git.sur5r.net Git - u-boot/blob - 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 && !dp2) {
 267                 /* return an end node */
 268                 ret = efi_dp_dup(&END);
 269         } else if (!dp1) {
 270                 ret = efi_dp_dup(dp2);
 271         } else if (!dp2) {
 272                 ret = efi_dp_dup(dp1);
 273         } else {
 274                 /* both dp1 and dp2 are non-null */
 275                 unsigned sz1 = efi_dp_size(dp1);
 276                 unsigned sz2 = efi_dp_size(dp2);
 277                 void *p = dp_alloc(sz1 + sz2 + sizeof(END));
 278                 if (!p)
 279                         return NULL;
 280                 memcpy(p, dp1, sz1);
 281                 /* the end node of the second device path has to be retained */
 282                 memcpy(p + sz1, dp2, sz2 + sizeof(END));
 283                 ret = p;
 284         }
 285
 286         return ret;
 287 }
 288
 289 struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
 290                                            const struct efi_device_path *node)
 291 {
 292         struct efi_device_path *ret;
 293
 294         if (!node && !dp) {
 295                 ret = efi_dp_dup(&END);
 296         } else if (!node) {
 297                 ret = efi_dp_dup(dp);
 298         } else if (!dp) {
 299                 unsigned sz = node->length;
 300                 void *p = dp_alloc(sz + sizeof(END));
 301                 if (!p)
 302                         return NULL;
 303                 memcpy(p, node, sz);
 304                 memcpy(p + sz, &END, sizeof(END));
 305                 ret = p;
 306         } else {
 307                 /* both dp and node are non-null */
 308                 unsigned sz = efi_dp_size(dp);
 309                 void *p = dp_alloc(sz + node->length + sizeof(END));
 310                 if (!p)
 311                         return NULL;
 312                 memcpy(p, dp, sz);
 313                 memcpy(p + sz, node, node->length);
 314                 memcpy(p + sz + node->length, &END, sizeof(END));
 315                 ret = p;
 316         }
 317
 318         return ret;
 319 }
 320
 321 struct efi_device_path *efi_dp_create_device_node(const u8 type,
 322                                                   const u8 sub_type,
 323                                                   const u16 length)
 324 {
 325         struct efi_device_path *ret;
 326
 327         ret = dp_alloc(length);
 328         if (!ret)
 329                 return ret;
 330         ret->type = type;
 331         ret->sub_type = sub_type;
 332         ret->length = length;
 333         return ret;
 334 }
 335
 336 #ifdef CONFIG_DM
 337 /* size of device-path not including END node for device and all parents
 338  * up to the root device.
 339  */
 340 static unsigned dp_size(struct udevice *dev)
 341 {
 342         if (!dev || !dev->driver)
 343                 return sizeof(ROOT);
 344
 345         switch (dev->driver->id) {
 346         case UCLASS_ROOT:
 347         case UCLASS_SIMPLE_BUS:
 348                 /* stop traversing parents at this point: */
 349                 return sizeof(ROOT);
 350         case UCLASS_ETH:
 351                 return dp_size(dev->parent) +
 352                         sizeof(struct efi_device_path_mac_addr);
 353 #ifdef CONFIG_BLK
 354         case UCLASS_BLK:
 355                 switch (dev->parent->uclass->uc_drv->id) {
 356 #ifdef CONFIG_IDE
 357                 case UCLASS_IDE:
 358                         return dp_size(dev->parent) +
 359                                 sizeof(struct efi_device_path_atapi);
 360 #endif
 361 #if defined(CONFIG_SCSI) && defined(CONFIG_DM_SCSI)
 362                 case UCLASS_SCSI:
 363                         return dp_size(dev->parent) +
 364                                 sizeof(struct efi_device_path_scsi);
 365 #endif
 366 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 367                 case UCLASS_MMC:
 368                         return dp_size(dev->parent) +
 369                                 sizeof(struct efi_device_path_sd_mmc_path);
 370 #endif
 371                 default:
 372                         return dp_size(dev->parent);
 373                 }
 374 #endif
 375 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 376         case UCLASS_MMC:
 377                 return dp_size(dev->parent) +
 378                         sizeof(struct efi_device_path_sd_mmc_path);
 379 #endif
 380         case UCLASS_MASS_STORAGE:
 381         case UCLASS_USB_HUB:
 382                 return dp_size(dev->parent) +
 383                         sizeof(struct efi_device_path_usb_class);
 384         default:
 385                 /* just skip over unknown classes: */
 386                 return dp_size(dev->parent);
 387         }
 388 }
 389
 390 /*
 391  * Recursively build a device path.
