On 10/07/2011 09:11 PM, Russell King - ARM Linux wrote:
But first, you need to fix your code so you're only reading 32-bit
quantities from the FIFO register.
Hi Russel, what to you think of doing it this way instead:
/*
* SDIO especially may want to send something that is
* not divisible by 4 (as opposed to card sectors
* etc), and the FIFO only accept full 32-bit reads.
*/
if (count < 4) {
unsigned char buf[4];
readsl(base + MMCIFIFO, buf, 1);
memcpy(ptr, buf, count);
}
else
readsl(base + MMCIFIFO, ptr, count >> 2);
This makes sure we only access the FIFO in a 32 bit way, and the only
overhead for the "standard" case (count >= 4) is the "if" clause. I have
verified this to work with our WLAN driver.
Best Regards
Stefan Nilsson
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