lib/efi_loader/efi_device_path.c

   1 /*
   2  * EFI device path from u-boot device-model mapping
   3  *
   4  * (C) Copyright 2017 Rob Clark
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #define LOG_CATEGORY LOGL_ERR
  10
  11 #include <common.h>
  12 #include <blk.h>
  13 #include <dm.h>
  14 #include <usb.h>
  15 #include <mmc.h>
  16 #include <efi_loader.h>
  17 #include <inttypes.h>
  18 #include <part.h>
  19
  20 /* template END node: */
  21 static const struct efi_device_path END = {
  22         .type     = DEVICE_PATH_TYPE_END,
  23         .sub_type = DEVICE_PATH_SUB_TYPE_END,
  24         .length   = sizeof(END),
  25 };
  26
  27 #define U_BOOT_GUID \
  28         EFI_GUID(0xe61d73b9, 0xa384, 0x4acc, \
  29                  0xae, 0xab, 0x82, 0xe8, 0x28, 0xf3, 0x62, 0x8b)
  30
  31 /* template ROOT node: */
  32 static const struct efi_device_path_vendor ROOT = {
  33         .dp = {
  34                 .type     = DEVICE_PATH_TYPE_HARDWARE_DEVICE,
  35                 .sub_type = DEVICE_PATH_SUB_TYPE_VENDOR,
  36                 .length   = sizeof(ROOT),
  37         },
  38         .guid = U_BOOT_GUID,
  39 };
  40
  41 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
  42 /*
  43  * Determine if an MMC device is an SD card.
  44  *
  45  * @desc        block device descriptor
  46  * @return      true if the device is an SD card
  47  */
  48 static bool is_sd(struct blk_desc *desc)
  49 {
  50         struct mmc *mmc = find_mmc_device(desc->devnum);
  51
  52         if (!mmc)
  53                 return false;
  54
  55         return IS_SD(mmc) != 0U;
  56 }
  57 #endif
  58
  59 static void *dp_alloc(size_t sz)
  60 {
  61         void *buf;
  62
  63         if (efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, sz, &buf) !=
  64             EFI_SUCCESS) {
  65                 debug("EFI: ERROR: out of memory in %s\n", __func__);
  66                 return NULL;
  67         }
  68
  69         return buf;
  70 }
  71
  72 /*
  73  * Iterate to next block in device-path, terminating (returning NULL)
  74  * at /End* node.
  75  */
  76 struct efi_device_path *efi_dp_next(const struct efi_device_path *dp)
  77 {
  78         if (dp == NULL)
  79                 return NULL;
  80         if (dp->type == DEVICE_PATH_TYPE_END)
  81                 return NULL;
  82         dp = ((void *)dp) + dp->length;
  83         if (dp->type == DEVICE_PATH_TYPE_END)
  84                 return NULL;
  85         return (struct efi_device_path *)dp;
  86 }
  87
  88 /*
  89  * Compare two device-paths, stopping when the shorter of the two hits
  90  * an End* node.  This is useful to, for example, compare a device-path
  91  * representing a device with one representing a file on the device, or
  92  * a device with a parent device.
  93  */
  94 int efi_dp_match(const struct efi_device_path *a,
  95                  const struct efi_device_path *b)
  96 {
  97         while (1) {
  98                 int ret;
  99
 100                 ret = memcmp(&a->length, &b->length, sizeof(a->length));
 101                 if (ret)
 102                         return ret;
 103
 104                 ret = memcmp(a, b, a->length);
 105                 if (ret)
 106                         return ret;
 107
 108                 a = efi_dp_next(a);
 109                 b = efi_dp_next(b);
 110
 111                 if (!a || !b)
 112                         return 0;
 113         }
 114 }
 115
 116 /*
 117  * See UEFI spec (section 3.1.2, about short-form device-paths..
 118  * tl;dr: we can have a device-path that starts with a USB WWID
 119  * or USB Class node, and a few other cases which don't encode
 120  * the full device path with bus hierarchy:
 121  *
 122  *   - MESSAGING:USB_WWID
 123  *   - MESSAGING:USB_CLASS
 124  *   - MEDIA:FILE_PATH
 125  *   - MEDIA:HARD_DRIVE
 126  *   - MESSAGING:URI
 127  */
 128 static struct efi_device_path *shorten_path(struct efi_device_path *dp)
 129 {
 130         while (dp) {
 131                 /*
 132                  * TODO: Add MESSAGING:USB_WWID and MESSAGING:URI..
