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https://github.com/gbraad/yocto-meta-raspi

Hardware specific BSP overlay for the RaspberryPi device (Yocto Project)
https://github.com/gbraad/yocto-meta-raspi

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Hardware specific BSP overlay for the RaspberryPi device (Yocto Project)

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README 

        
Quick links

===========

Git repository web frontend:

    http://git.yoctoproject.org/cgit/cgit.cgi/meta-raspberrypi/

Mailing list (yocto mailing list):

    [email protected]

Issues management (redmine):

    http://redmine.gherzan.ro/projects/meta-raspberrypi



Contents:

=========

1. Description

2. Yocto BSP Layer - Raspberry Pi

    2.A. Compressed deployed files

    2.B. GPU memory

    2.C. Add purchased license codecs

    2.D. Disable overscan

    2.E. Set overclocking options

    2.F. Optional - Video camera support with V4L2 drivers

    2.G. Optional - Enable offline compositing support

    2.H. Optional - Enable kgdb over console support

    2.I. Images

    2.J. Boot to U-Boot

    2.K. Image with Initramfs

    2.L. Device tree support

3. Extra apps

    3.A. omxplayer

4. Source code and mirrors

5. Contribution

    5.A. Mailing List

    5.B. Redmine

6. Maintainers



1. Description

==============



This is the general hardware specific BSP overlay for the RaspberryPi device.



More information can be found at:

                   http://www.raspberrypi.org/ (Official Site)



The core BSP part of meta-raspberrypi should work with different

OpenEmbedded/Yocto distributions and layer stacks, such as:

* Distro-less (only with OE-Core).

* Angstrom.

* Yocto/Poky (main focus of testing).



2. Yocto BSP Layer - RaspberryPi

================================



This layer depends on:



URI: git://git.yoctoproject.org/poky

branch: master

revision: HEAD



URI: git://git.openembedded.org/meta-openembedded

layers: meta-oe, meta-multimedia

branch: master

revision: HEAD



How to use it:



1. source poky/oe-init-build-env rpi-build

2. Add needed layer to bblayers.conf:

    - meta-raspberrypi

3  Set MACHINE to "raspberrypi"/"raspberrypi2" in local.conf

4. bitbake rpi-hwup-image

5. dd to a SD card the generated sdimg file (use xzcat if rpi-sdimg.xz is used)

6. Boot your RPI.



2.A. Optional - compressed deployed files:

==========================================

1. Overwrite IMAGE_FSTYPES in local.conf

    IMAGE_FSTYPES = "tar.bz2 ext3.xz"

2. Overwrite SDIMG_ROOTFS_TYPE in local.conf

    SDIMG_ROOTFS_TYPE = "ext3.xz"

3. Overwrite SDIMG_COMPRESSION in local.conf

    SDIMG_COMPRESSION = "xz"

*Accommodate the values above to your own needs (ex: ext3 / ext4).



2.B. Optional - GPU memory:

===========================

Variable    : Details

GPU_MEM     : GPU memory in megabyte. Sets the memory split between the ARM and

              GPU. ARM gets the remaining memory. Min 16. Default 64.

GPU_MEM_256 : GPU memory in megabyte for the 256MB Raspberry Pi. Ignored by the

              512MB RP. Overrides gpu_mem. Max 192. Default not set.

GPU_MEM_512 : GPU memory in megabyte for the 512MB Raspberry Pi. Ignored by the

              256MB RP. Overrides gpu_mem. Max 448. Default not set.



2.C.Optional - Add purchased license codecs:

============================================

To add you own licenses use variables KEY_DECODE_MPG2 and KEY_DECODE_WVC1 in

local.conf. Example:

KEY_DECODE_MPG2 = "12345678"

KEY_DECODE_WVC1 = "12345678"

You can supply more licenses separated by comma. Example:

KEY_DECODE_WVC1 = "0x12345678,0xabcdabcd,0x87654321"



2.D. Optional - Disable overscan:

=================================

By default the GPU adds a black border around the video output to compensate for

TVs which cut off part of the image. To disable this set this variable in

local.conf:

DISABLE_OVERSCAN = "0"



2.E. Optional - Set overclocking options:

=========================================

The Raspberry PI can be overclocked. As of now overclocking up to the "Turbo

Mode" is officially supported by the raspbery and does not void warranty.

