drivers/usb/core/config.c

   1 #include <linux/usb.h>
   2 #include <linux/usb/ch9.h>
   3 #include <linux/usb/hcd.h>
   4 #include <linux/usb/quirks.h>
   5 #include <linux/module.h>
   6 #include <linux/init.h>
   7 #include <linux/slab.h>
   8 #include <linux/device.h>
   9 #include <asm/byteorder.h>
  10 #include "usb.h"
  11
  12
  13 #define USB_MAXALTSETTING               128     /* Hard limit */
  14 #define USB_MAXENDPOINTS                30      /* Hard limit */
  15
  16 #define USB_MAXCONFIG                   8       /* Arbitrary limit */
  17
  18
  19 static inline const char *plural(int n)
  20 {
  21         return (n == 1 ? "" : "s");
  22 }
  23
  24 static int find_next_descriptor(unsigned char *buffer, int size,
  25     int dt1, int dt2, int *num_skipped)
  26 {
  27         struct usb_descriptor_header *h;
  28         int n = 0;
  29         unsigned char *buffer0 = buffer;
  30
  31         /* Find the next descriptor of type dt1 or dt2 */
  32         while (size > 0) {
  33                 h = (struct usb_descriptor_header *) buffer;
  34                 if (h->bDescriptorType == dt1 || h->bDescriptorType == dt2)
  35                         break;
  36                 buffer += h->bLength;
  37                 size -= h->bLength;
  38                 ++n;
  39         }
  40
  41         /* Store the number of descriptors skipped and return the
  42          * number of bytes skipped */
  43         if (num_skipped)
  44                 *num_skipped = n;
  45         return buffer - buffer0;
  46 }
  47
  48 static void usb_parse_ss_endpoint_companion(struct device *ddev, int cfgno,
  49                 int inum, int asnum, struct usb_host_endpoint *ep,
  50                 unsigned char *buffer, int size)
  51 {
  52         struct usb_ss_ep_comp_descriptor *desc;
  53         int max_tx;
  54
  55         /* The SuperSpeed endpoint companion descriptor is supposed to
  56          * be the first thing immediately following the endpoint descriptor.
  57          */
  58         desc = (struct usb_ss_ep_comp_descriptor *) buffer;
  59         if (desc->bDescriptorType != USB_DT_SS_ENDPOINT_COMP ||
  60                         size < USB_DT_SS_EP_COMP_SIZE) {
  61                 dev_warn(ddev, "No SuperSpeed endpoint companion for config %d "
  62                                 " interface %d altsetting %d ep %d: "
  63                                 "using minimum values\n",
  64                                 cfgno, inum, asnum, ep->desc.bEndpointAddress);
  65
  66                 /* Fill in some default values.
  67                  * Leave bmAttributes as zero, which will mean no streams for
  68                  * bulk, and isoc won't support multiple bursts of packets.
  69                  * With bursts of only one packet, and a Mult of 1, the max
  70                  * amount of data moved per endpoint service interval is one
  71                  * packet.
