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         memset(buf, 0, sz);
  70         return buf;
  71 }
  72
  73 /*
  74  * Iterate to next block in device-path, terminating (returning NULL)
  75  * at /End* node.
  76  */
  77 struct efi_device_path *efi_dp_next(const struct efi_device_path *dp)
  78 {
  79         if (dp == NULL)
  80                 return NULL;
  81         if (dp->type == DEVICE_PATH_TYPE_END)
  82                 return NULL;
  83         dp = ((void *)dp) + dp->length;
  84         if (dp->type == DEVICE_PATH_TYPE_END)
  85                 return NULL;
  86         return (struct efi_device_path *)dp;
  87 }
  88
  89 /*
  90  * Compare two device-paths, stopping when the shorter of the two hits
  91  * an End* node.  This is useful to, for example, compare a device-path
  92  * representing a device with one representing a file on the device, or
  93  * a device with a parent device.
  94  */
  95 int efi_dp_match(const struct efi_device_path *a,
  96                  const struct efi_device_path *b)
  97 {
  98         while (1) {
  99                 int ret;
 100
 101                 ret = memcmp(&a->length, &b->length, sizeof(a->length));
 102                 if (ret)
 103                         return ret;
 104
 105                 ret = memcmp(a, b, a->length);
 106                 if (ret)
 107                         return ret;
 108
 109                 a = efi_dp_next(a);
 110                 b = efi_dp_next(b);
 111
 112                 if (!a || !b)
 113                         return 0;
 114         }
 115 }
 116
 117 /*
 118  * See UEFI spec (section 3.1.2, about short-form device-paths..
 119  * tl;dr: we can have a device-path that starts with a USB WWID
 120  * or USB Class node, and a few other cases which don't encode
 121  * the full device path with bus hierarchy:
 122  *
 123  *   - MESSAGING:USB_WWID
 124  *   - MESSAGING:USB_CLASS
 125  *   - MEDIA:FILE_PATH
 126  *   - MEDIA:HARD_DRIVE
 127  *   - MESSAGING:URI
 128  */
 129 static struct efi_device_path *shorten_path(struct efi_device_path *dp)
 130 {
 131         while (dp) {
 132                 /*
 133                  * TODO: Add MESSAGING:USB_WWID and MESSAGING:URI..
 134                  * in practice fallback.efi just uses MEDIA:HARD_DRIVE
 135                  * so not sure when we would see these other cases.
 136                  */
 137                 if (EFI_DP_TYPE(dp, MESSAGING_DEVICE, MSG_USB_CLASS) ||
 138                     EFI_DP_TYPE(dp, MEDIA_DEVICE, HARD_DRIVE_PATH) ||
 139                     EFI_DP_TYPE(dp, MEDIA_DEVICE, FILE_PATH))
 140                         return dp;
 141
 142                 dp = efi_dp_next(dp);
 143         }
 144
 145         return dp;
 146 }
 147
 148 static struct efi_object *find_obj(struct efi_device_path *dp, bool short_path,
 149                                    struct efi_device_path **rem)
 150 {
 151         struct efi_object *efiobj;
 152         unsigned int dp_size = efi_dp_size(dp);
 153
 154         list_for_each_entry(efiobj, &efi_obj_list, link) {
 155                 struct efi_handler *handler;
 156                 struct efi_device_path *obj_dp;
 157                 efi_status_t ret;
 158
 159                 ret = efi_search_protocol(efiobj->handle,
 160                                           &efi_guid_device_path, &handler);
 161                 if (ret != EFI_SUCCESS)
 162                         continue;
 163                 obj_dp = handler->protocol_interface;
 164
 165                 do {
 166                         if (efi_dp_match(dp, obj_dp) == 0) {
 167                                 if (rem) {
 168                                         /*
 169                                          * Allow partial matches, but inform
 170                                          * the caller.
