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    Subject[PATCH 3.16 050/217] mmc: sdhci: fix data timeout (part 2)
    3.16.35-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Russell King <rmk+kernel@arm.linux.org.uk>

    commit 7f05538af71c7d30b5fc821cbe9f318edc645961 upstream.

    The calculation for the timeout based on the number of card clocks is
    incorrect. The calculation assumed:

    timeout in microseconds = clock cycles / clock in Hz

    which is clearly a several orders of magnitude wrong. Fix this by
    multiplying the clock cycles by 1000000 prior to dividing by the Hz
    based clock. Also, as per part 1, ensure that the division rounds
    up.

    As this needs 64-bit math via do_div(), avoid it if the clock cycles
    is zero.

    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
    Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
    Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
    Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    drivers/mmc/host/sdhci.c | 15 +++++++++++++--
    1 file changed, 13 insertions(+), 2 deletions(-)

    --- a/drivers/mmc/host/sdhci.c
    +++ b/drivers/mmc/host/sdhci.c
    @@ -661,8 +661,19 @@ static u8 sdhci_calc_timeout(struct sdhc
    target_timeout = cmd->busy_timeout * 1000;
    else {
    target_timeout = DIV_ROUND_UP(data->timeout_ns, 1000);
    - if (host->clock)
    - target_timeout += data->timeout_clks / host->clock;
    + if (host->clock && data->timeout_clks) {
    + unsigned long long val;
    +
    + /*
    + * data->timeout_clks is in units of clock cycles.
    + * host->clock is in Hz. target_timeout is in us.
    + * Hence, us = 1000000 * cycles / Hz. Round up.
    + */
    + val = 1000000 * data->timeout_clks;
    + if (do_div(val, host->clock))
    + target_timeout++;
    + target_timeout += val;
    + }
    }

    /*
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