Constructing an Android Automotive OS may not be a troublesome process by itself, however the lack of excellent tutorials makes it exceptionally exhausting. It solely will get more durable should you don’t have at hand any specialised {hardware} like R-Automotive or Dragonboard. Nonetheless, you may simply get a Raspberry Pi – a small ARM-powered, multi-usage pc and an ideal candidate to run AAOS. To make the method simpler for everybody combating this type of process, on this article, I’ll clarify step-by-step easy methods to construct and run the most recent model: Android Automotive OS 13.
Let’s get began!
Stipulations
To construct the system, you have to a Linux. You should utilize WSL or MacOS (keep in mind, you want a case-sensitive file system), however pure Linux is the most suitable choice.
{Hardware}
As within the earlier article, you want a Raspberry Pi 4B microcomputer, an influence adapter (or you may energy it out of your PC with a USB cable), a reminiscence card, and a show. It’s good to have a touchscreen, however you should use your mouse and, optionally, a keyboard if extra handy.
One other nice-to-have ingredient is a USB-TTL bridge for debugging. Discover my earlier article for extra particulars on easy methods to use it.
TL;DR;
Should you’re in search of the easy means, go to https://github.com/grapeup/aaos_local_manifest and comply with the readme. There are only a few instructions to obtain, construct and create a writeable IMG file in your Raspberry. However you want just a few hours to obtain and construct it anyway. Warning! It could not begin should you gained’t alter the show settings (see under for particulars).
Adjusting AOSP to make it AAOS
This mission relies on Raspberry Vanilla by KonstaT – an ideal AOSP port for Raspberry Pi. It covers every little thing you’ll want to run a pure Android in your Raspberry – an adjusted kernel, {hardware} drivers, and many others. Nonetheless, there isn’t any automotive construct, so you’ll want to assemble it.
There are 4 repositories in github.com/grapeup relating to AAOS – three forks based mostly on Raspberry Vanilla and one new one.
The repository aaos_local_manifest accommodates an inventory of modified and new repositories. All important modifications are positioned in gadget/brcm/rpi4 and gadget/brcm/rpi4-car initiatives outlined within the manifest_brcm_rpi4.xml file. Within the readme of this repository, you’ll discover steps to clone and construct the mission.
The following repository, aaos_device_brcm_rpi4, accommodates three parts:
The primary and most essential is to make the most of the brand new rpi4-car mission and take away conflicting objects from the bottom mission.
Within the aosp_rpi4.mk file, there’s a new line
$(name inherit-product, gadget/brcm/rpi4-car/rpi4_car.mk)
to incorporate a brand new mission.
Within the gadget.mk file, the product attribute is modified to “automotive,nosdcard“, and all customized overlays are eliminated, together with the overlay listing subsequent to the file.
Within the manifest.xml file, the “android.{hardware}.automotive.automobile“ HAL ({Hardware} Abstraction Layer) is added.
The second ingredient is to configure the construct for the display I use. I needed to set the display decision in vendor.prop and set the display density in BoardConfig.mk. You in all probability don’t want such modifications should you use an ordinary PC monitor, otherwise you want another one in your customized show. Bear in mind that the system gained’t begin in any respect if the decision configured right here is just not supported by your show.
The final ingredient accommodates my regional/language settings in aosp_rpi4.mk. I’ve determined to make use of this file, because it’s not automotive-related, and to depart it within the code to point out easy methods to alter it if wanted.
The principle half
Probably the most main modifications are positioned within the aaos_device_brcm_rpi4_car repository.
The rpi4_car.mk file relies on gadget/generic/automotive/widespread/automotive.mk with few modifications.
Conditional, particular settings for the Generic System Pictures are eliminated together with the emulator configuration (gadget/generic/automotive/widespread/config.ini) and the emulator audio package deal (android.{hardware}.audio.service-caremu).
As a substitute, you want a mix of vendor-specific and board-specific parts, not included within the widespread/automotive makefile designed for an emulator.
Android Automotive OS is strictly coupled with an audio engine, so you’ll want to add an automotive audio management package deal (android.{hardware}[email protected]) to make it work, even should you don’t need to join any audio system to your board. Additionally, AAOS makes use of a particular show controller with the power to make use of two shows on the identical time ([email protected]), so you’ll want to embrace it too. The following half is SELinux policy for actual boards (not an emulator).
