From 7f05538af71c7d30b5fc821cbe9f318edc645961 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 26 Jan 2016 13:41:04 +0000 Subject: [PATCH] mmc: sdhci: fix data timeout (part 2) 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 Signed-off-by: Adrian Hunter Cc: stable@vger.kernel.org # v3.15+ Tested-by: Gregory CLEMENT Signed-off-by: Ulf Hansson --- drivers/mmc/host/sdhci.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 1d1b3c5b06f7..5a7517f44187 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -636,8 +636,19 @@ static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd) 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; + } } /* -- 2.20.1