U-boot is made to suport many referense boards, but that the use of that? it looks more like small OS than bootloader. It finaly must be customized to support some specific design only.
But I have some problems with this. Can someone tell boot functions sequence? they are highly scattered between c modules. it taked very long even to find reset vector. u-boot source is not very clear. why random pars are in assembler and others in C ?
When init.S from /board/walnut405 directory is used? seems it is dublicated in /board/walnut405/walnut405.c but now in c language. when I dissasembled the compiled image I was unable to find anything from init.S
cpu/start.S does similar stuff and by some reason attempts to intialize some unknnown FPGA which is clearly unrelated to cpu at all, and should be moved to board specific module.
basicaly I would like to completely rewrite initialization procedure, and put it all in one source file. probably the best would be to discard all exsisting initialization source and write new one.
but I need boot function sequence for that. and point where the low level initialization is finished.
I need to make custom initialization for ram ,rom, blink leds on gpio. and mainly remove al pnp stuff, like spd. probably no real board will ever use spd for sram. also removing everyhing unnesecary is required, flash is not hdd aftreall. I need it for linuxAP the board is with single ppc405gp cpu with 1mb flash and 8mb ram, uart1 pins, and probably pci interface. so I need to fit uboot in something like 16kb or less, but first I need to make it run at least. (that 1mb must fit kernel , rootfs, cfgdata, and bootloader) with 486 type cpu it is not big problem
Maybe someone know how much u-boot can be stripped?