 133                  * in practice fallback.efi just uses MEDIA:HARD_DRIVE
 134                  * so not sure when we would see these other cases.
 135                  */
 136                 if (EFI_DP_TYPE(dp, MESSAGING_DEVICE, MSG_USB_CLASS) ||
 137                     EFI_DP_TYPE(dp, MEDIA_DEVICE, HARD_DRIVE_PATH) ||
 138                     EFI_DP_TYPE(dp, MEDIA_DEVICE, FILE_PATH))
 139                         return dp;
 140
 141                 dp = efi_dp_next(dp);
 142         }
 143
 144         return dp;
 145 }
 146
 147 static struct efi_object *find_obj(struct efi_device_path *dp, bool short_path,
 148                                    struct efi_device_path **rem)
 149 {
 150         struct efi_object *efiobj;
 151         unsigned int dp_size = efi_dp_size(dp);
 152
 153         list_for_each_entry(efiobj, &efi_obj_list, link) {
 154                 struct efi_handler *handler;
 155                 struct efi_device_path *obj_dp;
 156                 efi_status_t ret;
 157
 158                 ret = efi_search_protocol(efiobj->handle,
 159                                           &efi_guid_device_path, &handler);
 160                 if (ret != EFI_SUCCESS)
 161                         continue;
 162                 obj_dp = handler->protocol_interface;
 163
 164                 do {
 165                         if (efi_dp_match(dp, obj_dp) == 0) {
 166                                 if (rem) {
 167                                         /*
 168                                          * Allow partial matches, but inform
 169                                          * the caller.
 170                                          */
 171                                         *rem = ((void *)dp) +
 172                                                 efi_dp_size(obj_dp);
 173                                         return efiobj;
 174                                 } else {
 175                                         /* Only return on exact matches */
 176                                         if (efi_dp_size(obj_dp) == dp_size)
 177                                                 return efiobj;
 178                                 }
 179                         }
 180
 181                         obj_dp = shorten_path(efi_dp_next(obj_dp));
 182                 } while (short_path && obj_dp);
 183         }
 184
 185         return NULL;
 186 }
 187
 188 /*
 189  * Find an efiobj from device-path, if 'rem' is not NULL, returns the
 190  * remaining part of the device path after the matched object.
 191  */
 192 struct efi_object *efi_dp_find_obj(struct efi_device_path *dp,
 193                                    struct efi_device_path **rem)
 194 {
 195         struct efi_object *efiobj;
 196
 197         /* Search for an exact match first */
 198         efiobj = find_obj(dp, false, NULL);
 199
 200         /* Then for a fuzzy match */
 201         if (!efiobj)
 202                 efiobj = find_obj(dp, false, rem);
 203
 204         /* And now for a fuzzy short match */
 205         if (!efiobj)
 206                 efiobj = find_obj(dp, true, rem);
 207
 208         return efiobj;
 209 }
 210
 211 /*
 212  * Determine the last device path node that is not the end node.
