Hi Steve,

Hi Lukasz,

On 14-12-08 03:21 AM, Lukasz Majewski wrote:

...

Hi Steve,

...

Implement a feature to allow fastboot to write the downloaded image to the space reserved for the Protective MBR and the Primary GUID Partition Table.

Signed-off-by: Steve Rae srae@broadcom.com

README | 7 +++++++ common/fb_mmc.c | 19 ++++++++++++++++--- 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/README b/README index 66770b6..3b6ef7f 100644 --- a/README +++ b/README @@ -1769,6 +1769,13 @@ The following options need to be configured: regarding the non-volatile storage device. Define this to the eMMC device that fastboot should use to store the image.

• CONFIG_FASTBOOT_GPT_NAME
  

• The fastboot "flash" command supports writing the
  

downloaded

• image to the Protective MBR and the Primary GUID
  

Partition

• Table. This occurs when the specified "partition
  

name" on the

• "fastboot flash" command line matches this value.
  

• Default is GPT_ENTRY_NAME (currently "gpt") if
  

undefined. +

• Journaling Flash filesystem support: CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF,

CONFIG_JFFS2_NAND_SIZE, CONFIG_JFFS2_NAND_DEV diff --git a/common/fb_mmc.c b/common/fb_mmc.c index fb06d8a..89fbf23 100644 --- a/common/fb_mmc.c +++ b/common/fb_mmc.c @@ -4,12 +4,17 @@

• SPDX-License-Identifier: GPL-2.0+

*/

+#include <config.h> #include <common.h> #include <fb_mmc.h> #include <part.h> #include <aboot.h> #include <sparse_format.h>

+#ifndef CONFIG_FASTBOOT_GPT_NAME +#define CONFIG_FASTBOOT_GPT_NAME GPT_ENTRY_NAME +#endif

• /* The 64 defined bytes plus the '\0' */ #define RESPONSE_LEN (64 + 1)

@@ -62,9 +67,9 @@ static void write_raw_image(block_dev_desc_t *dev_desc, disk_partition_t *info, void fb_mmc_flash_write(const char *cmd, void *download_buffer, unsigned int download_bytes, char *response) {

• int ret; block_dev_desc_t *dev_desc; disk_partition_t info;

• lbaint_t blksz;

  /* initialize the response buffer */ response_str = response;

@@ -76,8 +81,16 @@ void fb_mmc_flash_write(const char *cmd, void *download_buffer, return; }

• ret = get_partition_info_efi_by_name(dev_desc, cmd,

&info);

• if (ret) {

• if (strcmp(cmd, CONFIG_FASTBOOT_GPT_NAME) == 0) {

• printf("%s: updating GUID Partition Table
  

(including MBR)\n",

•        __func__);
  

• /* start at Protective MBR */
  

• info.start = (GPT_PRIMARY_PARTITION_TABLE_LBA -
  

1);

• blksz = dev_desc->blksz;
  

• info.blksz = blksz;
  

• /* assume that the Partition Entry Array starts in
  

LBA 2 */

• info.size = (2 + (GPT_ENTRY_NUMBERS *
  

GPT_ENTRY_SIZE) / blksz);

• } else if (get_partition_info_efi_by_name(dev_desc, cmd,

&info)) { error("cannot find partition: '%s'\n", cmd); fastboot_fail("cannot find partition"); return;

Sorry for a late reply. I've just come back from a short holidays.

I'm curious if you have encountered any problems with GPT replaced in that way?

No -- this "technique" seems to be fine (for the Primary GPT)....

...

It seems strange to me that you only change primary GPT partition without taking care of the secondary (backup) one.

It seems that the device operates correctly with or without the Backup GPT, and it doesn't seem to matter if they are the same or not. Thus, we have gone back and forth on this one - should we automatically update the Backup GPT whenever the Primary GPT is updated, or should there be a second step (possibly a "fastboot oem" command) to update the Backup GPT... (currently, we are proposing the latter) What would you suggest?

I'd suggest updating both of them.

However, it is important to check all available CRC's in the received image.

In my opinion a separate command for Secondary GPT - "fastboot oem" - seems like an overkill.

...

From my experience when you export your eMMC to Host PC via UMS, host's PC tools will complain about mismatch in the GPT tables.

( I have never done this - what tools are you using? Could you provide instructions for me to try? Thanks! )

For Exynos based boards (e.g. Odroid-U3, Trats2) it is possible to use USB mass storage gadget (ums command in u-boot prompt), which exports the content of eMMC to host PC and is treated as an ordinary USB stick.

Also you can try "parted" linux utility.

...

Moreover, I would suggest transactional update of GPT by checking GPT image CRC before writing. In this way you can always perform recovery if needed.

This is a good idea - I'll look into it - Thanks!

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Thanks, Steve