ARM PL180 SD/MMC controller Help

Hello,

I am porting ARM PL180 SD/MMC controller. Its is working fine in
initialization, Read OCR, CSD etc. It also reads the block fine. Its
write block works fine for some blocks but then i receive TX under run
error in the status register. I am using block write.

I have tried the following workarounds:

1. Reduce the clock frequency [No success: situation remains same].
2. Put some delay after one block write so the card settles down[No
success].
3. Use stream mode instead of block mode.[Receive start bit error in
wide bus mode]


Any suggestion whats wrong?

Thanks for consideration.

Umar Waqas