Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932104AbcD0Aey (ORCPT ); Tue, 26 Apr 2016 20:34:54 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:39747 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753668AbcDZXNg (ORCPT ); Tue, 26 Apr 2016 19:13:36 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Gregory CLEMENT" , "Adrian Hunter" , "Russell King" , "Ulf Hansson" Date: Wed, 27 Apr 2016 01:02:21 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 050/217] mmc: sdhci: fix data timeout (part 2) In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1743 Lines: 54 3.16.35-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Russell King 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 Signed-off-by: Adrian Hunter Tested-by: Gregory CLEMENT Signed-off-by: Ulf Hansson Signed-off-by: Ben Hutchings --- 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; + } } /*