  72                  */
  73                 ep->ss_ep_comp.bLength = USB_DT_SS_EP_COMP_SIZE;
  74                 ep->ss_ep_comp.bDescriptorType = USB_DT_SS_ENDPOINT_COMP;
  75                 if (usb_endpoint_xfer_isoc(&ep->desc) ||
  76                                 usb_endpoint_xfer_int(&ep->desc))
  77                         ep->ss_ep_comp.wBytesPerInterval =
  78                                         ep->desc.wMaxPacketSize;
  79                 return;
  80         }
  81
  82         memcpy(&ep->ss_ep_comp, desc, USB_DT_SS_EP_COMP_SIZE);
  83
  84         /* Check the various values */
  85         if (usb_endpoint_xfer_control(&ep->desc) && desc->bMaxBurst != 0) {
  86                 dev_warn(ddev, "Control endpoint with bMaxBurst = %d in "
  87                                 "config %d interface %d altsetting %d ep %d: "
  88                                 "setting to zero\n", desc->bMaxBurst,
  89                                 cfgno, inum, asnum, ep->desc.bEndpointAddress);
  90                 ep->ss_ep_comp.bMaxBurst = 0;
  91         } else if (desc->bMaxBurst > 15) {
  92                 dev_warn(ddev, "Endpoint with bMaxBurst = %d in "
  93                                 "config %d interface %d altsetting %d ep %d: "
  94                                 "setting to 15\n", desc->bMaxBurst,
  95                                 cfgno, inum, asnum, ep->desc.bEndpointAddress);
  96                 ep->ss_ep_comp.bMaxBurst = 15;
  97         }
  98
  99         if ((usb_endpoint_xfer_control(&ep->desc) ||
 100                         usb_endpoint_xfer_int(&ep->desc)) &&
 101                                 desc->bmAttributes != 0) {
 102                 dev_warn(ddev, "%s endpoint with bmAttributes = %d in "
 103                                 "config %d interface %d altsetting %d ep %d: "
 104                                 "setting to zero\n",
 105                                 usb_endpoint_xfer_control(&ep->desc) ? "Control" : "Bulk",
 106                                 desc->bmAttributes,
 107                                 cfgno, inum, asnum, ep->desc.bEndpointAddress);
 108                 ep->ss_ep_comp.bmAttributes = 0;
 109         } else if (usb_endpoint_xfer_bulk(&ep->desc) &&
 110                         desc->bmAttributes > 16) {
 111                 dev_warn(ddev, "Bulk endpoint with more than 65536 streams in "
 112                                 "config %d interface %d altsetting %d ep %d: "
 113                                 "setting to max\n",
 114                                 cfgno, inum, asnum, ep->desc.bEndpointAddress);
 115                 ep->ss_ep_comp.bmAttributes = 16;
 116         } else if (usb_endpoint_xfer_isoc(&ep->desc) &&
 117                         desc->bmAttributes > 2) {
 118                 dev_warn(ddev, "Isoc endpoint has Mult of %d in "
 119                                 "config %d interface %d altsetting %d ep %d: "
 120                                 "setting to 3\n", desc->bmAttributes + 1,
 121                                 cfgno, inum, asnum, ep->desc.bEndpointAddress);
 122                 ep->ss_ep_comp.bmAttributes = 2;
 123         }
 124
 125         if (usb_endpoint_xfer_isoc(&ep->desc))
 126                 max_tx = ep->desc.wMaxPacketSize * (desc->bMaxBurst + 1) *
 127                         (desc->bmAttributes + 1);
 128         else if (usb_endpoint_xfer_int(&ep->desc))
 129                 max_tx = ep->desc.wMaxPacketSize * (desc->bMaxBurst + 1);
 130         else
 131                 max_tx = 999999;
 132         if (desc->wBytesPerInterval > max_tx) {
 133                 dev_warn(ddev, "%s endpoint with wBytesPerInterval of %d in "
 134                                 "config %d interface %d altsetting %d ep %d: "
 135                                 "setting to %d\n",
 136                                 usb_endpoint_xfer_isoc(&ep->desc) ? "Isoc" : "Int",
 137                                 desc->wBytesPerInterval,
 138                                 cfgno, inum, asnum, ep->desc.bEndpointAddress,
 139                                 max_tx);
 140                 ep->ss_ep_comp.wBytesPerInterval = max_tx;
 141         }
 142 }
 143
 144 static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
 145     int asnum, struct usb_host_interface *ifp, int num_ep,
 146     unsigned char *buffer, int size)
 147 {
 148         unsigned char *buffer0 = buffer;
 149         struct usb_endpoint_descriptor *d;
 150         struct usb_host_endpoint *endpoint;
 151         int n, i, j, retval;
 152
 153         d = (struct usb_endpoint_descriptor *) buffer;
 154         buffer += d->bLength;
 155         size -= d->bLength;
 156
 157         if (d->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE)
