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 = (desc->bMaxBurst + 1) * (desc->bmAttributes + 1) *
 127                         usb_endpoint_maxp(&ep->desc);
 128         else if (usb_endpoint_xfer_int(&ep->desc))
 129                 max_tx = usb_endpoint_maxp(&ep->desc) *
 130                         (desc->bMaxBurst + 1);
 131         else
 132                 max_tx = 999999;
 133         if (le16_to_cpu(desc->wBytesPerInterval) > max_tx) {
 134                 dev_warn(ddev, "%s endpoint with wBytesPerInterval of %d in "
 135                                 "config %d interface %d altsetting %d ep %d: "
 136                                 "setting to %d\n",
 137                                 usb_endpoint_xfer_isoc(&ep->desc) ? "Isoc" : "Int",
 138                                 le16_to_cpu(desc->wBytesPerInterval),
 139                                 cfgno, inum, asnum, ep->desc.bEndpointAddress,
 140                                 max_tx);
 141                 ep->ss_ep_comp.wBytesPerInterval = cpu_to_le16(max_tx);
 142         }
 143 }
 144
 145 static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
 146     int asnum, struct usb_host_interface *ifp, int num_ep,
 147     unsigned char *buffer, int size)
 148 {
 149         unsigned char *buffer0 = buffer;
 150         struct usb_endpoint_descriptor *d;
 151         struct usb_host_endpoint *endpoint;
 152         int n, i, j, retval;
 153
 154         d = (struct usb_endpoint_descriptor *) buffer;
 155         buffer += d->bLength;
 156         size -= d->bLength;
 157
 158         if (d->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE)
 159                 n = USB_DT_ENDPOINT_AUDIO_SIZE;
 160         else if (d->bLength >= USB_DT_ENDPOINT_SIZE)
 161                 n = USB_DT_ENDPOINT_SIZE;
 162         else {
 163                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
 164                     "invalid endpoint descriptor of length %d, skipping\n",
 165                     cfgno, inum, asnum, d->bLength);
 166                 goto skip_to_next_endpoint_or_interface_descriptor;
 167         }
 168
 169         i = d->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
 170         if (i >= 16 || i == 0) {
 171                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
 172                     "invalid endpoint with address 0x%X, skipping\n",
 173                     cfgno, inum, asnum, d->bEndpointAddress);
 174                 goto skip_to_next_endpoint_or_interface_descriptor;
 175         }
 176
 177         /* Only store as many endpoints as we have room for */
 178         if (ifp->desc.bNumEndpoints >= num_ep)
 179                 goto skip_to_next_endpoint_or_interface_descriptor;
 180
 181         endpoint = &ifp->endpoint[ifp->desc.bNumEndpoints];
 182         ++ifp->desc.bNumEndpoints;
 183
 184         memcpy(&endpoint->desc, d, n);
 185         INIT_LIST_HEAD(&endpoint->urb_list);
 186
 187         /* Fix up bInterval values outside the legal range. Use 32 ms if no
 188          * proper value can be guessed. */
 189         i = 0;          /* i = min, j = max, n = default */
 190         j = 255;
 191         if (usb_endpoint_xfer_int(d)) {
 192                 i = 1;
 193                 switch (to_usb_device(ddev)->speed) {
 194                 case USB_SPEED_SUPER:
 195                 case USB_SPEED_HIGH:
 196                         /* Many device manufacturers are using full-speed
 197                          * bInterval values in high-speed interrupt endpoint
 198                          * descriptors. Try to fix those and fall back to a
 199                          * 32 ms default value otherwise. */
 200                         n = fls(d->bInterval*8);
 201                         if (n == 0)
 202                                 n = 9;  /* 32 ms = 2^(9-1) uframes */
 203                         j = 16;
 204                         break;
 205                 default:                /* USB_SPEED_FULL or _LOW */
 206                         /* For low-speed, 10 ms is the official minimum.
