blob: b752927e8c690eb18f0ff328c1e5af85cb3ac8d4 [file] [log] [blame]
Konstantin Porotchkinfa61ef62016-12-08 12:22:28 +02001/*
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>
Konstantin Porotchkine559ef12017-01-08 16:52:06 +020021#ifdef CONFIG_BLK
22#include <blk.h>
23#endif
Konstantin Porotchkinfa61ef62016-12-08 12:22:28 +020024#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
34struct 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
60struct 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
73struct 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
89struct 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
96static ulong get_load_addr(void)
97{
98 const char *addr_str;
99 unsigned long addr;
100
101 addr_str = getenv("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#ifdef CONFIG_DM_MMC
114static 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;
Konstantin Porotchkine559ef12017-01-08 16:52:06 +0200122#ifdef CONFIG_BLK
123 struct blk_desc *blk_desc;
124#endif
Konstantin Porotchkinfa61ef62016-12-08 12:22:28 +0200125 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;
Konstantin Porotchkine559ef12017-01-08 16:52:06 +0200152#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
Konstantin Porotchkinfa61ef62016-12-08 12:22:28 +0200165 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,
Konstantin Porotchkine559ef12017-01-08 16:52:06 +0200170 start_lba, blk_count,
171 (void *)get_load_addr());
172#endif /* CONFIG_BLK */
Konstantin Porotchkinfa61ef62016-12-08 12:22:28 +0200173 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
187static 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
220static int is_mmc_active(void)
221{
222 return 1;
223}
224#else /* CONFIG_DM_MMC */
225static int mmc_burn_image(size_t image_size)
226{
227 return -ENODEV;
228}
229
230static size_t mmc_read_file(const char *file_name)
231{
232 return 0;
233}
234
235static 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
245static 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
289static int is_spi_active(void)
290{
291 return 1;
292}
293
294#else /* CONFIG_SPI_FLASH */
295static int spi_burn_image(size_t image_size)
296{
297 return -ENODEV;
298}
299
300static 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
310static int nand_burn_image(size_t image_size)
311{
312 int ret, block_size;
313 nand_info_t *nand;
314 int dev = nand_curr_device;
315
316 if ((dev < 0) || (dev >= CONFIG_SYS_MAX_NAND_DEVICE) ||
317 (!nand_info[dev].name)) {
318 puts("\nno devices available\n");
319 return -ENOMEDIUM;
320 }
321 nand = &nand_info[dev];
322 block_size = nand->erasesize;
323
324 /* Align U-Boot size to currently used blocksize */
325 image_size = ((image_size + (block_size - 1)) & (~(block_size - 1)));
326
327 /* Erase the U-BOOT image space */
328 printf("Erasing 0x%x - 0x%x:...", 0, (int)image_size);
329 ret = nand_erase(nand, 0, image_size);
330 if (ret) {
331 printf("Error!\n");
332 goto error;
333 }
334 printf("Done!\n");
335
336 /* Write the image to flash */
337 printf("Writing image:...");
338 printf("&image_size = 0x%p\n", (void *)&image_size);
339 ret = nand_write(nand, 0, &image_size, (void *)get_load_addr());
340 if (ret)
341 printf("Error!\n");
342 else
343 printf("Done!\n");
344
345error:
346 return ret;
347}
348
349static int is_nand_active(void)
350{
351 return 1;
352}
353
354#else /* CONFIG_CMD_NAND */
355static int nand_burn_image(size_t image_size)
356{
357 return -ENODEV;
358}
359
360static int is_nand_active(void)
361{
362 return 0;
363}
364#endif /* CONFIG_CMD_NAND */
365
366/********************************************************************
367 * USB services
