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SubjectRe: [PATCH] mmc_core: fix data timeout for SEND_EXT_CSD
ext Pierre Ossman wrote:
> On Wed, 11 Feb 2009 16:49:59 +0200
> Adrian Hunter <ext-adrian.hunter@nokia.com> wrote:
>
>> Commit 0d3e0460f307e84904968aad6cff97bd688583d8
>> "MMC: CSD and CID timeout values" inadvertently broke
>> the timeout for the MMC command SEND_EXT_CSD.
>>
>> This patch puts it back again.
>>
>> Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
>> ---
>> drivers/mmc/core/mmc_ops.c | 16 ++++++++++------
>> 1 files changed, 10 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
>> index 9c50e6f..418a270 100644
>> --- a/drivers/mmc/core/mmc_ops.c
>> +++ b/drivers/mmc/core/mmc_ops.c
>> @@ -248,12 +248,16 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
>>
>> sg_init_one(&sg, data_buf, len);
>>
>> - /*
>> - * The spec states that CSR and CID accesses have a timeout
>> - * of 64 clock cycles.
>> - */
>> - data.timeout_ns = 0;
>> - data.timeout_clks = 64;
>> + if (!mmc_host_is_spi(host) && opcode == MMC_SEND_EXT_CSD)
>> + mmc_set_data_timeout(&data, card);
>> + else {
>> + /*
>> + * The spec states that CSR and CID accesses have a timeout
>> + * of 64 clock cycles (8 for SPI).
>> + */
>> + data.timeout_ns = 0;
>> + data.timeout_clks = 64;
>> + }
>>
>> mmc_wait_for_req(host, &mrq);
>>
>
> 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.



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