 213  *
 214  * @dp          device path
 215  * @return      last node before the end node if it exists
 216  *              otherwise NULL
 217  */
 218 const struct efi_device_path *efi_dp_last_node(const struct efi_device_path *dp)
 219 {
 220         struct efi_device_path *ret;
 221
 222         if (!dp || dp->type == DEVICE_PATH_TYPE_END)
 223                 return NULL;
 224         while (dp) {
 225                 ret = (struct efi_device_path *)dp;
 226                 dp = efi_dp_next(dp);
 227         }
 228         return ret;
 229 }
 230
 231 /* return size not including End node: */
 232 unsigned efi_dp_size(const struct efi_device_path *dp)
 233 {
 234         unsigned sz = 0;
 235
 236         while (dp) {
 237                 sz += dp->length;
 238                 dp = efi_dp_next(dp);
 239         }
 240
 241         return sz;
 242 }
 243
 244 struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp)
 245 {
 246         struct efi_device_path *ndp;
 247         unsigned sz = efi_dp_size(dp) + sizeof(END);
 248
 249         if (!dp)
 250                 return NULL;
 251
 252         ndp = dp_alloc(sz);
 253         if (!ndp)
 254                 return NULL;
 255         memcpy(ndp, dp, sz);
 256
 257         return ndp;
 258 }
 259
 260 struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
 261                                       const struct efi_device_path *dp2)
 262 {
 263         struct efi_device_path *ret;
 264
 265         if (!dp1) {
 266                 ret = efi_dp_dup(dp2);
 267         } else if (!dp2) {
 268                 ret = efi_dp_dup(dp1);
 269         } else {
 270                 /* both dp1 and dp2 are non-null */
 271                 unsigned sz1 = efi_dp_size(dp1);
 272                 unsigned sz2 = efi_dp_size(dp2);
 273                 void *p = dp_alloc(sz1 + sz2 + sizeof(END));
 274                 if (!p)
 275                         return NULL;
 276                 memcpy(p, dp1, sz1);
 277                 memcpy(p + sz1, dp2, sz2);
 278                 memcpy(p + sz1 + sz2, &END, sizeof(END));
 279                 ret = p;
 280         }
 281
 282         return ret;
 283 }
 284
 285 struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
 286                                            const struct efi_device_path *node)
 287 {
 288         struct efi_device_path *ret;
 289
 290         if (!node && !dp) {
 291                 ret = efi_dp_dup(&END);
 292         } else if (!node) {
 293                 ret = efi_dp_dup(dp);
 294         } else if (!dp) {
 295                 unsigned sz = node->length;
 296                 void *p = dp_alloc(sz + sizeof(END));
 297                 if (!p)
 298                         return NULL;
 299                 memcpy(p, node, sz);
 300                 memcpy(p + sz, &END, sizeof(END));
 301                 ret = p;
 302         } else {
 303                 /* both dp and node are non-null */
 304                 unsigned sz = efi_dp_size(dp);
 305                 void *p = dp_alloc(sz + node->length + sizeof(END));
 306                 if (!p)
 307                         return NULL;
 308                 memcpy(p, dp, sz);
 309                 memcpy(p + sz, node, node->length);
 310                 memcpy(p + sz + node->length, &END, sizeof(END));
 311                 ret = p;
 312         }
 313
 314         return ret;
 315 }
 316
 317 #ifdef CONFIG_DM
 318 /* size of device-path not including END node for device and all parents
 319  * up to the root device.
 320  */
 321 static unsigned dp_size(struct udevice *dev)
 322 {
 323         if (!dev || !dev->driver)
 324                 return sizeof(ROOT);
 325
 326         switch (dev->driver->id) {
 327         case UCLASS_ROOT:
 328         case UCLASS_SIMPLE_BUS:
 329                 /* stop traversing parents at this point: */
 330                 return sizeof(ROOT);
 331         case UCLASS_ETH:
 332                 return dp_size(dev->parent) +
 333                         sizeof(struct efi_device_path_mac_addr);
 334 #ifdef CONFIG_BLK
 335         case UCLASS_BLK:
 336                 switch (dev->parent->uclass->uc_drv->id) {
 337 #ifdef CONFIG_IDE
 338                 case UCLASS_IDE:
 339                         return dp_size(dev->parent) +
 340                                 sizeof(struct efi_device_path_atapi);
 341 #endif
 342 #if defined(CONFIG_SCSI) && defined(CONFIG_DM_SCSI)
 343                 case UCLASS_SCSI:
 344                         return dp_size(dev->parent) +
 345                                 sizeof(struct efi_device_path_scsi);
 346 #endif
 347 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 348                 case UCLASS_MMC:
 349                         return dp_size(dev->parent) +
 350                                 sizeof(struct efi_device_path_sd_mmc_path);
 351 #endif
 352                 default:
 353                         return dp_size(dev->parent);
 354                 }
 355 #endif
 356 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 357         case UCLASS_MMC:
 358                 return dp_size(dev->parent) +
 359                         sizeof(struct efi_device_path_sd_mmc_path);
 360 #endif
 361         case UCLASS_MASS_STORAGE:
 362         case UCLASS_USB_HUB:
 363                 return dp_size(dev->parent) +
 364                         sizeof(struct efi_device_path_usb_class);
 365         default:
 366                 /* just skip over unknown classes: */
 367                 return dp_size(dev->parent);
 368         }
 369 }
 370
 371 /*
 372  * Recursively build a device path.
