Hi Alemao,
Alemao wrote:
Hi all,
Im having problems porting u-boot-2009.03 to a MPC8541 board.
In u-boot-1.2.0, if I use TEXT_BASE = 0xfff00000, u-boot.bin is created with 1MB size.
The .bin file is a binary image from the first location 0xfff00000 *contiguously filled* to the last location (the start vector at 0xfffffffc). U-Boot isn't that big, most of it is empty space, but your creation of a 0xFF-filled .bin file fills in the empty spaces.
But in u-boot-2009.03 it's created with only 516kB.
Your text base was probably 0xfff80000.
In cpu/mpc85xx/start.S says:
"The processor starts at 0xfffffffc and the code is first executed in the last 4K page(0xfffff000-0xffffffff) in flash/rom."
So I think there's nothing in 0xfffffffc, using u-boot.bin from u-boot-2009.03, cause it only has 516kB.
Do I have to set TEXT_BASE with the exact u-boot.bin size?
Or am I missing something?
* Don't use a .bin file (use the linker elf output directly)? * Does it matter?
Do you need to set your text base to 0xfff00000? You are better off setting your text base so that your u-boot and reset vector are close together. You did not say what processor you are using, but it sounds like a MPC74xx or MPC86xx or MPC85xx? I played with a MPC8548 and reconfigured it so that my u-boot was the last two sectors of flash and the env variables were saved in the sector *preceding* the u-boot image. That worked very nicely.
The typical u-boot places the env sector after the u-boot image, which works in most cases but doesn't work well where the top page/bytes of the memory are the reset vector. In those cases, it is better to have U-Boot and the reset vector/page at the top of memory and the env sector below U-Boot, otherwise you end up with the env taking a whole sector out of the middle plus waste another whole sector just to hold your reset vector/page.
Cheers,
-- Alemao
Best regards, gvb