board/ci20: create a SD card image

Add a genimage.cfg to create a working sdcard.img for the ci20
hardware.  We also need a uboot-env.txt to create the partition for
the uboot environment.

Update the board/ci20/readme.txt with the related information. Remove
the tftp netboot description from the readme as it is already to
complicated for a basic bootable example.

Signed-off-by: Johannes Schmitz <johannes.schmitz1@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

board/ci20/genimage.cfg

@@ -0,0 +1,29 @@
+image sdcard.img {
+    hdimage {
+    }
+
+    partition uboot-spl {
+        in-partition-table = "no"
+        image = "u-boot-spl.bin"
+        offset = 512
+    }
+
+    partition uboot {
+        in-partition-table = "no"
+        image = "u-boot.img"
+        offset = 14k
+    }
+
+    partition uboot-env {
+        in-partition-table = "no"
+        image = "uboot-env.bin"
+        offset = 526k
+    }
+
+    partition rootfs {
+        partition-type = 0x83
+        image = "rootfs.ext4"
+        offset = 2M
+        size = 60M
+    }
+}

board/ci20/readme.txt

@@ -2,41 +2,45 @@
 * MIPS Creator CI20 *
 *********************
 
+Introduction
+============
+
 The 'ci20_defconfig' will create a root filesystem and a kernel image
 under the 'output/images/' directory. This document will try to explain how
 to use them in order to run Buildroot in the MIPS Creator CI20 board.
 
-Assuming you are at the U-Boot prompt of the MIPS Creator CI20, you have to
+How to build it
-load the generated kernel image by using the 'tftpboot' command. In
+===============
-order to do that, you will need to get the network working. Here you
-have the instructions to set the ip address, netmask and gateway:
 
-  setenv ipaddr x.x.x.x
+Configure Buildroot
-  setenv netmask x.x.x.x
+-------------------
-  setenv gatewayip x.x.x.x
 
-Now you have to set the ip for the TFTP server you are going to load the
+  $ make ci20_defconfig
-kernel image from, and also the name of the kernel image file (we use
-'uImage' as a filename in this example):
 
-  setenv serverip x.x.x.x
+Build the rootfs
-  setenv bootfile uImage
+----------------
 
-And finally load the kernel image:
+Note: you will need to have access to the network, since Buildroot will
+download the packages' sources.
 
-  tftpboot
+You may now build your rootfs with:
 
-Now you have to extract the generated root filesystem into a USB drive
+  $ make
-or SD-Card. Here you have the instructions to boot from the two of them.
-You have to choose the one your prefer:
 
-From USB
+(This may take a while, consider getting yourself a coffee ;-) )
-  setenv bootargs console=ttyS4,115200 console=tty0 mem=256M@0x0
-mem=768M@0x30000000 root=/dev/sda1
 
-From SD-Card
+How to write the SD card
-  setenv bootargs console=ttyS4,115200 console=tty0 mem=256M@0x0
+========================
-mem=768M@0x30000000 root=/dev/mmcblk0p1
 
-And finally run this command to boot the board:
+Once the build process is finished you will have an image called
-  bootm
+"sdcard.img" in the output/images/ directory.
+
+Make sure the SD card is not mounted then copy the bootable "sdcard.img" onto
+it with "dd":
+
+  $ sudo dd if=output/images/sdcard.img of=/dev/sdX
+
+Insert the SDcard into your ci20, and power it up. Your new system
+should come up now and start a console on the UART HEADER.
+
+see: https://elinux.org/CI20_Hardware#Dedicated_UART_header

board/ci20/uboot-env.txt

@@ -0,0 +1,10 @@
+baudrate=115200
+board_mfr=NP
+bootargs=console=ttyS4,115200 console=tty0 mem=256M@0x0 mem=768M@0x30000000 rootwait root=/dev/mmcblk0p1 devtmpfs.mount=1 ip=dhcp
+bootcmd=run ethargs; ext4load mmc 0:1 0x88000000 /boot/uImage; bootm 0x88000000
+bootdelay=1
+ethargs=env set bootargs ${bootargs}
+loads_echo=1
+stderr=eserial0,eserial4
+stdin=eserial0,eserial4
+stdout=eserial0,eserial4

configs/ci20_defconfig

@@ -8,6 +8,10 @@ BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_3_18=y
 
 # system
 BR2_TARGET_GENERIC_GETTY_PORT="ttyS4"
+BR2_TARGET_ROOTFS_EXT2=y
+BR2_TARGET_ROOTFS_EXT2_4=y
+BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"
+BR2_ROOTFS_POST_SCRIPT_ARGS="-c board/ci20/genimage.cfg"
 
 # kernel
 BR2_LINUX_KERNEL=y
@@ -15,6 +19,7 @@ BR2_LINUX_KERNEL_CUSTOM_GIT=y
 BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://github.com/MIPS/CI20_linux.git"
 BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="7dff33297116643485ca37141d804eddd793e834"
 BR2_LINUX_KERNEL_DEFCONFIG="ci20"
+BR2_LINUX_KERNEL_INSTALL_TARGET=y
 
 # u-boot
 BR2_TARGET_UBOOT=y
@@ -26,3 +31,9 @@ BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="dd3c1b95dac7d10b2ca5806f65e5c1050d7dd0fa"
 BR2_TARGET_UBOOT_FORMAT_IMG=y
 BR2_TARGET_UBOOT_SPL=y
 BR2_TARGET_UBOOT_SPL_NAME="spl/u-boot-spl.bin"
+BR2_TARGET_UBOOT_ENVIMAGE=y
+BR2_TARGET_UBOOT_ENVIMAGE_SOURCE="board/ci20/uboot-env.txt"
+BR2_TARGET_UBOOT_ENVIMAGE_SIZE="32768"
+
+# host
+BR2_PACKAGE_HOST_GENIMAGE=y