Signed-off-by: Marek Belisko <email@example.com>
Official sunxi OpenEmbedded layer for Allwinner-based boards.
This layer depends on the additional layers:
Tested with core-image-base.
- Nicolas Aguirre firstname.lastname@example.org
- Enrico Butera email@example.com
- Sergey Lapin firstname.lastname@example.org
- Marek Belisko email@example.com
You can reach community + ask your question on gitter: https://matrix.to/#/#meta-sunxi:gitter.im
Kernel / U-Boot Version
Most Allwinner devices and hardware are supported in mainline kernel and U-Boot, so this layer builds mainline by default.
Legacy sunxi Kernel / U-Boot
There is a custom U-Boot and Kernel version for sunxi devices which includes some special drivers not mainlined. These versions are rather old (3.4 for kernel and 2014.04 for U-Boot), but may support more functions and devices than current mainline.
If you want to switch back to sunxi versions for some reasons (no device tree available, unsupported hardware), either:
change the file conf/machine/include/sunxi.inc to include the following block
edit your conf/local.conf to add the following block
PREFERRED_PROVIDER_u-boot="u-boot-sunxi" PREFERRED_PROVIDER_virtual/bootloader="u-boot-sunxi" PREFERRED_PROVIDER_virtual/kernel="linux-sunxi" KERNEL_DEVICETREE = ""
If you already have built the mainline versions it might be necessary to reset the build directories with:
bitbake -c clean virtual/kernel virtual/bootloader
Mainline Kernel / U-Boot
For mainline kernel we have now support for latest LTS and stable.
By default we use latest LTS. If you would like to change version please update
When using mainline kernel ≥ 5.2 it is now possible to use the mainline graphics drivers lima and panfrost, instead of the mali driver provided by ARM. To enable open source mainline graphics support add the following line in your
MACHINEOVERRIDES .= ":use-mailine-graphics"
The default machine settings are meant to be the lowest common denominator, maximizing generality. Significantly better performance (2x-3x) can be achieved with the following settings:
For Allwinner A20 (Cubieboard2/CubieTruck), the following tuning options are recommended:
Enable hardfloat, thumb2 and neon capabilities
DEFAULTTUNE = "cortexa7hf-neon-vfpv4"
This tuning profile takes advantage of the Allwinner A20 hardfloat, neon and vfpv4 capabilities.
Change CPU governor to ondemand, and tune settings
echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor echo 336000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq echo 912000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq #More aggressive #echo 1008000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq echo 40 > /sys/devices/system/cpu/cpufreq/ondemand/up_threshold echo 200000 > /sys/devices/system/cpu/cpufreq/ondemand/sampling_rate
This code changes the default CPU governor from fantasy to ondemand, and tunes its settings, as recommended at http://linux-sunxi.org/Cpufreq
For additional discussion, see https://github.com/linux-sunxi/meta-sunxi/issues/25