1 /* 2 * Copyright (C) 2016 Marvell International Ltd. 3 * 4 * SPDX-License-Identifier: GPL-2.0 5 * https://spdx.org/licenses 6 */ 7 8 #include <config.h> 9 #include <common.h> 10 #include <command.h> 11 #include <vsprintf.h> 12 #include <errno.h> 13 #include <dm.h> 14 15 #include <spi_flash.h> 16 #include <spi.h> 17 #include <nand.h> 18 #include <usb.h> 19 #include <fs.h> 20 #include <mmc.h> 21 #ifdef CONFIG_BLK 22 #include <blk.h> 23 #endif 24 #include <u-boot/sha1.h> 25 #include <u-boot/sha256.h> 26 27 #ifndef CONFIG_SYS_MMC_ENV_DEV 28 #define CONFIG_SYS_MMC_ENV_DEV 0 29 #endif 30 31 #if defined(CONFIG_ARMADA_8K) 32 #define MAIN_HDR_MAGIC 0xB105B002 33 34 struct mvebu_image_header { 35 u32 magic; /* 0-3 */ 36 u32 prolog_size; /* 4-7 */ 37 u32 prolog_checksum; /* 8-11 */ 38 u32 boot_image_size; /* 12-15 */ 39 u32 boot_image_checksum; /* 16-19 */ 40 u32 rsrvd0; /* 20-23 */ 41 u32 load_addr; /* 24-27 */ 42 u32 exec_addr; /* 28-31 */ 43 u8 uart_cfg; /* 32 */ 44 u8 baudrate; /* 33 */ 45 u8 ext_count; /* 34 */ 46 u8 aux_flags; /* 35 */ 47 u32 io_arg_0; /* 36-39 */ 48 u32 io_arg_1; /* 40-43 */ 49 u32 io_arg_2; /* 43-47 */ 50 u32 io_arg_3; /* 48-51 */ 51 u32 rsrvd1; /* 52-55 */ 52 u32 rsrvd2; /* 56-59 */ 53 u32 rsrvd3; /* 60-63 */ 54 }; 55 #elif defined(CONFIG_ARMADA_3700) /* A3700 */ 56 #define HASH_SUM_LEN 16 57 #define IMAGE_VERSION_3_6_0 0x030600 58 #define IMAGE_VERSION_3_5_0 0x030500 59 60 struct common_tim_data { 61 u32 version; 62 u32 identifier; 63 u32 trusted; 64 u32 issue_date; 65 u32 oem_unique_id; 66 u32 reserved[5]; /* Reserve 20 bytes */ 67 u32 boot_flash_sign; 68 u32 num_images; 69 u32 num_keys; 70 u32 size_of_reserved; 71 }; 72 73 struct mvebu_image_info { 74 u32 image_id; 75 u32 next_image_id; 76 u32 flash_entry_addr; 77 u32 load_addr; 78 u32 image_size; 79 u32 image_size_to_hash; 80 u32 hash_algorithm_id; 81 u32 hash[HASH_SUM_LEN]; /* Reserve 512 bits for the hash */ 82 u32 partition_number; 83 u32 enc_algorithm_id; 84 u32 encrypt_start_offset; 85 u32 encrypt_size; 86 }; 87 #endif /* CONFIG_ARMADA_XXX */ 88 89 struct bubt_dev { 90 char name[8]; 91 size_t (*read)(const char *file_name); 92 int (*write)(size_t image_size); 93 int (*active)(void); 94 }; 95 96 static ulong get_load_addr(void) 97 { 98 const char *addr_str; 99 unsigned long addr; 100 101 addr_str = env_get("loadaddr"); 102 if (addr_str) 103 addr = simple_strtoul(addr_str, NULL, 16); 104 else 105 addr = CONFIG_SYS_LOAD_ADDR; 106 107 return addr; 108 } 109 110 /******************************************************************** 111 * eMMC services 112 ********************************************************************/ 113 #if CONFIG_IS_ENABLED(DM_MMC) && CONFIG_IS_ENABLED(MMC_WRITE) 114 static int mmc_burn_image(size_t image_size) 115 { 116 struct mmc *mmc; 117 lbaint_t start_lba; 118 lbaint_t blk_count; 119 ulong blk_written; 120 int err; 121 const u8 mmc_dev_num = CONFIG_SYS_MMC_ENV_DEV; 122 #ifdef CONFIG_BLK 123 struct blk_desc *blk_desc; 124 #endif 125 mmc = find_mmc_device(mmc_dev_num); 126 if (!mmc) { 127 printf("No SD/MMC/eMMC card found\n"); 128 return -ENOMEDIUM; 129 } 130 131 err = mmc_init(mmc); 132 if (err) { 133 printf("%s(%d) init failed\n", IS_SD(mmc) ? "SD" : "MMC", 134 mmc_dev_num); 135 return err; 136 } 137 138 #ifdef CONFIG_SYS_MMC_ENV_PART 139 if (mmc->part_num != CONFIG_SYS_MMC_ENV_PART) { 140 err = mmc_switch_part(mmc_dev_num, CONFIG_SYS_MMC_ENV_PART); 141 if (err) { 142 printf("MMC partition switch failed\n"); 143 return err; 144 } 145 } 146 #endif 147 148 /* SD reserves LBA-0 for MBR and boots from LBA-1, 149 * MMC/eMMC boots from LBA-0 150 */ 151 start_lba = IS_SD(mmc) ? 