Re: [Buildroot] [PATCH v3 2/3] configs/stm32f746_disco_sd: new defconfig

[Thomas Petazzoni via buildroot <buildroot@buildroot.org>]

Hello,

On Thu, 22 Aug 2024 20:37:41 +0200
Dario Binacchi <dario.binacchi@amarulasolutions.com> wrote:

> diff --git a/board/stmicroelectronics/stm32f746-disco/flash_sd.sh b/board/stmicroelectronics/stm32f746-disco/flash_sd.sh
> new file mode 100755
> index 000000000000..4fe85448f984
> --- /dev/null
> +++ b/board/stmicroelectronics/stm32f746-disco/flash_sd.sh
> @@ -0,0 +1,22 @@
> +#!/bin/bash
> +
> +if [ $# -eq 0 ]; then
> +    OUTPUT_DIR=output
> +else
> +    OUTPUT_DIR=$1
> +fi
> +
> +if ! test -d "${OUTPUT_DIR}" ; then
> +    echo "ERROR: no output directory specified."
> +    echo "Usage: $0 OUTPUT_DIR"
> +    exit 1
> +fi
> +
> +"${OUTPUT_DIR}"/host/bin/openocd -f board/stm32f746g-disco.cfg \
> +  -c "init" \
> +  -c "reset init" \
> +  -c "flash probe 0" \
> +  -c "flash info 0" \
> +  -c "flash write_image erase ${OUTPUT_DIR}/images/u-boot.bin 0x08000000" \
> +  -c "reset run" \
> +  -c "shutdown"

Could you keep the indentation consistent? Above you used 4 spaces, and
here only 2.

> diff --git a/board/stmicroelectronics/stm32f746-disco/genimage.cfg b/board/stmicroelectronics/stm32f746-disco/genimage.cfg
> new file mode 100644
> index 000000000000..6743d41972c0
> --- /dev/null
> +++ b/board/stmicroelectronics/stm32f746-disco/genimage.cfg
> @@ -0,0 +1,27 @@
> +image boot.vfat {
> +	vfat {
> +		files = {
> +			"zImage",
> +			"stm32f746-disco.dtb",
> +			"extlinux"
> +		}
> +	}
> +
> +	size = 16M
> +}
> +
> +image sdcard.img {
> +	hdimage {
> +	}
> +
> +	partition u-boot {

Why is this partition called u-boot? It doesn't contain anything u-boot
related.

> +		partition-type = 0xC
> +		image = "boot.vfat"

But why is a VFAT partition needed in fact? Why can't U-Boot simply get
the kernel+DTB from the ext4 rootfs partition?


> diff --git a/board/stmicroelectronics/stm32f746-disco/post-build.sh b/board/stmicroelectronics/stm32f746-disco/post-build.sh
> new file mode 100755
> index 000000000000..2894ad851c66
> --- /dev/null
> +++ b/board/stmicroelectronics/stm32f746-disco/post-build.sh
> @@ -0,0 +1,9 @@
> +#!/bin/sh
> +BOARD_DIR="$(dirname "$0")"
> +
> +install -m 0644 -D "${BOARD_DIR}"/extlinux.conf "${BINARIES_DIR}"/extlinux/extlinux.conf
> +
> +# finalize the init script
> +INIT_PATH="${TARGET_DIR}/sbin/init"
> +sed -i "/^# Clear memory to reduce page fragmentation/d" "${INIT_PATH}"
> +sed -i "/^echo 3 > \/proc\/sys\/vm\/drop_caches/d" "${INIT_PATH}"

Meh, this kind of sucks. tinyinit does one thing and we have to undo it
here. Not great. Can we do better, i.e decide whether it makes sense to
do it or not? To be honest, I am not sure if this is really useful to
do at boot time.


> diff --git a/configs/stm32f746_disco_sd_defconfig b/configs/stm32f746_disco_sd_defconfig
> new file mode 100644
> index 000000000000..8c92afc5740e
> --- /dev/null
> +++ b/configs/stm32f746_disco_sd_defconfig
> @@ -0,0 +1,32 @@
> +BR2_arm=y
> +BR2_cortex_m7=y
> +BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_15=y
> +BR2_GLOBAL_PATCH_DIR="board/stmicroelectronics/stm32f746-disco/patches"
> +BR2_DOWNLOAD_FORCE_CHECK_HASHES=y
> +BR2_INIT_NONE=y
> +BR2_ROOTFS_POST_BUILD_SCRIPT="board/stmicroelectronics/stm32f746-disco/post-build.sh"
> +BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"
> +BR2_ROOTFS_POST_SCRIPT_ARGS="-c board/stmicroelectronics/stm32f746-disco/genimage.cfg"
> +BR2_LINUX_KERNEL=y
> +BR2_LINUX_KERNEL_CUSTOM_VERSION=y
> +BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.15.165"
> +BR2_LINUX_KERNEL_DEFCONFIG="stm32"
> +BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="board/stmicroelectronics/stm32f746-disco/linux.fragment"
> +BR2_LINUX_KERNEL_IMAGE_TARGET_CUSTOM=y
> +BR2_LINUX_KERNEL_IMAGE_TARGET_NAME="zImage"
> +BR2_LINUX_KERNEL_DTS_SUPPORT=y
> +BR2_LINUX_KERNEL_INTREE_DTS_NAME="stm32f746-disco"
> +BR2_PACKAGE_TINYINIT=y
> +BR2_TARGET_ROOTFS_EXT2=y
> +BR2_TARGET_ROOTFS_EXT2_SIZE="32M"
> +# BR2_TARGET_ROOTFS_TAR is not set
> +BR2_TARGET_UBOOT=y
> +BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
> +BR2_TARGET_UBOOT_CUSTOM_VERSION=y
> +BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2024.07"
> +BR2_TARGET_UBOOT_BOARD_DEFCONFIG="stm32f746-disco"
> +BR2_TARGET_UBOOT_NEEDS_OPENSSL=y
> +BR2_PACKAGE_HOST_DOSFSTOOLS=y
> +BR2_PACKAGE_HOST_GENIMAGE=y
> +BR2_PACKAGE_HOST_MTOOLS=y
> +BR2_PACKAGE_HOST_OPENOCD=y

If you drop the FAT partition, you can drop BR2_PACKAGE_HOST_MTOOLS=y
and BR2_PACKAGE_HOST_DOSFSTOOLS=y.

Thanks!

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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