 373  *
 374  * @buf         pointer to the end of the device path
 375  * @dev         device
 376  * @return      pointer to the end of the device path
 377  */
 378 static void *dp_fill(void *buf, struct udevice *dev)
 379 {
 380         if (!dev || !dev->driver)
 381                 return buf;
 382
 383         switch (dev->driver->id) {
 384         case UCLASS_ROOT:
 385         case UCLASS_SIMPLE_BUS: {
 386                 /* stop traversing parents at this point: */
 387                 struct efi_device_path_vendor *vdp = buf;
 388                 *vdp = ROOT;
 389                 return &vdp[1];
 390         }
 391 #ifdef CONFIG_DM_ETH
 392         case UCLASS_ETH: {
 393                 struct efi_device_path_mac_addr *dp =
 394                         dp_fill(buf, dev->parent);
 395                 struct eth_pdata *pdata = dev->platdata;
 396
 397                 dp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 398                 dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
 399                 dp->dp.length = sizeof(*dp);
 400                 memset(&dp->mac, 0, sizeof(dp->mac));
 401                 /* We only support IPv4 */
 402                 memcpy(&dp->mac, &pdata->enetaddr, ARP_HLEN);
 403                 /* Ethernet */
 404                 dp->if_type = 1;
 405                 return &dp[1];
 406         }
 407 #endif
 408 #ifdef CONFIG_BLK
 409         case UCLASS_BLK:
 410                 switch (dev->parent->uclass->uc_drv->id) {
 411 #ifdef CONFIG_IDE
 412                 case UCLASS_IDE: {
 413                         struct efi_device_path_atapi *dp =
 414                         dp_fill(buf, dev->parent);
 415                         struct blk_desc *desc = dev_get_uclass_platdata(dev);
 416
 417                         dp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 418                         dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_ATAPI;
 419                         dp->dp.length = sizeof(*dp);
 420                         dp->logical_unit_number = desc->devnum;
 421                         dp->primary_secondary = IDE_BUS(desc->devnum);
 422                         dp->slave_master = desc->devnum %
 423                                 (CONFIG_SYS_IDE_MAXDEVICE /
 424                                  CONFIG_SYS_IDE_MAXBUS);
 425                         return &dp[1];
 426                         }
 427 #endif
 428 #if defined(CONFIG_SCSI) && defined(CONFIG_DM_SCSI)
 429                 case UCLASS_SCSI: {
 430                         struct efi_device_path_scsi *dp =
 431                                 dp_fill(buf, dev->parent);
 432                         struct blk_desc *desc = dev_get_uclass_platdata(dev);
 433
 434                         dp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 435                         dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_SCSI;
 436                         dp->dp.length = sizeof(*dp);
 437                         dp->logical_unit_number = desc->lun;
 438                         dp->target_id = desc->target;
 439                         return &dp[1];
 440                         }
 441 #endif
 442 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 443                 case UCLASS_MMC: {
 444                         struct efi_device_path_sd_mmc_path *sddp =
 445                                 dp_fill(buf, dev->parent);
 446                         struct blk_desc *desc = dev_get_uclass_platdata(dev);
 447
 448                         sddp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 449                         sddp->dp.sub_type = is_sd(desc) ?
 450                                 DEVICE_PATH_SUB_TYPE_MSG_SD :
 451                                 DEVICE_PATH_SUB_TYPE_MSG_MMC;
 452                         sddp->dp.length   = sizeof(*sddp);
 453                         sddp->slot_number = dev->seq;
 454                         return &sddp[1];
 455                         }
 456 #endif
 457                 default:
 458                         debug("%s(%u) %s: unhandled parent class: %s (%u)\n",
 459                               __FILE__, __LINE__, __func__,
 460                               dev->name, dev->parent->uclass->uc_drv->id);
 461                         return dp_fill(buf, dev->parent);
 462                 }
 463 #endif
 464 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 465         case UCLASS_MMC: {
 466                 struct efi_device_path_sd_mmc_path *sddp =
 467                         dp_fill(buf, dev->parent);
 468                 struct mmc *mmc = mmc_get_mmc_dev(dev);
 469                 struct blk_desc *desc = mmc_get_blk_desc(mmc);
 470
 471                 sddp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 472                 sddp->dp.sub_type = is_sd(desc) ?