1 : 0; 152 #ifdef CONFIG_BLK 153 blk_count = image_size / mmc->write_bl_len; 154 if (image_size % mmc->write_bl_len) 155 blk_count += 1; 156 157 blk_desc = mmc_get_blk_desc(mmc); 158 if (!blk_desc) { 159 printf("Error - failed to obtain block descriptor\n"); 160 return -ENODEV; 161 } 162 blk_written = blk_dwrite(blk_desc, start_lba, blk_count, 163 (void *)get_load_addr()); 164 #else 165 blk_count = image_size / mmc->block_dev.blksz; 166 if (image_size % mmc->block_dev.blksz) 167 blk_count += 1; 168 169 blk_written = mmc->block_dev.block_write(mmc_dev_num, 170 start_lba, blk_count, 171 (void *)get_load_addr()); 172 #endif /* CONFIG_BLK */ 173 if (blk_written != blk_count) { 174 printf("Error - written %#lx blocks\n", blk_written); 175 return -ENOSPC; 176 } 177 printf("Done!\n"); 178 179 #ifdef CONFIG_SYS_MMC_ENV_PART 180 if (mmc->part_num != CONFIG_SYS_MMC_ENV_PART) 181 mmc_switch_part(mmc_dev_num, mmc->part_num); 182 #endif 183 184 return 0; 185 } 186 187 static size_t mmc_read_file(const char *file_name) 188 { 189 loff_t act_read = 0; 190 int rc; 191 struct mmc *mmc; 192 const u8 mmc_dev_num = CONFIG_SYS_MMC_ENV_DEV; 193 194 mmc = find_mmc_device(mmc_dev_num); 195 if (!mmc) { 196 printf("No SD/MMC/eMMC card found\n"); 197 return 0; 198 } 199 200 if (mmc_init(mmc)) { 201 printf("%s(%d) init failed\n", IS_SD(mmc) ? "SD" : "MMC", 202 mmc_dev_num); 203 return 0; 204 } 205 206 /* Load from data partition (0) */ 207 if (fs_set_blk_dev("mmc", "0", FS_TYPE_ANY)) { 208 printf("Error: MMC 0 not found\n"); 209 return 0; 210 } 211 212 /* Perfrom file read */ 213 rc = fs_read(file_name, get_load_addr(), 0, 0, &act_read); 214 if (rc) 215 return 0; 216 217 return act_read; 218 } 219 220 static int is_mmc_active(void) 221 { 222 return 1; 223 } 224 #else /* CONFIG_DM_MMC */ 225 static int mmc_burn_image(size_t image_size) 226 { 227 return -ENODEV; 228 } 229 230 static size_t mmc_read_file(const char *file_name) 231 { 232 return 0; 233 } 234 235 static int is_mmc_active(void) 236 { 237 return 0; 238 } 239 #endif /* CONFIG_DM_MMC */ 240 241 /******************************************************************** 242 * SPI services 243 ********************************************************************/ 244 #ifdef CONFIG_SPI_FLASH 245 static int spi_burn_image(size_t image_size) 246 { 247 int ret; 248 struct spi_flash *flash; 249 u32 erase_bytes; 250 251 /* Probe the SPI bus to get the flash device */ 252 flash = spi_flash_probe(CONFIG_ENV_SPI_BUS, 253 CONFIG_ENV_SPI_CS, 254 CONFIG_SF_DEFAULT_SPEED, 255 CONFIG_SF_DEFAULT_MODE); 256 if (!flash) { 257 printf("Failed to probe SPI Flash\n"); 258 return -ENOMEDIUM; 259 } 260 261 #ifdef CONFIG_SPI_FLASH_PROTECTION 262 spi_flash_protect(flash, 0); 263 #endif 264 erase_bytes = image_size + 265 (flash->erase_size - image_size % flash->erase_size); 266 printf("Erasing %d bytes (%d blocks) at offset 0 ...", 267 erase_bytes, erase_bytes / flash->erase_size); 268 ret = spi_flash_erase(flash, 0, erase_bytes); 269 if (ret) 270 printf("Error!