 171                                          */
 172                                         *rem = ((void *)dp) +
 173                                                 efi_dp_size(obj_dp);
 174                                         return efiobj;
 175                                 } else {
 176                                         /* Only return on exact matches */
 177                                         if (efi_dp_size(obj_dp) == dp_size)
 178                                                 return efiobj;
 179                                 }
 180                         }
 181
 182                         obj_dp = shorten_path(efi_dp_next(obj_dp));
 183                 } while (short_path && obj_dp);
 184         }
 185
 186         return NULL;
 187 }
 188
 189 /*
 190  * Find an efiobj from device-path, if 'rem' is not NULL, returns the
 191  * remaining part of the device path after the matched object.
 192  */
 193 struct efi_object *efi_dp_find_obj(struct efi_device_path *dp,
 194                                    struct efi_device_path **rem)
 195 {
 196         struct efi_object *efiobj;
 197
 198         /* Search for an exact match first */
 199         efiobj = find_obj(dp, false, NULL);
 200
 201         /* Then for a fuzzy match */
 202         if (!efiobj)
 203                 efiobj = find_obj(dp, false, rem);
 204
 205         /* And now for a fuzzy short match */
 206         if (!efiobj)
 207                 efiobj = find_obj(dp, true, rem);
 208
 209         return efiobj;
 210 }
 211
 212 /*
 213  * Determine the last device path node that is not the end node.
 214  *
 215  * @dp          device path
 216  * @return      last node before the end node if it exists
 217  *              otherwise NULL
 218  */
 219 const struct efi_device_path *efi_dp_last_node(const struct efi_device_path *dp)
 220 {
 221         struct efi_device_path *ret;
 222
 223         if (!dp || dp->type == DEVICE_PATH_TYPE_END)
 224                 return NULL;
 225         while (dp) {
 226                 ret = (struct efi_device_path *)dp;
 227                 dp = efi_dp_next(dp);
 228         }
 229         return ret;
 230 }
 231
 232 /* return size not including End node: */
 233 unsigned efi_dp_size(const struct efi_device_path *dp)
 234 {
 235         unsigned sz = 0;
 236
 237         while (dp) {
 238                 sz += dp->length;
 239                 dp = efi_dp_next(dp);
 240         }
 241
 242         return sz;
 243 }
 244
 245 struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp)
 246 {
 247         struct efi_device_path *ndp;
 248         unsigned sz = efi_dp_size(dp) + sizeof(END);
 249
 250         if (!dp)
 251                 return NULL;
 252
 253         ndp = dp_alloc(sz);
 254         if (!ndp)
 255                 return NULL;
 256         memcpy(ndp, dp, sz);
 257
 258         return ndp;
 259 }
 260
 261 struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
 262                                       const struct efi_device_path *dp2)
 263 {
 264         struct efi_device_path *ret;
 265
 266         if (!dp1) {
 267                 ret = efi_dp_dup(dp2);
 268         } else if (!dp2) {
 269                 ret = efi_dp_dup(dp1);
 270         } else {
 271                 /* both dp1 and dp2 are non-null */
 272                 unsigned sz1 = efi_dp_size(dp1);
 273                 unsigned sz2 = efi_dp_size(dp2);
 274                 void *p = dp_alloc(sz1 + sz2 + sizeof(END));
 275                 if (!p)
 276                         return NULL;
 277                 memcpy(p, dp1, sz1);
 278                 memcpy(p + sz1, dp2, sz2);
 279                 memcpy(p + sz1 + sz2, &END, sizeof(END));
 280                 ret = p;
 281         }
 282
 283         return ret;
 284 }
 285
 286 struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
 287                                            const struct efi_device_path *node)
 288 {
 289         struct efi_device_path *ret;
 290
 291         if (!node && !dp) {
 292                 ret = efi_dp_dup(&END);
 293         } else if (!node) {
 294                 ret = efi_dp_dup(dp);
 295         } else if (!dp) {
 296                 unsigned sz = node->length;
 297                 void *p = dp_alloc(sz + sizeof(END));
 298                 if (!p)
 299                         return NULL;
 300                 memcpy(p, node, sz);
 301                 memcpy(p + sz, &END, sizeof(END));
 302                 ret = p;
 303         } else {
 304                 /* both dp and node are non-null */
 305                 unsigned sz = efi_dp_size(dp);
 306                 void *p = dp_alloc(sz + node->length + sizeof(END));
 307                 if (!p)
 308                         return NULL;
 309                 memcpy(p, dp, sz);
 310                 memcpy(p + sz, node, node->length);
 311                 memcpy(p + sz + node->length, &END, sizeof(END));
 312                 ret = p;
 313         }
 314
 315         return ret;
 316 }
 317
 318 struct efi_device_path *efi_dp_create_device_node(const u8 type,
 319                                                   const u8 sub_type,
 320                                                   const u16 length)
 321 {
 322         struct efi_device_path *ret;
 323
 324         ret = dp_alloc(length);
 325         if (!ret)
 326                 return ret;
 327         ret->type = type;
 328         ret->sub_type = sub_type;
 329         ret->length = length;
 330         return ret;
 331 }
 332
 333 #ifdef CONFIG_DM
 334 /* size of device-path not including END node for device and all parents
 335  * up to the root device.
