = 0; i < n; ++i) {
 363                                 if (inums[i] == inum)
 364                                         break;
 365                         }
 366                         if (i < n) {
 367                                 if (nalts[i] < 255)
 368                                         ++nalts[i];
 369                         } else if (n < USB_MAXINTERFACES) {
 370                                 inums[n] = inum;
 371                                 nalts[n] = 1;
 372                                 ++n;
 373                         }
 374
 375                 } else if (header->bDescriptorType == USB_DT_DEVICE ||
 376                             header->bDescriptorType == USB_DT_CONFIG)
 377                         dev_warn(ddev, "config %d contains an unexpected "
 378                             "descriptor of type 0x%X, skipping\n",
 379                             cfgno, header->bDescriptorType);
 380
 381         }       /* for ((buffer2 = buffer, size2 = size); ...) */
 382         size = buffer2 - buffer;
 383         config->desc.wTotalLength = cpu_to_le16(buffer2 - buffer0);
 384
 385         if (n != nintf)
 386                 dev_warn(ddev, "config %d has %d interface%s, different from "
 387                     "the descriptor's value: %d\n",
 388                     cfgno, n, plural(n), nintf_orig);
 389         else if (n == 0)
 390                 dev_warn(ddev, "config %d has no interfaces?\n", cfgno);
 391         config->desc.bNumInterfaces = nintf = n;
 392
 393         /* Check for missing interface numbers */
 394         for (i = 0; i < nintf; ++i) {
 395                 for (j = 0; j < nintf; ++j) {
 396                         if (inums[j] == i)
 397                                 break;
 398                 }
 399                 if (j >= nintf)
 400                         dev_warn(ddev, "config %d has no interface number "
 401                             "%d\n", cfgno, i);
 402         }
 403
 404         /* Allocate the usb_interface_caches and altsetting arrays */
 405         for (i = 0; i < nintf; ++i) {
 406                 j = nalts[i];
 407                 if (j > USB_MAXALTSETTING) {
 408                         dev_warn(ddev, "too many alternate settings for "
 409                             "config %d interface %d: %d, "
 410                             "using maximum allowed: %d\n",
 411                             cfgno, inums[i], j, USB_MAXALTSETTING);
 412                         nalts[i] = j = USB_MAXALTSETTING;
 413                 }
 414
 415                 len = sizeof(*intfc) + sizeof(struct usb_host_interface) * j;
 416                 config->intf_cache[i] = intfc = kzalloc(len, GFP_KERNEL);
 417                 if (!intfc)
 418                         return -ENOMEM;
 419                 kref_init(&intfc->ref);
 420         }
 421
 422         /* Skip over any Class Specific or Vendor Specific descriptors;
 423          * find the first interface descriptor */
 424         config->extra = buffer;
 425         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 426             USB_DT_INTERFACE, &n);
 427         config->extralen = i;
 428         if (n > 0)
 429                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 430                     n, plural(n), "configuration");
 431         buffer += i;
 432         size -= i;
 433
 434         /* Parse all the interface/altsetting descriptors */
 435         while (size > 0) {
 436                 retval = usb_parse_interface(ddev, cfgno, config,
 437                     buffer, size, inums, nalts);
 438                 if (retval < 0)
 439                         return retval;
 440
 441                 buffer += retval;
 442                 size -= retval;
 443         }
 444
 445         /* Check for missing altsettings */
 446         for (i = 0; i < nintf; ++i) {
 447                 intfc = config->intf_cache[i];
 448                 for (j = 0; j < intfc->num_altsetting; ++j) {
 449                         for (n = 0; n < intfc->num_altsetting; ++n) {
 450                                 if (intfc->altsetting[n].desc.
 451                                     bAlternateSetting == j)
 452                                         break;
 453                         }
 454                         if (n >= intfc->num_altsetting)
 455                                 dev_warn(ddev, "config %d interface %d has no "
 456                                     "altsetting %d\n", cfgno, inums[i], j);
 457                 }
 458         }
 459
 460         return 0;
 461 }
 462
 463 // hub-only!! ... and only exported for reset/reinit path.
