Hi, > On August 8, 2018 at 9:52 AM Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > > > On Tue, Jul 31, 2018 at 01:20:12PM +0200, Giorgio Dal Molin wrote: > > Hi all, > > > > I'm trying to find out the best method to define the root= > > parameter when booting the linux kernel from barebox. > > > > My system boots from an sd card partitioned with a GPT. > > The sd card has two independent set of partitions with > > the following labels: > > > > 1) boot_1 + rootfs_1 > > 2) boot_2 + rootfs_2 > > > > for redondance in case one set gets damaged while updating. > > > > 'boot_1' is formatted with ext4 and contains the kernel + dtb images > > for the userland in 'rootfs_1'; and the same for 'boot_2' and 'rootfs_2'. > > > > Currently I hardcode the 'root' parameter to '/dev/mmcblk0p3' or > > '/dev/mmcblk0p4' corresponding to the kernel in 'boot_1' or > > 'boot_2' and it actually works but is there a better way to do > > this ? > > You could use bootloader spec. That would at least allow you to store a > suitable root= parameter in the config files in the boot_1 and boot_2 > partitions. > > Not sure if that's what you are looking for though. > > Sascha > as I already wrote to Uwe Kleine-Koenig I wanted to keep the kernel image and the dtb in a separate partition because these are the files the bootloader *must* be able to read to boot the system. Having the userland in a separate partition lets me choose an image format for it independently from what barebox supports; as an example I could pack my userland in a btrfs image. Moreover I can be more selective when updating the firmware: I can update only the kernel+dtb or only the userland image. What I would like to have is an automatic way to set the root= kernel command line parameter similar to what barebox does with the 'bootm.appendroot' but a bit more flexible. Looking at the kernel function name_to_dev_t() in the source init/do_mounts.c, it accepts also the format 'PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF': my idea was to somehow tell barebox 'use the partition with label "rootfs_1" for the "root" parameter' and barebox should be able to match my label with the partition UUID and automatically generate the root= value. giorgio _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
