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