 207                          * But some "overclocked" devices might want faster
 208                          * polling so we'll allow it. */
 209                         n = 32;
 210                         break;
 211                 }
 212         } else if (usb_endpoint_xfer_isoc(d)) {
 213                 i = 1;
 214                 j = 16;
 215                 switch (to_usb_device(ddev)->speed) {
 216                 case USB_SPEED_HIGH:
 217                         n = 9;          /* 32 ms = 2^(9-1) uframes */
 218                         break;
 219                 default:                /* USB_SPEED_FULL */
 220                         n = 6;          /* 32 ms = 2^(6-1) frames */
 221                         break;
 222                 }
 223         }
 224         if (d->bInterval < i || d->bInterval > j) {
 225                 dev_warn(ddev, "config %d interface %d altsetting %d "
 226                     "endpoint 0x%X has an invalid bInterval %d, "
 227                     "changing to %d\n",
 228                     cfgno, inum, asnum,
 229                     d->bEndpointAddress, d->bInterval, n);
 230                 endpoint->desc.bInterval = n;
 231         }
 232
 233         /* Some buggy low-speed devices have Bulk endpoints, which is
 234          * explicitly forbidden by the USB spec.  In an attempt to make
 235          * them usable, we will try treating them as Interrupt endpoints.
 236          */
 237         if (to_usb_device(ddev)->speed == USB_SPEED_LOW &&
 238                         usb_endpoint_xfer_bulk(d)) {
 239                 dev_warn(ddev, "config %d interface %d altsetting %d "
 240                     "endpoint 0x%X is Bulk; changing to Interrupt\n",
 241                     cfgno, inum, asnum, d->bEndpointAddress);
 242                 endpoint->desc.bmAttributes = USB_ENDPOINT_XFER_INT;
 243                 endpoint->desc.bInterval = 1;
 244                 if (usb_endpoint_maxp(&endpoint->desc) > 8)
 245                         endpoint->desc.wMaxPacketSize = cpu_to_le16(8);
 246         }
 247
 248         /*
 249          * Some buggy high speed devices have bulk endpoints using
 250          * maxpacket sizes other than 512.  High speed HCDs may not
 251          * be able to handle that particular bug, so let's warn...
 252          */
 253         if (to_usb_device(ddev)->speed == USB_SPEED_HIGH
 254                         && usb_endpoint_xfer_bulk(d)) {
 255                 unsigned maxp;
 256
 257                 maxp = usb_endpoint_maxp(&endpoint->desc) & 0x07ff;
 258                 if (maxp != 512)
 259                         dev_warn(ddev, "config %d interface %d altsetting %d "
 260                                 "bulk endpoint 0x%X has invalid maxpacket %d\n",
 261                                 cfgno, inum, asnum, d->bEndpointAddress,
 262                                 maxp);
 263         }
 264
 265         /* Parse a possible SuperSpeed endpoint companion descriptor */
 266         if (to_usb_device(ddev)->speed == USB_SPEED_SUPER)
 267                 usb_parse_ss_endpoint_companion(ddev, cfgno,
 268                                 inum, asnum, endpoint, buffer, size);
 269
 270         /* Skip over any Class Specific or Vendor Specific descriptors;
 271          * find the next endpoint or interface descriptor */
 272         endpoint->extra = buffer;
 273         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 274                         USB_DT_INTERFACE, &n);
 275         endpoint->extralen = i;
 276         retval = buffer - buffer0 + i;
 277         if (n > 0)
 278                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 279                     n, plural(n), "endpoint");
 280         return retval;
 281
 282 skip_to_next_endpoint_or_interface_descriptor:
 283         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 284             USB_DT_INTERFACE, NULL);
 285         return buffer - buffer0 + i;
 286 }
 287
 288 void usb_release_interface_cache(struct kref *ref)
 289 {
 290         struct usb_interface_cache *intfc = ref_to_usb_interface_cache(ref);
 291         int j;
 292
 293         for (j = 0; j < intfc->num_altsetting; j++) {
 294                 struct usb_host_interface *alt = &intfc->altsetting[j];
 295
 296                 kfree(alt->endpoint);
 297                 kfree(alt->string);
 298         }
 299         kfree(intfc);
 300 }
 301
