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>

3 files changed, 68 insertions, 25 deletions

diff --git a/board/ci20/genimage.cfg b/board/ci20/genimage.cfg
new file mode 100644
index 0000000000..fa3e7368d3
--- /dev/null
+++ b/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
+    }
+}
diff --git a/board/ci20/readme.txt b/board/ci20/readme.txt
index ca7bb52917..71d5070694 100644
--- a/board/ci20/readme.txt
+++ b/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
-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:
+How to build it
+===============
+
+Configure Buildroot
+-------------------
+
+  $ make ci20_defconfig
+
+Build the rootfs
+----------------
+
+Note: you will need to have access to the network, since Buildroot will
+download the packages' sources.
 
-  setenv ipaddr x.x.x.x
-  setenv netmask x.x.x.x
-  setenv gatewayip x.x.x.x
+You may now build your rootfs with:
 
-Now you have to set the ip for the TFTP server you are going to load the
-kernel image from, and also the name of the kernel image file (we use
-'uImage' as a filename in this example):
+  $ make
 
-  setenv serverip x.x.x.x
-  setenv bootfile uImage
+(This may take a while, consider getting yourself a coffee ;-) )
 
-And finally load the kernel image:
+How to write the SD card
+========================
 
-  tftpboot
+Once the build process is finished you will have an image called
+"sdcard.img" in the output/images/ directory.
 
-Now you have to extract the generated root filesystem into a USB drive
-or SD-Card. Here you have the instructions to boot from the two of them.
-You have to choose the one your prefer:
+Make sure the SD card is not mounted then copy the bootable "sdcard.img" onto
+it with "dd":
 
-From USB
-  setenv bootargs console=ttyS4,115200 console=tty0 mem=256M@0x0
-mem=768M@0x30000000 root=/dev/sda1
+  $ sudo dd if=output/images/sdcard.img of=/dev/sdX
 
-From SD-Card
-  setenv bootargs console=ttyS4,115200 console=tty0 mem=256M@0x0
-mem=768M@0x30000000 root=/dev/mmcblk0p1
+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.
 
-And finally run this command to boot the board:
-  bootm
+see: https://elinux.org/CI20_Hardware#Dedicated_UART_header
diff --git a/board/ci20/uboot-env.txt b/board/ci20/uboot-env.txt
new file mode 100644
index 0000000000..3093496cc9
--- /dev/null
+++ b/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