[meta-freescale] [meta-fsl-arm-extra][PATCH 3/5] wandboard: Add support to use uboot extlinux

[Fabio Estevam]

On Mon, Oct 17, 2016 at 5:21 PM, Fabio Berton
<fabio.berton at ossystems.com.br> wrote:
> Class that allows extlinux.conf generation for U-Boot use was introduced
> on OE-core commits:
>
>   - 7c18abeb2a6ef8b7bb53aa92a9ee76bd465fada2
>   - 33df3a65f3e8e136811da715d0cc247ce66ae0ea
>
> To use this feature we need to set UBOOT_EXTLINUX variable to 1 and
> UBOOT_EXTLINUX_ROOT with root path used by kernel cmdline.
>
> Signed-off-by: Fabio Berton <fabio.berton at ossystems.com.br>
> ---
>  conf/machine/wandboard.conf | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/conf/machine/wandboard.conf b/conf/machine/wandboard.conf
> index b1e49b3..36dfc2e 100644
> --- a/conf/machine/wandboard.conf
> +++ b/conf/machine/wandboard.conf
> @@ -14,6 +14,9 @@ UBOOT_SUFFIX = "img"
>  SPL_BINARY = "SPL"
>  UBOOT_MACHINE = "wandboard_config"
>
> +UBOOT_EXTLINUX = "1"
> +UBOOT_EXTLINUX_ROOT = "root=/dev/mmcblk2p2"

This is too fragile and changes from kernel to kernel. It also depends
on how many SD cards there are connected in the board.

Much better approach is to use UUID solution as provided by U-Boot mainline.