Porting Android

[platinum95]

Hi there,
I'm currently working on porting Android (I haven't seen anyone else being successful in doing this so far).
I think I almost have it. I've got the Source built, a custom kernel made, and put it all on the SD card. Plug it in, kernel loads, and I get the A N D R O I D text, then a kernel panic.
And all this without even making my own config for the android source (which I'm doing right now).

Anyway, just thought I'd let everyone know about this. I'll post as soon as I have it working (if I get it working, I have no other experience in this)

-Peter

[abishur]

Neat! Which version of Android are you working on porting?

[platinum95]

I did some research, and Gingerbread seemed like it was the best way to go. It's a pity though, there would be a lot more potential if there was more RAM. Even 512 megs should be able to run ics smoothly enough. Ah well, we'll save that for future Pi revisions

[abishur]

That's good, Gingerbread is enough to get a lot of nifty apps if you get it working

[platinum95]

I think the main problem here isn't about the hardware limitations, it's more of the fact that I'm new to Linux.
Ah well, you know what they say, "No better way to learn Linux than to port Android to a bare-minimum arm-based mini-computer"

[arturo777]

Despite the ram limitation, ICS might be worth considering rather than Gingerbread. I have installed CyanogenMod 9 (actually miniCM9) on a Sony Xperia X8 for development work, which also has 256 MB (or less - I'm not quite sure, some sources say 168MB) and have been quite impressed. Most of the apps (Gmail, skype, Angrybirds, Maps, Google Reader) work fine. Although the CPU on the pi is probably a lot slower, the advantage of ICS is that it makes use of hardware accelerated graphics, something which if the drivers can be ported, the pi can do very well.

In any case, porting android is certainly a very interesting learning project, regardless of the results.

[jasonslack]

@platinum95 how's the port going?

[platinum95]

So what I've been doing up to now is basically a really sloppy job, getting everything done really quick and easy, just for testing purposes. First go of this sloppy job and I almost get a boot. Android starts to load, but kernel panics after about 15 seconds of loading. Which means the testing worked, and now I'm doing a proper clean job of it. At the moment, I'm merging the rpi kernel and the android kernel. Lots of conflicts that need to be resolved, so itll take a few days.
After that, I make a product config for the pi under the Gingerbread source and compile it. Then it's fairly simple - get the pi firmware, partition the sd card and load on the files.
Considering I'm not sure right now HOW to resolve the kernel conflicts, it'll be a few days before i have a working kernel

[lb]

Maybe it's more useful in the long run to work instead on the device tree Raspberry Pi kernel, since that's based on the very latest kernel code, and Linux has Android support out of the box since 3.3.

The device tree kernel is still incomplete, though. Check out Sim Arlott's repository: https://github.com/lp0/linux/tree/rpi-linear

[platinum95]

Awesome, thanks for that. Have it cloning as we speak

[fodi]

Hi there,
I'm currently working on porting Android (I haven't seen anyone else being successful in doing this so far).
I think I almost have it. I've got the Source built, a custom kernel made, and put it all on the SD card. Plug it in, kernel loads, and I get the A N D R O I D text, then a kernel panic.
And all this without even making my own config for the android source (which I'm doing right now).

Anyway, just thought I'd let everyone know about this. I'll post as soon as I have it working (if I get it working, I have no other experience in this)

-Peter

that is very impressive news

and from vanilla gingerbread (i guess you are working on google sources not cyanogenmod ones) we can relatively easily port cm7 and miui as well

[ligi]

Awesome news platinum95! Sooo looking forward to Android on the Raspberry - can't wait to test it - how buggy it might be - all I really need working is a ADB connection

[CovertReaper]

That is great news. I am so glad that someone is working on porting Android to the Raspberry Pi.

I do have one question? Since the Pi only has 256MB of memory, would it make any difference using a larger swap partition? Or perhaps assigning the Swap Partition to a 4GB USB Flashdrive, so the Pi can read the OS and Swap Partition simultaneously. The way I understand it, the Swap Partition works very similar to Virtual Memory in Windows. When your 256MB of system memory gets full, it dumps the remaining data into the Swap Partition for processing as resources become available.

[platinum95]

Sorry about the delay, I had to reinstall Arch linux and then my backup hard drive with all the 28gb of android files thinks that copying at 500 kb/sec is somewhat acceptable.
I have the android source built for Armv6 and I am just trying to get a kernel working. After that, it's just a matter of marrying the two and setting the android config files.

