Failsafe booting to alternate linux image/fs
Hi,
Before I embark on my own implementation of a failsafe bootloading process from my embedded system (Xilinx Zynq board booting from SD Card), I thought I'd quickly ask the experts if there are any standard implementations in u-boot.
The current u-boot being used is from 2015. It probably needs to be updated (for various reasons). It is loaded from the first partition (64MB/FAT32) of an SD Card as part of a file called `BOOT.BIN`. The `Env.txt` file contains settings for two linux root systems (including kernel and dtb) on separate partitions (ext4/1GB). The first statement in `Env.txt` has a `part=2` or `part=3` to indicate, which partition to boot from (load kernel and set cmdline for rootfs, etc).
My simple approach was to store a env var for the number of reboot attempts. On every boot attempt, the env var would be incremented. If linux booted successfully it would set the env var to zero (I believe there are linux tools to do that). If linux didn't boot successfully, eventually the reboot count env var would reach some value, where the alternative partition would be selected as an attempt to get something booting and up and running.
NOTE: the devices are remote and need to be up as much as possible so they can be monitored/managed.
*Does this type of functionality exist already in u-boot?* I'm guessing/hoping it does (and hope to use it directly or leverage the features that make sense) rather than reinventing the wheel.
*Where is the best place to go to get information/documentation on this?*
Finally, I'm looking at migrating to EMMC, maybe with a golden image for failsafe use, and two partitions for current filesystem and next/upgrade filesystem.
*Is there any documentation that might be a useful in this use case?*
Thanks, Brendan.
I came across the "Boot Count Limit" feature in the U-Boot wiki, and it looks like it will do exactly what I want.
https://www.denx.de/wiki/view/DULG/UBootBootCountLimit
However, it also states that the "feature is available only for MPC8xx, MPC82xx and MPC5200 Power Architecture® processors"
Is that accurate? Is it not available for ARM processors (e.g. A9 CPU system within Xilinx Zynq 7000 series SoCs) ?
Thanks, Brendan,
--
On 28/5/20 5:14 pm, Brendan Simon (eTRIX) wrote:
Hi,
Before I embark on my own implementation of a failsafe bootloading process from my embedded system (Xilinx Zynq board booting from SD Card), I thought I'd quickly ask the experts if there are any standard implementations in u-boot.
The current u-boot being used is from 2015. It probably needs to be updated (for various reasons). It is loaded from the first partition (64MB/FAT32) of an SD Card as part of a file called `BOOT.BIN`. The `Env.txt` file contains settings for two linux root systems (including kernel and dtb) on separate partitions (ext4/1GB). The first statement in `Env.txt` has a `part=2` or `part=3` to indicate, which partition to boot from (load kernel and set cmdline for rootfs, etc).
My simple approach was to store a env var for the number of reboot attempts. On every boot attempt, the env var would be incremented. If linux booted successfully it would set the env var to zero (I believe there are linux tools to do that). If linux didn't boot successfully, eventually the reboot count env var would reach some value, where the alternative partition would be selected as an attempt to get something booting and up and running.
NOTE: the devices are remote and need to be up as much as possible so they can be monitored/managed.
*Does this type of functionality exist already in u-boot?* I'm guessing/hoping it does (and hope to use it directly or leverage the features that make sense) rather than reinventing the wheel.
*Where is the best place to go to get information/documentation on this?*
Finally, I'm looking at migrating to EMMC, maybe with a golden image for failsafe use, and two partitions for current filesystem and next/upgrade filesystem.
*Is there any documentation that might be a useful in this use case?*
Thanks, Brendan.
Hi,
On 29. 05. 20 1:25, Brendan Simon (eTRIX) wrote:
I came across the "Boot Count Limit" feature in the U-Boot wiki, and it looks like it will do exactly what I want.
https://www.denx.de/wiki/view/DULG/UBootBootCountLimitHowever, it also states that the "feature is available only for MPC8xx, MPC82xx and MPC5200 Power Architecture® processors"
Is that accurate? Is it not available for ARM processors (e.g. A9 CPU system within Xilinx Zynq 7000 series SoCs) ?
It is generic feature and you should be able to use it with any cpu. And Zynq platform included.
Thanks, Michal
participants (2)
-
Brendan Simon (eTRIX) -
Michal Simek