 336  */
 337 static unsigned dp_size(struct udevice *dev)
 338 {
 339         if (!dev || !dev->driver)
 340                 return sizeof(ROOT);
 341
 342         switch (dev->driver->id) {
 343         case UCLASS_ROOT:
 344         case UCLASS_SIMPLE_BUS:
 345                 /* stop traversing parents at this point: */
 346                 return sizeof(ROOT);
 347         case UCLASS_ETH:
 348                 return dp_size(dev->parent) +
 349                         sizeof(struct efi_device_path_mac_addr);
 350 #ifdef CONFIG_BLK
 351         case UCLASS_BLK:
 352                 switch (dev->parent->uclass->uc_drv->id) {
 353 #ifdef CONFIG_IDE
 354                 case UCLASS_IDE:
 355                         return dp_size(dev->parent) +
 356                                 sizeof(struct efi_device_path_atapi);
 357 #endif
 358 #if defined(CONFIG_SCSI) && defined(CONFIG_DM_SCSI)
 359                 case UCLASS_SCSI:
 360                         return dp_size(dev->parent) +
 361                                 sizeof(struct efi_device_path_scsi);
 362 #endif
 363 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 364                 case UCLASS_MMC:
 365                         return dp_size(dev->parent) +
 366                                 sizeof(struct efi_device_path_sd_mmc_path);
 367 #endif
 368                 default:
 369                         return dp_size(dev->parent);
 370                 }
 371 #endif
 372 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 373         case UCLASS_MMC:
 374                 return dp_size(dev->parent) +
 375                         sizeof(struct efi_device_path_sd_mmc_path);
 376 #endif
 377         case UCLASS_MASS_STORAGE:
 378         case UCLASS_USB_HUB:
 379                 return dp_size(dev->parent) +
 380                         sizeof(struct efi_device_path_usb_class);
 381         default:
 382                 /* just skip over unknown classes: */
 383                 return dp_size(dev->parent);
 384         }
 385 }
 386
 387 /*
 388  * Recursively build a device path.
