mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-16 01:38:22 +00:00
d4451d3503
This patch adds the a4m2k MPC5200B board port. Its a derivate of the a3m071 board with only minor changes. Additionally this patch includes some clean-up changes: - Remove I2C support from a3m071 as its unused - Fix/enhance default env variables - Fix some comments - Add newly introduced CONFIG_SPL_TARGET to automatically build "u-boot-img.bin" - Fix dtb patching in READ desciption for SPL Linux booting: "fdt chosen" needs to get called to patch/create the chosen node. - Add missing call to spl_board_init(): Define CONFIG_SPL_BOARD_INIT so that spl_board_init() will get called in the SPL version. Signed-off-by: Stefan Roese <sr@denx.de>
80 lines
2.5 KiB
Text
80 lines
2.5 KiB
Text
------------------------------------------------------------------------
|
|
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;fdt chosen;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
|