Re: [U-Boot] [PATCH v4 6/6] env: am57xx: Implement A/B boot process

Hi Igor,

On Tue, Jul 2, 2019 at 11:51 AM Igor Opaniuk igor.opaniuk@gmail.com wrote:

From: Ruslan Trofymenko ruslan.trofymenko@linaro.org

Add support for A/B boot process on AM57xx based boards:

1. Define 'slot_suffix' variable (using 'ab_select' command)
2. Extend 'emmc_android_boot' boot command (add commands for A/B boot process)

'ab_select' command is used to decide which slot should be used for booting up. A/B metadata resides in 'misc' partition.

To activate the A/B boot process, the following config options must be set:

CONFIG_ANDROID_AB=y
CONFIG_CMD_AB_SELECT=y

For successful A/B boot, the corresponding A/B infrastructure must be involved on Android side [1] (including mounting system as root), and disk must be partitioned accordingly.

When A/B boot is enabled, there are some known limitations currently exist (not related to A/B patches, need to be implemented later):

1. The 'Verified Boot' sequence is not supported
2. dev path to system partition (system_a or system_b) is passed via 'bootargs' as 'root=' argument like 'root=/dev/mmcblk1p12', but further we'll need to rework it with respect to dm-verity requirements [2]

In case when A/B partitions are not present in system (and A/B boot is enabled), boot up process will be terminated and next message will be shown:

"boot_a(b) partition not found"

[1] https://source.android.com/devices/tech/ota/ab [2] https://source.android.com/devices/tech/ota/ab/ab_implement#kernel

Signed-off-by: Ruslan Trofymenko ruslan.trofymenko@linaro.org Signed-off-by: Igor Opaniuk igor.opaniuk@gmail.com Reviewed-by: Alistair Strachan astrachan@google.com Reviewed-by: Sam Protsenko semen.protsenko@linaro.org Reviewed-by: Simon Glass sjg@chromium.org

---

Changes in v4: None Changes in v3: None

Changes in v2:

• Add changes related to command renaming (android_ab_select -> ab_select).
• Slotted sections (e.g. system_a and system_b) are added to the default sections if CONFIG_CMD_AB_SELECT flag is defined
• Rebased on top of master
• system partitions sizes increased to 1024 MiB (to be consistent with recent changes to boot.h file)

include/environment/ti/boot.h | 58 +++++++++++++++++++++++++++++++---- 1 file changed, 52 insertions(+), 6 deletions(-)

diff --git a/include/environment/ti/boot.h b/include/environment/ti/boot.h index 943adcad40..e340164245 100644 --- a/include/environment/ti/boot.h +++ b/include/environment/ti/boot.h @@ -23,6 +23,18 @@ #define VBMETA_PART "" #endif

+#if defined(CONFIG_CMD_AB_SELECT) +#define COMMON_PARTS \

•   "name=boot_a,size=10M,uuid=${uuid_gpt_boot_a};" \
  

•   "name=boot_b,size=10M,uuid=${uuid_gpt_boot_b};" \
  

I guess this patch will be applied on top of this one:

https://patchwork.ozlabs.org/patch/1126434/

So can you please increase size= param for boot_a and boot_b from 10M to 20M?

•   "name=system_a,size=1024M,uuid=${uuid_gpt_system_a};" \
  

•   "name=system_b,size=1024M,uuid=${uuid_gpt_system_b};"
  

+#else +#define COMMON_PARTS \

•   "name=boot,size=10M,uuid=${uuid_gpt_boot};" \
  

The same here, should be 20M.

•   "name=system,size=1024M,uuid=${uuid_gpt_system};"
  

+#endif

#ifndef PARTS_DEFAULT /* Define the default GPT table for eMMC */ #define PARTS_DEFAULT \ @@ -38,8 +50,7 @@ "name=uboot-env,start=2432K,size=256K,uuid=${uuid_gpt_reserved};" \ "name=misc,size=128K,uuid=${uuid_gpt_misc};" \ "name=recovery,size=40M,uuid=${uuid_gpt_recovery};" \

•   "name=boot,size=20M,uuid=${uuid_gpt_boot};" \
  

•   "name=system,size=1024M,uuid=${uuid_gpt_system};" \
  

•   COMMON_PARTS \
    "name=vendor,size=256M,uuid=${uuid_gpt_vendor};" \
    VBMETA_PART \
    "name=userdata,size=-,uuid=${uuid_gpt_userdata}"
  

@@ -58,6 +69,35 @@ #define AVB_VERIFY_CMD "" #endif

+#define CONTROL_PARTITION "misc"

+#if defined(CONFIG_CMD_AB_SELECT) +#define AB_SELECT \

•   "if part number mmc 1 " CONTROL_PARTITION " control_part_number; " \
  

•   "then " \
  

•           "echo " CONTROL_PARTITION \
  

•                   " partition number:${control_part_number};" \
  

•           "ab_select slot_name mmc ${mmcdev}:${control_part_number};" \
  

•   "else " \
  

•           "echo " CONTROL_PARTITION " partition not found;" \
  

•           "exit;" \
  

•   "fi;" \
  

•   "setenv slot_suffix _${slot_name};" \
  

•   "if part number mmc ${mmcdev} system${slot_suffix} " \
  

•   "system_part_number; then " \
  

•           "setenv bootargs_ab " \
  

•           "ro root=/dev/mmcblk${mmcdev}p${system_part_number} " \
  

•           "rootwait init=/init skip_initramfs " \
  

•           "androidboot.slot_suffix=${slot_suffix};" \
  

•           "echo A/B cmdline addition: ${bootargs_ab};" \
  

•           "setenv bootargs ${bootargs} ${bootargs_ab};" \
  

•   "else " \
  

•           "echo system${slot_suffix} partition not found;" \
  

•   "fi;"
  

+#else +#define AB_SELECT "" +#endif

#define DEFAULT_COMMON_BOOT_TI_ARGS \ "console=" CONSOLEDEV ",115200n8\0" \ "fdtfile=undefined\0" \ @@ -86,10 +126,16 @@ "mmc dev $mmcdev; " \ "mmc rescan; " \ AVB_VERIFY_CHECK \

•           "part start mmc ${mmcdev} boot boot_start; " \
  

•           "part size mmc ${mmcdev} boot boot_size; " \
  

•           "mmc read ${loadaddr} ${boot_start} ${boot_size}; " \
  

•           "bootm ${loadaddr}#${fdtfile};\0 "
  

•           AB_SELECT \
  

•           "if part start mmc ${mmcdev} boot${slot_suffix} boot_start; " \
  

•           "then " \
  

•                   "part size mmc ${mmcdev} boot${slot_suffix} " \
  

•                           "boot_size; " \
  

•                   "mmc read ${loadaddr} ${boot_start} ${boot_size}; " \
  

•                   "bootm ${loadaddr}#${fdtfile}; " \
  

•           "else " \
  

•                   "echo boot${slot_suffix} partition not found; " \
  

•           "fi;\0"
  
  

#ifdef CONFIG_OMAP54XX

-- 2.17.1