 389  *
 390  * @buf         pointer to the end of the device path
 391  * @dev         device
 392  * @return      pointer to the end of the device path
 393  */
 394 static void *dp_fill(void *buf, struct udevice *dev)
 395 {
 396         if (!dev || !dev->driver)
 397                 return buf;
 398
 399         switch (dev->driver->id) {
 400         case UCLASS_ROOT:
 401         case UCLASS_SIMPLE_BUS: {
 402                 /* stop traversing parents at this point: */
 403                 struct efi_device_path_vendor *vdp = buf;
 404                 *vdp = ROOT;
 405                 return &vdp[1];
 406         }
 407 #ifdef CONFIG_DM_ETH
 408         case UCLASS_ETH: {
 409                 struct efi_device_path_mac_addr *dp =
 410                         dp_fill(buf, dev->parent);
 411                 struct eth_pdata *pdata = dev->platdata;
 412
 413                 dp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 414                 dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
 415                 dp->dp.length = sizeof(*dp);
 416                 memset(&dp->mac, 0, sizeof(dp->mac));
 417                 /* We only support IPv4 */
 418                 memcpy(&dp->mac, &pdata->enetaddr, ARP_HLEN);
 419                 /* Ethernet */
 420                 dp->if_type = 1;
 421                 return &dp[1];
 422         }
 423 #endif
 424 #ifdef CONFIG_BLK
 425         case UCLASS_BLK:
 426                 switch (dev->parent->uclass->uc_drv->id) {
 427 #ifdef CONFIG_IDE
 428                 case UCLASS_IDE: {
 429                         struct efi_device_path_atapi *dp =
 430                         dp_fill(buf, dev->parent);
 431                         struct blk_desc *desc = dev_get_uclass_platdata(dev);
 432
 433                         dp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 434                         dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_ATAPI;
 435                         dp->dp.length = sizeof(*dp);
 436                         dp->logical_unit_number = desc->devnum;
 437                         dp->primary_secondary = IDE_BUS(desc->devnum);
 438                         dp->slave_master = desc->devnum %
 439                                 (CONFIG_SYS_IDE_MAXDEVICE /
 440                                  CONFIG_SYS_IDE_MAXBUS);
 441                         return &dp[1];
 442                         }
 443 #endif
 444 #if defined(CONFIG_SCSI) && defined(CONFIG_DM_SCSI)
 445                 case UCLASS_SCSI: {
 446                         struct efi_device_path_scsi *dp =
 447                                 dp_fill(buf, dev->parent);
 448                         struct blk_desc *desc = dev_get_uclass_platdata(dev);
 449
 450                         dp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 451                         dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_SCSI;
 452                         dp->dp.length = sizeof(*dp);
 453                         dp->logical_unit_number = desc->lun;
 454                         dp->target_id = desc->target;
 455                         return &dp[1];
 456                         }
 457 #endif
 458 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 459                 case UCLASS_MMC: {
 460                         struct efi_device_path_sd_mmc_path *sddp =
 461                                 dp_fill(buf, dev->parent);
 462                         struct blk_desc *desc = dev_get_uclass_platdata(dev);
 463
 464                         sddp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 465                         sddp->dp.sub_type = is_sd(desc) ?
 466                                 DEVICE_PATH_SUB_TYPE_MSG_SD :
 467                                 DEVICE_PATH_SUB_TYPE_MSG_MMC;
 468                         sddp->dp.length   = sizeof(*sddp);
 469                         sddp->slot_number = dev->seq;
 470                         return &sddp[1];
 471                         }
 472 #endif
 473                 default:
 474                         debug("%s(%u) %s: unhandled parent class: %s (%u)\n",
 475                               __FILE__, __LINE__, __func__,
 476                               dev->name, dev->parent->uclass->uc_drv->id);
 477                         return dp_fill(buf, dev->parent);
 478                 }
 479 #endif
 480 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 481         case UCLASS_MMC: {
 482                 struct efi_device_path_sd_mmc_path *sddp =
 483                         dp_fill(buf, dev->parent);
 484                 struct mmc *mmc = mmc_get_mmc_dev(dev);
 485                 struct blk_desc *desc = mmc_get_blk_desc(mmc);
 486
 487                 sddp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 488                 sddp->dp.sub_type = is_sd(desc) ?