368 ********************************************************************/
369#if defined(CONFIG_USB_STORAGE) && defined(CONFIG_BLK)
370static size_t usb_read_file(const char *file_name)
371{
372 loff_t act_read = 0;
373 struct udevice *dev;
374 int rc;
375
376 usb_stop();
377
378 if (usb_init() < 0) {
379 printf("Error: usb_init failed\n");
380 return 0;
381 }
382
383 /* Try to recognize storage devices immediately */
384 blk_first_device(IF_TYPE_USB, &dev);
385 if (!dev) {
386 printf("Error: USB storage device not found\n");
387 return 0;
388 }
389
390 /* Always load from usb 0 */
391 if (fs_set_blk_dev("usb", "0", FS_TYPE_ANY)) {
392 printf("Error: USB 0 not found\n");
393 return 0;
394 }
395
396 /* Perfrom file read */
397 rc = fs_read(file_name, get_load_addr(), 0, 0, &act_read);
398 if (rc)
399 return 0;
400
401 return act_read;
402}
403
404static int is_usb_active(void)
405{
406 return 1;
407}
408
409#else /* defined(CONFIG_USB_STORAGE) && defined (CONFIG_BLK) */
410static size_t usb_read_file(const char *file_name)
411{
412 return 0;
413}
414
415static int is_usb_active(void)
416{
417 return 0;
418}
419#endif /* defined(CONFIG_USB_STORAGE) && defined (CONFIG_BLK) */
420
421/********************************************************************
422 * Network services
423 ********************************************************************/
424#ifdef CONFIG_CMD_NET
425static size_t tftp_read_file(const char *file_name)
426{
427 /* update global variable load_addr before tftp file from network */
428 load_addr = get_load_addr();
429 return net_loop(TFTPGET);
430}
431
432static int is_tftp_active(void)
433{
434 return 1;
435}
436
437#else
438static size_t tftp_read_file(const char *file_name)
439{
440 return 0;
441}
442
443static int is_tftp_active(void)
444{
445 return 0;
446}
447#endif /* CONFIG_CMD_NET */
448
449enum bubt_devices {
450 BUBT_DEV_NET = 0,
451 BUBT_DEV_USB,
452 BUBT_DEV_MMC,
453 BUBT_DEV_SPI,
454 BUBT_DEV_NAND,
455
456 BUBT_MAX_DEV
457};
458
459struct bubt_dev bubt_devs[BUBT_MAX_DEV] = {
460 {"tftp", tftp_read_file, NULL, is_tftp_active},
461 {"usb", usb_read_file, NULL, is_usb_active},
462 {"mmc", mmc_read_file, mmc_burn_image, is_mmc_active},
463 {"spi", NULL, spi_burn_image, is_spi_active},
464 {"nand", NULL, nand_burn_image, is_nand_active},
465};
466
467static int bubt_write_file(struct bubt_dev *dst, size_t image_size)
468{
469 if (!dst->write) {
470 printf("Error: Write not supported on device %s\n", dst->name);
471 return -ENOTSUPP;
472 }
473
474 return dst->write(image_size);
475}
476
477#if defined(CONFIG_ARMADA_8K)
478u32 do_checksum32(u32 *start, int32_t len)
479{
480 u32 sum = 0;
481 u32 *startp = start;
482
483 do {
484 sum += *startp;
485 startp++;
486 len -= 4;
487 } while (len > 0);
488
489 return sum;
490}
491
492static int check_image_header(void)
493{
494 struct mvebu_image_header *hdr =
495 (struct mvebu_image_header *)get_load_addr();
496 u32 header_len = hdr->prolog_size;
497 u32 checksum;
498 u32 checksum_ref = hdr->prolog_checksum;
499
500 /*
501 * For now compare checksum, and magic. Later we can
502 * verify more stuff on the header like interface type, etc
503 */
504 if (hdr->magic != MAIN_HDR_MAGIC) {
505 printf("ERROR: Bad MAGIC 0x%08x != 0x%08x\n",
506 hdr->magic, MAIN_HDR_MAGIC);
507 return -ENOEXEC;
508 }
509
510 /* The checksum value is discarded from checksum calculation */
511 hdr->prolog_checksum = 0;
512
513 checksum = do_checksum32((u32 *)hdr, header_len);
514 if (checksum != checksum_ref) {
515 printf("Error: Bad Image checksum. 0x%x != 0x%x\n",
516 checksum, checksum_ref);
517 return -ENOEXEC;
518 }
519
520 /* Restore the checksum before writing */
