[Buildroot] [PATCH 1/1] board: resurrect support for RIoTboard

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello Nikolay,

On Mon,  3 Sep 2018 05:03:33 +0300, Nikolay Dimitrov wrote:
> Resurrect support for RIoTboard after 2018.02.x deprecation.
> 
> Signed-off-by: Nikolay Dimitrov <nikolay.dimitrov@retrohub.org>

Thanks a lot for this contribution. It looks mostly good, I just have a
few comments below.

> diff --git a/board/embest/riotboard/readme.txt b/board/embest/riotboard/readme.txt
> new file mode 100644
> index 0000000000..b7390d0d57
> --- /dev/null
> +++ b/board/embest/riotboard/readme.txt
> @@ -0,0 +1,46 @@
> +Buildroot for Embest RIoTboard
> +==============================
> +

Perhaps add a link to a web page that gives more details about this
board.

> +1. Compiling buildroot
> +----------------------
> +
> +make riotboard_defconfig
> +make
> +
> +2. Installing buildroot
> +-----------------------
> +
> +Prepare an SD-card and plug it into your card reader. Write the bootloader to
> +your SD-card:
> +
> +sudo dd if=output/images/u-boot.imx of=/dev/sdX bs=1k seek=1
> +
> +Create 1 partition on the SD-card using your favourite tool. The
> +partition should be big enough to hold your rootfs, for example
> +128MiB. Here's an example partition layout:
> +
> +   Device Boot      Start         End      Blocks   Id  System
> +/dev/sdX1            2048      264191      131072   83  Linux
> +
> +Format the SD-card partition with your favourite filesystem:
> +
> +sudo mkfs.ext2 /dev/sdX1
> +
> +Deploy your rootfs to the SD-card:
> +
> +sudo mkdir /mnt/sdcard/
> +sudo mount /dev/sdX1 /mnt/sdcard/
> +sudo tar xf output/images/rootfs.tar -C /mnt/sdcard/
> +sudo umount /dev/sdX1

Please replace this by using genimage. For Freescale/NXP platforms,
there is even a common genimage.cfg file. See how
configs/freescale_imx6dlsabreauto_defconfig does it.

Thanks to genimage, it will directly produce a SD card image that has
the bootloader, a partition table, etc.

> diff --git a/board/embest/riotboard/rootfs_overlay/boot/extlinux/extlinux.conf b/board/embest/riotboard/rootfs_overlay/boot/extlinux/extlinux.conf
> new file mode 100644
> index 0000000000..eee6ea4a95
> --- /dev/null
> +++ b/board/embest/riotboard/rootfs_overlay/boot/extlinux/extlinux.conf
> @@ -0,0 +1,6 @@
> +default buildroot
> +
> +label buildroot
> +kernel /boot/uImage

Is there a reason to still use a uImage ?

> +devicetree /boot/imx6dl-riotboard.dtb
> +append console=ttymxc1,115200 root=/dev/mmcblk1p1 rw
> diff --git a/configs/riotboard_defconfig b/configs/riotboard_defconfig
> new file mode 100644
> index 0000000000..45bbd2cbad
> --- /dev/null
> +++ b/configs/riotboard_defconfig
> @@ -0,0 +1,36 @@
> +# architecture
> +BR2_arm=y
> +BR2_cortex_a9=y
> +BR2_ARM_ENABLE_NEON=y
> +BR2_ARM_ENABLE_VFP=y
> +BR2_ARM_FPU_VFPV3=y
> +# system
> +BR2_TARGET_GENERIC_GETTY=y
> +BR2_TARGET_GENERIC_GETTY_PORT="ttymxc1"
> +
> +# rootfs
> +BR2_TARGET_ROOTFS_EXT2=y
> +BR2_TARGET_ROOTFS_EXT2_2r1=y

Use:

BR2_TARGET_ROOTFS_EXT2_4=y

instead

> +BR2_ROOTFS_OVERLAY="board/embest/riotboard/rootfs_overlay"
> +
> +# bootloader
> +BR2_TARGET_UBOOT=y
> +BR2_TARGET_UBOOT_CUSTOM_VERSION=y
> +BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2018.05"
> +BR2_TARGET_UBOOT_BOARDNAME="riotboard"
> +BR2_TARGET_UBOOT_FORMAT_IMX=y
> +
> +# Linux headers same as kernel, a 4.15 series
> +BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_15=y
> +
> +# kernel
> +BR2_LINUX_KERNEL=y
> +BR2_LINUX_KERNEL_CUSTOM_VERSION=y
> +BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.15"

Why 4.15 specifically ?

> +BR2_LINUX_KERNEL_DEFCONFIG="imx_v6_v7"
> +BR2_LINUX_KERNEL_UIMAGE=y
> +BR2_LINUX_KERNEL_UIMAGE_LOADADDR="0x10008000"

Same question as above, why uImage instead of zImage ?

> +BR2_LINUX_KERNEL_DTS_SUPPORT=y
> +BR2_LINUX_KERNEL_INTREE_DTS_NAME="imx6dl-riotboard"
> +BR2_LINUX_KERNEL_INSTALL_TARGET=y

Could you fix those details and send an updated version ?

Thanks a lot!

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com