 489                         DEVICE_PATH_SUB_TYPE_MSG_SD :
 490                         DEVICE_PATH_SUB_TYPE_MSG_MMC;
 491                 sddp->dp.length   = sizeof(*sddp);
 492                 sddp->slot_number = dev->seq;
 493
 494                 return &sddp[1];
 495         }
 496 #endif
 497         case UCLASS_MASS_STORAGE:
 498         case UCLASS_USB_HUB: {
 499                 struct efi_device_path_usb_class *udp =
 500                         dp_fill(buf, dev->parent);
 501                 struct usb_device *udev = dev_get_parent_priv(dev);
 502                 struct usb_device_descriptor *desc = &udev->descriptor;
 503
 504                 udp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 505                 udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB_CLASS;
 506                 udp->dp.length   = sizeof(*udp);
 507                 udp->vendor_id   = desc->idVendor;
 508                 udp->product_id  = desc->idProduct;
 509                 udp->device_class    = desc->bDeviceClass;
 510                 udp->device_subclass = desc->bDeviceSubClass;
 511                 udp->device_protocol = desc->bDeviceProtocol;
 512
 513                 return &udp[1];
 514         }
 515         default:
 516                 debug("%s(%u) %s: unhandled device class: %s (%u)\n",
 517                       __FILE__, __LINE__, __func__,
 518                       dev->name, dev->driver->id);
 519                 return dp_fill(buf, dev->parent);
 520         }
 521 }
 522
 523 /* Construct a device-path from a device: */
 524 struct efi_device_path *efi_dp_from_dev(struct udevice *dev)
 525 {
 526         void *buf, *start;
 527
 528         start = buf = dp_alloc(dp_size(dev) + sizeof(END));
 529         if (!buf)
 530                 return NULL;
 531         buf = dp_fill(buf, dev);
 532         *((struct efi_device_path *)buf) = END;
 533
 534         return start;
 535 }
 536 #endif
 537
 538 static unsigned dp_part_size(struct blk_desc *desc, int part)
 539 {
 540         unsigned dpsize;
 541
 542 #ifdef CONFIG_BLK
 543         {
 544                 struct udevice *dev;
 545                 int ret = blk_find_device(desc->if_type, desc->devnum, &dev);
 546
 547                 if (ret)
 548                         dev = desc->bdev->parent;
 549                 dpsize = dp_size(dev);
 550         }
 551 #else
 552         dpsize = sizeof(ROOT) + sizeof(struct efi_device_path_usb);
 553 #endif
 554
 555         if (part == 0) /* the actual disk, not a partition */
 556                 return dpsize;
 557
 558         if (desc->part_type == PART_TYPE_ISO)
 559                 dpsize += sizeof(struct efi_device_path_cdrom_path);
 560         else
 561                 dpsize += sizeof(struct efi_device_path_hard_drive_path);
 562
 563         return dpsize;
 564 }
 565
 566 /*
 567  * Create a device node for a block device partition.
 568  *
 569  * @buf         buffer to which the device path is wirtten
 570  * @desc        block device descriptor
 571  * @part        partition number, 0 identifies a block device
 572  */
 573 static void *dp_part_node(void *buf, struct blk_desc *desc, int part)
 574 {
 575         disk_partition_t info;
 576
 577         part_get_info(desc, part, &info);
 578
 579         if (desc->part_type == PART_TYPE_ISO) {
 580                 struct efi_device_path_cdrom_path *cddp = buf;
 581
 582                 cddp->boot_entry = part;
 583                 cddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 584                 cddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_CDROM_PATH;
 585                 cddp->dp.length = sizeof(*cddp);
 586                 cddp->partition_start = info.start;
 587                 cddp->partition_end = info.size;
 588
 589                 buf = &cddp[1];
 590         } else {
 591                 struct efi_device_path_hard_drive_path *hddp = buf;
 592
 593                 hddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 594                 hddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH;
 595                 hddp->dp.length = sizeof(*hddp);
 596                 hddp->partition_number = part;
 597                 hddp->partition_start = info.start;
 598                 hddp->partition_end = info.size;
 599                 if (desc->part_type == PART_TYPE_EFI)
 600                         hddp->partmap_type = 2;
 601                 else
 602                         hddp->partmap_type = 1;
 603
 604                 switch (desc->sig_type) {
 605                 case SIG_TYPE_NONE:
 606                 default:
 607                         hddp->signature_type = 0;
 608                         memset(hddp->partition_signature, 0,
 609                                sizeof(hddp->partition_signature));
 610                         break;
 611                 case SIG_TYPE_MBR:
 612                         hddp->signature_type = 1;
 613                         memset(hddp->partition_signature, 0,
 614                                sizeof(hddp->partition_signature));
 615                         memcpy(hddp->partition_signature, &desc->mbr_sig,
 616                                sizeof(desc->mbr_sig));
 617                         break;
 618                 case SIG_TYPE_GUID:
 619                         hddp->signature_type = 2;
 620                         memcpy(hddp->partition_signature, &desc->guid_sig,
 621                                sizeof(hddp->partition_signature));
 622                         break;
 623                 }
 624
 625                 buf = &hddp[1];
 626         }
 627
 628         return buf;
 629 }
 630
 631 /*
 632  * Create a device path for a block device or one of its partitions.
