Difference between revisions of "Kernel status"

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= Introduction =
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#REDIRECT [[Ångström#Kernel_status]]
The first [[firmware]] release is based on a heavily patched linux-2.6.27-omap1 kernel. linux-omap used to be OMAP community kernel fork, nowadays its code was either merged to mainline or dropped. Further OMAP development continues on mainline kernels, linux-omap tree is mainly used to queue developed code to mainline. So most of the interesting features that 2.6.27 lack (like sleep modes) are available there, but development effort is needed to port all drivers first.
 
 
 
= Status =
 
This is mostly about pandora specific support for 2.6.35 or newer. Things that are already in mainline and come "for free" (like SD card support) are not mentioned.
 
 
 
== merged code (already in mainline as of 2.6.36) ==
 
* board support (enables UART, I2C, SPI, RTC, MMC{1,2,3}, NAND, OTG, EHCI, gpio-keys, leds-gpio, keypad, touchscreen, regulators)
 
* sound: [[ALSA]] ASoC machine driver
 
* [[bq27500]] fuel gauge
 
* LCD panel driver
 
* wl1251 [[wifi driver]] glue (portions only in 2.6.37)
 
* charging (partial only, 2.6.37)
 
* [[wl1251]] complete powerdown/suspend using runtime_pm (2.6.38).
 
 
 
this doesn't list various bugfix patches to get above working :)
 
 
 
== finished code, but not merged==
 
now in openpandora.org GIT (mainline merge status in brackets)
 
* nubs (aka vsense, needs rework for mainline)
 
* backlight driver (needs rework)
 
* keypad fn handling (not allowed in mainline)
 
* PWM LEDs (needs rework)
 
 
 
== missing stuff ==
 
* Charging missing bits.
 
* Bluetooth. 2.6.27 has rather old Nokia code (not mainlined), Nokia device/maemo kernels need to be checked and later versions integrated from there. There is alternative to this: expose UART port and try to use userspace [[bluez]] drivers, but this could result in less efficient power saving (if any).
 
* low [[power modes]]. This requires lots of testing, support in drivers and board files.
 
* DSP mess: [http://elinux.org/BeagleBoard/DSP_Clarification gateway, bridge or link] ?
 
* more things that I forgot
 
 
 
= openpandora.org git structure =
 
{{merge|Firmware governance}}
 
Support for various kernels is available in pandora-XX branches or tags, XX corresponds to last part of kernel version number. 2.6.27 is an exception, it's in pandora-27-omap1 branch.
 
 
 
Branches based on pre-release -rc kernels will be often rebased. This means you can't do 'git pull' on them, use 'git fetch; git reset --hard origin/pandora-XX' instead. '''Warning''': this will destroy all your changes (even if they are commited), backup them first!
 
 
 
See also:
 
* [[Firmware governance]]
 
 
 
= Configuring newer kernels =
 
When compiling mainline kernel, use
 
<source lang="bash">make omap2plus_defconfig</source>
 
for openpandora.org kernels you can use omap3_pandora_defconfig
 
<source lang="bash">make omap3_pandora_defconfig</source>
 
after either of those are run, you can tune the configuration for your needs:
 
<source lang="bash">make menuconfig</source>
 
Now you should be able to build a working kernel. More info available at [[Kernel build instructions]].
 
 
 
= Running =
 
Easiest way is to place your new uImage to root of SD ([[FAT]] or [[ext2]], ext2 may need a bootloader update) along with a file named '[[autoboot.txt]]', which contains u-boot commands such as:
 
fatload mmc 0 0x80300000 uImage; bootm 0x80300000
 
Kernel bootargs can be changed by adding 'setenv' line before fatload:
 
setenv bootargs debug console=ttyO2,115200n8 ...
 
 
 
== serial port ==
 
In an unlikely event that you can get serial output from EXT port, be aware that serial device has changed several times (due to the driver and port configuration changes in the kernel):
 
* openpandora.org 2.6.27: ttyS0
 
* mainline upto 2.6.36: ttyS2
 
* mainline/openpandora.org 2.6.37 and up: ttyO2
 
This is relevant for console= bootarg.
 
 
 
= Contributing =
 
Help is always welcome, usually in form of testing or writing patches. In most cases it's best to file a bug report or feature request in the [http://bugs.openpandora.org bug tracker] so that things don't get lost.
 
 
 
== Submitting patches ==
 
It's best to send formal GIT-generated patch so that you get proper credit for your work and to make applying the patch easier. You also should add 'Signed-off-by' line ('-s' on 'git commit' will do it for you), which has [http://elinux.org/Developer_Certificate_Of_Origin the same meaning as for mainline Linux].
 
 
 
So basic workflow would be:
 
<source lang="bash">
 
<make changes>
 
git config --global user.name "My Name"
 
git config --global user.email "myname@domain.com"
 
git add <changed files>
 
git commit -s
 
git format-patch -o /somewhere/ -1
 
</source>
 
Then create a new feature request in bugtracker and attach the generated file(s).
 
 
 
[[Category:Official OpenPandora Development]]
 
[[Category:Kernel]]
 

Latest revision as of 11:11, 6 November 2013