 473                         DEVICE_PATH_SUB_TYPE_MSG_SD :
 474                         DEVICE_PATH_SUB_TYPE_MSG_MMC;
 475                 sddp->dp.length   = sizeof(*sddp);
 476                 sddp->slot_number = dev->seq;
 477
 478                 return &sddp[1];
 479         }
 480 #endif
 481         case UCLASS_MASS_STORAGE:
 482         case UCLASS_USB_HUB: {
 483                 struct efi_device_path_usb_class *udp =
 484                         dp_fill(buf, dev->parent);
 485                 struct usb_device *udev = dev_get_parent_priv(dev);
 486                 struct usb_device_descriptor *desc = &udev->descriptor;
 487
 488                 udp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 489                 udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB_CLASS;
 490                 udp->dp.length   = sizeof(*udp);
 491                 udp->vendor_id   = desc->idVendor;
 492                 udp->product_id  = desc->idProduct;
 493                 udp->device_class    = desc->bDeviceClass;
 494                 udp->device_subclass = desc->bDeviceSubClass;
 495                 udp->device_protocol = desc->bDeviceProtocol;
 496
 497                 return &udp[1];
 498         }
 499         default:
 500                 debug("%s(%u) %s: unhandled device class: %s (%u)\n",
 501                       __FILE__, __LINE__, __func__,
 502                       dev->name, dev->driver->id);
 503                 return dp_fill(buf, dev->parent);
 504         }
 505 }
 506
 507 /* Construct a device-path from a device: */
 508 struct efi_device_path *efi_dp_from_dev(struct udevice *dev)
 509 {
 510         void *buf, *start;
 511
 512         start = buf = dp_alloc(dp_size(dev) + sizeof(END));
 513         if (!buf)
 514                 return NULL;
 515         buf = dp_fill(buf, dev);
 516         *((struct efi_device_path *)buf) = END;
 517
 518         return start;
 519 }
 520 #endif
 521
 522 static unsigned dp_part_size(struct blk_desc *desc, int part)
 523 {
 524         unsigned dpsize;
 525
 526 #ifdef CONFIG_BLK
 527         {
 528                 struct udevice *dev;
 529                 int ret = blk_find_device(desc->if_type, desc->devnum, &dev);
 530
 531                 if (ret)
 532                         dev = desc->bdev->parent;
 533                 dpsize = dp_size(dev);
 534         }
 535 #else
 536         dpsize = sizeof(ROOT) + sizeof(struct efi_device_path_usb);
 537 #endif
 538
 539         if (part == 0) /* the actual disk, not a partition */
 540                 return dpsize;
 541
 542         if (desc->part_type == PART_TYPE_ISO)
 543                 dpsize += sizeof(struct efi_device_path_cdrom_path);
 544         else
 545                 dpsize += sizeof(struct efi_device_path_hard_drive_path);
 546
 547         return dpsize;
 548 }
 549
 550 /*
 551  * Create a device node for a block device partition.
 552  *
 553  * @buf         buffer to which the device path is wirtten
 554  * @desc        block device descriptor
 555  * @part        partition number, 0 identifies a block device
 556  */
 557 static void *dp_part_node(void *buf, struct blk_desc *desc, int part)
 558 {
 559         disk_partition_t info;
 560
 561         part_get_info(desc, part, &info);
 562
 563         if (desc->part_type == PART_TYPE_ISO) {
 564                 struct efi_device_path_cdrom_path *cddp = buf;
 565
 566                 cddp->boot_entry = part;
 567                 cddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 568                 cddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_CDROM_PATH;
 569                 cddp->dp.length = sizeof(*cddp);
 570                 cddp->partition_start = info.start;
 571                 cddp->partition_end = info.size;
 572
 573                 buf = &cddp[1];
 574         } else {
 575                 struct efi_device_path_hard_drive_path *hddp = buf;
 576
 577                 hddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 578                 hddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH;
 579                 hddp->dp.length = sizeof(*hddp);
 580                 hddp->partition_number = part;
 581                 hddp->partition_start = info.start;
 582                 hddp->partition_end = info.size;
 583                 if (desc->part_type == PART_TYPE_EFI)
 584                         hddp->partmap_type = 2;
 585                 else
 586                         hddp->partmap_type = 1;
 587
 588                 switch (desc->sig_type) {
 589                 case SIG_TYPE_NONE:
 590                 default:
 591                         hddp->signature_type = 0;
 592                         memset(hddp->partition_signature, 0,
 593                                sizeof(hddp->partition_signature));
 594                         break;
 595                 case SIG_TYPE_MBR:
 596                         hddp->signature_type = 1;
 597                         memset(hddp->partition_signature, 0,
 598                                sizeof(hddp->partition_signature));
 599                         memcpy(hddp->partition_signature, &desc->mbr_sig,
 600                                sizeof(desc->mbr_sig));
 601                         break;
 602                 case SIG_TYPE_GUID:
 603                         hddp->signature_type = 2;
 604                         memcpy(hddp->partition_signature, &desc->guid_sig,
 605                                sizeof(hddp->partition_signature));
 606                         break;
 607                 }
 608
 609                 buf = &hddp[1];
 610         }
 611
 612         return buf;
 613 }
 614
 615 /*
 616  * Create a device path for a block device or one of its partitions.