 633  *
 634  * @buf         buffer to which the device path is wirtten
 635  * @desc        block device descriptor
 636  * @part        partition number, 0 identifies a block device
 637  */
 638 static void *dp_part_fill(void *buf, struct blk_desc *desc, int part)
 639 {
 640 #ifdef CONFIG_BLK
 641         {
 642                 struct udevice *dev;
 643                 int ret = blk_find_device(desc->if_type, desc->devnum, &dev);
 644
 645                 if (ret)
 646                         dev = desc->bdev->parent;
 647                 buf = dp_fill(buf, dev);
 648         }
 649 #else
 650         /*
 651          * We *could* make a more accurate path, by looking at if_type
 652          * and handling all the different cases like we do for non-
 653          * legacy (ie CONFIG_BLK=y) case.  But most important thing
 654          * is just to have a unique device-path for if_type+devnum.
 655          * So map things to a fictitious USB device.
 656          */
 657         struct efi_device_path_usb *udp;
 658
 659         memcpy(buf, &ROOT, sizeof(ROOT));
 660         buf += sizeof(ROOT);
 661
 662         udp = buf;
 663         udp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 664         udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB;
 665         udp->dp.length = sizeof(*udp);
 666         udp->parent_port_number = desc->if_type;
 667         udp->usb_interface = desc->devnum;
 668         buf = &udp[1];
 669 #endif
 670
 671         if (part == 0) /* the actual disk, not a partition */
 672                 return buf;
 673
 674         return dp_part_node(buf, desc, part);
 675 }
 676
 677 /* Construct a device-path from a partition on a blk device: */
 678 struct efi_device_path *efi_dp_from_part(struct blk_desc *desc, int part)
 679 {
 680         void *buf, *start;
 681
 682         start = buf = dp_alloc(dp_part_size(desc, part) + sizeof(END));
 683         if (!buf)
 684                 return NULL;
 685
 686         buf = dp_part_fill(buf, desc, part);
 687
 688         *((struct efi_device_path *)buf) = END;
 689
 690         return start;
 691 }
 692
 693 /*
 694  * Create a device node for a block device partition.
 695  *
 696  * @buf         buffer to which the device path is wirtten
 697  * @desc        block device descriptor
 698  * @part        partition number, 0 identifies a block device
 699  */
 700 struct efi_device_path *efi_dp_part_node(struct blk_desc *desc, int part)
 701 {
 702         efi_uintn_t dpsize;
 703         void *buf;
 704
 705         if (desc->part_type == PART_TYPE_ISO)
 706                 dpsize = sizeof(struct efi_device_path_cdrom_path);
 707         else
 708                 dpsize = sizeof(struct efi_device_path_hard_drive_path);
 709         buf = dp_alloc(dpsize);
 710
 711         dp_part_node(buf, desc, part);
 712
 713         return buf;
 714 }
 715
 716 /* convert path to an UEFI style path (ie. DOS style backslashes and utf16) */
 717 static void path_to_uefi(u16 *uefi, const char *path)
 718 {
 719         while (*path) {
 720                 char c = *(path++);
 721                 if (c == '/')
 722                         c = '\\';
 723                 *(uefi++) = c;
 724         }
 725         *uefi = '\0';
 726 }
 727
 728 /*
 729  * If desc is NULL, this creates a path with only the file component,
 730  * otherwise it creates a full path with both device and file components
 731  */
 732 struct efi_device_path *efi_dp_from_file(struct blk_desc *desc, int part,
 733                 const char *path)
 734 {
 735         struct efi_device_path_file_path *fp;
 736         void *buf, *start;
 737         unsigned dpsize = 0, fpsize;
 738
 739         if (desc)
 740                 dpsize = dp_part_size(desc, part);
 741
 742         fpsize = sizeof(struct efi_device_path) + 2 * (strlen(path) + 1);
 743         dpsize += fpsize;
 744
 745         start = buf = dp_alloc(dpsize + sizeof(END));
