[Buildroot] [PATCH] configs: add defconfig for Digilent Zybo

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello,

Thanks for this new version! I was almost going to apply it, but there
is still one thing that I can't fix on my own without asking you some
more details.

As a side note, please use "-v 2" when generating the patch for the
second iteration of a patch. This will turn the [PATCH] prefix into
[PATCH v2]. Also, normally we like when people include a small
changelog of what has been modified.

On Thu, 7 Jul 2016 19:51:15 +0200, Sebastien Van Cauwenberghe wrote:

> diff --git a/board/digilent/zybo/post-image.sh b/board/digilent/zybo/post-image.sh
> new file mode 100755
> index 0000000..bba0f5a
> --- /dev/null
> +++ b/board/digilent/zybo/post-image.sh
> @@ -0,0 +1,26 @@
> +#!/bin/sh
> +
> +BOARD_DIR="$(dirname $0)"
> +BOARD_NAME="$(basename ${BOARD_DIR})"
> +GENIMAGE_CFG="${BOARD_DIR}/genimage-${BOARD_NAME}.cfg"
> +GENIMAGE_TMP="${BUILD_DIR}/genimage.tmp"
> +OUTPUT_DIR="output/images"

This is wrong, the OUTPUT_DIR is not necessarily in output/. Just use
BINARIES_DIR, which is an environment variable that points to
$(O)/images.

> +# Mark the kernel as DT-enabled
> +#mkdir -p "${BINARIES_DIR}/kernel-marked"
> +#${HOST_DIR}/usr/bin/mkknlimg "${BINARIES_DIR}/zImage" \
> +#	"${BINARIES_DIR}/kernel-marked/zImage"

Remove those commented lines.

> +
> +rm -rf "${GENIMAGE_TMP}"
> +
> +cp board/digilent/zybo/uEnv.txt ${OUTPUT_DIR}

Use ${BINARIES_DIR} here.

> +cp board/digilent/zybo/system.bit ${OUTPUT_DIR}

What is this zero length file? It seems pretty useless to have a zero
length file.

> diff --git a/board/digilent/zybo/readme.txt b/board/digilent/zybo/readme.txt
> new file mode 100644
> index 0000000..88697af
> --- /dev/null
> +++ b/board/digilent/zybo/readme.txt
> @@ -0,0 +1,83 @@

Maybe start with the name of the board here, like:

Digilent Zybo
=============

> +This is the buildroot board support for the Digilent Zybo. The Zybo is

buildroot -> Buildroot

> +a development board based on the Xilinx Zynq-7000 based All-Programmable
> +System-On-Chip.
> +
> +Zybo information including schematics, reference designs, and manuals are
> +available from http://store.digilentinc.com/zybo-zynq-7000-arm-fpga-soc-trainer-board/ .
> +
> +If you want a custom FPGA bitstream to be loaded by U-Boot, copy it as
> +system.bit in board/digilent/zybo/.

Ah that's why you have a zero length file: to make genimage happy when
creating the VFAT partition.

> +Steps to create a working system for Zybo:
> +
> +1) make zynq_zybo_defconfig
> +2) make
> +3) write your SD Card with the sdcard.img file using dd
> +4) insert the SD Card and power up your Zybo
> +
> +The expected output:
> +
> + U-Boot SPL 2016.05 (May 20 2016 - 16:16:24)
> + mmc boot
> + Trying to boot from MMC1
> + reading system.dtb
> + spl_load_image_fat_os: error reading image system.dtb, err - -1
> + reading u-boot-dtb.img
> + reading u-boot-dtb.img
> +
> +
> + U-Boot 2016.05 (May 20 2016 - 16:16:24 +0200)
> +
> + Model: Zynq ZYBO Development Board
> + Board: Xilinx Zynq
> + I2C:   ready
> + DRAM:  ECC disabled 512 MiB
> + MMC:   sdhci at e0100000: 0
> + SF: Detected S25FL128S_64K with page size 256 Bytes, erase size 64 KiB, total 16 MiB
> + In:    serial at e0001000
> + Out:   serial at e0001000
> + Err:   serial at e0001000
> + Model: Zynq ZYBO Development Board
> + Board: Xilinx Zynq
> + Net:   ZYNQ GEM: e000b000, phyaddr 0, interface rgmii-id
> + I2C EEPROM MAC address read failed
> +
> + Warning: ethernet at e000b000 (eth0) using random MAC address - 56:64:dd:a7:6d:94
> + eth0: ethernet at e000b000
> + ...
> +
> +Resulting system
> +----------------
> +Once the build process is finished you will have an image called "sdcard.img"
> +in the output/images/ directory.
> +
> +Copy the bootable "sdcard.img" onto an SD card with "dd":
> +
> +  $ sudo dd if=output/images/sdcard.img of=/dev/sdX

This repeats what you have said above, so please merge it with the
above explanations.

