[U-Boot] Appended DTB Android boot image support

[Ramon Fried]

On Tue, May 1, 2018 at 2:12 AM, Simon Glass <sjg at chromium.org> wrote:
> Hi Ramon,
>
> On 30 April 2018 at 07:04, Ramon Fried <ramon.fried at gmail.com> wrote:
>> Hi all.
>> I'm currently adding support for Qualcomm Dragonboards  to U-boot as a
>> primary bootloader without chain-loading using LK which is currently
>> already supported in mainline U-boot.
>>
>> Qualcomm Android images are regular android images where the DTB's are
>> appended to the image. Qualcomm used the "unused" field in the image
>> header to populate the size of the DTB *.
>>
>> I'm looking for a more standard version for supporting these kind of images.
>> Currently, to boot these images, you must provide DTB somewhere in mem
>> and provide it as argument to bootm for instance.
>>
>> My goal is to add support that U-boot will parse the image, see that
>> the DTB is included and use that as the FDT automatically.
>>
>> I'm looking at the "secondary" fields which are currently not used as
>> a valid option to point to the DTB and it's size.
>>
>> Do you know if someone is working on something similar, or do you have
>> any suggestions for the right approach to this issue ?
>
> Have you thought of using FIT? It suppose multiple DTB files, multiple
> kernels, compression, etc. and is readily extensible.
It's an option I'm considering, but I think it will much more suitable
to keep the
android image format, this way I could support fastboot and also still
use qualcomm proprietary tools
for flashing the images in the right place.

I did notice also that building uImage in Linux kernel doesn't work on
arm64 targets, did I miss something ?
>
> Regards,
> Simon