Check the config.txt for a detailed description of options and modes. Example:

# Turbo mode

ARM_FREQ = "1000"

CORE_FREQ = "500"

SDRAM_FREQ = "500"

OVER_VOLTAGE = "6"



2.F. Optional - Video camera support with V4L2 drivers

======================================================

Set this variable to enable support for the video camera (Linux 3.12.4+ required)

VIDEO_CAMERA = "1"



2.G. Optional - Enable offline compositing support

==================================================



Set this variable to enable support for dispmanx offline compositing

DISMANX_OFFLINE = "1"



This will enable the firmware to fall back to off-line compositing of

Dispmanx elements. Normally the compositing is done on-line, during scanout,

but cannot handle too many elements. With off-line enabled, an off-screen

buffer is allocated for compositing. When scene complexity (number and sizes

of elements) is high, compositing will happen off-line into the buffer.



Heavily recommended for Wayland/Weston.



See: http://wayland.freedesktop.org/raspberrypi.html



2.H. Optional - Enable kgdb over console support

================================================

To add the kdbg over console (kgdboc) parameter to the kernel command line,

set this variable in local.conf:

ENABLE_KGDB = "1"



2.I. Images

===========

* rpi-hwup-image

    Hardware up image

* rpi-basic-image

    Based on rpi-hwup-image with some added features (ex: splash)

* rpi-test-image

    Image based on rpi-basic-image which includes most of the packages in this

    layer and some media samples.



2.J. Boot to U-Boot

===================

To have u-boot load kernel image, set in your local.conf

KERNEL_IMAGETYPE = "uImage"



This will make kernel.img be u-boot image which will load uImage.

By default, kernel.img is the actual kernel image (ex. Image).



2.K. Image with Initramfs

=========================

To build an initramfs image :

    * Set this 3 kernel variables (in linux-raspberrypi.inc for example)

        - kernel_configure_variable BLK_DEV_INITRD y

        - kernel_configure_variable INITRAMFS_SOURCE ""

        - kernel_configure_variable RD_GZIP y

    * Set the yocto variables (in linux-raspberrypi.inc for example)

        - INITRAMFS_IMAGE = ""

        - INITRAMFS_IMAGE_BUNDLE = "1"

    * Set the meta-rasberrypi variable (in raspberrypi.conf for example)

        - KERNEL_INITRAMFS = "-initramfs"



2.L. Device tree support

=========================

Device tree for RPi is only supported when using linux-raspberrypi 3.18+

kernels.



    * Set KERNEL_DEVICETREE (in conf/machine/raspberrypi.conf)

        - the trailer is added to the kernel image before kernel install task.

          While creating the SDCard image, this modified kernel is put on

          boot partition (as kernel.img) as well as DeviceTree blobs (.dtb files).



NOTE: KERNEL_DEVICETREE is default enabled for kernel >= 3.18 and always disabled for

      older kernel versions.



3. Extra apps

=============



3.A. omxplayer

==============

omxplayer depends on libav which has a commercial license. So in order to be

able to compile omxplayer you will need to whiteflag the commercial license

adding to you local.conf:

LICENSE_FLAGS_WHITELIST = "commercial"



4. Source code and mirrors

==========================



Main repo:

    git://git.yoctoproject.org/meta-raspberrypi

    http://git.yoctoproject.org/git/meta-raspberrypi



Github mirror:

    https://github.com/agherzan/meta-raspberrypi



Bitbucket mirror:

    https://bitbucket.org/agherzan/meta-raspberrypi



5. Contributing

===============



5.A. Mailing list

=================

The main communication tool we use is a mailing list:

    [email protected]

    https://lists.yoctoproject.org/listinfo/yocto



Feel free to ask any kind of questions but always prepend your email subject

with "[meta-raspberrypi]". This is because we use the 'yocto' mailing list and

not a perticular 'meta-raspberrypi' mailing list.



To contribute to this layer you should send the patches for review to the

above specified mailing list.

The patches should be compliant with the openembedded patch guidelines:

http://www.openembedded.org/wiki/Commit_Patch_Message_Guidelines



When creating patches, please use something like:



    git format-patch -s --subject-prefix='meta-raspberrypi][PATCH' origin



When sending patches to mailing list, please use something like:



    git send-email --to [email protected] 



5.B. Redmine

============

In order to manage and trace the meta-raspberrypi issues, we use redmine:

    http://redmine.gherzan.ro/projects/meta-raspberrypi



Here we report, trace and develop bugs, features or support tickets for this

yocto BSP later.



If you push patches which have a redmine issue associated, please provide the

issue number in the commit log just before "Signed-off-by" line(s). Example line

for a bug:

    [Bug #13]



6. Maintainers

==============



    Andrei Gherzan