From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brendan Simon (eTRIX) Date: Mon, 7 Dec 2015 21:45:34 +1100 Subject: [U-Boot] u-boot retries with fallback to other images In-Reply-To: <20151207062318.020A9383F2E@gemini.denx.de> References: <5663B74E.7000204@etrix.com.au> <20151207062318.020A9383F2E@gemini.denx.de> Message-ID: <5665634E.8050004@etrix.com.au> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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.