> +
> +Insert the SDcard into your Zybo, and power it up. Your new system
> +should come up now and starts one console on the second serial port
> +exposed by the Zybo board (115200 bauds).

Ditto.

> +
> +The first partition is a FAT32 partition created at the beginning of the SD Card
> +that contains the following files :
> +	/BOOT.BIN
> +	/zynq-zybo.dtb
> +    /uEnv.txt
> +    /system.bit
> +	/uImage
> +	/u-boot-dtb.img
> +
> +The second partition is an ext4 partition that contains the root filesystem.
> +
> +There is a patch attached that redefines the U-Boot's environment
> +to work with Buildroot out-of-the-box.

A patch cannot be "attached" in a readme.txt file.

> +
> +You can alter the booting procedure by creating a file uEnv.txt

"a file uEnv.txt" -> "a uEnv.txt fil"

> +in the root of the SD card. It is a plain text file in format

"the root of the SD card" is not very precise, since you have two
partitions.

> +++ b/board/digilent/zybo/uEnv.txt
> @@ -0,0 +1,6 @@
> +bootargs=root=/dev/mmcblk0p2 rootwait rw rootfstype=ext4
> +fpga_image=system.bit
> +fpgaboot=if fatload mmc 0 0x1000000 ${fpga_image}; then echo Booting FPGA from ${fpga_image}; fpga info 0 && fpga loadb 0 0x1000000 $filesize; else echo FPGA image ${fpga_image} was not found, skipping...; fi;
> +kernel_image=uImage
> +sdboot=echo Booting from SD...; run fpgaboot; fatload mmc 0 0x1000000 ${kernel_image} && fatload mmc 0 0x2000000 zynq-zybo.dtb && bootm 0x1000000 - 0x2000000
> +

Unnecessary last line.

> diff --git a/configs/zynq_zybo_defconfig b/configs/zynq_zybo_defconfig
> new file mode 100644
> index 0000000..34137c6
> --- /dev/null
> +++ b/configs/zynq_zybo_defconfig
> @@ -0,0 +1,28 @@
> +BR2_arm=y
> +BR2_cortex_a9=y
> +BR2_ARM_ENABLE_NEON=y
> +# BR2_COMPILER_PARANOID_UNSAFE_PATH is not set

Please don't change this option from the default.

> +BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_6=y
> +BR2_TARGET_GENERIC_GETTY_PORT="ttyPS0"
> +BR2_ROOTFS_POST_IMAGE_SCRIPT="board/digilent/zybo/post-image.sh"
> +BR2_LINUX_KERNEL=y
> +BR2_LINUX_KERNEL_CUSTOM_VERSION=y
> +BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.6.3"
> +BR2_LINUX_KERNEL_DEFCONFIG="multi_v7"
> +BR2_LINUX_KERNEL_UIMAGE=y
> +BR2_LINUX_KERNEL_UIMAGE_LOADADDR="0x8000"
> +BR2_LINUX_KERNEL_DTS_SUPPORT=y
> +BR2_LINUX_KERNEL_INTREE_DTS_NAME="zynq-zybo"
> +BR2_TARGET_ROOTFS_EXT2=y
> +BR2_TARGET_ROOTFS_EXT2_4=y
> +BR2_TARGET_UBOOT=y
> +BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
> +BR2_TARGET_UBOOT_CUSTOM_VERSION=y
> +BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2016.05"
> +BR2_TARGET_UBOOT_BOARD_DEFCONFIG="zynq_zybo"
> +BR2_TARGET_UBOOT_NEEDS_DTC=y
> +BR2_TARGET_UBOOT_FORMAT_DTB_IMG=y
> +BR2_TARGET_UBOOT_SPL=y
> +BR2_TARGET_UBOOT_ZYNQ_IMAGE=y
> +BR2_PACKAGE_HOST_GENIMAGE=y
> +BR2_PACKAGE_HOST_UBOOT_TOOLS=y

Other than that, looks good! It's almost ready to be applied.

Thanks!

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