\n"); 271 else 272 printf("Done!\n"); 273 274 printf("Writing %d bytes from 0x%lx to offset 0 ...", 275 (int)image_size, get_load_addr()); 276 ret = spi_flash_write(flash, 0, image_size, (void *)get_load_addr()); 277 if (ret) 278 printf("Error!\n"); 279 else 280 printf("Done!\n"); 281 282 #ifdef CONFIG_SPI_FLASH_PROTECTION 283 spi_flash_protect(flash, 1); 284 #endif 285 286 return ret; 287 } 288 289 static int is_spi_active(void) 290 { 291 return 1; 292 } 293 294 #else /* CONFIG_SPI_FLASH */ 295 static int spi_burn_image(size_t image_size) 296 { 297 return -ENODEV; 298 } 299 300 static int is_spi_active(void) 301 { 302 return 0; 303 } 304 #endif /* CONFIG_SPI_FLASH */ 305 306 /******************************************************************** 307 * NAND services 308 ********************************************************************/ 309 #ifdef CONFIG_CMD_NAND 310 static int nand_burn_image(size_t image_size) 311 { 312 int ret; 313 uint32_t block_size; 314 struct mtd_info *mtd; 315 316 mtd = get_nand_dev_by_index(nand_curr_device); 317 if (!mtd) { 318 puts("\nno devices available\n"); 319 return -ENOMEDIUM; 320 } 321 block_size = mtd->erasesize; 322 323 /* Align U-Boot size to currently used blocksize */ 324 image_size = ((image_size + (block_size - 1)) & (~(block_size - 1))); 325 326 /* Erase the U-BOOT image space */ 327 printf("Erasing 0x%x - 0x%x:...", 0, (int)image_size); 328 ret = nand_erase(mtd, 0, image_size); 329 if (ret) { 330 printf("Error!\n"); 331 goto error; 332 } 333 printf("Done!\n"); 334 335 /* Write the image to flash */ 336 printf("Writing %d bytes from 0x%lx to offset 0 ... ", 337 (int)image_size, get_load_addr()); 338 ret = nand_write(mtd, 0, &image_size, (void *)get_load_addr()); 339 if (ret) 340 printf("Error!\n"); 341 else 342 printf("Done!\n"); 343 344 error: 345 return ret; 346 } 347 348 static int is_nand_active(void) 349 { 350 return 1; 351 } 352 353 #else /* CONFIG_CMD_NAND */ 354 static int nand_burn_image(size_t image_size) 355 { 356 return -ENODEV; 357 } 358 359 static int is_nand_active(void) 360 { 361 return 0; 362 } 363 #endif /* CONFIG_CMD_NAND */ 364 365 /******************************************************************** 366 * USB services 367 ********************************************************************/ 368 #if defined(CONFIG_USB_STORAGE) && defined(CONFIG_BLK) 369 static size_t usb_read_file(const char *file_name) 370 { 371 loff_t act_read = 0; 372 struct udevice *dev; 373 int rc; 374 375 usb_stop(); 376 377 if (usb_init() < 0) { 378 printf("Error: usb_init failed\n"); 379 return 0; 380 } 381 382 /* Try to recognize storage devices immediately */ 383 blk_first_device(IF_TYPE_USB, &dev); 384 if (!dev) { 385 printf("Error: USB storage device not found\n"); 386 return 0; 387 } 388 389 /* Always load from usb 0 */ 390 if (fs_set_blk_dev("usb", "0", FS_TYPE_ANY)) { 391 printf("Error: USB 0 not found\n"); 392 return 0; 393 } 394 395 /* Perfrom file read */ 396 rc = fs_read(file_name, get_load_addr(), 0, 0, &act_read); 397 if (rc) 398 return 0; 399 400 return act_read; 401 } 402 403 static int is_usb_active(void) 404 { 405 return 1; 406 } 407 408 #else /* defined(CONFIG_USB_STORAGE) && defined (CONFIG_BLK) */ 409 static size_t usb_read_file(const char *file_name) 410 { 411 return 0; 412 } 413 414 static int is_usb_active(void) 415 { 416 return 