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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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