 302 static int usb_parse_interface(struct device *ddev, int cfgno,
 303     struct usb_host_config *config, unsigned char *buffer, int size,
 304     u8 inums[], u8 nalts[])
 305 {
 306         unsigned char *buffer0 = buffer;
 307         struct usb_interface_descriptor *d;
 308         int inum, asnum;
 309         struct usb_interface_cache *intfc;
 310         struct usb_host_interface *alt;
 311         int i, n;
 312         int len, retval;
 313         int num_ep, num_ep_orig;
 314
 315         d = (struct usb_interface_descriptor *) buffer;
 316         buffer += d->bLength;
 317         size -= d->bLength;
 318
 319         if (d->bLength < USB_DT_INTERFACE_SIZE)
 320                 goto skip_to_next_interface_descriptor;
 321
 322         /* Which interface entry is this? */
 323         intfc = NULL;
 324         inum = d->bInterfaceNumber;
 325         for (i = 0; i < config->desc.bNumInterfaces; ++i) {
 326                 if (inums[i] == inum) {
 327                         intfc = config->intf_cache[i];
 328                         break;
 329                 }
 330         }
 331         if (!intfc || intfc->num_altsetting >= nalts[i])
 332                 goto skip_to_next_interface_descriptor;
 333
 334         /* Check for duplicate altsetting entries */
 335         asnum = d->bAlternateSetting;
 336         for ((i = 0, alt = &intfc->altsetting[0]);
 337               i < intfc->num_altsetting;
 338              (++i, ++alt)) {
 339                 if (alt->desc.bAlternateSetting == asnum) {
 340                         dev_warn(ddev, "Duplicate descriptor for config %d "
 341                             "interface %d altsetting %d, skipping\n",
 342                             cfgno, inum, asnum);
 343                         goto skip_to_next_interface_descriptor;
 344                 }
 345         }
 346
 347         ++intfc->num_altsetting;
 348         memcpy(&alt->desc, d, USB_DT_INTERFACE_SIZE);
 349
 350         /* Skip over any Class Specific or Vendor Specific descriptors;
 351          * find the first endpoint or interface descriptor */
 352         alt->extra = buffer;
 353         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 354             USB_DT_INTERFACE, &n);
 355         alt->extralen = i;
 356         if (n > 0)
 357                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 358                     n, plural(n), "interface");
 359         buffer += i;
 360         size -= i;
 361
 362         /* Allocate space for the right(?) number of endpoints */
 363         num_ep = num_ep_orig = alt->desc.bNumEndpoints;
 364         alt->desc.bNumEndpoints = 0;            /* Use as a counter */
 365         if (num_ep > USB_MAXENDPOINTS) {
 366                 dev_warn(ddev, "too many endpoints for config %d interface %d "
 367                     "altsetting %d: %d, using maximum allowed: %d\n",
 368                     cfgno, inum, asnum, num_ep, USB_MAXENDPOINTS);
 369                 num_ep = USB_MAXENDPOINTS;
 370         }
 371
 372         if (num_ep > 0) {
 373                 /* Can't allocate 0 bytes */
 374                 len = sizeof(struct usb_host_endpoint) * num_ep;
 375                 alt->endpoint = kzalloc(len, GFP_KERNEL);
 376                 if (!alt->endpoint)
 377                         return -ENOMEM;
 378         }
 379
 380         /* Parse all the endpoint descriptors */
 381         n = 0;
 382         while (size > 0) {
 383                 if (((struct usb_descriptor_header *) buffer)->bDescriptorType
 384                      == USB_DT_INTERFACE)
 385                         break;
 386                 retval = usb_parse_endpoint(ddev, cfgno, inum, asnum, alt,
 387                     num_ep, buffer, size);
 388                 if (retval < 0)
 389                         return retval;
 390                 ++n;
 391
 392                 buffer += retval;
 393                 size -= retval;
 394         }
 395
 396         if (n != num_ep_orig)
 397                 dev_warn(ddev, "config %d interface %d altsetting %d has %d "
 398                     "endpoint descriptor%s, different from the interface "
 399                     "descriptor's value: %d\n",
 400                     cfgno, inum, asnum, n, plural(n), num_ep_orig);
 401         return buffer - buffer0;
 402
 403 skip_to_next_interface_descriptor:
 404         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 405             USB_DT_INTERFACE, NULL);