 158                 n = USB_DT_ENDPOINT_AUDIO_SIZE;
 159         else if (d->bLength >= USB_DT_ENDPOINT_SIZE)
 160                 n = USB_DT_ENDPOINT_SIZE;
 161         else {
 162                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
 163                     "invalid endpoint descriptor of length %d, skipping\n",
 164                     cfgno, inum, asnum, d->bLength);
 165                 goto skip_to_next_endpoint_or_interface_descriptor;
 166         }
 167
 168         i = d->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
 169         if (i >= 16 || i == 0) {
 170                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
 171                     "invalid endpoint with address 0x%X, skipping\n",
 172                     cfgno, inum, asnum, d->bEndpointAddress);
 173                 goto skip_to_next_endpoint_or_interface_descriptor;
 174         }
 175
 176         /* Only store as many endpoints as we have room for */
 177         if (ifp->desc.bNumEndpoints >= num_ep)
 178                 goto skip_to_next_endpoint_or_interface_descriptor;
 179
 180         endpoint = &ifp->endpoint[ifp->desc.bNumEndpoints];
 181         ++ifp->desc.bNumEndpoints;
 182
 183         memcpy(&endpoint->desc, d, n);
 184         INIT_LIST_HEAD(&endpoint->urb_list);
 185
 186         /* Fix up bInterval values outside the legal range. Use 32 ms if no
 187          * proper value can be guessed. */
 188         i = 0;          /* i = min, j = max, n = default */
 189         j = 255;
 190         if (usb_endpoint_xfer_int(d)) {
 191                 i = 1;
 192                 switch (to_usb_device(ddev)->speed) {
 193                 case USB_SPEED_SUPER:
 194                 case USB_SPEED_HIGH:
 195                         /* Many device manufacturers are using full-speed
 196                          * bInterval values in high-speed interrupt endpoint
 197                          * descriptors. Try to fix those and fall back to a
 198                          * 32 ms default value otherwise. */
 199                         n = fls(d->bInterval*8);
 200                         if (n == 0)
 201                                 n = 9;  /* 32 ms = 2^(9-1) uframes */
 202                         j = 16;
 203                         break;
 204                 default:                /* USB_SPEED_FULL or _LOW */
 205                         /* For low-speed, 10 ms is the official minimum.
 206                          * But some "overclocked" devices might want faster
 207                          * polling so we'll allow it. */
 208                         n = 32;
 209                         break;
 210                 }
 211         } else if (usb_endpoint_xfer_isoc(d)) {
 212                 i = 1;
 213                 j = 16;
 214                 switch (to_usb_device(ddev)->speed) {
 215                 case USB_SPEED_HIGH:
 216                         n = 9;          /* 32 ms = 2^(9-1) uframes */
 217                         break;
 218                 default:                /* USB_SPEED_FULL */
 219                         n = 6;          /* 32 ms = 2^(6-1) frames */
 220                         break;
 221                 }
 222         }
 223         if (d->bInterval < i || d->bInterval > j) {
 224                 dev_warn(ddev, "config %d interface %d altsetting %d "
 225                     "endpoint 0x%X has an invalid bInterval %d, "
 226                     "changing to %d\n",
 227                     cfgno, inum, asnum,
 228                     d->bEndpointAddress, d->bInterval, n);
 229                 endpoint->desc.bInterval = n;
 230         }
 231
 232         /* Some buggy low-speed devices have Bulk endpoints, which is
 233          * explicitly forbidden by the USB spec.  In an attempt to make
 234          * them usable, we will try treating them as Interrupt endpoints.
 235          */
 236         if (to_usb_device(ddev)->speed == USB_SPEED_LOW &&
 237                         usb_endpoint_xfer_bulk(d)) {
 238                 dev_warn(ddev, "config %d interface %d altsetting %d "
 239                     "endpoint 0x%X is Bulk; changing to Interrupt\n",
 240                     cfgno, inum, asnum, d->bEndpointAddress);
 241                 endpoint->desc.bmAttributes = USB_ENDPOINT_XFER_INT;
 242                 endpoint->desc.bInterval = 1;
 243                 if (le16_to_cpu(endpoint->desc.wMaxPacketSize) > 8)
 244                         endpoint->desc.wMaxPacketSize = cpu_to_le16(8);
 245         }
 246
 247         /*
 248          * Some buggy high speed devices have bulk endpoints using
 249          * maxpacket sizes other than 512.  High speed HCDs may not
 250          * be able to handle that particular bug, so let's warn...
