U-Boot for TX48
                                        ===============

Building U-Boot
---------------

Unpacking the source
--------------------
mkdir u-boot
cd u-boot
tar -xjf /cdrom/U-Boot/u-boot-src.tar.bz2

Alternatively you can access the current source via the git repository:
git://git.kernelconcepts.de/karo-tx-uboot.git master


Compiling U-Boot
----------------
export ARCH=arm
export CROSS_COMPILE=arm-cortexa8-linux-gnueabi-
make tx48_config
make


Flashing U-Boot Image
---------------------
If you want to replace a working U-Boot with a new version, you can
load the new U-Boot image via TFTP and program it like any other flash
partition with:
nand erase.part u-boot;nand write.trimffs ${fileaddr} u-boot ${filesize}

If you want to revive a bricked module, U-Boot can be downloaded via
xmodem protocol over the serial port in recovery boot mode (Jumper ST3
on Starterkit-5 baseboard closed). See TX48-U-Boot.pdf for details.


U-Boot Features
---------------

Environment variables:

cpu_clk       <CPU freq [MHz]>
touchpanel    {tsc2007|edt-ft5x06}
otg_mode      [host|device|none]
video_mode    <video mode as understood by Linux fb_find_mode() function>
              e.g.: 640x480MR-24@60
baseboard     {stk5-v3|stk5-v5} selects type of baseboard
splashimage   either: memory address (e.g. ${loadaddr}) of a BMP file
	      to be displayed instead of the built-in logo. Since NAND
	      flash is not accessible in a memory mapped fashion,
	      U-Boot will try to load the contents of the flash
	      partition 'logo.bmp' to the address given with
	      'splashimage'.

	      or: the name of an MTD partition, that contains a raw
	      dump of the frame buffer contents which will be loaded
	      to the framebuffer.

splashpos     (when 'splashimage' contains a memory address) the
	      position ('x,y') on the screen at which the BMP image
	      will be displayed.
	      Setting splashpos to 'm,m' will center the image on the
	      screen.

Note: Some variables (like 'cpu_clk' or 'splashimage') may render the
      board unbootable if incorrectly set. Therefore these variables
      will not be evaluated in case the board has been reset through a
      watchdog reset or a character is available on the serial console
      during startup to give the user a chance to recover from this
      situation.