| Running Linux on Cellphones |
| =========================== |
| |
| At this moment (2014), there are no modern cellphones completely |
| supported by mainline kernel. Another problem is lack of hackable |
| userspace to run on cellphone, even when kernel support is available. |
| |
| Openmoko was first phone running Linux with X. GSM support there was |
| based on freesmartphone.org daemons. |
| |
| Sony has project to merge kernel support for Xperia Z1. |
| |
| Mainline has support for Mitac Mio A701, but that having only 64MiB |
| RAM, QTopia is the software to use there. |
| |
| Nokia N900 |
| ---------- |
| |
| Nokia N900 orignally shipped with Maemo-based userland, which is close |
| enough to GNU/X/apt based Linux; key components communicate using dbus |
| and application can be written in pygtk. Kernel patches were |
| relatively clean, and the core stuff is merged, unfortunately there's |
| quite a lot of non-core stuff and pieces of userland are closed |
| source; including some critical support such as bridge between CPU and |
| modem for voice calls. |
| |
| Unfortunately, that means that kernel development is hard, because it |
| is non-trivial to test all the various devices in the phone due to |
| lack of suitable userspace and userspace development is hard, because |
| there's no suitable kernel to work with. |
| |
| Here are instructions for getting usable userspace for kernel testing, |
| and suggestions for some tests. Setting up nfsroot (needs non-mainline |
| patch) is strongly recommended for development. |
| |
| I'm using Debian 7 for testing/development. It works well including |
| touchscreen and X support, as of 3.18-rc1. Instructions are here: |
| |
| https://wiki.debian.org/n900-wheezy-armhf |
| https://wiki.debian.org/MaemoAndSqueeze |
| |
| Following packages are useful on N900: |
| |
| libts-bin evtest ntpdate module-init-tools udev netbase ifupdown openssh-server |
| locales whiptail less mpg123 mplayer ofono gcc strace mdbus2 |
| |
| This calibrates display to usable state on recent kernel and Debian 7: |
| |
| DISPLAY=:0.0 xinput --set-prop --type=float 8 115 1.10 0.00 -0.05 0.00 1.18 -0.10 0.00 0.00 1.00 |
| DISPLAY=:0.0 xinput --set-prop --type=int 8 249 0 1 |
| |
| And these are commands you can use to test various subsystems |
| |
| # Test vibrations |
| echo 5 | fftest /dev/input/event2 |
| |
| # Test LEDs |
| VAL=30 |
| echo $VAL > lp5523\:kb1/brightness |
| echo $VAL > lp5523\:kb1/brightness |
| echo $VAL > lp5523\:kb2/brightness |
| echo $VAL > lp5523\:kb3/brightness |
| echo $VAL > lp5523\:kb4/brightness |
| echo $VAL > lp5523\:kb5/brightness |
| echo $VAL > lp5523\:kb6/brightness |
| echo $VAL > lp5523\:r/brightness |
| echo $VAL > lp5523\:g/brightness |
| echo $VAL > lp5523\:b/brightness |
| echo 100 > /sys/class/backlight/acx565akm/brightness |
| echo mem > /sys/power/state |
| |
| # Display battery/charging state |
| cd /sys/bus/i2c/drivers/bq27x00-battery/2-0055/power_supply/bq27200-0 |
| grep -r . . |
| |
| # Start up ofono in debug mode |
| rmdir /dev/cmt |
| ln -s /sys/bus/hsi/devices/n900-modem/ /dev/cmt |
| killall ofonod |
| sleep .1 |
| ofonod --nodetach --debug & |
| |
| # Test modem works |
| # enable the modem |
| mdbus2 -s org.ofono /n900_0 org.ofono.Modem.SetProperty Powered true |
| # enable modem's RF parts |
| mdbus2 -s org.ofono /n900_0 org.ofono.Modem.SetProperty Online true |
| # scan for available networks (takes some time) |
| mdbus2 -s org.ofono /n900_0 org.ofono.NetworkRegistration.Scan |
| |
| ofone python script can be used to provide GUI for calls and |
| messages. Note that audio connection does not yet work. |
| |
| Useful information about merge progress is at http://elinux.org/N900 . |
| |
| Good luck! |
| |
| Pavel |
| |