521 hdr->prolog_checksum = checksum_ref;
522 printf("Image checksum...OK!\n");
523
524 return 0;
525}
526#elif defined(CONFIG_ARMADA_3700) /* Armada 3700 */
527static int check_image_header(void)
528{
529 struct common_tim_data *hdr = (struct common_tim_data *)get_load_addr();
530 int image_num;
531 u8 hash_160_output[SHA1_SUM_LEN];
532 u8 hash_256_output[SHA256_SUM_LEN];
533 sha1_context hash1_text;
534 sha256_context hash256_text;
535 u8 *hash_output;
536 u32 hash_algorithm_id;
537 u32 image_size_to_hash;
538 u32 flash_entry_addr;
539 u32 *hash_value;
540 u32 internal_hash[HASH_SUM_LEN];
541 const u8 *buff;
542 u32 num_of_image = hdr->num_images;
543 u32 version = hdr->version;
544 u32 trusted = hdr->trusted;
545
546 /* bubt checksum validation only supports nontrusted images */
547 if (trusted == 1) {
548 printf("bypass image validation, ");
549 printf("only untrusted image is supported now\n");
550 return 0;
551 }
552 /* only supports image version 3.5 and 3.6 */
553 if (version != IMAGE_VERSION_3_5_0 && version != IMAGE_VERSION_3_6_0) {
554 printf("Error: Unsupported Image version = 0x%08x\n", version);
555 return -ENOEXEC;
556 }
557 /* validate images hash value */
558 for (image_num = 0; image_num < num_of_image; image_num++) {
559 struct mvebu_image_info *info =
560 (struct mvebu_image_info *)(get_load_addr() +
561 sizeof(struct common_tim_data) +
562 image_num * sizeof(struct mvebu_image_info));
563 hash_algorithm_id = info->hash_algorithm_id;
564 image_size_to_hash = info->image_size_to_hash;
565 flash_entry_addr = info->flash_entry_addr;
566 hash_value = info->hash;
567 buff = (const u8 *)(get_load_addr() + flash_entry_addr);
568
569 if (image_num == 0) {
570 /*
571 * The first image includes hash values in its content.
572 * For hash calculation, we need to save the original
573 * hash values to a local variable that will be
574 * copied back for comparsion and set all zeros to
575 * the orignal hash values for calculating new value.
576 * First image original format :
577 * x...x (datum1) x...x(orig. hash values) x...x(datum2)
578 * Replaced first image format :
579 * x...x (datum1) 0...0(hash values) x...x(datum2)
580 */
581 memcpy(internal_hash, hash_value,
582 sizeof(internal_hash));
583 memset(hash_value, 0, sizeof(internal_hash));
584 }
585 if (image_size_to_hash == 0) {
586 printf("Warning: Image_%d hash checksum is disabled, ",
587 image_num);
588 printf("skip the image validation.\n");
589 continue;
590 }
591 switch (hash_algorithm_id) {
592 case SHA1_SUM_LEN:
593 sha1_starts(&hash1_text);
594 sha1_update(&hash1_text, buff, image_size_to_hash);
595 sha1_finish(&hash1_text, hash_160_output);
596 hash_output = hash_160_output;
597 break;
598 case SHA256_SUM_LEN:
599 sha256_starts(&hash256_text);
600 sha256_update(&hash256_text, buff, image_size_to_hash);
601 sha256_finish(&hash256_text, hash_256_output);
602 hash_output = hash_256_output;
603 break;
604 default:
605 printf("Error: Unsupported hash_algorithm_id = %d\n",
606 hash_algorithm_id);
607 return -ENOEXEC;
608 }
609 if (image_num == 0)
610 memcpy(hash_value, internal_hash,
611 sizeof(internal_hash));
612 if (memcmp(hash_value, hash_output, hash_algorithm_id) != 0) {
613 printf("Error: Image_%d checksum is not correct\n",
614 image_num);
615 return -ENOEXEC;
616 }
617 }
618 printf("Image checksum...OK!\n");
619
620 return 0;
621}
622
623#else /* Not ARMADA? */
624static int check_image_header(void)
625{
626 printf("bubt cmd does not support this SoC device or family!\n");
627 return -ENOEXEC;
628}
629#endif
630
631static int bubt_verify(size_t image_size)
632{
633 int err;
634
635 /* Check a correct image header exists */
636 err = check_image_header();
