Hi Wolfgang,
On 7/12/2015 5:23 PM, Wolfgang Denk wrote:
Dear Brendan,
In message 5663B74E.7000204@etrix.com.au you wrote:
Is there any documentation or u-boot support for having a list of boot images to try, starting with the first in the list, trying 1, 2 or 3 times, then trying the next in the list.
e.g. boot kernel at mmcblk0p3, then mmcblk0p2, then mmcblk1p2, then tftp/nfs last resort fallback ? or boot off partition 3 of eMMC, then partition2 of eMMC, then partition 2 of SD card, then tftp/nfs ?
Define a set of boot commands, say bootcmd1, bootcmd2, ... and then simply do
run bootcmd1; run bootcmd2; ...
The furst one that succeeds will not return.
Note that the key problem with such a simplistic approach is that it will not help you in case an image looks OK, but hangs during boot - in that case, you need a watchdow and support for the bootcount feature.
Best regards, Wolfgang Denk
Yes, the watchdog and bootcount feature is the advanced stuff I'm looking for. I would think this has been implemented numerous times, and I didn't want to reinvent the wheel if there was some commonly used infrastructure to support this. If software does boot, then at some stage would set a u-boot variable to say everything booted ok, so that it can be used again on next boot.
My use case is not that uncommon -- lots of embedded devices installed in remote locations that are not easily accessible, but require remote monitor and software updates.
Is there anything that is "standard" in u-boot to support this? Or any work that is published that has attempted this?
Thanks, Brendan.