[DarkWrath669]

If you can pull this off so many of us will be so happy.

I'm happy to play with Debian, but really looking forward to this.

My father however who saw my tiny computer and decided it would be perfect to turn his lounge TV into a smart TV wouldn't be able to get past the Linux login for Debian or other distros.
A nice fluffy GUI with good user friendly interfaces will be perfect for home use.

Many thanks for putting the effort in.

[itimpi]

Why not use the OpenElec or RaspBmc distributions for this. They boot straight into XBMC without the need to log in.

[DarkWrath669]

Why not use the OpenElec or RaspBmc distributions for this. They boot straight into XBMC without the need to log in.

Mainly to use for web browsing and light desktop work, ie word processing.
Looked into intalling software like FireFox on XBMC and it doesn't seem to be plain straight forward.

Not looked into OpenElec.

Benefit of Android is installing any apps without having to learn basic command line. Tried to teach my dad some of this stuff but at 55, he is not so interested.

[jamesh]

Android will be a lot slower than a pure Linux distro.

[Max]

Maybe it's more useful in the long run to work instead on the device tree Raspberry Pi kernel, since that's based on the very latest kernel code, and Linux has Android support out of the box since 3.3.

Does it work with all hardware nowadays, or still puts additional requirements on individual modules?

E.g. with previous versions of Android your framebuffer driver needed to have support for double buffering. (which I don't think is implemented in the current Pi module).

[profeta]

Hi,

To run Android on machine with limited RAM, consider enabling ZRam functionality.

http://en.wikipedia.org/wiki/ZRam

Results are quite impressive.

[mahjongg]

Only works if you have enough RAM to begin with, and has a very big penalty on performance.
in other words, do not expect miracles.

[platinum95]

Right, everything is built. But, since I'm not very good at this, it's not working (what a surprise). Getting the "not syncing - attempted to kill init" error.

So far I've tried:
Creating partitions with the debian partition, deleting all the debian and firmware files then replacing them with the latest firmware, the kernel I built and the android files.
-
Putting all the files (firmware/kernel/android) onto one partition (tried ext4,vfat and msdos)
-
Using the generic build instead of rpi.

All of these had the same result, the same kernel panic, so it seems that the problem lies in the init file, as the panic suggests.
Init.rc is as follows:

on early-init
start ueventd

on init

sysclktz 0

loglevel 3

# setup the global environment
export PATH /sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin
export LD_LIBRARY_PATH /vendor/lib:/system/lib
export ANDROID_BOOTLOGO 1
export ANDROID_ROOT /system
export ANDROID_ASSETS /system/app
export ANDROID_DATA /data
export EXTERNAL_STORAGE /mnt/sdcard
export ASEC_MOUNTPOINT /mnt/asec
export LOOP_MOUNTPOINT /mnt/obb
export BOOTCLASSPATH /system/framework/core.jar:/system/framework/bouncycastle.jar:/system/framework/ext.jar:/system/framework/framework.jar:/system/framework/android.policy.jar:/system/framework/services.jar:/system/framework/core-junit.jar

# Backward compatibility
symlink /system/etc /etc
symlink /sys/kernel/debug /d

# Right now vendor lives on the same filesystem as system,
# but someday that may change.
symlink /system/vendor /vendor

# create mountpoints
mkdir /mnt 0775 root system
mkdir /mnt/sdcard 0000 system system

# Create cgroup mount point for cpu accounting
mkdir /acct
mount cgroup none /acct cpuacct
mkdir /acct/uid

# Backwards Compat - XXX: Going away in G*
symlink /mnt/sdcard /sdcard

mkdir /system
mkdir /data 0771 system system
mkdir /cache 0770 system cache
mkdir /config 0500 root root

# Directory for putting things only root should see.
mkdir /mnt/secure 0700 root root

# Directory for staging bindmounts
mkdir /mnt/secure/staging 0700 root root

# Directory-target for where the secure container
# imagefile directory will be bind-mounted
mkdir /mnt/secure/asec 0700 root root

# Secure container public mount points.
mkdir /mnt/asec 0700 root system
mount tmpfs tmpfs /mnt/asec mode=0755,gid=1000

# Filesystem image public mount points.
mkdir /mnt/obb 0700 root system
mount tmpfs tmpfs /mnt/obb mode=0755,gid=1000

write /proc/sys/kernel/panic_on_oops 1
write /proc/sys/kernel/hung_task_timeout_secs 0
write /proc/cpu/alignment 4
write /proc/sys/kernel/sched_latency_ns 10000000
write /proc/sys/kernel/sched_wakeup_granularity_ns 2000000
write /proc/sys/kernel/sched_compat_yield 1
write /proc/sys/kernel/sched_child_runs_first 0

