Re: [PATCH] mmc_core: fix data timeout for SEND_EXT_CSD

From: Adrian Hunter
Date: Thu Feb 19 2009 - 06:58:52 EST


Matt Fleming wrote:
On Thu, Feb 19, 2009 at 09:33:48AM +0200, Adrian Hunter wrote:
ext Pierre Ossman wrote:
I'm confused. Where did the 64 come from in the first place? That
function will not be called for CID/CSD when !SPI. So the way I see it
the code should be:

if ((opcode == MMC_SEND_CSD) || (opcode == (MMC_SEND_CID)) {
data.timeout_ns = 0;
data.timeout_clks = 8;
} else {
mmc_set_data_timeout(&data, card);
}
Theoretically yes, it should be 8 not 64 - if all the SPI devices obey
the standard. As I do not have an SPI device I did not feel comfortable
changing it. Also 64 clocks is not a long time anyway, so it did not
seem to do any harm.

When I wrote the code, I got the 64 clock cycle timeout from the MMC
spec that I was looking at. Unfortunately, I don't have the spec in
front of me at the moment. It is possible that I read the timeout for
the !SPI case, though.

No it is my mistake. The value is 8 but the unit is 8 clock cycles
i.e. 64 clock cycles. So my comment was wrong.

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