[Buildroot] [PATCH] odroid_xu4: new board

[Thomas Petazzoni]

Hello,

Sorry for the late review. It generally looks good, but I still have a
number of comments which should be addressed in order for the patch to
be applied.

On Fri,  6 Nov 2015 20:08:06 +0100, Jan Viktorin wrote:
> This patch provides support for the board Odroid XU4:
> 
>   http://odroid.com/dokuwiki/doku.php?id=en:odroid-xu4
> 
> The support utilizes the Linux Kernel 4.2 experimental from:
> 
>   https://github.com/tobetter/linux  odroidxu4-v4.2

There is a v4.6 branch now, perhaps using it would be good (but it's
definitely not mandatory).

> 
>   (currently: 5eb40d45b291ee129cbfac2073f1ca7aa32ff4c5)
> 
> and a customized linux defconfig which disables various (mostly)
> useless drivers to minimalize the Buildroot initial system. It
> compiles the r8152 driver into the kernel to have a working
> Ethernet out-of-the-box.

Please use odroidxu4_defconfig from the upstream tree. It is not
necessary to have a strictly minimal kernel configuration, we very much
prefer using an upstream defconfig.

> diff --git a/board/hardkernel/linux-odroidxu4-v4.2.config b/board/hardkernel/linux-odroidxu4-v4.2.config

Please use a subdirectory for the board:

	board/<vendor>/<board>/

So in your case:

	board/hardkernel/odroid-xu4/


> diff --git a/board/hardkernel/readme.txt b/board/hardkernel/readme.txt
> new file mode 100644
> index 0000000..d7a77db
> --- /dev/null
> +++ b/board/hardkernel/readme.txt
> @@ -0,0 +1,49 @@
> +Odroid XU4
> +==========
> +
> +http://www.hardkernel.com/main/products/prdt_info.php?g_code=G143452239825
> +http://www.hardkernel.com/main/products/prdt_info.php?g_code=G143452239825
> +
> +The Buildroot odroid_xu4_defconfig configuration builds:
> +
> +  u-boot.bin -> u-boot.bin.hardkernel
> +  zImage
> +  exynos5422-odroidxu4.dtb
> +  rootfs.ext3
> +
> +and prepares:
> +
> +  bl1.bin.hardkernel
> +  bl2.bin.hardkernel
> +  tzsw.bin.hardkernel
> +  sd_fusing.sh
> +  boot.ini
> +
> +As the board requires signed 1st bootloader, it is necessary to use
> +the provided BLOBs.
> +
> +
> +Installation:
> +
> + - suppose ${SD} points to eg. /dev/sdc (your SD card)
> +
> + 1) make odroid_xu4_defconfig
> + 2) make
> + 3) cd output/images
> + 4) create 2 partitions (fdisk, cfdisk, ...):
> +    FAT (~128 MB), ext3 (rest).
> +
> + 5) sudo ./sd_fusing ${SD}
> +    Installs the bootloaders, trust zone and the built U-Boot.
> +
> + 6) sudo dd if=rootfs.ext3 of=${SD}2
> +    Write to eg. /dev/sdc2.
> +
> + 7) sudo mount ${SD}1 /mnt
> +    Mount the FAT partition (eg. /dev/sdc1).
> +
> + 8) sudo cp -v zImage boot.ini exynos5422-odroidxu4.dtb /mnt
> + 9) sudo umount ${SD}1

Please use the genimage mechanism to directly generate a bootable SD
card. Look at the other boards supported in Buildroot, many of them are
using genimage.

> diff --git a/configs/odroid_xu4_defconfig b/configs/odroid_xu4_defconfig
> new file mode 100644
> index 0000000..3790db7
> --- /dev/null
> +++ b/configs/odroid_xu4_defconfig
> @@ -0,0 +1,27 @@
> +BR2_arm=y
> +BR2_cortex_a15=y
> +BR2_ARM_FPU_NEON=y

Using NEON as the FPU is really not recommended. Please use the VFP
unit for floating point by default.

> +BR2_KERNEL_HEADERS_4_2=y

This needs to be changed to:

BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_2=y

> +BR2_TARGET_GENERIC_HOSTNAME="odroid-xu4"
> +BR2_TARGET_GENERIC_ISSUE="Welcome to Odroid XU4!"
> +BR2_TARGET_GENERIC_GETTY_PORT="ttySAC2"
> +BR2_TARGET_GENERIC_GETTY_BAUDRATE_115200=y

Aren't the default setting (use the kernel console) working for yuo?

> +BR2_ROOTFS_POST_IMAGE_SCRIPT="board/hardkernel/odroid-post.sh"

We usually call it post-image.sh.

> +BR2_ROOTFS_POST_SCRIPT_ARGS="$(BR2_TARGET_UBOOT_VERSION)"
> +BR2_LINUX_KERNEL=y
> +BR2_LINUX_KERNEL_CUSTOM_GIT=y
> +BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://github.com/tobetter/linux"
> +BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="odroidxu4-v4.2"
> +BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
> +BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/hardkernel/linux-odroidxu4-v4.2.config"
> +BR2_LINUX_KERNEL_ZIMAGE=y
> +BR2_LINUX_KERNEL_DTS_SUPPORT=y
> +BR2_LINUX_KERNEL_INTREE_DTS_NAME="exynos5422-odroidxu4"
> +BR2_TARGET_ROOTFS_EXT2=y
> +BR2_TARGET_ROOTFS_EXT2_3=y
> +# BR2_TARGET_ROOTFS_TAR is not set
> +BR2_TARGET_UBOOT=y
> +BR2_TARGET_UBOOT_BOARDNAME="odroid"
> +BR2_TARGET_UBOOT_CUSTOM_GIT=y
> +BR2_TARGET_UBOOT_CUSTOM_REPO_URL="https://github.com/hardkernel/u-boot.git"
> +BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="odroidxu3-v2012.07"

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com