 392  *
 393  * @buf         pointer to the end of the device path
 394  * @dev         device
 395  * @return      pointer to the end of the device path
 396  */
 397 static void *dp_fill(void *buf, struct udevice *dev)
 398 {
 399         if (!dev || !dev->driver)
 400                 return buf;
 401
 402         switch (dev->driver->id) {
 403         case UCLASS_ROOT:
 404         case UCLASS_SIMPLE_BUS: {
 405                 /* stop traversing parents at this point: */
 406                 struct efi_device_path_vendor *vdp = buf;
 407                 *vdp = ROOT;
 408                 return &vdp[1];
 409         }
 410 #ifdef CONFIG_DM_ETH
 411         case UCLASS_ETH: {
 412                 struct efi_device_path_mac_addr *dp =
 413                         dp_fill(buf, dev->parent);
 414                 struct eth_pdata *pdata = dev->platdata;
 415
 416                 dp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 417                 dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
 418                 dp->dp.length = sizeof(*dp);
 419                 memset(&dp->mac, 0, sizeof(dp->mac));
 420                 /* We only support IPv4 */
 421                 memcpy(&dp->mac, &pdata->enetaddr, ARP_HLEN);
 422                 /* Ethernet */
 423                 dp->if_type = 1;
 424                 return &dp[1];
 425         }
 426 #endif
 427 #ifdef CONFIG_BLK
 428         case UCLASS_BLK:
 429                 switch (dev->parent->uclass->uc_drv->id) {
 430 #ifdef CONFIG_IDE
 431                 case UCLASS_IDE: {
 432                         struct efi_device_path_atapi *dp =
 433                         dp_fill(buf, dev->parent);
 434                         struct blk_desc *desc = dev_get_uclass_platdata(dev);
 435
 436                         dp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 437                         dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_ATAPI;
 438                         dp->dp.length = sizeof(*dp);
 439                         dp->logical_unit_number = desc->devnum;
 440                         dp->primary_secondary = IDE_BUS(desc->devnum);
 441                         dp->slave_master = desc->devnum %
 442                                 (CONFIG_SYS_IDE_MAXDEVICE /
 443                                  CONFIG_SYS_IDE_MAXBUS);
 444                         return &dp[1];
 445                         }
 446 #endif
 447 #if defined(CONFIG_SCSI) && defined(CONFIG_DM_SCSI)
 448                 case UCLASS_SCSI: {
 449                         struct efi_device_path_scsi *dp =
 450                                 dp_fill(buf, dev->parent);
 451                         struct blk_desc *desc = dev_get_uclass_platdata(dev);
 452
 453                         dp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 454                         dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_SCSI;
 455                         dp->dp.length = sizeof(*dp);
 456                         dp->logical_unit_number = desc->lun;
 457                         dp->target_id = desc->target;
 458                         return &dp[1];
 459                         }
 460 #endif
 461 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 462                 case UCLASS_MMC: {
 463                         struct efi_device_path_sd_mmc_path *sddp =
 464                                 dp_fill(buf, dev->parent);
 465                         struct blk_desc *desc = dev_get_uclass_platdata(dev);
 466
 467                         sddp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 468                         sddp->dp.sub_type = is_sd(desc) ?
 469                                 DEVICE_PATH_SUB_TYPE_MSG_SD :
 470                                 DEVICE_PATH_SUB_TYPE_MSG_MMC;
 471                         sddp->dp.length   = sizeof(*sddp);
 472                         sddp->slot_number = dev->seq;
 473                         return &sddp[1];
 474                         }
 475 #endif
 476                 default:
 477                         debug("%s(%u) %s: unhandled parent class: %s (%u)\n",
 478                               __FILE__, __LINE__, __func__,
 479                               dev->name, dev->parent->uclass->uc_drv->id);
 480                         return dp_fill(buf, dev->parent);
 481                 }
 482 #endif
 483 #if defined(CONFIG_DM_MMC) && defined(CONFIG_MMC)
 484         case UCLASS_MMC: {
 485                 struct efi_device_path_sd_mmc_path *sddp =
 486                         dp_fill(buf, dev->parent);
 487                 struct mmc *mmc = mmc_get_mmc_dev(dev);
 488                 struct blk_desc *desc = mmc_get_blk_desc(mmc);
 489
 490                 sddp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 491                 sddp->dp.sub_type = is_sd(desc) ?