# Create cgroup mount points for process groups
mkdir /dev/cpuctl
mount cgroup none /dev/cpuctl cpu
chown system system /dev/cpuctl
chown system system /dev/cpuctl/tasks
chmod 0777 /dev/cpuctl/tasks
write /dev/cpuctl/cpu.shares 1024

mkdir /dev/cpuctl/fg_boost
chown system system /dev/cpuctl/fg_boost/tasks
chmod 0777 /dev/cpuctl/fg_boost/tasks
write /dev/cpuctl/fg_boost/cpu.shares 1024

mkdir /dev/cpuctl/bg_non_interactive
chown system system /dev/cpuctl/bg_non_interactive/tasks
chmod 0777 /dev/cpuctl/bg_non_interactive/tasks
# 5.0 %
write /dev/cpuctl/bg_non_interactive/cpu.shares 52

#on fs
# mount mtd partitions
# Mount /system rw first to give the filesystem a chance to save a checkpoint
#mount yaffs2 mtd@system /system
#mount yaffs2 mtd@system /system ro remount
#mount yaffs2 mtd@userdata /data nosuid nodev
#mount yaffs2 mtd@cache /cache nosuid nodev

on post-fs
# once everything is setup, no need to modify /
#mount rootfs rootfs / ro remount

# We chown/chmod /data again so because mount is run as root + defaults
chown system system /data
chmod 0771 /data

# Create dump dir and collect dumps.
# Do this before we mount cache so eventually we can use cache for
# storing dumps on platforms which do not have a dedicated dump partition.

mkdir /data/dontpanic
chown root log /data/dontpanic
chmod 0750 /data/dontpanic

# Collect apanic data, free resources and re-arm trigger
copy /proc/apanic_console /data/dontpanic/apanic_console
chown root log /data/dontpanic/apanic_console
chmod 0640 /data/dontpanic/apanic_console

copy /proc/apanic_threads /data/dontpanic/apanic_threads
chown root log /data/dontpanic/apanic_threads
chmod 0640 /data/dontpanic/apanic_threads

write /proc/apanic_console 1

# Same reason as /data above
chown system cache /cache
chmod 0770 /cache

# This may have been created by the recovery system with odd permissions
chown system cache /cache/recovery
chmod 0770 /cache/recovery

#change permissions on vmallocinfo so we can grab it from bugreports
chown root log /proc/vmallocinfo
chmod 0440 /proc/vmallocinfo

#change permissions on kmsg & sysrq-trigger so bugreports can grab kthread stacks
chown root system /proc/kmsg
chmod 0440 /proc/kmsg
chown root system /proc/sysrq-trigger
chmod 0220 /proc/sysrq-trigger

# create basic filesystem structure
mkdir /data/misc 01771 system misc
mkdir /data/misc/bluetoothd 0770 bluetooth bluetooth
mkdir /data/misc/bluetooth 0770 system system
mkdir /data/misc/keystore 0700 keystore keystore
mkdir /data/misc/vpn 0770 system system
mkdir /data/misc/systemkeys 0700 system system
mkdir /data/misc/vpn/profiles 0770 system system
# give system access to wpa_supplicant.conf for backup and restore
mkdir /data/misc/wifi 0770 wifi wifi
chmod 0770 /data/misc/wifi
chmod 0660 /data/misc/wifi/wpa_supplicant.conf
mkdir /data/local 0771 shell shell
mkdir /data/local/tmp 0771 shell shell
mkdir /data/data 0771 system system
mkdir /data/app-private 0771 system system
mkdir /data/app 0771 system system
mkdir /data/property 0700 root root

# create dalvik-cache and double-check the perms
mkdir /data/dalvik-cache 0771 system system
chown system system /data/dalvik-cache
chmod 0771 /data/dalvik-cache

# create the lost+found directories, so as to enforce our permissions
mkdir /data/lost+found 0770
mkdir /cache/lost+found 0770