 406         return buffer - buffer0 + i;
 407 }
 408
 409 static int usb_parse_configuration(struct usb_device *dev, int cfgidx,
 410     struct usb_host_config *config, unsigned char *buffer, int size)
 411 {
 412         struct device *ddev = &dev->dev;
 413         unsigned char *buffer0 = buffer;
 414         int cfgno;
 415         int nintf, nintf_orig;
 416         int i, j, n;
 417         struct usb_interface_cache *intfc;
 418         unsigned char *buffer2;
 419         int size2;
 420         struct usb_descriptor_header *header;
 421         int len, retval;
 422         u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];
 423         unsigned iad_num = 0;
 424
 425         memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
 426         if (config->desc.bDescriptorType != USB_DT_CONFIG ||
 427             config->desc.bLength < USB_DT_CONFIG_SIZE) {
 428                 dev_err(ddev, "invalid descriptor for config index %d: "
 429                     "type = 0x%X, length = %d\n", cfgidx,
 430                     config->desc.bDescriptorType, config->desc.bLength);
 431                 return -EINVAL;
 432         }
 433         cfgno = config->desc.bConfigurationValue;
 434
 435         buffer += config->desc.bLength;
 436         size -= config->desc.bLength;
 437
 438         nintf = nintf_orig = config->desc.bNumInterfaces;
 439         if (nintf > USB_MAXINTERFACES) {
 440                 dev_warn(ddev, "config %d has too many interfaces: %d, "
 441                     "using maximum allowed: %d\n",
 442                     cfgno, nintf, USB_MAXINTERFACES);
 443                 nintf = USB_MAXINTERFACES;
 444         }
 445
 446         /* Go through the descriptors, checking their length and counting the
 447          * number of altsettings for each interface */
 448         n = 0;
 449         for ((buffer2 = buffer, size2 = size);
 450               size2 > 0;
 451              (buffer2 += header->bLength, size2 -= header->bLength)) {
 452
 453                 if (size2 < sizeof(struct usb_descriptor_header)) {
 454                         dev_warn(ddev, "config %d descriptor has %d excess "
 455                             "byte%s, ignoring\n",
 456                             cfgno, size2, plural(size2));
 457                         break;
 458                 }
 459
 460                 header = (struct usb_descriptor_header *) buffer2;
 461                 if ((header->bLength > size2) || (header->bLength < 2)) {
 462                         dev_warn(ddev, "config %d has an invalid descriptor "
 463                             "of length %d, skipping remainder of the config\n",
 464                             cfgno, header->bLength);
 465                         break;
 466                 }
 467
 468                 if (header->bDescriptorType == USB_DT_INTERFACE) {
 469                         struct usb_interface_descriptor *d;
 470                         int inum;
 471
 472                         d = (struct usb_interface_descriptor *) header;
 473                         if (d->bLength < USB_DT_INTERFACE_SIZE) {
 474                                 dev_warn(ddev, "config %d has an invalid "
 475                                     "interface descriptor of length %d, "
 476                                     "skipping\n", cfgno, d->bLength);
 477                                 continue;
 478                         }
 479
 480                         inum = d->bInterfaceNumber;
 481
 482                         if ((dev->quirks & USB_QUIRK_HONOR_BNUMINTERFACES) &&
 483                             n >= nintf_orig) {
 484                                 dev_warn(ddev, "config %d has more interface "
 485                                     "descriptors, than it declares in "
 486                                     "bNumInterfaces, ignoring interface "
 487                                     "number: %d\n", cfgno, inum);
 488                                 continue;
 489                         }
 490
 491                         if (inum >= nintf_orig)
 492                                 dev_warn(ddev, "config %d has an invalid "
 493                                     "interface number: %d but max is %d\n",
 494                                     cfgno, inum, nintf_orig - 1);
 495
 496                         /* Have we already encountered this interface?
