A little while ago I wrote Building Jelly Bean 4.3 AOSP for Beaglebone Black which describes how to install Android on a micro SD card and boot the BeagleBone from it. Then I did some research on integrating fastboot into U-Boot and wrote Android fastboot for BeagleBone Black. Now I am bringing the two together.
I did think about editing the first article, but I think it is cleaner to have a new tutoruial that works for the new use case.
To recap: I wanted to create an Android install for the BeagelBone Black for my Android training classes. I looked at the Rowboat project (http://arowboat.org) but found that some things were not done "in the Android way" for no good reason. So I re-packaged Rowboat to:
Overall, the steps are
Before you begin, make sure that you have a system capable to building AOSP in a reasonable amount of time as described here http://source.android.com/source/building.html. Then follow these steps to set it up http://source.android.com/source/initializing.html. For reference, I tested on two machines: one a laptop with dual core i7 and 4 GiB RAM running Ubuntu 12.04 64 bit (AOSP build takes more than 2 hours), and the other an octo core AMD FX-8150 with 16 GiB RAM running Ubuntu 10.04 64 bit (takes 35 minutes).
Note: in the following I am installing and building everything in the home directory (“~”). You may use whichever directory you wish but you will have to modify the paths used below accordingly.
Begin by getting the repo tool and using it to download the AOSP:
$ curl http://commondatastorage.googleapis.com/git-repo-downloads/repo > ~/bin/repo $ chmod a+x ~/bin/repo $ mkdir ~/aosp-4.3_r2.1 $ cd aosp-4.3_r2.1 $ repo init -u https://android.googlesource.com/platform/manifest -b android-4.3_r2.1 $ repo sync
This takes several hours because there is 17 GiB to download. When complete you will have all the Android source in ~/aosp-4.3_r2.1.
Get my device files for the Beaglebone Black into device/ti/beagleboneblack
$ cd ~/aosp-4.3_r2.1/device/ti $ git clone https://github.com/csimmonds/bbb-android-device-files.git beagleboneblack $ cd beagleboneblack $ git checkout jb4.3-fastboot $ cd ~/aosp-4.3_r2.1 $ . build/envsetup.sh $ lunch beagleboneblack-eng
The kernel comes from the Rowboat project. It is version 3.2, without device tree support, but it works well enough for me.
$ cd ~/aosp-4.3_r2.1 $ git clone git://gitorious.org/rowboat/kernel.git $ cd kernel $ git checkout rowboat-am335x-kernel-3.2
You can use the Android ARM cross compiler, arm-eabi-gcc, to build. Assuming that you have already sourced build/envsetup.sh and run lunch then you can:
$ cd ~/aosp-4.3_r2.1/kernel $ make ARCH=arm CROSS_COMPILE=arm-eabi- am335x_evm_android_defconfig $ make ARCH=arm CROSS_COMPILE=arm-eabi- -j4 zImage $ croot $ cp kernel/arch/arm/boot/zImage device/ti/beagleboneblack/kernel
Now you are ready to run the first AOSP build. Note: the -j option to "make" determines the number of parallel jobs to run. My rule of thumb is to use the number of CPU cores plus 2
$ cd ~/aosp-4.3_r2.1 $ make -j10
This takes an hour or so. When complete you will find the compiled Android system in ~/aosp-4.3_r2.1/out/target/product/beagleboneblack/
Once again I am getting these from Rowboat. This is messy because they are not very well integrated with the AOSP code. One issue is that the makefile has some paths hard coded which is why it has to be put into hardware/ti/sgx, and also why the kernel has to be in directory kernel/.
$ cd ~/aosp-4.3_r2.1/hardware/ti $ git clone git://git.gitorious.org/rowboat/hardware-ti-sgx.git sgx $ cd sgx $ git checkout ti_sgx_sdk-ddk_1.10-jb-4.3
With Rowboat, the binaries are copied into out/target/product/beagleboneblack/system after the AOSP build is complete and then post-processed into the install tar ball. I want to have them built as part of the AOSP build, so I edit one of the makefiles to put the binaries into my device directory. Then they get sucked into the final images by the rules in my device.mk. So, edit Rules.make: line 23 and change
This next bit has to be run in a completely new shell. I'm sorry, but for some reason it won't build in a shell that has been set up for an AOSP build (i.e. has ". build/emvsetup.sh").
Note: W=1 is needed to avoid turning warnings into errors...
$ cd ~/aosp-4.3_r2.1/hardware/ti/sgx $ PATH=$HOME/aosp-4.3_r2.1/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin:$PATH $ make TARGET_PRODUCT=beagleboneblack OMAPES=4.x ANDROID_ROOT_DIR=$HOME/aosp-4.3_r2.1 W=1 $ make TARGET_PRODUCT=beagleboneblack OMAPES=4.x ANDROID_ROOT_DIR=$HOME/aosp-4.3_r2.1 W=1 install
That will result in populating device/ti/beagleboneblack/sgx
The droid VNC server is useful if you want to test Android on your BeagleBone but don't have a screen:
$ cd ~/aosp-4.3_r2.1/external $ git clone git://gitorious.org/rowboat/droid-vnc-server
Now you need to regenerate the Android image files to include the SGX binaries. This should only take a few minutes.
$ cd ~/aosp-4.3_r2.1 $ . build/envsetup.sh $ lunch beagleboneblack-eng $ make installclean $ make -j10
If you haven't already, install U-Boot with fastboot as described in this tutorial
Now you can use fastboot to flash the Android images:
$ croot $ fastboot flash userdata $ fastboot flash cache $ fastboot flashall
The last command flashes boot.img, recovery.img and sytem.img and then reboots the device.
You have three options
There is a 720p output (1280 x 720) on the HDMI port. Plug this into a suitable display, plug a mouse in to the USB and you have a usable system. This is your best bet.
I have tried it with the LCD7 cape (800 x 480). The display is fine but the resistive touch screen is a dead loss. OK for demos.
If all else fails...
Run "androidvncserver" on the Beagleboard. Now you can connect to it either over USB or Ethernet. For USB you need to use adb to forward the VNC port and run a VNC client such as vinagre like so:
$ adb forward tcp:5901 tcp:5901 $ vinagre localhost:5901
To use Ethernet, you need to know what the IP address of the Beagleboard:
# netcfg lo UP 127.0.0.1/8 0x00000049 00:00:00:00:00:00 sit0 DOWN 0.0.0.0/0 0x00000080 00:00:00:00:00:00 eth0 UP 192.168.1.19/24 0x00001043 90:59:af:5d:85:78
Then on the PC
$ vinagre 192.168.1.19:5901
There is an irritating quirk you should know about: any keys you press in vinagre will not be transmitted to the device until you click the left mouse button.
After this fairly lengthy set of instructions you should have JB 4.3 running on your BeagleBone, and more importantly you will have experienced the stages of putting together an AOSP build, including fastboot!