BOARD_SEPOLICY_DIRS += gadget/generic/automotive/widespread/sepolicy
Then you’ll want to add permissions to a couple pre-installed, automotive-oriented packages, to permit them to run within the system or person areas.
PRODUCT_COPY_FILES += gadget/google/cuttlefish/shared/auto/preinstalled-packages-product-car-cuttlefish.xml:$(TARGET_COPY_OUT_PRODUCT)/and many others/sysconfig/preinstalled-packages-product-car-cuttlefish.xml
The following element is EVS – Exterior View System launched to AAOS 13. Even should you don’t actually need to join a number of cameras to the system to date, you must embrace the default implementation of the element and configure it to work as a mock.
DEVICE_PACKAGE_OVERLAYS += gadget/google/cuttlefish/shared/auto/overlay
ENABLE_EVS_SERVICE ?= true
ENABLE_MOCK_EVSHAL ?= true
ENABLE_CAREVSSERVICE_SAMPLE ?= true
ENABLE_SAMPLE_EVS_APP ?= true
ENABLE_CARTELEMETRY_SERVICE ?= true
CUSTOMIZE_EVS_SERVICE_PARAMETER := true
PRODUCT_PACKAGES += android.{hardware}[email protected]
PRODUCT_COPY_FILES += gadget/google/cuttlefish/shared/auto/evs/init.evs.rc:$(TARGET_COPY_OUT_VENDOR)/and many others/init/init.evs.rc
BOARD_SEPOLICY_DIRS += gadget/google/cuttlefish/shared/auto/sepolicy/evs
The final half is to regulate variables for a system when operating. You set two system properties immediately within the makefile (to permit a pressured orientation and to allow the AVRCP Bluetooth profile).
PRODUCT_SYSTEM_DEFAULT_PROPERTIES +=
config.override_forced_orient=true
persist.bluetooth.enablenewavrcp=false
In the long run, you override the next system variables, utilizing predefined and customized overlays.
PRODUCT_PACKAGE_OVERLAYS +=
gadget/brcm/rpi4-car/overlay
gadget/generic/automotive/widespread/overlay
Usually talking, PRODUCT_PACKAGE_OVERLAYS permits us to overwrite any worth from a property file positioned within the supply code. For instance, in our case the overlay root listing is gadget/brcm/rpi4-car/overlay, so the file gadget/brcm/rpi4-car/overlay/frameworks/base/core/res/res/values/config.xml overwrites properties from the file frameworks/base/core/res/res/values/config.xml.
Let’s dive into properties modified.
- frameworks/base/core/res/res/values/config.xml file:
- config_useVolumeKeySounds disables utilization of {hardware} quantity keys, as they don’t seem to be current in our setup,
- config_voice_capable permits data-only mode, as there isn’t any chance to make a voice name from our board,
- config_sms_capable disables SMS capabilities for a similar purpose,
- networkAttributes and radioAttributes units the system to make use of WiFi, Bluetooth and ethernet connections solely, as there isn’t any GSM modem onboard,
- config_longPressOnPowerBehavior disables long-press on an influence button, as there isn’t any energy button linked,
- config_disableUsbPermissionDialogs disables USB permission display, because it shouldn’t be used within the AAOS,
- config_defaultUiModeType permits the automotive launcher by default,
- config_defaultNightMode permits evening mode because the default one.
- frameworks/base/packages/SettingsProvider/res/values/defaults.xml file:
- def_wifi_on permits WiFi by default,
- def_accelerometer_rotation units the default orientation,
- def_auto_time permits acquiring time from the Web when linked,
- def_screen_brightness units the default display brightness,
- def_bluetooth_on permits Bluetooth by default,
- def_location_mode permits functions to make use of location providers by default,
- def_lockscreen_disabled disables the lockscreen,
- def_stay_on_while_plugged_in units the gadget to remain enabled on a regular basis.
packages/apps/Automotive/LatinIME/res/format/input_keyboard.xmlfile units the default foreground colour of the default keyboard, because the default one is just not very readable. SetkeyTextColorPrimaryandtextColorparameters to regulate it.packages/apps/Automotive/LatinIME/res/values/colours.xmlunits colours or image characters on the default keyboard and the letter/symbols swap on the underside proper nook.packages/apps/Automotive/SystemUI/res/values/colours.xml units the background colour of the standing bar fast settings to make the default font colour readable.-
packages/apps/Automotive/SystemUI/res/values/config.xmlhides brightness settings from the highest bar, because it doesn’t work with out a particular drivers for the show.
