On Fri, May 4, 2018, 10:38 PM Simon Glass sjg@chromium.org wrote:
Hi,
On 1 May 2018 at 04:52, Ramon Fried ramon.fried@gmail.com wrote:
On Tue, May 1, 2018 at 12:20 PM, Alex Deymo deymo+@google.com wrote:
Hi Ramon,
What "header_version" is the boot image you have? The include/android_image.h in U-Boot is a little bit old so it only
defines the
v0 format. The "unused" field in v0 was renamed to "header_version"
where 0
means v0. The v1 adds a few more fields, including a DTB/DTBO for
*recovery*
mode. See
https://android.googlesource.com/platform/system/core/+/master/mkbootimg/inc...
Yes, the U-boot has the v0 version.
Having multiple DTs and picking one or merge overlays at runtime is a reasonable thing and there's some documentation in AOSP on how to do it
in
Android: https://source.android.com/devices/architecture/dto/multiple
(and
other sections around it). There are some options on where to store
these
and even a supported format for placing multiple .dtbo in a single
"dtbo"
partition (but appending multiple DTBs at the end of the kernel is not
one
of these).
Which are the "seconday" fields you are referring to?
uint32_t second_size; /* size in bytes */ uint32_t second_addr; /* physical load addr */
In
https://android.googlesource.com/platform/system/core/+/master/mkbootimg/inc...
I'm not familiar with the Dragonboard images, but it looks like they
just
extended this over the reserved space in a different way. Maybe you can convert the header to the newer format, but that still requires work in U-Boot to support the new format.
I'm willing to do it, I just want to get some approval from maintainers before I dive in.
Thanks, Ramon
Regards, Alex
Le lun. 30 avr. 2018 à 16:17, Ramon Fried ramon.fried@gmail.com a
écrit :
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 ?
Does every vendor just do its own thing, or is there a standard header structure?
I don't know. I'm familiar only with Qualcomm way. Not sure about the rest.
How can we detect multiple incompatible options? Just by the machine architecture?
Qualcomm is using the unused fields in version 1 of Android boot header. I guess that ifdef in the source code is the only way.
Can we just use FIT perhaps?
Of course we can, I already booted successfully with FIT. But it will require users to repackage their kernel boot image.
Thanks, Ramon
- Actually, Qualcomm appends a pack of DTBs with offset table and
chooses the right DTB in runtime. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
Regards, Simon