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

[Otavio Salvador]

On Mon, Oct 17, 2016 at 5:34 PM, Fabio Estevam <festevam at gmail.com> wrote:
> 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.

This is a later improvement. We need to have a way to identify the
UUID of the image during the image generation and it is a "chicken /
egg" type of problem. We need to address this on OE-Core before start
using it here.

For OE-Core-based systems, UUID does not seem to be the ideal solution
as it needs to mangle the image generation process. I believe we will
end using label for this.

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
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