zynq_zed: bump U-Boot to xilinx-v2016.2

This is the latest release tag in the Xilinx repository, based on
U-Boot v2016.01 in the mainline.

Commit 46d6a561be41 ("zedboard: Generate BOOT.BIN automatically")
switched from the Xilinx GitHub repository to the U-Boot mainline,
but this commit gets it back to the Xilinx GitHub repository for the
following reasons:

 - This defconfig still relies on the Xilinx's local repository for
   the kernel.  The vendor does the best test for the combination of
   U-Boot and the kernel with the same release tag (xilinx-v2016.2
   in this case).

 - At the time of commit 46d6a561be41, the u-boot-xlnx still needed
   manual copy of ps7_init(_gpl).c/h in order to build a working SPL
   image.  So, the mainline U-Boot had advantage in that point of
   time.  However, the improvement in the mainline U-Boot was merged
   into the u-boot-xlnx at the xilinx-v2015.3 release.  Now, the
   mainline and the u-boot-xlnx are even in this point of view.

 - The mainline U-Boot defaults to boot FIT, so something must be
   done; either patch environments around with a local patch to
   switch to uImage booting (current solution), or build an FIT
   with a post build script (chromebook snow does this).  On the
   other hand, the Xilinx repository defaults to uImage booting,
   so it is straightforward, and needs no addition care.

This commit does:

 - Switch to the Xilinx custom git repository, and stick to the
   xilinx-v2016.2 tag.

 - Delete the local patch board/avnet/zedboard/uboot/0001...
   since the Xilinx custom repository can boot uImage by default.

 - Enable BR2_TARGET_UBOOT_FORMAT_IMG instead of ..._FORMAT_DTB_IMG
   since all the Zynq boards in U-Boot enable CONFIG_OF_EMBED.

 - Replace BR2_TARGET_UBOOT_ZYNQ_IMAGE with BR2_TARGET_UBOOT_SPL_NAME
   since U-Boot can natively generate the Zynq boot image now. The
   Zynq image support for mkimage tool was upstreamed at v2016.01
   (so xilinx-v2016.1 as well), so no additional tool is needed
   any more.

 - Update readme.txt

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Matt Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

board/avnet/zedboard/readme.txt

@@ -9,52 +9,16 @@ Steps to create a working system for Zedboard:
 
 1) make zynq_zed_defconfig
 2) make
-3) copy files BOOT.BIN, u-boot-dtb.img, rootfs.cpio.uboot,
-	uImage, zynq-zed.dtb into your SD card
+3) All needed files will be available in the output/images directory.
+   Create a FAT32 partition at the beginning of your SD Card and copy files:
+     - boot.bin
+     - u-boot.img
+     - uImage
+     - uramdisk.image.gz (should be renamed from rootfs.cpio.uboot)
+     - devicetree.dtb (should be renamed from 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:

board/avnet/zedboard/uboot/0001-zynq-Create-zedboard-specific-U-Boot-environment.patch

@@ -1,45 +0,0 @@
-From a4c0058967a551385da5e16d2787d9f704cab225 Mon Sep 17 00:00:00 2001
-From: Jan Viktorin <viktorin@rehivetech.com>
-Date: Thu, 18 Jun 2015 16:26:02 +0200
-Subject: [PATCH 2/2] zynq: Create zedboard-specific U-Boot environment
-
----
- include/configs/zynq_zed.h | 25 +++++++++++++++++++++++++
- 1 file changed, 25 insertions(+)
-
-diff --git a/include/configs/zynq_zed.h b/include/configs/zynq_zed.h
-index 946de95..2400a88 100644
---- a/include/configs/zynq_zed.h
-+++ b/include/configs/zynq_zed.h
-@@ -24,0 +24,0 @@
-
- #include <configs/zynq-common.h>
-
-+#undef CONFIG_EXTRA_ENV_SETTINGS
-+#define CONFIG_EXTRA_ENV_SETTINGS \
-+	"envload=mmc info && if fatload mmc 0 0x1000 uEnv.txt;"\
-+	" then echo Importing uEnv.txt; env import -t 0x1000"  \
-+	" $filesize; fi;\0"                                    \
-+	"bootcmd=run envload; run $modeboot\0"                 \
-+	"modeboot=sdboot\0"                                    \
-+	"baudrate=115200\0"                                    \
-+	"bootenv=uEnv.txt\0"                                   \
-+	"devicetree_image=zynq-zed.dtb\0"                      \
-+	"kernel_image=uImage\0"                                \
-+	"ramdisk_image=rootfs.cpio.uboot\0"                    \
-+	"fpga_image=system.bit\0"                              \
-+	"sdboot=echo Booting from SD...; run fpgaboot;"        \
-+	" fatload mmc 0 0x1000000 ${kernel_image}"             \
-+	" && fatload mmc 0 0x3000000 ${ramdisk_image}"         \
-+	" && fatload mmc 0 0x2000000 ${devicetree_image}"      \
-+	" && bootm 0x1000000 0x3000000 0x2000000\0"            \
-+	"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;\0"
-+
- #endif /* __CONFIG_ZYNQ_ZED_H */
---
-2.4.3
-

configs/zynq_zed_defconfig

@@ -17,10 +17,10 @@ BR2_TARGET_ROOTFS_CPIO_GZIP=y
 BR2_TARGET_ROOTFS_CPIO_UIMAGE=y
 BR2_TARGET_UBOOT=y
 BR2_TARGET_UBOOT_BOARDNAME="zynq_zed"
-BR2_TARGET_UBOOT_CUSTOM_VERSION=y
-BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2015.07"
-BR2_TARGET_UBOOT_PATCH="$(TOPDIR)/board/avnet/zedboard/uboot"
+BR2_TARGET_UBOOT_CUSTOM_GIT=y
+BR2_TARGET_UBOOT_CUSTOM_REPO_URL="https://github.com/Xilinx/u-boot-xlnx.git"
+BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="xilinx-v2016.2"
 BR2_TARGET_UBOOT_NEEDS_DTC=y
-BR2_TARGET_UBOOT_FORMAT_DTB_IMG=y
+BR2_TARGET_UBOOT_FORMAT_IMG=y
 BR2_TARGET_UBOOT_SPL=y
-BR2_TARGET_UBOOT_ZYNQ_IMAGE=y
+BR2_TARGET_UBOOT_SPL_NAME="spl/boot.bin"