How to customize the STM32MPU distribution for Android

Coming soon

This articles explain how you can customize the STM32MPU distribution forAndroid. It's intent to be used by distribution package users.

1. Prerequisites

The environment used must have been installed using the right Distribution Package for your selected microprocessor device. See Distribution_Package.

To be able to execute following instructions you need to work from your distribution root directory and initialise your environment:

 source build/envsetup.sh
 lunch aosp-<BoardId>-userdebug

2. Layout configuration

It is possible to configuration the memory layout. The file android_layout.config located device/stm/<SocId>/layout contains all the necessary informations.

When changes is done you need to reload the environment with:

 source build/envsetup.sh
 lunch aosp-<BoardId>-userdebug

2.1. Memory type

To adapt your build to the memory you desire, you must change in the file android_layout.config the parameter PART_MEMORY_TYPE.

For exemple the possible values can be:

• sd
• emmc

2.2. Memory size

To adapt your build to the size of your memory you can change in the file android_layout.config the parameter PART_MEMORY_SIZE.

For exemple the possible values can be:

• 4GiB
• 8GiB

This value must match the parameter at the end of the file that looks like PART_<Memory size>_MEMORY_MAX_SIZE

It may be necessary to change the value attach to this parameter. For exemple:

PART_8GiB_MEMORY_MAX_SIZE 7432M x1 sd

The 7536M must be adapt if your memory is less than its definition.

To find the correct value execute:

 sgdisk -p /dev/mmcblk<x>

It will output something looking like:

Disk /dev/mmcblk0: 15433728 sectors, 7.4 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXX
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 15433694
Partitions will be aligned on 2-sector boundaries
Total free space is 0 sectors (0 bytes)

First line show the microSD card available size: here 15433728 sectors.

To calculate the size in MiB:

size = (NbSectors * SectorSize) / 1024 / 1024
In this example: (15433728 * 512) / 1024 / 1024 = 7536 MiB

Report this value for the parameter PART_8GiB_MEMORY_MAX_SIZE

PART_8GiB_MEMORY_MAX_SIZE 7536M x1 sd

You can refere to the README file in the same folder for more details.

2.3. Partition size

If you decide to change the size of some partition you need to change in the file android_layout.config.

You need to adapt all parameter that looks like

PART_<NAME> <PART_SIZE> <PART_NB> <PART_LABEL> <PART_SUFFIX> <PART_ENABLE>
NAME: name of the local variable (last partition MUST start with PART_LAST_)
PART_SIZE: as xxxMB or xxxKB or xxxGB
PART_NB: number of instances of partition (x1 or x2)
PART_LABEL: name of the partition label
PART_SUFFIX (optional): name of the suffix in case PART_NB equal x2 (_a/_b by default)
PART_ENABLE (optional): device for which the partition is only applicable (sd)

When this is done you also need to adapt every FlashLayout_*.tsv under device/stm/<SocId>/layout/programmer to match your changes.

3. Bluetooth configuration

The configuration is stored in bdroid_buildcfg.h located in device/stm/<SocId>/<BoardId>/network/bt.

The Bluetooth is enabled in device/stm/<SocId>/<BoardId>/BoardConfig.mk

BOARD_HAVE_BLUETOOTH := true
BOARD_HAVE_BLUETOOTH_LINUX := true

The path of the configuration file overlay bdroid_buildcfg.h must be also added:

BOARD_BLUETOOTH_BDROID_BUILDCFG_INCLUDE_DIR ?= device/stm/<SocId>/<BoardId>/network/bt

The Android Bluetooth stack (located in system/bt) can be configured thanks to the file device/stm/<BoardId>/network/bt/bdroid_buildcfg.h.

It must at least contain the definition of the Class of Device (CoD) (see more information in the Bluetooth Specification)

#define BTA_DM_COD {0x5A, 0x01, 0x1C}

Additionally, it can contain the Bluetooth Stack profile configuration. If a variable is not set in this file, the default configuration is selected in the stack.

By default, all the profiles are selected (see system/bt/include/bt_target.h). Example for the PAN profile:

#ifndef BTA_PAN_INCLUDED
#define BTA_PAN_INCLUDED TRUE
#endif

If you want to disable it, add the following line in bdroid_buildcfg.h:

#define BTA_PAN_INCLUDED FALSE

Several unnecessary profiles are disabled by default.

More details in Android Bluetooth.

4. Audio configuration

The configuration is stored in device/stm/<SocId>/<BoardId>/media/audio

For more details please refer to How to change audio device for Android

5. Wi-Fi configuration

The configuration is stored in device/stm/<SocId>/<BoardId>/network/wifi.

You can change various configuration:

• p2p
• wpa supplicant
• dhcp

6. Patch AOSP file

It may be necessary to patch some files from the AOSP.

To do so make the changes you need in the AOSP repository and create a patch file containing your changes.

Then copy this file to device/stm/<SocId>/patch/android/<repoName>.

You need to add you file name in the configuration file android_patch.config at the appropriate section.

For example if you need to change a file in the repository framework/base, do your changes, then:

 git commit -m "Some comment"
 git format-patch -1 #Where 1 is the numbre to commit to include.

The output result of a file name 0001-commitName.

Then copy it to device/stm/<SocId>/patch/android/framework_base.

In the configuration file it would result of:

PATCH_PATH frameworks/base
PATCH_X frameworks_base/0001-commitName #Where X is the patch order

To apply this change you need to:

 stm32mp1clear -p
 stm32mp1setup
 make -j

eval,disco (Generic term used, to complete configuration modules paths depending on used board)

technology for wireless local area networking with devices based on the IEEE 802.11 standards

Android Open Source Project