 492                         DEVICE_PATH_SUB_TYPE_MSG_SD :
 493                         DEVICE_PATH_SUB_TYPE_MSG_MMC;
 494                 sddp->dp.length   = sizeof(*sddp);
 495                 sddp->slot_number = dev->seq;
 496
 497                 return &sddp[1];
 498         }
 499 #endif
 500         case UCLASS_MASS_STORAGE:
 501         case UCLASS_USB_HUB: {
 502                 struct efi_device_path_usb_class *udp =
 503                         dp_fill(buf, dev->parent);
 504                 struct usb_device *udev = dev_get_parent_priv(dev);
 505                 struct usb_device_descriptor *desc = &udev->descriptor;
 506
 507                 udp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 508                 udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB_CLASS;
 509                 udp->dp.length   = sizeof(*udp);
 510                 udp->vendor_id   = desc->idVendor;
 511                 udp->product_id  = desc->idProduct;
 512                 udp->device_class    = desc->bDeviceClass;
 513                 udp->device_subclass = desc->bDeviceSubClass;
 514                 udp->device_protocol = desc->bDeviceProtocol;
 515
 516                 return &udp[1];
 517         }
 518         default:
 519                 debug("%s(%u) %s: unhandled device class: %s (%u)\n",
 520                       __FILE__, __LINE__, __func__,
 521                       dev->name, dev->driver->id);
 522                 return dp_fill(buf, dev->parent);
 523         }
 524 }
 525
 526 /* Construct a device-path from a device: */
 527 struct efi_device_path *efi_dp_from_dev(struct udevice *dev)
 528 {
 529         void *buf, *start;
 530
 531         start = buf = dp_alloc(dp_size(dev) + sizeof(END));
 532         if (!buf)
 533                 return NULL;
 534         buf = dp_fill(buf, dev);
 535         *((struct efi_device_path *)buf) = END;
 536
 537         return start;
 538 }
 539 #endif
 540
 541 static unsigned dp_part_size(struct blk_desc *desc, int part)
 542 {
 543         unsigned dpsize;
 544
 545 #ifdef CONFIG_BLK
 546         {
 547                 struct udevice *dev;
 548                 int ret = blk_find_device(desc->if_type, desc->devnum, &dev);
 549
 550                 if (ret)
 551                         dev = desc->bdev->parent;
 552                 dpsize = dp_size(dev);
 553         }
 554 #else
 555         dpsize = sizeof(ROOT) + sizeof(struct efi_device_path_usb);
 556 #endif
 557
 558         if (part == 0) /* the actual disk, not a partition */
 559                 return dpsize;
 560
 561         if (desc->part_type == PART_TYPE_ISO)
 562                 dpsize += sizeof(struct efi_device_path_cdrom_path);
 563         else
 564                 dpsize += sizeof(struct efi_device_path_hard_drive_path);
 565
 566         return dpsize;
 567 }
 568
 569 /*
 570  * Create a device node for a block device partition.
 571  *
 572  * @buf         buffer to which the device path is wirtten
 573  * @desc        block device descriptor
 574  * @part        partition number, 0 identifies a block device
 575  */
 576 static void *dp_part_node(void *buf, struct blk_desc *desc, int part)
 577 {
 578         disk_partition_t info;
 579
 580         part_get_info(desc, part, &info);
 581
 582         if (desc->part_type == PART_TYPE_ISO) {
 583                 struct efi_device_path_cdrom_path *cddp = buf;
 584
 585                 cddp->boot_entry = part;
 586                 cddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 587                 cddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_CDROM_PATH;
 588                 cddp->dp.length = sizeof(*cddp);
 589                 cddp->partition_start = info.start;
 590                 cddp->partition_end = info.size;
 591
 592                 buf = &cddp[1];
 593         } else {
 594                 struct efi_device_path_hard_drive_path *hddp = buf;
 595
 596                 hddp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 597                 hddp->dp.sub_type = DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH;
 598                 hddp->dp.length = sizeof(*hddp);
 599                 hddp->partition_number = part;
 600                 hddp->partition_start = info.start;
 601                 hddp->partition_end = info.size;
 602                 if (desc->part_type == PART_TYPE_EFI)
 603                         hddp->partmap_type = 2;
 604                 else
 605                         hddp->partmap_type = 1;
 606
 607                 switch (desc->sig_type) {
 608                 case SIG_TYPE_NONE:
 609                 default:
 610                         hddp->signature_type = 0;
 611                         memset(hddp->partition_signature, 0,
 612                                sizeof(hddp->partition_signature));
 613                         break;
 614                 case SIG_TYPE_MBR:
 615                         hddp->signature_type = 1;
 616                         memset(hddp->partition_signature, 0,
 617                                sizeof(hddp->partition_signature));
 618                         memcpy(hddp->partition_signature, &desc->mbr_sig,
 619                                sizeof(desc->mbr_sig));
 620                         break;
 621                 case SIG_TYPE_GUID:
 622                         hddp->signature_type = 2;
 623                         memcpy(hddp->partition_signature, &desc->guid_sig,
 624                                sizeof(hddp->partition_signature));
 625                         break;
 626                 }
 627
 628                 buf = &hddp[1];
 629         }
 630
 631         return buf;
 632 }
 633
 634 /*
 635  * Create a device path for a block device or one of its partitions.
