Merge patch series "bootstd: Add Android support"

Mattijs Korpershoek <[email protected]> says:

Android boot flow is a bit different than a regular Linux distro.
Android relies on multiple partitions in order to boot.

A typical boot flow would be:
1. Parse the Bootloader Control Block (BCB, misc partition)
2. If BCB requested bootonce-bootloader, start fastboot and wait.
3. If BCB requested recovery or normal android, run the following:
   a. Get slot (A/B) from BCB
   b. Run AVB (Android Verified Boot) on boot partitions
   c. Load boot and vendor_boot partitions
   d. Load device-tree, ramdisk and boot

The AOSP documentation has more details at [1], [2], [3]

This has been implemented via complex boot scripts such as [4].
However, these boot script are neither very maintainable nor generic.
Moreover, DISTRO_DEFAULTS is being deprecated [5].

Add a generic Android bootflow implementation for bootstd.

For this initial version, only boot image v4 is supported.

This has been tested on sandbox using:
$ ./test/py/test.py --bd sandbox --build -k test_ut

This has also been tested on the AM62X SK EVM using TI's Android SDK[6]
To test on TI board, the following (WIP) patch is needed as well:
https://gitlab.baylibre.com/baylibre/ti/ti-u-boot/-/commit/84cceb912bccd7cdd7f9dd69bca0e5d987a1fd04

[1] https://source.android.com/docs/core/architecture/bootloader
[2] https://source.android.com/docs/core/architecture/partitions
[3] https://source.android.com/docs/core/architecture/partitions/generic-boot
[4] https://source.denx.de/u-boot/u-boot/-/blob/master/include/configs/meson64_android.h
[5] https://lore.kernel.org/r/all/[email protected]/
[6] https://software-dl.ti.com/processor-sdk-android/esd/AM62X/09_02_00/docs/android/Overview.html

2 files changed, 23 insertions, 0 deletions

diff --git a/include/bootflow.h b/include/bootflow.h
index 6affc5e1a4f..4d2fc7b69b5 100644
--- a/include/bootflow.h
+++ b/include/bootflow.h
@@ -409,6 +409,15 @@ void bootflow_remove(struct bootflow *bflow);
 int bootflow_iter_check_blk(const struct bootflow_iter *iter);
 
 /**
+ * bootflow_iter_check_mmc() - Check that a bootflow uses a MMC device
+ *
+ * This checks the bootdev in the bootflow to make sure it uses a mmc device
+ *
+ * Return: 0 if OK, -ENOTSUPP if some other device is used (e.g. ethernet)
+ */
+int bootflow_iter_check_mmc(const struct bootflow_iter *iter);
+
+/**
  * bootflow_iter_check_sf() - Check that a bootflow uses SPI FLASH
  *
  * This checks the bootdev in the bootflow to make sure it uses SPI flash
diff --git a/include/image.h b/include/image.h
index 9daaee15cdb..dd4042d1bd9 100644
--- a/include/image.h
+++ b/include/image.h
@@ -1972,6 +1972,13 @@ bool is_android_vendor_boot_image_header(const void *vendor_boot_img);
 ulong get_abootimg_addr(void);
 
 /**
+ * set_abootimg_addr() - Set Android boot image address
+ *
+ * Return: no returned results
+ */
+void set_abootimg_addr(ulong addr);
+
+/**
  * get_ainit_bootimg_addr() - Get Android init boot image address
  *
  * Return: Android init boot image address
@@ -1986,6 +1993,13 @@ ulong get_ainit_bootimg_addr(void);
 ulong get_avendor_bootimg_addr(void);
 
 /**
+ * set_abootimg_addr() - Set Android vendor boot image address
+ *
+ * Return: no returned results
+ */
+void set_avendor_bootimg_addr(ulong addr);
+
+/**
  * board_fit_config_name_match() - Check for a matching board name
  *
  * This is used when SPL loads a FIT containing multiple device tree files