cmd: mvebu/bubt: Add support for selecting eMMC HW partition

Support for burning into the correct eMMC HW boot partition was broken and
removed in commit 96be2f072768 ("mvebu: bubt: Drop dead code"). Reimplement
this functionality and bring it back again.

Fixes: 96be2f072768 ("mvebu: bubt: Drop dead code")
Signed-off-by: Pali Rohár <pali@kernel.org>

1 files changed, 15 insertions, 6 deletions

diff --git a/doc/mvebu/cmd/bubt.txt b/doc/mvebu/cmd/bubt.txt
index 6051243f116..1fe1f07dd18 100644
--- a/doc/mvebu/cmd/bubt.txt
+++ b/doc/mvebu/cmd/bubt.txt
@@ -14,8 +14,7 @@ Examples:
 
 Notes:
 - For the TFTP interface set serverip and ipaddr.
-- To burn image to SD/eMMC device, the target is defined
-  by parameters CONFIG_SYS_MMC_ENV_DEV and CONFIG_SYS_MMC_ENV_PART.
+- To burn image to SD/eMMC device, the target is defined by HW partition.
 
 Bubt command details (burn image step by-step)
 ----------------------------------------------
@@ -40,10 +39,20 @@ Notes:
   Number 0 is used for user data partition and should not be utilized for storing
   boot images and U-Boot environment in RAW mode since it will break file system
   structures usually located here.
-  The default boot partition is BOOT0. It is selected by the following parameter:
-  CONFIG_SYS_MMC_ENV_PART=1
-  Valid values for this parameter are 1 for BOOT0 and 2 for BOOT1.
-  Please never use partition number 0 here!
+
+  Currently configured boot partition can be printed by command:
+  # mmc partconf 0
+  (search for BOOT_PARTITION_ACCESS output, number 7 is user data)
+
+  Change it to BOOT0:
+  # mmc partconf 0 0 1 1
+
+  Change it to BOOT1:
+  # mmc partconf 0 0 2 2
+
+  Change it to user data:
+  # mmc partconf 0 0 7 0
+
 - The partition number is ignored if the target device is SD card.
 - The boot image offset starts at block 0 for eMMC and block 1 for SD devices.
   The block 0 on SD devices is left for MBR storage.