# double check the perms, in case lost+found already exists, and set owner
chown root root /data/lost+found
chmod 0770 /data/lost+found
chown root root /cache/lost+found
chmod 0770 /cache/lost+found

on boot
# basic network init
ifup lo
hostname localhost
domainname localdomain

# set RLIMIT_NICE to allow priorities from 19 to -20
setrlimit 13 40 40

# Define the oom_adj values for the classes of processes that can be
# killed by the kernel. These are used in ActivityManagerService.
setprop ro.FOREGROUND_APP_ADJ 0
setprop ro.VISIBLE_APP_ADJ 1
setprop ro.PERCEPTIBLE_APP_ADJ 2
setprop ro.HEAVY_WEIGHT_APP_ADJ 3
setprop ro.SECONDARY_SERVER_ADJ 4
setprop ro.BACKUP_APP_ADJ 5
setprop ro.HOME_APP_ADJ 6
setprop ro.HIDDEN_APP_MIN_ADJ 7
setprop ro.EMPTY_APP_ADJ 15

# Define the memory thresholds at which the above process classes will
# be killed. These numbers are in pages (4k).
setprop ro.FOREGROUND_APP_MEM 2048
setprop ro.VISIBLE_APP_MEM 3072
setprop ro.PERCEPTIBLE_APP_MEM 4096
setprop ro.HEAVY_WEIGHT_APP_MEM 4096
setprop ro.SECONDARY_SERVER_MEM 6144
setprop ro.BACKUP_APP_MEM 6144
setprop ro.HOME_APP_MEM 6144
setprop ro.HIDDEN_APP_MEM 7168
setprop ro.EMPTY_APP_MEM 8192

# Write value must be consistent with the above properties.
# Note that the driver only supports 6 slots, so we have combined some of
# the classes into the same memory level; the associated processes of higher
# classes will still be killed first.
write /sys/module/lowmemorykiller/parameters/adj 0,1,2,4,7,15

write /proc/sys/vm/overcommit_memory 1
write /proc/sys/vm/min_free_order_shift 4
write /sys/module/lowmemorykiller/parameters/minfree 2048,3072,4096,6144,7168,8192

# Set init its forked children's oom_adj.
write /proc/1/oom_adj -16

# Tweak background writeout
write /proc/sys/vm/dirty_expire_centisecs 200
write /proc/sys/vm/dirty_background_ratio 5

# Permissions for System Server and daemons.
chown radio system /sys/android_power/state
chown radio system /sys/android_power/request_state
chown radio system /sys/android_power/acquire_full_wake_lock
chown radio system /sys/android_power/acquire_partial_wake_lock
chown radio system /sys/android_power/release_wake_lock
chown radio system /sys/power/state
chown radio system /sys/power/wake_lock
chown radio system /sys/power/wake_unlock
chmod 0660 /sys/power/state
chmod 0660 /sys/power/wake_lock
chmod 0660 /sys/power/wake_unlock
chown system system /sys/class/timed_output/vibrator/enable
chown system system /sys/class/leds/keyboard-backlight/brightness
chown system system /sys/class/leds/lcd-backlight/brightness
chown system system /sys/class/leds/button-backlight/brightness
chown system system /sys/class/leds/jogball-backlight/brightness
chown system system /sys/class/leds/red/brightness
chown system system /sys/class/leds/green/brightness
chown system system /sys/class/leds/blue/brightness
chown system system /sys/class/leds/red/device/grpfreq
chown system system /sys/class/leds/red/device/grppwm
chown system system /sys/class/leds/red/device/blink
chown system system /sys/class/leds/red/brightness
chown system system /sys/class/leds/green/brightness
chown system system /sys/class/leds/blue/brightness
chown system system /sys/class/leds/red/device/grpfreq
chown system system /sys/class/leds/red/device/grppwm
chown system system /sys/class/leds/red/device/blink
chown system system /sys/class/timed_output/vibrator/enable
chown system system /sys/module/sco/parameters/disable_esco
chown system system /sys/kernel/ipv4/tcp_wmem_min
chown system system /sys/kernel/ipv4/tcp_wmem_def
chown system system /sys/kernel/ipv4/tcp_wmem_max
chown system system /sys/kernel/ipv4/tcp_rmem_min
chown system system /sys/kernel/ipv4/tcp_rmem_def
chown system system /sys/kernel/ipv4/tcp_rmem_max
chown root radio /proc/cmdline