 497                          * Count its altsettings */
 498                         for (i = 0; i < n; ++i) {
 499                                 if (inums[i] == inum)
 500                                         break;
 501                         }
 502                         if (i < n) {
 503                                 if (nalts[i] < 255)
 504                                         ++nalts[i];
 505                         } else if (n < USB_MAXINTERFACES) {
 506                                 inums[n] = inum;
 507                                 nalts[n] = 1;
 508                                 ++n;
 509                         }
 510
 511                 } else if (header->bDescriptorType ==
 512                                 USB_DT_INTERFACE_ASSOCIATION) {
 513                         if (iad_num == USB_MAXIADS) {
 514                                 dev_warn(ddev, "found more Interface "
 515                                                "Association Descriptors "
 516                                                "than allocated for in "
 517                                                "configuration %d\n", cfgno);
 518                         } else {
 519                                 config->intf_assoc[iad_num] =
 520                                         (struct usb_interface_assoc_descriptor
 521                                         *)header;
 522                                 iad_num++;
 523                         }
 524
 525                 } else if (header->bDescriptorType == USB_DT_DEVICE ||
 526                             header->bDescriptorType == USB_DT_CONFIG)
 527                         dev_warn(ddev, "config %d contains an unexpected "
 528                             "descriptor of type 0x%X, skipping\n",
 529                             cfgno, header->bDescriptorType);
 530
 531         }       /* for ((buffer2 = buffer, size2 = size); ...) */
 532         size = buffer2 - buffer;
 533         config->desc.wTotalLength = cpu_to_le16(buffer2 - buffer0);
 534
 535         if (n != nintf)
 536                 dev_warn(ddev, "config %d has %d interface%s, different from "
 537                     "the descriptor's value: %d\n",
 538                     cfgno, n, plural(n), nintf_orig);
 539         else if (n == 0)
 540                 dev_warn(ddev, "config %d has no interfaces?\n", cfgno);
 541         config->desc.bNumInterfaces = nintf = n;
 542
 543         /* Check for missing interface numbers */
 544         for (i = 0; i < nintf; ++i) {
 545                 for (j = 0; j < nintf; ++j) {
 546                         if (inums[j] == i)
 547                                 break;
 548                 }
 549                 if (j >= nintf)
 550                         dev_warn(ddev, "config %d has no interface number "
 551                             "%d\n", cfgno, i);
 552         }
 553
 554         /* Allocate the usb_interface_caches and altsetting arrays */
 555         for (i = 0; i < nintf; ++i) {
 556                 j = nalts[i];
 557                 if (j > USB_MAXALTSETTING) {
 558                         dev_warn(ddev, "too many alternate settings for "
 559                             "config %d interface %d: %d, "
 560                             "using maximum allowed: %d\n",
 561                             cfgno, inums[i], j, USB_MAXALTSETTING);
 562                         nalts[i] = j = USB_MAXALTSETTING;
 563                 }
 564
 565                 len = sizeof(*intfc) + sizeof(struct usb_host_interface) * j;
 566                 config->intf_cache[i] = intfc = kzalloc(len, GFP_KERNEL);
 567                 if (!intfc)
 568                         return -ENOMEM;
 569                 kref_init(&intfc->ref);
 570         }
 571
 572         /* FIXME: parse the BOS descriptor */
 573
 574         /* Skip over any Class Specific or Vendor Specific descriptors;
 575          * find the first interface descriptor */
 576         config->extra = buffer;
 577         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 578             USB_DT_INTERFACE, &n);
 579         config->extralen = i;
 580         if (n > 0)
 581                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 582                     n, plural(n), "configuration");
 583         buffer += i;
 584         size -= i;
 585
 586         /* Parse all the interface/altsetting descriptors */
 587         while (size > 0) {
 588                 retval = usb_parse_interface(ddev, cfgno, config,
 589                     buffer, size, inums, nalts);
 590                 if (retval < 0)
 591                         return retval;
 592
 593                 buffer += retval;
 594                 size -= retval;
 595         }
 596
 597         /* Check for missing altsettings */
 598         for (i = 0; i < nintf; ++i) {
 599                 intfc = config->intf_cache[i];
 600                 for (j = 0; j < intfc->num_altsetting; ++j) {
 601                         for (n = 0; n < intfc->num_altsetting; ++n) {
 602                                 if (intfc->altsetting[n].desc.
 603                                     bAlternateSetting == j)
 604                                         break;
 605                         }
 606                         if (n >= intfc->num_altsetting)
 607                                 dev_warn(ddev, "config %d interface %d has no "
 608                                     "altsetting %d\n", cfgno, inums[i], j);
 609                 }
 610         }
 611
 612         return 0;
 613 }
 614
 615 /* hub-only!! ... and only exported for reset/reinit path.
 616  * otherwise used internally on disconnect/destroy path
 617  */
 618 void usb_destroy_configuration(struct usb_device *dev)
 619 {
 620         int c, i;
 621
 622         if (!dev->config)
 623                 return;
 624
 625         if (dev->rawdescriptors) {
 626                 for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
 627                         kfree(dev->rawdescriptors[i]);
 628
 629                 kfree(dev->rawdescriptors);
 630                 dev->rawdescriptors = NULL;
 631         }
 632
 633         for (c = 0; c < dev->descriptor.bNumConfigurations; c++) {
 634                 struct usb_host_config *cf = &dev->config[c];
 635
 636                 kfree(cf->string);
 637                 for (i = 0; i < cf->desc.bNumInterfaces; i++) {
 638                         if (cf->intf_cache[i])
 639                                 kref_put(&cf->intf_cache[i]->ref,
 640                                           usb_release_interface_cache);
 641                 }
 642         }
 643         kfree(dev->config);
 644         dev->config = NULL;
 645 }
 646
 647
 648 /*
 649  * Get the USB config descriptors, cache and parse'em
 650  *
 651  * hub-only!! ... and only in reset path, or usb_new_device()
 652  * (used by real hubs and virtual root hubs)
 653  *
 654  * NOTE: if this is a WUSB device and is not authorized, we skip the
 655  *       whole thing. A non-authorized USB device has no
 656  *       configurations.