 251          */
 252         if (to_usb_device(ddev)->speed == USB_SPEED_HIGH
 253                         && usb_endpoint_xfer_bulk(d)) {
 254                 unsigned maxp;
 255
 256                 maxp = le16_to_cpu(endpoint->desc.wMaxPacketSize) & 0x07ff;
 257                 if (maxp != 512)
 258                         dev_warn(ddev, "config %d interface %d altsetting %d "
 259                                 "bulk endpoint 0x%X has invalid maxpacket %d\n",
 260                                 cfgno, inum, asnum, d->bEndpointAddress,
 261                                 maxp);
 262         }
 263
 264         /* Parse a possible SuperSpeed endpoint companion descriptor */
 265         if (to_usb_device(ddev)->speed == USB_SPEED_SUPER)
 266                 usb_parse_ss_endpoint_companion(ddev, cfgno,
 267                                 inum, asnum, endpoint, buffer, size);
 268
 269         /* Skip over any Class Specific or Vendor Specific descriptors;
 270          * find the next endpoint or interface descriptor */
 271         endpoint->extra = buffer;
 272         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 273                         USB_DT_INTERFACE, &n);
 274         endpoint->extralen = i;
 275         retval = buffer - buffer0 + i;
 276         if (n > 0)
 277                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 278                     n, plural(n), "endpoint");
 279         return retval;
 280
 281 skip_to_next_endpoint_or_interface_descriptor:
 282         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 283             USB_DT_INTERFACE, NULL);
 284         return buffer - buffer0 + i;
 285 }
 286
 287 void usb_release_interface_cache(struct kref *ref)
 288 {
 289         struct usb_interface_cache *intfc = ref_to_usb_interface_cache(ref);
 290         int j;
 291
 292         for (j = 0; j < intfc->num_altsetting; j++) {
 293                 struct usb_host_interface *alt = &intfc->altsetting[j];
 294
 295                 kfree(alt->endpoint);
 296                 kfree(alt->string);
 297         }
 298         kfree(intfc);
 299 }
 300
 301 static int usb_parse_interface(struct device *ddev, int cfgno,
 302     struct usb_host_config *config, unsigned char *buffer, int size,
 303     u8 inums[], u8 nalts[])
 304 {
 305         unsigned char *buffer0 = buffer;
 306         struct usb_interface_descriptor *d;
 307         int inum, asnum;
 308         struct usb_interface_cache *intfc;
 309         struct usb_host_interface *alt;
 310         int i, n;
 311         int len, retval;
 312         int num_ep, num_ep_orig;
 313
 314         d = (struct usb_interface_descriptor *) buffer;
 315         buffer += d->bLength;
 316         size -= d->bLength;
 317
 318         if (d->bLength < USB_DT_INTERFACE_SIZE)
 319                 goto skip_to_next_interface_descriptor;
 320
 321         /* Which interface entry is this? */
 322         intfc = NULL;
 323         inum = d->bInterfaceNumber;
 324         for (i = 0; i < config->desc.bNumInterfaces; ++i) {
 325                 if (inums[i] == inum) {
 326                         intfc = config->intf_cache[i];
 327                         break;
 328                 }
 329         }
 330         if (!intfc || intfc->num_altsetting >= nalts[i])
 331                 goto skip_to_next_interface_descriptor;
 332
 333         /* Check for duplicate altsetting entries */
 334         asnum = d->bAlternateSetting;
 335         for ((i = 0, alt = &intfc->altsetting[0]);
 336               i < intfc->num_altsetting;
 337              (++i, ++alt)) {
 338                 if (alt->desc.bAlternateSetting == asnum) {
 339                         dev_warn(ddev, "Duplicate descriptor for config %d "
 340                             "interface %d altsetting %d, skipping\n",
 341                             cfgno, inum, asnum);
 342                         goto skip_to_next_interface_descriptor;
 343                 }
 344         }
 345
 346         ++intfc->num_altsetting;
 347         memcpy(&alt->desc, d, USB_DT_INTERFACE_SIZE);
 348
 349         /* Skip over any Class Specific or Vendor Specific descriptors;
 350          * find the first endpoint or interface descriptor */
 351         alt->extra = buffer;
 352         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 353             USB_DT_INTERFACE, &n);
 354         alt->extralen = i;
 355         if (n > 0)
 356                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 357                     n, plural(n), "interface");
