From 13b4f639495db2d351be3882eebc4fefdf42d5b4 Mon Sep 17 00:00:00 2001 From: Stefan Roese Date: Tue, 14 Aug 2012 15:04:19 +0200 Subject: mpc5200: Add a3m071 board support This patch adds support for the a3m071 board based on the MPC5200. Signed-off-by: Stefan Roese --- board/a3m071/README | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 board/a3m071/README (limited to 'board/a3m071/README') diff --git a/board/a3m071/README b/board/a3m071/README new file mode 100644 index 0000000000..7698614a62 --- /dev/null +++ b/board/a3m071/README @@ -0,0 +1,80 @@ +------------------------------------------------------------------------ +A3M071 board support +------------------------------------------------------------------------ + + +SPL NOR flash support: +---------------------- +To boot fast into the OS (Linux), this board port integrates the SPL +framework. This means, that a special, stripped-down version of +U-Boot runs in the beginning. In the case of the A3M071 board, this +SPL U-Boot version is less than 16 KiB big. This SPL U-Boot can either +boot the OS (Linux) or a "real", full-blown U-Boot. This detection +on whether to boot Linux or U-Boot is done by using the "boot_os" +environment variable. If "boot_os" is set to "yes", Linux will be +loaded and booted from the SPL U-Boot version. Otherwise, the +full-blown U-Boot version will be loaded and run. + +Enabling Linux booting: +----------------------- +From U-Boot: +=> setenv boot_os yes +=> saveenv + +From Linux: +$ fw_setenv boot_os yes + +Enabling U-Boot booting: +------------------------ +From U-Boot: +=> setenv boot_os no +=> saveenv + +From Linux: +$ fw_setenv boot_os no + + +Preparing Linux image(s) for booting from SPL U-Boot: +----------------------------------------------------- +To boot the Linux kernel from the SPL, the DT blob (fdt) needs to get +prepard/patched first. U-Boot usually inserts some dynamic values into +the DT binary (blob), e.g. autodetected memory size, MAC addresses, +clocks speeds etc. To generate this patched DT blob, you can use +the following command: + +1. Load fdt blob to SDRAM: +=> tftp 1800000 a3m071/a3m071.dtb + +2. Set bootargs as desired for Linux booting (e.g. flash_mtd): +=> run mtdargs addip2 addtty + +3. Use "fdt" commands to patch the DT blob: +=> fdt addr 1800000 +=> fdt boardsetup +=> fdt chosen + +4. Display patched DT blob (optional): +=> fdt print + +5. Save fdt to NOR flash: +=> erase fc060000 fc07ffff +=> cp.b 1800000 fc060000 10000 + +All this can be integrated into an environment command: +=> setenv upd_fdt 'tftp 1800000 a3m071/a3m071.dtb;run mtdargs addip2 addtty; \ + fdt addr 1800000;fdt boardsetup;erase fc060000 fc07ffff; \ + cp.b 1800000 fc060000 10000' +=> saveenv + +After this, only "run upd_fdt" needs to get called to load, patch +and save the DT blob into NOR flash. + +Additionally, the Linux kernel image has to be saved uncompressed in +its uImage file (and not gzip compressed). This can be done with this +command: + +$ mkimage -A ppc -O linux -T kernel -C none -a 0 -e 0 \ + -n "Linux Kernel Image" -d vmlinux.bin uImage.uncompressed + +------------------------------------------------------------------------ +Stefan Roese, 2012-08-23 -- cgit v1.2.1