- packages/apps/Settings/res/values/config.xml file:
- config_show_call_volume disables quantity management throughout calls,
- config_show_charging_sounds disables charging sounds,
- config_show_top_level_battery disables battery stage icon.
- packages/modules/Wifi/service/ServiceWifiResources/res/values/config.xml permits 5Ghz assist for the WiFi.
-
packages/providers/Automotive/service/res/values/config.xmldisables operating a devoted utility when the system begins up or a driver is modified.
You may learn extra about every of these settings within the feedback within the unique recordsdata which these settings got here from.
The final repository is aaos_android_hardware_interfaces . You don’t want it, however there’s one helpful property hardcoded right here. In Android, there’s a idea referred to as HAL – {Hardware} Abstraction Layer. For AAOS, there’s VHAL – Car {Hardware} Abstraction Layer. It’s accountable, amongst others, for HVAC – Heating, Air flow, and Air Conditioning. In our setup, there isn’t any automobile {hardware} and no bodily HVAC, so you utilize android.{hardware}[email protected] whose default implementation is positioned beneath {hardware}/interfaces/automotive/automobile. To alter the default models utilized by HVAC from imperial to rest-of-the-world, you’ll want to alter the {hardware}/interfaces/automotive/automobile/aidl/impl/default_config/embrace/DefaultConfig.h file.
Constructing
The constructing course of for AAOS 13 for Raspberry Pi is far simpler than the one for AAOS 11. The kernel is already precompiled and there’s a lot much less to do.
Simply name these three instructions:
. construct/envsetup.sh
lunch aosp_rpi4-userdebug
make bootimage systemimage vendorimage
On a Home windows laptop computer (utilizing WSL, in fact) with the i7-12850HX processor and 32GB RAM, it takes round 1 hour and 40 minutes to perform the construct.
Making a bootable SD card
There are two choices – with or with out the mkimg.sh script. The script is positioned beneath gadget/brcm/rpi4 listing and linked in the principle listing of the mission as rpi4-mkimg.sh. The script creates a digital picture and places 4 partitions inside – boot, system, vendor, and userdata. It’s helpful as a result of you should use Raspberry Pi Imager to write down it into an SD card nevertheless, it has just a few limitations. The picture at all times has 7GB (you may change it by adjusting the IMGSIZE variable within the script), so that you gained’t use the remainder of your card, regardless of how massive it’s. Moreover that, you at all times want to write down 7GB to your card – even when you must replace solely a single partition, and together with writing zeros to an empty userdata partition.
The choice means is to write down it on the cardboard by hand. It’s difficult beneath Home windows as WSL doesn’t include card reader drivers, but it surely’s handy in different working methods. All required recordsdata are constructed within the out/goal/product/rpi4 listing. Let’s put together and write the cardboard. Warning! In my system, the SD card is seen as /dev/sdb. Please alter the instructions under to not destroy your knowledge.
OK, let’s clear the cardboard. It is advisable wipe every partition earlier than wiping your entire gadget to take away file methods signatures.
sudo umount /dev/sdb*
sudo wipefs -a /dev/sdb*
sudo wipefs -a /dev/sdb
Now let’s put together the cardboard. This line will use fdisk to create 4 partitions and set flags and filesystems.
echo -e "nnnnn+128Mnantn0cnnnnnn+2Gnnnnnn+256Mnnnpnnnwn" | sudo fdisk /dev/sdb
The final step is to write down knowledge and put together the final partition.
sudo dd if=boot.img of=/dev/sdb1 bs=1M
sudo dd if=system.img of=/dev/sdb2 bs=1M
sudo dd if=vendor.img of=/dev/sdb3 bs=1M
sudo mkfs.ext4 -L userdata /dev/sdb4
sudo umount /dev/sdb*
Abstract
Android Automotive OS is a big leap for the automotive business. As there isn’t any manufacturing automobile with AAOS 13 to date, you may expertise the longer term with this handbook. What’s extra, you are able to do it with a low-budget Raspberry Pi pc. This manner, I hope you may develop your functions and play with the system simply with out an extra layer of utilizing emulators. Good luck and comfortable coding!