 746         if (!buf)
 747                 return NULL;
 748
 749         if (desc)
 750                 buf = dp_part_fill(buf, desc, part);
 751
 752         /* add file-path: */
 753         fp = buf;
 754         fp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 755         fp->dp.sub_type = DEVICE_PATH_SUB_TYPE_FILE_PATH;
 756         fp->dp.length = fpsize;
 757         path_to_uefi(fp->str, path);
 758         buf += fpsize;
 759
 760         *((struct efi_device_path *)buf) = END;
 761
 762         return start;
 763 }
 764
 765 #ifdef CONFIG_NET
 766 struct efi_device_path *efi_dp_from_eth(void)
 767 {
 768 #ifndef CONFIG_DM_ETH
 769         struct efi_device_path_mac_addr *ndp;
 770 #endif
 771         void *buf, *start;
 772         unsigned dpsize = 0;
 773
 774         assert(eth_get_dev());
 775
 776 #ifdef CONFIG_DM_ETH
 777         dpsize += dp_size(eth_get_dev());
 778 #else
 779         dpsize += sizeof(ROOT);
 780         dpsize += sizeof(*ndp);
 781 #endif
 782
 783         start = buf = dp_alloc(dpsize + sizeof(END));
 784         if (!buf)
 785                 return NULL;
 786
 787 #ifdef CONFIG_DM_ETH
 788         buf = dp_fill(buf, eth_get_dev());
 789 #else
 790         memcpy(buf, &ROOT, sizeof(ROOT));
 791         buf += sizeof(ROOT);
 792
 793         ndp = buf;
 794         ndp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 795         ndp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
 796         ndp->dp.length = sizeof(*ndp);
 797         ndp->if_type = 1; /* Ethernet */
 798         memcpy(ndp->mac.addr, eth_get_ethaddr(), ARP_HLEN);
 799         buf = &ndp[1];
 800 #endif
 801
 802         *((struct efi_device_path *)buf) = END;
 803
 804         return start;
 805 }
 806 #endif
 807
 808 /* Construct a device-path for memory-mapped image */
 809 struct efi_device_path *efi_dp_from_mem(uint32_t memory_type,
 810                                         uint64_t start_address,
 811                                         uint64_t end_address)
 812 {
 813         struct efi_device_path_memory *mdp;
 814         void *buf, *start;
 815
 816         start = buf = dp_alloc(sizeof(*mdp) + sizeof(END));
 817         if (!buf)
 818                 return NULL;
 819
 820         mdp = buf;
 821         mdp->dp.type = DEVICE_PATH_TYPE_HARDWARE_DEVICE;
 822         mdp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MEMORY;
 823         mdp->dp.length = sizeof(*mdp);
 824         mdp->memory_type = memory_type;
 825         mdp->start_address = start_address;
 826         mdp->end_address = end_address;
 827         buf = &mdp[1];
 828
 829         *((struct efi_device_path *)buf) = END;
 830
 831         return start;
 832 }
 833
 834 /*
 835  * Helper to split a full device path (containing both device and file
 836  * parts) into it's constituent parts.
 837  */
 838 efi_status_t efi_dp_split_file_path(struct efi_device_path *full_path,
 839                                     struct efi_device_path **device_path,
 840                                     struct efi_device_path **file_path)
 841 {
 842         struct efi_device_path *p, *dp, *fp;
 843
 844         *device_path = NULL;
 845         *file_path = NULL;
 846         dp = efi_dp_dup(full_path);
 847         if (!dp)
 848                 return EFI_OUT_OF_RESOURCES;
 849         p = dp;
 850         while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH)) {
 851                 p = efi_dp_next(p);
 852                 if (!p)
 853                         return EFI_OUT_OF_RESOURCES;
 854         }
 855         fp = efi_dp_dup(p);
 856         if (!fp)
 857                 return EFI_OUT_OF_RESOURCES;
 858         p->type = DEVICE_PATH_TYPE_END;
 859         p->sub_type = DEVICE_PATH_SUB_TYPE_END;
 860         p->length = sizeof(*p);
 861
 862         *device_path = dp;
 863         *file_path = fp;
 864         return EFI_SUCCESS;
 865 }