[U-Boot] U-boot to DE2 board with MMC interface (PIO based) and FAT support enabled

[ivanchuklist ivanchu]

Hi list,

I'm working with an Altera DE2 board (Nios II processor without MMU). I
developed a sd interface implemented with pio cores. In order to compile
u-boot correctly i modified the Makefile to match my binutils. I also
changed the file common/cmd_mem.c because it has a little problem when it
needs to manage the card to copy the data to main memory or from main
memory. I can't deduce the direction of data knowing only the address
because his address space isn't mapped on the bus like a common flash
memory. I added a command named dmcc (cmd_dmmc) to set the desired direction
of data, ie to or from mmc, to call correctly to the functions mmc_read and
mmc_write.
I have made a device block, filling the structure block_dev_desc_t and
defining mmc_get_dev(), to have access to the partition table (FAT). Now
u-boot is able to list the files inside the card (fatls mmc 0:0) and it
copies them to main memory (fatload mmc 0:0 500000 zimage).
I had to modify the source common/cmd_mmc.c because it has a reference to
mmc.h, but it gives problems with the linking process because of double
reference between the objects cmd_mmc.o and cmd_mem.o. The solution was to
declare extern the function mmc_init.
I also added my board to u-boot package.
I don't know how to post all what i did. I have made the diff files, i could
post them but i don't know how the patches are managed. In fact it's not a
patch at all, just a little branch.

Regards,
Iván Llopard.