637 if (err) {
638 printf("Error: Image header verification failed\n");
639 return err;
640 }
641
642 return 0;
643}
644
645static int bubt_read_file(struct bubt_dev *src)
646{
647 size_t image_size;
648
649 if (!src->read) {
650 printf("Error: Read not supported on device \"%s\"\n",
651 src->name);
652 return 0;
653 }
654
655 image_size = src->read(net_boot_file_name);
656 if (image_size <= 0) {
657 printf("Error: Failed to read file %s from %s\n",
658 net_boot_file_name, src->name);
659 return 0;
660 }
661
662 return image_size;
663}
664
665static int bubt_is_dev_active(struct bubt_dev *dev)
666{
667 if (!dev->active) {
668 printf("Device \"%s\" not supported by U-BOOT image\n",
669 dev->name);
670 return 0;
671 }
672
673 if (!dev->active()) {
674 printf("Device \"%s\" is inactive\n", dev->name);
675 return 0;
676 }
677
678 return 1;
679}
680
681struct bubt_dev *find_bubt_dev(char *dev_name)
682{
683 int dev;
684
685 for (dev = 0; dev < BUBT_MAX_DEV; dev++) {
686 if (strcmp(bubt_devs[dev].name, dev_name) == 0)
687 return &bubt_devs[dev];
688 }
689
690 return 0;
691}
692
693#define DEFAULT_BUBT_SRC "tftp"
694
695#ifndef DEFAULT_BUBT_DST
696#ifdef CONFIG_MVEBU_SPI_BOOT
697#define DEFAULT_BUBT_DST "spi"
698#elif defined(CONFIG_MVEBU_NAND_BOOT)
699#define DEFAULT_BUBT_DST "nand"
700#elif defined(CONFIG_MVEBU_MMC_BOOT)
701#define DEFAULT_BUBT_DST "mmc"
702else
703#define DEFAULT_BUBT_DST "error"
704#endif
705#endif /* DEFAULT_BUBT_DST */
706
707int do_bubt_cmd(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
708{
709 struct bubt_dev *src, *dst;
710 size_t image_size;
711 char src_dev_name[8];
712 char dst_dev_name[8];
713 char *name;
714 int err;
715
716 if (argc < 2)
717 copy_filename(net_boot_file_name,
718 CONFIG_MVEBU_UBOOT_DFLT_NAME,
719 sizeof(net_boot_file_name));
720 else
721 copy_filename(net_boot_file_name, argv[1],
722 sizeof(net_boot_file_name));
723
724 if (argc >= 3) {
725 strncpy(dst_dev_name, argv[2], 8);
726 } else {
727 name = DEFAULT_BUBT_DST;
728 strncpy(dst_dev_name, name, 8);
729 }
730
731 if (argc >= 4)
732 strncpy(src_dev_name, argv[3], 8);
733 else
734 strncpy(src_dev_name, DEFAULT_BUBT_SRC, 8);
735
736 /* Figure out the destination device */
737 dst = find_bubt_dev(dst_dev_name);
738 if (!dst) {
739 printf("Error: Unknown destination \"%s\"\n", dst_dev_name);
740 return -EINVAL;
741 }
742
743 if (!bubt_is_dev_active(dst))
744 return -ENODEV;
745
746 /* Figure out the source device */
747 src = find_bubt_dev(src_dev_name);
748 if (!src) {
749 printf("Error: Unknown source \"%s\"\n", src_dev_name);
750 return 1;
751 }
752
753 if (!bubt_is_dev_active(src))
754 return -ENODEV;
755
756 printf("Burning U-BOOT image \"%s\" from \"%s\" to \"%s\"\n",
757 net_boot_file_name, src->name, dst->name);
758
759 image_size = bubt_read_file(src);
760 if (!image_size)
761 return -EIO;
762
763 err = bubt_verify(image_size);
764 if (err)
765 return err;
766
767 err = bubt_write_file(dst, image_size);
768 if (err)
769 return err;
770
771 return 0;
772}
773
774U_BOOT_CMD(
775 bubt, 4, 0, do_bubt_cmd,
776 "Burn a u-boot image to flash",
777 "[file-name] [destination [source]]\n"
778 "\t-file-name The image file name to burn. Default = flash-image.bin\n"
779 "\t-destination Flash to burn to [spi, nand, mmc]. Default = active boot device\n"
780 "\t-source The source to load image from [tftp, usb, mmc]. Default = tftp\n"
781 "Examples:\n"
782 "\tbubt - Burn flash-image.bin from tftp to active boot device\n"
783 "\tbubt flash-image-new.bin nand - Burn flash-image-new.bin from tftp to NAND flash\n"
784 "\tbubt backup-flash-image.bin mmc usb - Burn backup-flash-image.bin from usb to MMC\n"
785
786);