 464 // otherwise used internally on disconnect/destroy path
 465 void usb_destroy_configuration(struct usb_device *dev)
 466 {
 467         int c, i;
 468
 469         if (!dev->config)
 470                 return;
 471
 472         if (dev->rawdescriptors) {
 473                 for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
 474                         kfree(dev->rawdescriptors[i]);
 475
 476                 kfree(dev->rawdescriptors);
 477                 dev->rawdescriptors = NULL;
 478         }
 479
 480         for (c = 0; c < dev->descriptor.bNumConfigurations; c++) {
 481                 struct usb_host_config *cf = &dev->config[c];
 482
 483                 kfree(cf->string);
 484                 for (i = 0; i < cf->desc.bNumInterfaces; i++) {
 485                         if (cf->intf_cache[i])
 486                                 kref_put(&cf->intf_cache[i]->ref,
 487                                           usb_release_interface_cache);
 488                 }
 489         }
 490         kfree(dev->config);
 491         dev->config = NULL;
 492 }
 493
 494
 495 // hub-only!! ... and only in reset path, or usb_new_device()
 496 // (used by real hubs and virtual root hubs)
 497 int usb_get_configuration(struct usb_device *dev)
 498 {
 499         struct device *ddev = &dev->dev;
 500         int ncfg = dev->descriptor.bNumConfigurations;
 501         int result = -ENOMEM;
 502         unsigned int cfgno, length;
 503         unsigned char *buffer;
 504         unsigned char *bigbuffer;
 505         struct usb_config_descriptor *desc;
 506
 507         if (ncfg > USB_MAXCONFIG) {
 508                 dev_warn(ddev, "too many configurations: %d, "
 509                     "using maximum allowed: %d\n", ncfg, USB_MAXCONFIG);
 510                 dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
 511         }
 512
 513         if (ncfg < 1) {
 514                 dev_err(ddev, "no configurations\n");
 515                 return -EINVAL;
 516         }
 517
 518         length = ncfg * sizeof(struct usb_host_config);
 519         dev->config = kzalloc(length, GFP_KERNEL);
 520         if (!dev->config)
 521                 goto err2;
 522
 523         length = ncfg * sizeof(char *);
 524         dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
 525         if (!dev->rawdescriptors)
 526                 goto err2;
 527
 528         buffer = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
 529         if (!buffer)
 530                 goto err2;
 531         desc = (struct usb_config_descriptor *)buffer;
 532
 533         for (cfgno = 0; cfgno < ncfg; cfgno++) {
 534                 /* We grab just the first descriptor so we know how long
 535                  * the whole configuration is */
 536                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 537                     buffer, USB_DT_CONFIG_SIZE);
 538                 if (result < 0) {
 539                         dev_err(ddev, "unable to read config index %d "
 540                             "descriptor/%s\n", cfgno, "start");
 541                         dev_err(ddev, "chopping to %d config(s)\n", cfgno);
 542                         dev->descriptor.bNumConfigurations = cfgno;
 543                         break;
 544                 } else if (result < 4) {
 545                         dev_err(ddev, "config index %d descriptor too short "
 546                             "(expected %i, got %i)\n", cfgno,
 547                             USB_DT_CONFIG_SIZE, result);
 548                         result = -EINVAL;
 549                         goto err;
 550                 }
 551                 length = max((int) le16_to_cpu(desc->wTotalLength),
 552                     USB_DT_CONFIG_SIZE);
 553
 554                 /* Now that we know the length, get the whole thing */
 555                 bigbuffer = kmalloc(length, GFP_KERNEL);
 556                 if (!bigbuffer) {
 557                         result = -ENOMEM;
 558                         goto err;
 559                 }
 560                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 561                     bigbuffer, length);
 562                 if (result < 0) {
 563                         dev_err(ddev, "unable to read config index %d "
 564                             "descriptor/%s\n", cfgno, "all");
 565                         kfree(bigbuffer);
 566                         goto err;
 567                 }
 568                 if (result < length) {
 569                         dev_warn(ddev, "config index %d descriptor too short "
 570                             "(expected %i, got %i)\n", cfgno, length, result);
 571                         length = result;
 572                 }
 573
 574                 dev->rawdescriptors[cfgno] = bigbuffer;
 575
 576                 result = usb_parse_configuration(&dev->dev, cfgno,
 577                     &dev->config[cfgno], bigbuffer, length);
 578                 if (result < 0) {
 579                         ++cfgno;
 580                         goto err;
 581                 }
 582         }
 583         result = 0;
 584
 585 err:
 586         kfree(buffer);
 587         dev->descriptor.bNumConfigurations = cfgno;
 588 err2:
 589         if (result == -ENOMEM)
 590                 dev_err(ddev, "out of memory\n");
 591         return result;
 592 }