On 10/05/2016 10:38 PM, Petr Kulhavy wrote:

The current fastboot implementation is only able to flash partition images. However sometimes it is needed to write the raw MMC, e.g. when storing the U-boot environment image or SPL.

This patch adds the possibility to write MMC as a block device using a special target name composed of "lba:" followed by the block address. The address can be in decimal or hexadecimal with the "0x" prefix.

Signed-off-by: Petr Kulhavy brain@jikos.cz

common/fb_mmc.c | 38 +++++++++++++++++++++++++++++++++++++- doc/README.android-fastboot | 15 +++++++++++++++ 2 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/common/fb_mmc.c b/common/fb_mmc.c index 81a3bd0..c4fe2ac 100644 --- a/common/fb_mmc.c +++ b/common/fb_mmc.c @@ -27,6 +27,9 @@ #define CONFIG_FASTBOOT_MBR_NAME "mbr" #endif

+#define FB_RAW_PREFIX "lba:" +#define FB_RAW_PREFIX_LEN 4

struct fb_mmc_sparse { struct blk_desc *dev_desc; }; @@ -68,6 +71,29 @@ static lbaint_t fb_mmc_sparse_reserve(struct sparse_storage *info, return blkcnt; }

+/*

• • attempt to interpret the partition name as raw LBA
• • on success return 1 and fill info
• • on failure (not a LBA matching name) return 0 (info undefined)
• */

+static int get_raw_part_info(const struct blk_desc *dev_desc, const char *name,

• disk_partition_t *info)
  

Is it right about "const struct blk_desc ..."? Why use "const"?

+{

• if (strlen(name) <= FB_RAW_PREFIX_LEN ||

•    strncmp(name, FB_RAW_PREFIX, FB_RAW_PREFIX_LEN) != 0)
  

strlen(name) was need to check?

• return 0;
  

+#if CONFIG_SYS_64BIT_LBA

• info->start = simple_strtoull(name + FB_RAW_PREFIX_LEN, NULL, 10);

+#else

• info->start = simple_strtoul(name + FB_RAW_PREFIX_LEN, NULL, 10);

+#endif

• info->size = dev_desc->lba - info->start;
• info->blksz = dev_desc->blksz;
• return 1;

+}

static void write_raw_image(struct blk_desc *dev_desc, disk_partition_t *info, const char *part_name, void *buffer, unsigned int download_bytes) @@ -153,7 +179,17 @@ void fb_mmc_flash_write(const char *cmd, void *download_buffer, } #endif

• if (part_get_info_by_name_or_alias(dev_desc, cmd, &info)) {

• /* first try to interpret as a raw write */
• if (get_raw_part_info(dev_desc, cmd, &info)) {

• printf("%s: writing raw data at LBA 0x%llx\n", __func__,
  

•        (unsigned long long) info.start);
  

• /* check if start is within the media */
  

• if (info.start >= dev_desc->lba) {
  

• 	error("Attempt to write beyond the end of media\n");
  

• 	fastboot_fail("LBA write out of media");
  

• 	return;
  

• }
  

• } else if (part_get_info_by_name_or_alias(dev_desc, cmd, &info)) { error("cannot find partition: '%s'\n", cmd); fastboot_fail("cannot find partition"); return;

diff --git a/doc/README.android-fastboot b/doc/README.android-fastboot index b8afa15..cbc42a1 100644 --- a/doc/README.android-fastboot +++ b/doc/README.android-fastboot @@ -97,6 +97,21 @@ configuration options: CONFIG_FASTBOOT_GPT_NAME CONFIG_FASTBOOT_MBR_NAME

+Writing as a Block Device +========================= +Sometimes it is useful to write sections of eMMC which are not allocated as +partitions. For instance to store the SPL or U-Boot environment.

+This can be achieved by writing a special target with the name "lba:" (lower +case) followed by the block address at which the image should be stored. The +block address can be noted in decimal or hexadecimal (prefixed with "0x").

+Example command:

• $ fastboot flash "lba:1024" uboot-env.bin

+This writes the uboot-env.bin image file at logical block 1024, i.e. 512KiB.

In Action

Enter into fastboot by executing the fastboot command in u-boot and you