 358         buffer += i;
 359         size -= i;
 360
 361         /* Allocate space for the right(?) number of endpoints */
 362         num_ep = num_ep_orig = alt->desc.bNumEndpoints;
 363         alt->desc.bNumEndpoints = 0;            /* Use as a counter */
 364         if (num_ep > USB_MAXENDPOINTS) {
 365                 dev_warn(ddev, "too many endpoints for config %d interface %d "
 366                     "altsetting %d: %d, using maximum allowed: %d\n",
 367                     cfgno, inum, asnum, num_ep, USB_MAXENDPOINTS);
 368                 num_ep = USB_MAXENDPOINTS;
 369         }
 370
 371         if (num_ep > 0) {
 372                 /* Can't allocate 0 bytes */
 373                 len = sizeof(struct usb_host_endpoint) * num_ep;
 374                 alt->endpoint = kzalloc(len, GFP_KERNEL);
 375                 if (!alt->endpoint)
 376                         return -ENOMEM;
 377         }
 378
 379         /* Parse all the endpoint descriptors */
 380         n = 0;
 381         while (size > 0) {
 382                 if (((struct usb_descriptor_header *) buffer)->bDescriptorType
 383                      == USB_DT_INTERFACE)
 384                         break;
 385                 retval = usb_parse_endpoint(ddev, cfgno, inum, asnum, alt,
 386                     num_ep, buffer, size);
 387                 if (retval < 0)
 388                         return retval;
 389                 ++n;
 390
 391                 buffer += retval;
 392                 size -= retval;
 393         }
 394
 395         if (n != num_ep_orig)
 396                 dev_warn(ddev, "config %d interface %d altsetting %d has %d "
 397                     "endpoint descriptor%s, different from the interface "
 398                     "descriptor's value: %d\n",
 399                     cfgno, inum, asnum, n, plural(n), num_ep_orig);
 400         return buffer - buffer0;
 401
 402 skip_to_next_interface_descriptor:
 403         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 404             USB_DT_INTERFACE, NULL);
 405         return buffer - buffer0 + i;
 406 }
 407
 408 static int usb_parse_configuration(struct usb_device *dev, int cfgidx,
 409     struct usb_host_config *config, unsigned char *buffer, int size)
 410 {
 411         struct device *ddev = &dev->dev;
 412         unsigned char *buffer0 = buffer;
 413         int cfgno;
 414         int nintf, nintf_orig;
 415         int i, j, n;
 416         struct usb_interface_cache *intfc;
 417         unsigned char *buffer2;
 418         int size2;
 419         struct usb_descriptor_header *header;
 420         int len, retval;
 421         u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];
 422         unsigned iad_num = 0;
 423
 424         memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
 425         if (config->desc.bDescriptorType != USB_DT_CONFIG ||
 426             config->desc.bLength < USB_DT_CONFIG_SIZE) {
 427                 dev_err(ddev, "invalid descriptor for config index %d: "
 428                     "type = 0x%X, length = %d\n", cfgidx,
 429                     config->desc.bDescriptorType, config->desc.bLength);
 430                 return -EINVAL;
 431         }
 432         cfgno = config->desc.bConfigurationValue;
 433
 434         buffer += config->desc.bLength;
 435         size -= config->desc.bLength;
 436
 437         nintf = nintf_orig = config->desc.bNumInterfaces;
 438         if (nintf > USB_MAXINTERFACES) {
 439                 dev_warn(ddev, "config %d has too many interfaces: %d, "
 440                     "using maximum allowed: %d\n",
 441                     cfgno, nintf, USB_MAXINTERFACES);
 442                 nintf = USB_MAXINTERFACES;
 443         }
 444
 445         /* Go through the descriptors, checking their length and counting the
 446          * number of altsettings for each interface */
 447         n = 0;
 448         for ((buffer2 = buffer, size2 = size);
 449               size2 > 0;
 450              (buffer2 += header->bLength, size2 -= header->bLength)) {
 451
 452                 if (size2 < sizeof(struct usb_descriptor_header)) {
 453                         dev_warn(ddev, "config %d descriptor has %d excess "
 454                             "byte%s, ignoring\n",
 455                             cfgno, size2, plural(size2));
 456                         break;
 457                 }
 458
 459                 header = (struct usb_descriptor_header *) buffer2;