 617  *
 618  * @buf         buffer to which the device path is wirtten
 619  * @desc        block device descriptor
 620  * @part        partition number, 0 identifies a block device
 621  */
 622 static void *dp_part_fill(void *buf, struct blk_desc *desc, int part)
 623 {
 624 #ifdef CONFIG_BLK
 625         {
 626                 struct udevice *dev;
 627                 int ret = blk_find_device(desc->if_type, desc->devnum, &dev);
 628
 629                 if (ret)
 630                         dev = desc->bdev->parent;
 631                 buf = dp_fill(buf, dev);
 632         }
 633 #else
 634         /*
 635          * We *could* make a more accurate path, by looking at if_type
 636          * and handling all the different cases like we do for non-
 637          * legacy (ie CONFIG_BLK=y) case.  But most important thing
 638          * is just to have a unique device-path for if_type+devnum.
 639          * So map things to a fictitious USB device.
 640          */
 641         struct efi_device_path_usb *udp;
 642
 643         memcpy(buf, &ROOT, sizeof(ROOT));
 644         buf += sizeof(ROOT);
 645
 646         udp = buf;
 647         udp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 648         udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB;
 649         udp->dp.length = sizeof(*udp);
 650         udp->parent_port_number = desc->if_type;
 651         udp->usb_interface = desc->devnum;
 652         buf = &udp[1];
 653 #endif
 654
 655         if (part == 0) /* the actual disk, not a partition */
 656                 return buf;
 657
 658         return dp_part_node(buf, desc, part);
 659 }
 660
 661 /* Construct a device-path from a partition on a blk device: */
 662 struct efi_device_path *efi_dp_from_part(struct blk_desc *desc, int part)
 663 {
 664         void *buf, *start;
 665
 666         start = buf = dp_alloc(dp_part_size(desc, part) + sizeof(END));
 667         if (!buf)
 668                 return NULL;
 669
 670         buf = dp_part_fill(buf, desc, part);
 671
 672         *((struct efi_device_path *)buf) = END;
 673
 674         return start;
 675 }
 676
 677 /*
 678  * Create a device node for a block device partition.
 679  *
 680  * @buf         buffer to which the device path is wirtten
 681  * @desc        block device descriptor
 682  * @part        partition number, 0 identifies a block device
 683  */
 684 struct efi_device_path *efi_dp_part_node(struct blk_desc *desc, int part)
 685 {
 686         efi_uintn_t dpsize;
 687         void *buf;
 688
 689         if (desc->part_type == PART_TYPE_ISO)
 690                 dpsize = sizeof(struct efi_device_path_cdrom_path);
 691         else
 692                 dpsize = sizeof(struct efi_device_path_hard_drive_path);
 693         buf = dp_alloc(dpsize);
 694
 695         dp_part_node(buf, desc, part);
 696
 697         return buf;
 698 }
 699
 700 /* convert path to an UEFI style path (ie. DOS style backslashes and utf16) */
 701 static void path_to_uefi(u16 *uefi, const char *path)
 702 {
 703         while (*path) {
 704                 char c = *(path++);
 705                 if (c == '/')
 706                         c = '\\';
 707                 *(uefi++) = c;
 708         }
 709         *uefi = '\0';
 710 }
 711
 712 /*
 713  * If desc is NULL, this creates a path with only the file component,
 714  * otherwise it creates a full path with both device and file components
 715  */
 716 struct efi_device_path *efi_dp_from_file(struct blk_desc *desc, int part,
 717                 const char *path)
 718 {
 719         struct efi_device_path_file_path *fp;
 720         void *buf, *start;
 721         unsigned dpsize = 0, fpsize;
 722
 723         if (desc)
 724                 dpsize = dp_part_size(desc, part);
 725
 726         fpsize = sizeof(struct efi_device_path) + 2 * (strlen(path) + 1);
 727         dpsize += fpsize;
 728