 636  *
 637  * @buf         buffer to which the device path is wirtten
 638  * @desc        block device descriptor
 639  * @part        partition number, 0 identifies a block device
 640  */
 641 static void *dp_part_fill(void *buf, struct blk_desc *desc, int part)
 642 {
 643 #ifdef CONFIG_BLK
 644         {
 645                 struct udevice *dev;
 646                 int ret = blk_find_device(desc->if_type, desc->devnum, &dev);
 647
 648                 if (ret)
 649                         dev = desc->bdev->parent;
 650                 buf = dp_fill(buf, dev);
 651         }
 652 #else
 653         /*
 654          * We *could* make a more accurate path, by looking at if_type
 655          * and handling all the different cases like we do for non-
 656          * legacy (ie CONFIG_BLK=y) case.  But most important thing
 657          * is just to have a unique device-path for if_type+devnum.
 658          * So map things to a fictitious USB device.
 659          */
 660         struct efi_device_path_usb *udp;
 661
 662         memcpy(buf, &ROOT, sizeof(ROOT));
 663         buf += sizeof(ROOT);
 664
 665         udp = buf;
 666         udp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 667         udp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_USB;
 668         udp->dp.length = sizeof(*udp);
 669         udp->parent_port_number = desc->if_type;
 670         udp->usb_interface = desc->devnum;
 671         buf = &udp[1];
 672 #endif
 673
 674         if (part == 0) /* the actual disk, not a partition */
 675                 return buf;
 676
 677         return dp_part_node(buf, desc, part);
 678 }
 679
 680 /* Construct a device-path from a partition on a blk device: */
 681 struct efi_device_path *efi_dp_from_part(struct blk_desc *desc, int part)
 682 {
 683         void *buf, *start;
 684
 685         start = buf = dp_alloc(dp_part_size(desc, part) + sizeof(END));
 686         if (!buf)
 687                 return NULL;
 688
 689         buf = dp_part_fill(buf, desc, part);
 690
 691         *((struct efi_device_path *)buf) = END;
 692
 693         return start;
 694 }
 695
 696 /*
 697  * Create a device node for a block device partition.
 698  *
 699  * @buf         buffer to which the device path is wirtten
 700  * @desc        block device descriptor
 701  * @part        partition number, 0 identifies a block device
 702  */
 703 struct efi_device_path *efi_dp_part_node(struct blk_desc *desc, int part)
 704 {
 705         efi_uintn_t dpsize;
 706         void *buf;
 707
 708         if (desc->part_type == PART_TYPE_ISO)
 709                 dpsize = sizeof(struct efi_device_path_cdrom_path);
 710         else
 711                 dpsize = sizeof(struct efi_device_path_hard_drive_path);
 712         buf = dp_alloc(dpsize);
 713
 714         dp_part_node(buf, desc, part);
 715
 716         return buf;
 717 }
 718
 719 /* convert path to an UEFI style path (ie. DOS style backslashes and utf16) */
 720 static void path_to_uefi(u16 *uefi, const char *path)
 721 {
 722         while (*path) {
 723                 char c = *(path++);
 724                 if (c == '/')
 725                         c = '\\';
 726                 *(uefi++) = c;
 727         }
 728         *uefi = '\0';
 729 }
 730
 731 /*
 732  * If desc is NULL, this creates a path with only the file component,
 733  * otherwise it creates a full path with both device and file components
 734  */
 735 struct efi_device_path *efi_dp_from_file(struct blk_desc *desc, int part,
 736                 const char *path)
 737 {
 738         struct efi_device_path_file_path *fp;
 739         void *buf, *start;
 740         unsigned dpsize = 0, fpsize;
 741
 742         if (desc)
 743                 dpsize = dp_part_size(desc, part);
 744
 745         fpsize = sizeof(struct efi_device_path) + 2 * (strlen(path) + 1);
 746         dpsize += fpsize;
 747
 748         start = buf = dp_alloc(dpsize + sizeof(END));
