How to use vanilla kernel on APF28

By default, the kernel for APF28 is the 2.6.35 version (from Freescale BSP). Migration to Mainline (3.1x+) is in progress but not finished, this article explains how to use (test) these kernels with latest armadeus trunk.

Mainline support is done with Device Tree.

Lazy guys instructions

• Get the latest trunk version with command :

$ git clone git://git.code.sf.net/p/armadeus/code armadeus-trunk

• Configure the view for APF28 "mainline" :

$ cd armadeus-trunk
$ make apf28mainline_defconfig

• Update your board:

BIOS> run update_uboot; reset
BIOS> run flash_reset_env; reset
BIOS> setenv fdt_addr_r 41000000
BIOS> setenv consoledev ttyAMA0
BIOS> saveenv
BIOS> run update_dtb
BIOS> run update_kernel
BIOS> run update_rootfs

For the one who wants to know the details

• Get the latest trunk version with command :

$ git clone git://git.code.sf.net/p/armadeus/code armadeus-trunk

• Configure the view for APF28 :

$ cd armadeus-trunk
$ make apf28_defconfig

• On menuconfig select :

Toolchain  --->
    Kernel Headers (Linux 2.6 (manually specified version))  --->
    (3.8) linux version
...
System configuration  --->
    (ttyAMA0) Port to run a getty (login prompt) on
...
Kernel  --->
    (3.8) Kernel version
    (40008000) load address (for 3.7+ multi-platform image)
    (../patches/linux/$(BR2_LINUX_KERNEL_VERSION)) Custom kernel patches
    (imx28-apf28dev) Device Tree Source file names

• Then build :

$ make

U-Boot modification

• Linux nand driver has changed on kernel 3.8, then U-Boot code must be modified to match it (maybe now no more needed, since 3.12 ??).
  • Edit file :

buildroot/target/device/armadeus/apf28/apf28-u-boot-2013.04.h

• • And change line 153:

#define CONFIG_MTDMAP			"gpmi-nand"

• • Then re-build U-Boot:

make uboot-dirclean; make uboot;

• • you will have to reflash U-Boot on your APF28 and probably cleanup your environment variables:

BIOS> run flash_reset_env

• Serial port used for console has now a different name: ttyAMA0. So if you want to see something on your serial console please do the following before booting:

BIOS> setenv consoledev ttyAMA0

• Kernel 3.8 use device tree, then this paramter must be set too:

BIOS> setenv fdt_addr_r 41000000
BIOS> saveenv

• To boot with NFS boot use:

BIOS> run nfsboot

• But nand boot work now, just don't forget to update the dtb (if you run update_all it's already done):

BIOS> run update_dtb
BIOS> boot

Which devices are supported ?

• Kernel-upstream-status

Roadmap

1. SPI
2. touchscreen