tree 58f4907d60c421fd90e589b07c54d4cb26ac5b7f
parent aae460258ddd67b3763f00052ca4c266e52b7e03
author Sam Protsenko <joe.skb7@gmail.com> 1579881220 +0200
committer Lokesh Vutla <lokeshvutla@ti.com> 1580787444 +0530

image: android: Add functions for handling dtb field

Android Boot Image v2 adds "DTB" payload (and corresponding field in the
image header). Provide functions for its handling:

  - android_image_get_dtb_by_index(): Obtain DTB blob from "DTB" part of
    boot image, by blob's index
  - android_image_print_dtb_contents(): Iterate over all DTB blobs in
    "DTB" part of boot image and print those blobs info

"DTB" payload might be in one of the following formats:
  1. concatenated DTB blobs
  2. Android DTBO format

The latter requires "android-image-dt.c" functionality, so this commit
selects that file for building for CONFIG_ANDROID_BOOT_IMAGE option.

Right now this new functionality isn't used, but it can be used further.
As it's required to apply some specific dtbo blob(s) from "dtbo"
partition, we can't automate this process inside of "bootm" command. But
we can do next:
  - come up with some new command like "abootimg" to extract dtb blob
    from boot image (using functions from this patch)
  - extract desired dtbo blobs from "dtbo" partition using "adtimg"
    command
  - merge dtbo blobs into dtb blob using "fdt apply" command
  - pass resulting dtb blob into bootm command in order to boot the
    Android kernel with Android ramdisk from boot image

Signed-off-by: Sam Protsenko <joe.skb7@gmail.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>