AM4378: A/B Partitioning for bootloader

Veysel Oguz

Part Number: AM4378

Tool/software:

Hi,

We use ti-processor-sdk-linux-am437x-hs-evm-06.03.00.106 bsp version. We are trying to implement A/B partitioning method for u-boot.img. It means that we want to have 2 different boot partition and we want to choose which partition to load u-boot.img for some conditions. According to documents, I saw that ROM code loads SPL and SPL loads u-boot.img and we are able to make some changes on SPL source code (ex: common/spl/spl_mmc.c). I saw this implementation examples for kernel and rootfs but I did not see anything about u-boot part.

1- Is it possible to implement A/B partitioning for u-boot.img for our case?

2- If yes, how can we do this? Are there any references or documents for this?

7 months ago

0 Hong Guan64 7 months ago

TI__Guru 69240 points

I'd recommend oneline resources, and here is one example
https://bootlin.com/pub/conferences/2022/elce/opdenacker-implementing-A-B-system-updates-with-u-boot/opdenacker-implementing-A-B-system-updates-with-u-boot.pdf,
Best,
-Hong

0 Veysel Oguz 7 months ago in reply to Hong Guan64

Prodigy 210 points

I think you did not exactly understand our case. This recommended resources is A/B partitioning for rootfs. So, all partition choose mechanism run on u-boot.
I want that partition choose mechanism runs on SPL code, so I can update u-boot.img. I dont need A/B system updates for rootfs

0 Hong Guan64 7 months ago in reply to Veysel Oguz

TI__Guru 69240 points

The first stage boot loader (SPL) is loaded by onchip boot rom from the boot media configured by SYSBOOT mode pins, and SPL continue loading the next stage boot loader (u-boot.img) from the same boot media by default. But it is possible for user to re-configure the boot media/partition in SPL code to load u-boot. I'm attaching my note on AM43xx SPL boot flow on early SDK for your reference. You may want to look into the folders on the core, the board, and the common SPL as listed below
https://git.ti.com/cgit/ti-u-boot/ti-u-boot/tree/arch/arm/mach-omap2?h=11.00.02
https://git.ti.com/cgit/ti-u-boot/ti-u-boot/tree/board/ti/am43xx?h=11.00.02
https://git.ti.com/cgit/ti-u-boot/ti-u-boot/tree/common/spl?h=11.00.02
Best,
-Hong

0601.spl_boot_flow_v1.pdf

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AM4378: A/B Partitioning for bootloader