topic Re: u-boot bootcount functionality in i.MX Processors

u-boot bootcount functionality

AB22 — Wed, 29 Jan 2025 20:52:15 GMT

I have made the following modifications to the u-boot configuration (Yocto Scarthgap/i.MX8M Plus):

CONFIG_BOOTCOUNT=y
CONFIG_BOOTCOUNT_LIMIT=y
CONFIG_BOOTCOUNT_BOOTLIMIT=3

Every time I printenv bootcount at the u-boot prompt, the value is 1. I would like for the bootcount functionality to indicate when to fallback to a working partition during dual-copy update (SWUpdate) in the event the boot process repeatedly fails. What conditions cause the bootcount to increment? I can corrupt files and cause a stall at the u-boot prompt but nothing is providing a mechanism to initiate fallback.

Re: u-boot bootcount functionality

xacov — Thu, 30 Jan 2025 03:46:25 GMT

It should not be a question.

https://github.com/nxp-imx/uboot-imx/blob/lf-6.1.55-2.2.0/drivers/bootcount/Kconfig

config BOOTCOUNT_ENV

bool "Boot counter in environment"

help

If no softreset save registers are found on the hardware

"bootcount" is stored in the environment. To prevent a

saveenv on all reboots, the environment variable

"upgrade_available" is used. If "upgrade_available" is

0, "bootcount" is always 0. If "upgrade_available" is 1,

"bootcount" is incremented in the environment.

So the Userspace Application must set the "upgrade_available"

and "bootcount" variables to 0, if the system booted successfully.

Re: u-boot bootcount functionality

Manuel_Salas — Thu, 30 Jan 2025 16:22:56 GMT

Hello @AB22

I hope you are doing very well.

You can see the bootcount_env.c file under uboot-imx/drivers/bootcount.

// SPDX-License-Identifier: GPL-2.0+ /* * (C) Copyright 2013 * Heiko Schocher, DENX Software Engineering, hs@denx.de. */ #include <common.h> #include <env.h> void bootcount_store(ulong a) { int upgrade_available = env_get_ulong("upgrade_available", 10, 0); if (upgrade_available) { env_set_ulong("bootcount", a); env_save(); } } ulong bootcount_load(void) { int upgrade_available = env_get_ulong("upgrade_available", 10, 0); ulong val = 0; if (upgrade_available) val = env_get_ulong("bootcount", 10, 0); return val; }

You need to set the environment variable called upgrade_available on your U-boot.

u-boot=> setenv upgrade_available 1

After reset:

u-boot=> printenv bootcount bootcount=2

I hope this can helps to you.

Best regards,

Salas.

Re: u-boot bootcount functionality

AB22 — Thu, 30 Jan 2025 16:43:05 GMT

Thank you for pointing me to that file. It is quite helpful.

Re: u-boot bootcount functionality

AB22 — Thu, 30 Jan 2025 16:45:36 GMT

That is quite helpful. I misunderstood the usage of upgrade_available. Thank you.