From: Russell King Subject: [PATCH 20/17] mmc: sdhci: fix data timeout (part 2) Date: Sun, 20 Dec 2015 08:27:05 +0000 Message-ID: References: <20151219202851.GS8644@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Return-path: Received: from pandora.arm.linux.org.uk ([78.32.30.218]:37197 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754236AbbLTI1O (ORCPT ); Sun, 20 Dec 2015 03:27:14 -0500 In-Reply-To: <20151219202851.GS8644@n2100.arm.linux.org.uk> Content-Disposition: inline Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ulf Hansson Cc: Marcin Wojtas , Gregory CLEMENT , Shawn Guo , Sascha Hauer , linux-mmc@vger.kernel.org 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 --- 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 82e799fde113..65b230ea179e 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -631,8 +631,19 @@ 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; + } } /* -- 2.1.0