 749         if (!buf)
 750                 return NULL;
 751
 752         if (desc)
 753                 buf = dp_part_fill(buf, desc, part);
 754
 755         /* add file-path: */
 756         fp = buf;
 757         fp->dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
 758         fp->dp.sub_type = DEVICE_PATH_SUB_TYPE_FILE_PATH;
 759         fp->dp.length = fpsize;
 760         path_to_uefi(fp->str, path);
 761         buf += fpsize;
 762
 763         *((struct efi_device_path *)buf) = END;
 764
 765         return start;
 766 }
 767
 768 #ifdef CONFIG_NET
 769 struct efi_device_path *efi_dp_from_eth(void)
 770 {
 771 #ifndef CONFIG_DM_ETH
 772         struct efi_device_path_mac_addr *ndp;
 773 #endif
 774         void *buf, *start;
 775         unsigned dpsize = 0;
 776
 777         assert(eth_get_dev());
 778
 779 #ifdef CONFIG_DM_ETH
 780         dpsize += dp_size(eth_get_dev());
 781 #else
 782         dpsize += sizeof(ROOT);
 783         dpsize += sizeof(*ndp);
 784 #endif
 785
 786         start = buf = dp_alloc(dpsize + sizeof(END));
 787         if (!buf)
 788                 return NULL;
 789
 790 #ifdef CONFIG_DM_ETH
 791         buf = dp_fill(buf, eth_get_dev());
 792 #else
 793         memcpy(buf, &ROOT, sizeof(ROOT));
 794         buf += sizeof(ROOT);
 795
 796         ndp = buf;
 797         ndp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
 798         ndp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
 799         ndp->dp.length = sizeof(*ndp);
 800         ndp->if_type = 1; /* Ethernet */
 801         memcpy(ndp->mac.addr, eth_get_ethaddr(), ARP_HLEN);
 802         buf = &ndp[1];
 803 #endif
 804
 805         *((struct efi_device_path *)buf) = END;
 806
 807         return start;
 808 }
 809 #endif
 810
 811 /* Construct a device-path for memory-mapped image */
 812 struct efi_device_path *efi_dp_from_mem(uint32_t memory_type,
 813                                         uint64_t start_address,
 814                                         uint64_t end_address)
 815 {
 816         struct efi_device_path_memory *mdp;
 817         void *buf, *start;
 818
 819         start = buf = dp_alloc(sizeof(*mdp) + sizeof(END));
 820         if (!buf)
 821                 return NULL;
 822
 823         mdp = buf;
 824         mdp->dp.type = DEVICE_PATH_TYPE_HARDWARE_DEVICE;
 825         mdp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MEMORY;
 826         mdp->dp.length = sizeof(*mdp);
 827         mdp->memory_type = memory_type;
 828         mdp->start_address = start_address;
 829         mdp->end_address = end_address;
 830         buf = &mdp[1];
 831
 832         *((struct efi_device_path *)buf) = END;
 833
 834         return start;
 835 }
 836
 837 /*
 838  * Helper to split a full device path (containing both device and file
 839  * parts) into it's constituent parts.
 840  */
 841 efi_status_t efi_dp_split_file_path(struct efi_device_path *full_path,
 842                                     struct efi_device_path **device_path,
 843                                     struct efi_device_path **file_path)
 844 {
 845         struct efi_device_path *p, *dp, *fp;
 846
 847         *device_path = NULL;
 848         *file_path = NULL;
 849         dp = efi_dp_dup(full_path);
 850         if (!dp)
 851                 return EFI_OUT_OF_RESOURCES;
 852         p = dp;
 853         while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH)) {
 854                 p = efi_dp_next(p);
 855                 if (!p)
 856                         return EFI_OUT_OF_RESOURCES;
 857         }
 858         fp = efi_dp_dup(p);
 859         if (!fp)
 860                 return EFI_OUT_OF_RESOURCES;
 861         p->type = DEVICE_PATH_TYPE_END;
 862         p->sub_type = DEVICE_PATH_SUB_TYPE_END;
 863         p->length = sizeof(*p);
 864
 865         *device_path = dp;
 866         *file_path = fp;
 867         return EFI_SUCCESS;
 868 }