# Define TCP buffer sizes for various networks
# ReadMin, ReadInitial, ReadMax, WriteMin, WriteInitial, WriteMax,
setprop net.tcp.buffersize.default 4096,87380,110208,4096,16384,110208
setprop net.tcp.buffersize.wifi 4095,87380,110208,4096,16384,110208
setprop net.tcp.buffersize.umts 4094,87380,110208,4096,16384,110208
setprop net.tcp.buffersize.edge 4093,26280,35040,4096,16384,35040
setprop net.tcp.buffersize.gprs 4092,8760,11680,4096,8760,11680

class_start default

## Daemon processes to be run by init.
##
service ueventd /sbin/ueventd
critical

service console /system/bin/sh
console
disabled
user shell
group log

on property:ro.secure=0
start console

# adbd is controlled by the persist.service.adb.enable system property
service adbd /sbin/adbd
disabled

# adbd on at boot in emulator
on property:ro.kernel.qemu=1
start adbd

on property:persist.service.adb.enable=1
start adbd

on property:persist.service.adb.enable=0
stop adbd

service servicemanager /system/bin/servicemanager
user system
critical
onrestart restart zygote
onrestart restart media

service vold /system/bin/vold
socket vold stream 0660 root mount
ioprio be 2

service netd /system/bin/netd
socket netd stream 0660 root system

service debuggerd /system/bin/debuggerd

service ril-daemon /system/bin/rild
socket rild stream 660 root radio
socket rild-debug stream 660 radio system
user root
group radio cache inet misc audio sdcard_rw

service zygote /system/bin/app_process -Xzygote /system/bin --zygote --start-system-server
socket zygote stream 666
onrestart write /sys/android_power/request_state wake
onrestart write /sys/power/state on
onrestart restart media
onrestart restart netd

service media /system/bin/mediaserver
user media
group system audio camera graphics inet net_bt net_bt_admin net_raw
ioprio rt 4

service bootanim /system/bin/bootanimation
user graphics
group graphics
disabled
oneshot

service dbus /system/bin/dbus-daemon --system --nofork
socket dbus stream 660 bluetooth bluetooth
user bluetooth
group bluetooth net_bt_admin

service bluetoothd /system/bin/bluetoothd -n
socket bluetooth stream 660 bluetooth bluetooth
socket dbus_bluetooth stream 660 bluetooth bluetooth
# init.rc does not yet support applying capabilities, so run as root and
# let bluetoothd drop uid to bluetooth with the right linux capabilities
group bluetooth net_bt_admin misc
disabled

service hfag /system/bin/sdptool add --channel=10 HFAG
user bluetooth
group bluetooth net_bt_admin
disabled
oneshot

service hsag /system/bin/sdptool add --channel=11 HSAG
user bluetooth
group bluetooth net_bt_admin
disabled
oneshot

service opush /system/bin/sdptool add --channel=12 OPUSH
user bluetooth
group bluetooth net_bt_admin
disabled
oneshot

service pbap /system/bin/sdptool add --channel=19 PBAP
user bluetooth
group bluetooth net_bt_admin
disabled
oneshot

service installd /system/bin/installd
socket installd stream 600 system system

service flash_recovery /system/etc/install-recovery.sh
oneshot

service racoon /system/bin/racoon
socket racoon stream 600 system system
# racoon will setuid to vpn after getting necessary resources.
group net_admin
disabled
oneshot

service mtpd /system/bin/mtpd
socket mtpd stream 600 system system
user vpn
group vpn net_admin net_raw
disabled
oneshot

service keystore /system/bin/keystore /data/misc/keystore
user keystore
group keystore
socket keystore stream 666

service dumpstate /system/bin/dumpstate -s
socket dumpstate stream 0660 shell log
disabled
oneshot



-------------------------
If anyone has any ideas, post them here.

[the_lurker]

I don't know anything about porting android but I've found some sites that might help.

http://www.freeyourandroid.com/guide/porting-android
http://blogs.arm.com/software-enablemen ... -platform/

[fodi]

I've found some other sites you might find useful:
http://www.linuxfordevices.com/c/a/Linu ... ew-device/
http://wiki.kldp.org/wiki.php/AndroidPo ... RealTarget

the first one describes in details how a team ported android to a nokia phone back then with a list of android's kernel changes compared to standard linux
the second one describes android's under the hood components a bit

[AndrewS]

Benefit of Android is installing any apps without having to learn basic command line. Tried to teach my dad some of this stuff but at 55, he is not so interested.

You could try using synaptic on Debian - software installer GUI.