0; 417 } 418 #endif /* defined(CONFIG_USB_STORAGE) && defined (CONFIG_BLK) */ 419 420 /******************************************************************** 421 * Network services 422 ********************************************************************/ 423 #ifdef CONFIG_CMD_NET 424 static size_t tftp_read_file(const char *file_name) 425 { 426 /* update global variable load_addr before tftp file from network */ 427 load_addr = get_load_addr(); 428 return net_loop(TFTPGET); 429 } 430 431 static int is_tftp_active(void) 432 { 433 return 1; 434 } 435 436 #else 437 static size_t tftp_read_file(const char *file_name) 438 { 439 return 0; 440 } 441 442 static int is_tftp_active(void) 443 { 444 return 0; 445 } 446 #endif /* CONFIG_CMD_NET */ 447 448 enum bubt_devices { 449 BUBT_DEV_NET = 0, 450 BUBT_DEV_USB, 451 BUBT_DEV_MMC, 452 BUBT_DEV_SPI, 453 BUBT_DEV_NAND, 454 455 BUBT_MAX_DEV 456 }; 457 458 struct bubt_dev bubt_devs[BUBT_MAX_DEV] = { 459 {"tftp", tftp_read_file, NULL, is_tftp_active}, 460 {"usb", usb_read_file, NULL, is_usb_active}, 461 {"mmc", mmc_read_file, mmc_burn_image, is_mmc_active}, 462 {"spi", NULL, spi_burn_image, is_spi_active}, 463 {"nand", NULL, nand_burn_image, is_nand_active}, 464 }; 465 466 static int bubt_write_file(struct bubt_dev *dst, size_t image_size) 467 { 468 if (!dst->write) { 469 printf("Error: Write not supported on device %s\n", dst->name); 470 return -ENOTSUPP; 471 } 472 473 return dst->write(image_size); 474 } 475 476 #if defined(CONFIG_ARMADA_8K) 477 u32 do_checksum32(u32 *start, int32_t len) 478 { 479 u32 sum = 0; 480 u32 *startp = start; 481 482 do { 483 sum += *startp; 484 startp++; 485 len -= 4; 486 } while (len > 0); 487 488 return sum; 489 } 490 491 static int check_image_header(void) 492 { 493 struct mvebu_image_header *hdr = 494 (struct mvebu_image_header *)get_load_addr(); 495 u32 header_len = hdr->prolog_size; 496 u32 checksum; 497 u32 checksum_ref = hdr->prolog_checksum; 498 499 /* 500 * For now compare checksum, and magic. Later we can 501 * verify more stuff on the header like interface type, etc 502 */ 503 if (hdr->magic != MAIN_HDR_MAGIC) { 504 printf("ERROR: Bad MAGIC 0x%08x != 0x%08x\n", 505 hdr->magic, MAIN_HDR_MAGIC); 506 return -ENOEXEC; 507 } 508 509 /* The checksum value is discarded from checksum calculation */ 510 hdr->prolog_checksum = 0; 511 512 checksum = do_checksum32((u32 *)hdr, header_len); 513 if (checksum != checksum_ref) { 514 printf("Error: Bad Image checksum. 0x%x != 0x%x\n", 515 checksum, checksum_ref); 516 return -ENOEXEC; 517 } 518 519 /* Restore the checksum before writing */ 520 hdr->prolog_checksum = checksum_ref; 521 printf("Image checksum...OK!\n"); 522 523 return 0; 524 } 525 #elif defined(CONFIG_ARMADA_3700) /* Armada 3700 */ 526 static int check_image_header(void) 527 { 528 struct common_tim_data *hdr = (struct common_tim_data *)get_load_addr(); 529 int image_num; 530 u8 hash_160_output[SHA1_SUM_LEN]; 531 u8 hash_256_output[SHA256_SUM_LEN]; 532 sha1_context hash1_text; 533 sha256_context hash256_text; 534 u8 *hash_output; 535 u32 hash_algorithm_id; 536 u32 image_size_to_hash; 537 u32 flash_entry_addr; 538 u32 *hash_value; 539 u32 internal_hash[HASH_SUM_LEN]; 540 const u8 *buff; 541 u32 num_of_image = hdr->num_images; 542 u32 version = hdr->version; 543 u32 trusted = hdr->trusted; 544 545 /* bubt