Re: [PATCH] Add support for SPL MMC load redundant U-Boot

Hi Ayrton,

On 19.07.23 11:38, Ayrton Leyssens wrote:

From 99512830410551132e8f7577615b3af4f5f1c137 Mon Sep 17 00:00:00 2001 From: Ayrton Leyssens ayrton.leyssens@scioteq.com Date: Wed, 19 Jul 2023 11:27:19 +0200 Subject: [PATCH Add support for SPL mmc load redundant U-Boot

This patch adds support for loading a redundant / second U-Boot from a MMC. In some cases you want to update U-Boot, to have a "selectable" bootloader and keep the "old" and "new" one. In this patch we use the environment for a user-defined variable. Maybe this could be extended to some other ways as well.

I find the selection based on an environment variable quite weak. A wrong value could lead to unbootable device. IMHO the selection should be done in a way similar as what we have for the environment itself, that means the information if a u-boot image is valid or not should be inside the image itself. For example this is true in case u-boot is packed inside a fitImage.

A simple selection is not sufficient, there should be a mechanism like for the environmant to fallback to the other partition if the chosen is not working or at least, integrity check is broken.

Best regards, Stefano

Signed-off-by: Ayrton Leyssens ayrton.leyssens@scioteq.com

common/spl/Kconfig | 29 +++++++++++++++++++++++++++++ common/spl/spl_mmc.c | 10 ++++++++++ 2 files changed, 39 insertions(+)

diff --git a/common/spl/Kconfig b/common/spl/Kconfig index bee231b583..2c0ffd4363 100644 --- a/common/spl/Kconfig +++ b/common/spl/Kconfig @@ -824,6 +824,25 @@ config SYS_MMCSD_FS_BOOT Enable MMC FS Boot mode. Partition is selected by option SYS_MMCSD_FS_BOOT_PARTITION. +config SYS_MMCSD_FS_BOOT_PARTITION_FAILSAFE

•         bool "Use MMC Boot Partition Failsafe"
  

•         depends on SYS_MMCSD_FS_BOOT
  

•         depends on SPL_ENV_SUPPORT
  

•         default false
  

•         help
  

•           Use a redundant partition to load U-Boot from.
  

+config SYS_MMCSD_FS_BOOT_PARTITION_SELECTOR

•         string "MMC Boot Partition Selector"
  

•         depends on SYS_MMCSD_FS_BOOT
  

•         depends on SYS_MMCSD_FS_BOOT_PARTITION_FAILSAFE
  

•         default ""
  

•         help
  

•           Environment variable in U-Boot to use for the partition selection
  

•           to boot U-Boot from.
  

•           A 1 selects the "normal" partition, any other value selects the
  

•           redundant partition.
  

config SYS_MMCSD_FS_BOOT_PARTITION int "MMC Boot Partition" depends on SYS_MMCSD_FS_BOOT @@ -833,6 +852,16 @@ config SYS_MMCSD_FS_BOOT_PARTITION used in fs mode. Use -1 as a special value to use the first bootable partition. +config SYS_MMCSD_FS_BOOT_PARTITION_REDUNDANT

•         int "MMC Boot Partition Redundant"
  

•         depends on SYS_MMCSD_FS_BOOT
  

•         depends on SYS_MMCSD_FS_BOOT_PARTITION_FAILSAFE
  

•         default 2
  

•         help
  

•           Redundant Partition on the MMC to load U-Boot from when the MMC is being
  

•           used in fs mode.
  

•           Use -1 as a special value to use the first bootable partition.
  

config SPL_MMC_TINY bool "Tiny MMC framework in SPL" depends on SPL_MMC diff --git a/common/spl/spl_mmc.c b/common/spl/spl_mmc.c index a665091b00..bf804fabcc 100644 --- a/common/spl/spl_mmc.c +++ b/common/spl/spl_mmc.c @@ -10,6 +10,7 @@ #include <log.h> #include <part.h> #include <spl.h> +#include <env.h> #include <linux/compiler.h> #include <errno.h> #include <asm/u-boot.h> @@ -281,6 +282,7 @@ static int spl_mmc_do_fs_boot(struct spl_image_info *spl_image, int err = -ENOSYS; __maybe_unused int partition = CONFIG_SYS_MMCSD_FS_BOOT_PARTITION;

•         __maybe_unused int env_partition_selector = 0;
  

  #if CONFIG_SYS_MMCSD_FS_BOOT_PARTITION == -1 {

@@ -303,7 +305,15 @@ static int spl_mmc_do_fs_boot(struct spl_image_info *spl_image, } } #endif +#ifdef CONFIG_SYS_MMCSD_FS_BOOT_PARTITION_FAILSAFE

•         env_init();
  

•         env_relocate();
  

•         env_partition_selector = env_get_ulong(CONFIG_SYS_MMCSD_FS_BOOT_PARTITION_SELECTOR, 10, 0);
  

•         if (env_partition_selector != 1)
  

•                         partition = CONFIG_SYS_MMCSD_FS_BOOT_PARTITION_REDUNDANT;
  

+#endif #ifdef CONFIG_SPL_FS_FAT if (!spl_start_uboot()) { err = spl_load_image_fat_os(spl_image, bootdev, mmc_get_blk_desc(mmc), -- 2.25.1