 460                 if ((header->bLength > size2) || (header->bLength < 2)) {
 461                         dev_warn(ddev, "config %d has an invalid descriptor "
 462                             "of length %d, skipping remainder of the config\n",
 463                             cfgno, header->bLength);
 464                         break;
 465                 }
 466
 467                 if (header->bDescriptorType == USB_DT_INTERFACE) {
 468                         struct usb_interface_descriptor *d;
 469                         int inum;
 470
 471                         d = (struct usb_interface_descriptor *) header;
 472                         if (d->bLength < USB_DT_INTERFACE_SIZE) {
 473                                 dev_warn(ddev, "config %d has an invalid "
 474                                     "interface descriptor of length %d, "
 475                                     "skipping\n", cfgno, d->bLength);
 476                                 continue;
 477                         }
 478
 479                         inum = d->bInterfaceNumber;
 480
 481                         if ((dev->quirks & USB_QUIRK_HONOR_BNUMINTERFACES) &&
 482                             n >= nintf_orig) {
 483                                 dev_warn(ddev, "config %d has more interface "
 484                                     "descriptors, than it declares in "
 485                                     "bNumInterfaces, ignoring interface "
 486                                     "number: %d\n", cfgno, inum);
 487                                 continue;
 488                         }
 489
 490                         if (inum >= nintf_orig)
 491                                 dev_warn(ddev, "config %d has an invalid "
 492                                     "interface number: %d but max is %d\n",
 493                                     cfgno, inum, nintf_orig - 1);
 494
 495                         /* Have we already encountered this interface?
 496                          * Count its altsettings */
 497                         for (i = 0; i < n; ++i) {
 498                                 if (inums[i] == inum)
 499                                         break;
 500                         }
 501                         if (i < n) {
 502                                 if (nalts[i] < 255)
 503                                         ++nalts[i];
 504                         } else if (n < USB_MAXINTERFACES) {
 505                                 inums[n] = inum;
 506                                 nalts[n] = 1;
 507                                 ++n;
 508                         }
 509
 510                 } else if (header->bDescriptorType ==
 511                                 USB_DT_INTERFACE_ASSOCIATION) {
 512                         if (iad_num == USB_MAXIADS) {
 513                                 dev_warn(ddev, "found more Interface "
 514                                                "Association Descriptors "
 515                                                "than allocated for in "
 516                                                "configuration %d\n", cfgno);
 517                         } else {
 518                                 config->intf_assoc[iad_num] =
 519                                         (struct usb_interface_assoc_descriptor
 520                                         *)header;
 521                                 iad_num++;
 522                         }
 523
 524                 } else if (header->bDescriptorType == USB_DT_DEVICE ||
 525                             header->bDescriptorType == USB_DT_CONFIG)
 526                         dev_warn(ddev, "config %d contains an unexpected "
 527                             "descriptor of type 0x%X, skipping\n",
 528                             cfgno, header->bDescriptorType);
 529
 530         }       /* for ((buffer2 = buffer, size2 = size); ...) */
 531         size = buffer2 - buffer;
 532         config->desc.wTotalLength = cpu_to_le16(buffer2 - buffer0);
 533
 534         if (n != nintf)
 535                 dev_warn(ddev, "config %d has %d interface%s, different from "
 536                     "the descriptor's value: %d\n",
 537                     cfgno, n, plural(n), nintf_orig);
 538         else if (n == 0)
 539                 dev_warn(ddev, "config %d has no interfaces?\n", cfgno);
 540         config->desc.bNumInterfaces = nintf = n;
 541
 542         /* Check for missing interface numbers */
 543         for (i = 0; i < nintf; ++i) {
 544                 for (j = 0; j < nintf; ++j) {