checksum validation only supports nontrusted images */ 546 if (trusted == 1) { 547 printf("bypass image validation, "); 548 printf("only untrusted image is supported now\n"); 549 return 0; 550 } 551 /* only supports image version 3.5 and 3.6 */ 552 if (version != IMAGE_VERSION_3_5_0 && version != IMAGE_VERSION_3_6_0) { 553 printf("Error: Unsupported Image version = 0x%08x\n", version); 554 return -ENOEXEC; 555 } 556 /* validate images hash value */ 557 for (image_num = 0; image_num < num_of_image; image_num++) { 558 struct mvebu_image_info *info = 559 (struct mvebu_image_info *)(get_load_addr() + 560 sizeof(struct common_tim_data) + 561 image_num * sizeof(struct mvebu_image_info)); 562 hash_algorithm_id = info->hash_algorithm_id; 563 image_size_to_hash = info->image_size_to_hash; 564 flash_entry_addr = info->flash_entry_addr; 565 hash_value = info->hash; 566 buff = (const u8 *)(get_load_addr() + flash_entry_addr); 567 568 if (image_num == 0) { 569 /* 570 * The first image includes hash values in its content. 571 * For hash calculation, we need to save the original 572 * hash values to a local variable that will be 573 * copied back for comparsion and set all zeros to 574 * the orignal hash values for calculating new value. 575 * First image original format : 576 * x...x (datum1) x...x(orig. hash values) x...x(datum2) 577 * Replaced first image format : 578 * x...x (datum1) 0...0(hash values) x...x(datum2) 579 */ 580 memcpy(internal_hash, hash_value, 581 sizeof(internal_hash)); 582 memset(hash_value, 0, sizeof(internal_hash)); 583 } 584 if (image_size_to_hash == 0) { 585 printf("Warning: Image_%d hash checksum is disabled, ", 586 image_num); 587 printf("skip the image validation.\n"); 588 continue; 589 } 590 switch (hash_algorithm_id) { 591 case SHA1_SUM_LEN: 592 sha1_starts(&hash1_text); 593 sha1_update(&hash1_text, buff, image_size_to_hash); 594 sha1_finish(&hash1_text, hash_160_output); 595 hash_output = hash_160_output; 596 break; 597 case SHA256_SUM_LEN: 598 sha256_starts(&hash256_text); 599 sha256_update(&hash256_text, buff, image_size_to_hash); 600 sha256_finish(&hash256_text, hash_256_output); 601 hash_output = hash_256_output; 602 break; 603 default: 604 printf("Error: Unsupported hash_algorithm_id = %d\n", 605 hash_algorithm_id); 606 return -ENOEXEC; 607 } 608 if (image_num == 0) 609 memcpy(hash_value, internal_hash, 610 sizeof(internal_hash)); 611 if (memcmp(hash_value, hash_output, hash_algorithm_id) != 0) { 612 printf("Error: Image_%d checksum is not correct\n", 613 image_num); 614 return -ENOEXEC; 615 } 616 } 617 printf("Image checksum...OK!\n"); 618 619 return 0; 620 } 621 622 #else /* Not ARMADA? */ 623 static int check_image_header(void) 624 { 625 printf("bubt cmd does not support this SoC device or family!\n"); 626 return -ENOEXEC; 627 } 628 #endif 629 630 static int bubt_verify(size_t image_size) 631 { 632 int err; 633 634 /* Check a correct image header exists */ 635 err = check_image_header(); 636 if (err) { 637 printf("Error: Image header verification failed\n"); 638 return err; 639 } 640 641 return 0; 642 } 643 644 static int bubt_read_file(struct bubt_dev *src) 645 { 646 size_t image_size; 647 648 if (!src->read) { 649 printf("Error: Read not supported on device \"%s\"\n", 650 src->name); 651 return 0; 652 } 653 654 image_size = src->read(net_boot_file_name); 