kumquat-buildroot/board/avnet/zedboard
Gwenhael Goavec-Merou d761f0f408 zedboard: uboot: load env earlier
By default, with the original patch bootcmd runs sdboot before loading uEnv.txt.
Consequently, if the user change modeboot, the user's defined content is updated
too late.
By loading uEnv.txt before 'run $modeboot' the correct boot mode is used instead
of default mode.

Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
Acked-By: Jan Viktorin <viktorin@rehivetech.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2015-11-16 21:53:48 +01:00
..
uboot zedboard: uboot: load env earlier 2015-11-16 21:53:48 +01:00
readme.txt

This is the buildroot board support for the Avnet Zedboard. The Zedboard is
a development board based on the Xilinx Zynq-7000 based All-Programmable
System-On-Chip.

Zedboard information including schematics, reference designs, and manuals are
available from http://www.zedboard.org .

Steps to create a working system for Zedboard:

1) make zedboard_defconfig
2) make
3) copy files BOOT.BIN, u-boot-dtb.img, rootfs.cpio.uboot,
	uImage, zynq-zed.dtb into your SD card
4) boot your Zedboard

The expected output:

 U-Boot SPL 2015.07 (Jul 22 2015 - 12:01:55)
 mmc boot
 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 2015.07 (Jul 22 2015 - 12:01:55 +0200)

 Model: Zynq ZED Board
 I2C:   ready
 DRAM:  ECC disabled 512 MiB
 MMC:   zynq_sdhci: 0
 Using default environment
 ...

When using an older U-Boot then 2015.07, a working ps7_init.c
file is required to be installed into the U-Boot directory
structure. From 2015.07, the major Zynq-based boards are
supported without any manual intervention.

Resulting system
----------------
A FAT32 partition should be created at the beginning of the SD Card
and the following files should be installed:
	/BOOT.BIN
	/zynq-zed.dtb
	/uImage
	/rootfs-cpio.uboot
	/u-boot-dtb.img


All needed files can be taken from output/images/

BOOT.BIN, uImage and u-boot-dtb.img are direct copies of the same files
available on output/images/

There is a patch attached that redefines the U-Boot's environment
to work with Buildroot out-of-the-box.

You can alter the booting procedure by creating a file uEnv.txt
in the root of the SD card. It is a plain text file in format
<key>=<value> one per line:

kernel_image=myimage
modeboot=myboot
myboot=...