 545                         if (inums[j] == i)
 546                                 break;
 547                 }
 548                 if (j >= nintf)
 549                         dev_warn(ddev, "config %d has no interface number "
 550                             "%d\n", cfgno, i);
 551         }
 552
 553         /* Allocate the usb_interface_caches and altsetting arrays */
 554         for (i = 0; i < nintf; ++i) {
 555                 j = nalts[i];
 556                 if (j > USB_MAXALTSETTING) {
 557                         dev_warn(ddev, "too many alternate settings for "
 558                             "config %d interface %d: %d, "
 559                             "using maximum allowed: %d\n",
 560                             cfgno, inums[i], j, USB_MAXALTSETTING);
 561                         nalts[i] = j = USB_MAXALTSETTING;
 562                 }
 563
 564                 len = sizeof(*intfc) + sizeof(struct usb_host_interface) * j;
 565                 config->intf_cache[i] = intfc = kzalloc(len, GFP_KERNEL);
 566                 if (!intfc)
 567                         return -ENOMEM;
 568                 kref_init(&intfc->ref);
 569         }
 570
 571         /* FIXME: parse the BOS descriptor */
 572
 573         /* Skip over any Class Specific or Vendor Specific descriptors;
 574          * find the first interface descriptor */
 575         config->extra = buffer;
 576         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 577             USB_DT_INTERFACE, &n);
 578         config->extralen = i;
 579         if (n > 0)
 580                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 581                     n, plural(n), "configuration");
 582         buffer += i;
 583         size -= i;
 584
 585         /* Parse all the interface/altsetting descriptors */
 586         while (size > 0) {
 587                 retval = usb_parse_interface(ddev, cfgno, config,
 588                     buffer, size, inums, nalts);
 589                 if (retval < 0)
 590                         return retval;
 591
 592                 buffer += retval;
 593                 size -= retval;
 594         }
 595
 596         /* Check for missing altsettings */
 597         for (i = 0; i < nintf; ++i) {
 598                 intfc = config->intf_cache[i];
 599                 for (j = 0; j < intfc->num_altsetting; ++j) {
 600                         for (n = 0; n < intfc->num_altsetting; ++n) {
 601                                 if (intfc->altsetting[n].desc.
 602                                     bAlternateSetting == j)
 603                                         break;
 604                         }
 605                         if (n >= intfc->num_altsetting)
 606                                 dev_warn(ddev, "config %d interface %d has no "
 607                                     "altsetting %d\n", cfgno, inums[i], j);
 608                 }
 609         }
 610
 611         return 0;
 612 }
 613
 614 /* hub-only!! ... and only exported for reset/reinit path.
 615  * otherwise used internally on disconnect/destroy path
 616  */
 617 void usb_destroy_configuration(struct usb_device *dev)
 618 {
 619         int c, i;
 620
 621         if (!dev->config)
 622                 return;
 623
 624         if (dev->rawdescriptors) {
 625                 for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
 626                         kfree(dev->rawdescriptors[i]);
 627
 628                 kfree(dev->rawdescriptors);
 629                 dev->rawdescriptors = NULL;
 630         }
 631
 632         for (c = 0; c < dev->descriptor.bNumConfigurations; c++) {
 633                 struct usb_host_config *cf = &dev->config[c];
 634
 635                 kfree(cf->string);
 636                 for (i = 0; i < cf->desc.bNumInterfaces; i++) {
 637                         if (cf->intf_cache[i])
 638                                 kref_put(&cf->intf_cache[i]->ref,
 639                                           usb_release_interface_cache);
 640                 }
 641         }
 642         kfree(dev->config);
 643         dev->config = NULL;
 644 }
 645
 646
 647 /*
 648  * Get the USB config descriptors, cache and parse'em
 649  *
 650  * hub-only!! ... and only in reset path, or usb_new_device()
 651  * (used by real hubs and virtual root hubs)
 652  *
 653  * NOTE: if this is a WUSB device and is not authorized, we skip the
 654  *       whole thing. A non-authorized USB device has no
 655  *       configurations.