 729         start = buf = dp_alloc(dpsize + sizeof(END));
 730         if (!buf)
 731                 return NULL;
 732
 733         if (desc)
 734                 buf = dp_part_fill(buf, desc, part);
 735
 736         /* add file-path: */
 737         fp = buf;
 738         fp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 739         fp->dp.sub_type = DEVICE_PATH_SUB_TYPE_FILE_PATH;
 740         fp->dp.length = fpsize;
 741         path_to_uefi(fp->str, path);
 742         buf += fpsize;
 743
 744         *((struct efi_device_path *)buf) = END;
 745
 746         return start;
 747 }
 748
 749 #ifdef CONFIG_NET
 750 struct efi_device_path *efi_dp_from_eth(void)
 751 {
 752         struct efi_device_path_mac_addr *ndp;
 753         void *buf, *start;
 754         unsigned dpsize = 0;
 755
 756         assert(eth_get_dev());
 757
 758 #ifdef CONFIG_DM_ETH
 759         dpsize += dp_size(eth_get_dev());
 760 #else
 761         dpsize += sizeof(ROOT);
 762 #endif
 763         dpsize += sizeof(*ndp);
 764
 765         start = buf = dp_alloc(dpsize + sizeof(END));
 766         if (!buf)
 767                 return NULL;
 768
 769 #ifdef CONFIG_DM_ETH
 770         buf = dp_fill(buf, eth_get_dev());
 771 #else
 772         memcpy(buf, &ROOT, sizeof(ROOT));
 773         buf += sizeof(ROOT);
 774 #endif
 775
 776         ndp = buf;
 777         ndp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 778         ndp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
 779         ndp->dp.length = sizeof(*ndp);
 780         memcpy(ndp->mac.addr, eth_get_ethaddr(), ARP_HLEN);
 781         buf = &ndp[1];
 782
 783         *((struct efi_device_path *)buf) = END;
 784
 785         return start;
 786 }
 787 #endif
 788
 789 /* Construct a device-path for memory-mapped image */
 790 struct efi_device_path *efi_dp_from_mem(uint32_t memory_type,
 791                                         uint64_t start_address,
 792                                         uint64_t end_address)
 793 {
 794         struct efi_device_path_memory *mdp;
 795         void *buf, *start;
 796
 797         start = buf = dp_alloc(sizeof(*mdp) + sizeof(END));
 798         if (!buf)
 799                 return NULL;
 800
 801         mdp = buf;
 802         mdp->dp.type = DEVICE_PATH_TYPE_HARDWARE_DEVICE;
 803         mdp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MEMORY;
 804         mdp->dp.length = sizeof(*mdp);
 805         mdp->memory_type = memory_type;
 806         mdp->start_address = start_address;
 807         mdp->end_address = end_address;
 808         buf = &mdp[1];
 809
 810         *((struct efi_device_path *)buf) = END;
 811
 812         return start;
 813 }
 814
 815 /*
 816  * Helper to split a full device path (containing both device and file
 817  * parts) into it's constituent parts.
 818  */
 819 efi_status_t efi_dp_split_file_path(struct efi_device_path *full_path,
 820                                     struct efi_device_path **device_path,
 821                                     struct efi_device_path **file_path)
 822 {
 823         struct efi_device_path *p, *dp, *fp;
 824
 825         *device_path = NULL;
 826         *file_path = NULL;
 827         dp = efi_dp_dup(full_path);
 828         if (!dp)
 829                 return EFI_OUT_OF_RESOURCES;
 830         p = dp;
 831         while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH)) {
 832                 p = efi_dp_next(p);
 833                 if (!p)
 834                         return EFI_OUT_OF_RESOURCES;
 835         }
 836         fp = efi_dp_dup(p);
 837         if (!fp)
 838                 return EFI_OUT_OF_RESOURCES;
 839         p->type = DEVICE_PATH_TYPE_END;
 840         p->sub_type = DEVICE_PATH_SUB_TYPE_END;
 841         p->length = sizeof(*p);
 842
 843         *device_path = dp;
 844         *file_path = fp;
 845         return EFI_SUCCESS;
 846 }