 657  */
 658 int usb_get_configuration(struct usb_device *dev)
 659 {
 660         struct device *ddev = &dev->dev;
 661         int ncfg = dev->descriptor.bNumConfigurations;
 662         int result = 0;
 663         unsigned int cfgno, length;
 664         unsigned char *bigbuffer;
 665         struct usb_config_descriptor *desc;
 666
 667         cfgno = 0;
 668         if (dev->authorized == 0)       /* Not really an error */
 669                 goto out_not_authorized;
 670         result = -ENOMEM;
 671         if (ncfg > USB_MAXCONFIG) {
 672                 dev_warn(ddev, "too many configurations: %d, "
 673                     "using maximum allowed: %d\n", ncfg, USB_MAXCONFIG);
 674                 dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
 675         }
 676
 677         if (ncfg < 1) {
 678                 dev_err(ddev, "no configurations\n");
 679                 return -EINVAL;
 680         }
 681
 682         length = ncfg * sizeof(struct usb_host_config);
 683         dev->config = kzalloc(length, GFP_KERNEL);
 684         if (!dev->config)
 685                 goto err2;
 686
 687         length = ncfg * sizeof(char *);
 688         dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
 689         if (!dev->rawdescriptors)
 690                 goto err2;
 691
 692         desc = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
 693         if (!desc)
 694                 goto err2;
 695
 696         result = 0;
 697         for (; cfgno < ncfg; cfgno++) {
 698                 /* We grab just the first descriptor so we know how long
 699                  * the whole configuration is */
 700                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 701                     desc, USB_DT_CONFIG_SIZE);
 702                 if (result < 0) {
 703                         dev_err(ddev, "unable to read config index %d "
 704                             "descriptor/%s: %d\n", cfgno, "start", result);
 705                         dev_err(ddev, "chopping to %d config(s)\n", cfgno);
 706                         dev->descriptor.bNumConfigurations = cfgno;
 707                         break;
 708                 } else if (result < 4) {
 709                         dev_err(ddev, "config index %d descriptor too short "
 710                             "(expected %i, got %i)\n", cfgno,
 711                             USB_DT_CONFIG_SIZE, result);
 712                         result = -EINVAL;
 713                         goto err;
 714                 }
 715                 length = max((int) le16_to_cpu(desc->wTotalLength),
 716                     USB_DT_CONFIG_SIZE);
 717
 718                 /* Now that we know the length, get the whole thing */
 719                 bigbuffer = kmalloc(length, GFP_KERNEL);
 720                 if (!bigbuffer) {
 721                         result = -ENOMEM;
 722                         goto err;
 723                 }
 724                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 725                     bigbuffer, length);
 726                 if (result < 0) {
 727                         dev_err(ddev, "unable to read config index %d "
 728                             "descriptor/%s\n", cfgno, "all");
 729                         kfree(bigbuffer);
 730                         goto err;
 731                 }
 732                 if (result < length) {
 733                         dev_warn(ddev, "config index %d descriptor too short "
 734                             "(expected %i, got %i)\n", cfgno, length, result);
 735                         length = result;
 736                 }
 737
 738                 dev->rawdescriptors[cfgno] = bigbuffer;
 739
 740                 result = usb_parse_configuration(dev, cfgno,
 741                     &dev->config[cfgno], bigbuffer, length);
 742                 if (result < 0) {
 743                         ++cfgno;
 744                         goto err;
 745                 }
 746         }
 747         result = 0;
 748
 749 err:
 750         kfree(desc);
 751 out_not_authorized:
 752         dev->descriptor.bNumConfigurations = cfgno;
 753 err2:
 754         if (result == -ENOMEM)
 755                 dev_err(ddev, "out of memory\n");
 756         return result;
 757 }