 656  */
 657 int usb_get_configuration(struct usb_device *dev)
 658 {
 659         struct device *ddev = &dev->dev;
 660         int ncfg = dev->descriptor.bNumConfigurations;
 661         int result = 0;
 662         unsigned int cfgno, length;
 663         unsigned char *bigbuffer;
 664         struct usb_config_descriptor *desc;
 665
 666         cfgno = 0;
 667         if (dev->authorized == 0)       /* Not really an error */
 668                 goto out_not_authorized;
 669         result = -ENOMEM;
 670         if (ncfg > USB_MAXCONFIG) {
 671                 dev_warn(ddev, "too many configurations: %d, "
 672                     "using maximum allowed: %d\n", ncfg, USB_MAXCONFIG);
 673                 dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
 674         }
 675
 676         if (ncfg < 1) {
 677                 dev_err(ddev, "no configurations\n");
 678                 return -EINVAL;
 679         }
 680
 681         length = ncfg * sizeof(struct usb_host_config);
 682         dev->config = kzalloc(length, GFP_KERNEL);
 683         if (!dev->config)
 684                 goto err2;
 685
 686         length = ncfg * sizeof(char *);
 687         dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
 688         if (!dev->rawdescriptors)
 689                 goto err2;
 690
 691         desc = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
 692         if (!desc)
 693                 goto err2;
 694
 695         result = 0;
 696         for (; cfgno < ncfg; cfgno++) {
 697                 /* We grab just the first descriptor so we know how long
 698                  * the whole configuration is */
 699                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 700                     desc, USB_DT_CONFIG_SIZE);
 701                 if (result < 0) {
 702                         dev_err(ddev, "unable to read config index %d "
 703                             "descriptor/%s: %d\n", cfgno, "start", result);
 704                         dev_err(ddev, "chopping to %d config(s)\n", cfgno);
 705                         dev->descriptor.bNumConfigurations = cfgno;
 706                         break;
 707                 } else if (result < 4) {
 708                         dev_err(ddev, "config index %d descriptor too short "
 709                             "(expected %i, got %i)\n", cfgno,
 710                             USB_DT_CONFIG_SIZE, result);
 711                         result = -EINVAL;
 712                         goto err;
 713                 }
 714                 length = max((int) le16_to_cpu(desc->wTotalLength),
 715                     USB_DT_CONFIG_SIZE);
 716
 717                 /* Now that we know the length, get the whole thing */
 718                 bigbuffer = kmalloc(length, GFP_KERNEL);
 719                 if (!bigbuffer) {
 720                         result = -ENOMEM;
 721                         goto err;
 722                 }
 723                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 724                     bigbuffer, length);
 725                 if (result < 0) {
 726                         dev_err(ddev, "unable to read config index %d "
 727                             "descriptor/%s\n", cfgno, "all");
 728                         kfree(bigbuffer);
 729                         goto err;
 730                 }
 731                 if (result < length) {
 732                         dev_warn(ddev, "config index %d descriptor too short "
 733                             "(expected %i, got %i)\n", cfgno, length, result);
 734                         length = result;
 735                 }
 736
 737                 dev->rawdescriptors[cfgno] = bigbuffer;
 738
 739                 result = usb_parse_configuration(dev, cfgno,
 740                     &dev->config[cfgno], bigbuffer, length);
 741                 if (result < 0) {
 742                         ++cfgno;
 743                         goto err;
 744                 }
 745         }
 746         result = 0;
 747
 748 err:
 749         kfree(desc);
 750 out_not_authorized:
 751         dev->descriptor.bNumConfigurations = cfgno;
 752 err2:
 753         if (result == -ENOMEM)
 754                 dev_err(ddev, "out of memory\n");
 755         return result;
 756 }