655 if (image_size <= 0) { 656 printf("Error: Failed to read file %s from %s\n", 657 net_boot_file_name, src->name); 658 return 0; 659 } 660 661 return image_size; 662 } 663 664 static int bubt_is_dev_active(struct bubt_dev *dev) 665 { 666 if (!dev->active) { 667 printf("Device \"%s\" not supported by U-BOOT image\n", 668 dev->name); 669 return 0; 670 } 671 672 if (!dev->active()) { 673 printf("Device \"%s\" is inactive\n", dev->name); 674 return 0; 675 } 676 677 return 1; 678 } 679 680 struct bubt_dev *find_bubt_dev(char *dev_name) 681 { 682 int dev; 683 684 for (dev = 0; dev < BUBT_MAX_DEV; dev++) { 685 if (strcmp(bubt_devs[dev].name, dev_name) == 0) 686 return &bubt_devs[dev]; 687 } 688 689 return 0; 690 } 691 692 #define DEFAULT_BUBT_SRC "tftp" 693 694 #ifndef DEFAULT_BUBT_DST 695 #ifdef CONFIG_MVEBU_SPI_BOOT 696 #define DEFAULT_BUBT_DST "spi" 697 #elif defined(CONFIG_MVEBU_NAND_BOOT) 698 #define DEFAULT_BUBT_DST "nand" 699 #elif defined(CONFIG_MVEBU_MMC_BOOT) 700 #define DEFAULT_BUBT_DST "mmc" 701 else 702 #define DEFAULT_BUBT_DST "error" 703 #endif 704 #endif /* DEFAULT_BUBT_DST */ 705 706 int do_bubt_cmd(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) 707 { 708 struct bubt_dev *src, *dst; 709 size_t image_size; 710 char src_dev_name[8]; 711 char dst_dev_name[8]; 712 char *name; 713 int err; 714 715 if (argc < 2) 716 copy_filename(net_boot_file_name, 717 CONFIG_MVEBU_UBOOT_DFLT_NAME, 718 sizeof(net_boot_file_name)); 719 else 720 copy_filename(net_boot_file_name, argv[1], 721 sizeof(net_boot_file_name)); 722 723 if (argc >= 3) { 724 strncpy(dst_dev_name, argv[2], 8); 725 } else { 726 name = DEFAULT_BUBT_DST; 727 strncpy(dst_dev_name, name, 8); 728 } 729 730 if (argc >= 4) 731 strncpy(src_dev_name, argv[3], 8); 732 else 733 strncpy(src_dev_name, DEFAULT_BUBT_SRC, 8); 734 735 /* Figure out the destination device */ 736 dst = find_bubt_dev(dst_dev_name); 737 if (!dst) { 738 printf("Error: Unknown destination \"%s\"\n", dst_dev_name); 739 return -EINVAL; 740 } 741 742 if (!bubt_is_dev_active(dst)) 743 return -ENODEV; 744 745 /* Figure out the source device */ 746 src = find_bubt_dev(src_dev_name); 747 if (!src) { 748 printf("Error: Unknown source \"%s\"\n", src_dev_name); 749 return 1; 750 } 751 752 if (!bubt_is_dev_active(src)) 753 return -ENODEV; 754 755 printf("Burning U-BOOT image \"%s\" from \"%s\" to \"%s\"\n", 756 net_boot_file_name, src->name, dst->name); 757 758 image_size = bubt_read_file(src); 759 if (!image_size) 760 return -EIO; 761 762 err = bubt_verify(image_size); 763 if (err) 764 return err; 765 766 err = bubt_write_file(dst, image_size); 767 if (err) 768 return err; 769 770 return 0; 771 } 772 773 U_BOOT_CMD( 774 bubt, 4, 0, do_bubt_cmd, 775 "Burn a u-boot image to flash", 776 "[file-name] [destination [source]]\n" 777 "\t-file-name The image file name to burn. Default = flash-image.bin\n" 778 "\t-destination Flash to burn to [spi, nand, mmc]. Default = active boot device\n" 779 "\t-source The source to load image from [tftp, usb, mmc]. Default = tftp\n" 780 "Examples:\n" 781 "\tbubt - Burn flash-image.bin from tftp to active boot device\n" 782 "\tbubt flash-image-new.bin nand - Burn flash-image-new.bin from tftp to NAND flash\n" 783 "\tbubt backup-flash-image.bin mmc usb - Burn backup-flash-image.bin from usb to MMC\n" 784 785 ); 786