From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120411231312.018775228@linuxfoundation.org> Date: Wed, 11 Apr 2012 16:13:34 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Ludovic Desroches , Nicolas Ferre , Chris Ball Subject: [ 27/42] mmc: atmel-mci: correct data timeout computation In-Reply-To: <20120411231443.GA808@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ludovic Desroches commit 66292ad92c6d3f2f1c137a1c826b331ca8595dfd upstream. The HSMCI operates at a rate of up to Master Clock divided by two. Moreover previous calculation can cause overflows and so wrong timeouts. Signed-off-by: Ludovic Desroches Acked-by: Nicolas Ferre Signed-off-by: Chris Ball Signed-off-by: Greg Kroah-Hartman --- drivers/mmc/host/atmel-mci.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/drivers/mmc/host/atmel-mci.c +++ b/drivers/mmc/host/atmel-mci.c @@ -468,7 +468,14 @@ err: static inline unsigned int ns_to_clocks(struct atmel_mci *host, unsigned int ns) { - return (ns * (host->bus_hz / 1000000) + 999) / 1000; + /* + * It is easier here to use us instead of ns for the timeout, + * it prevents from overflows during calculation. + */ + unsigned int us = DIV_ROUND_UP(ns, 1000); + + /* Maximum clock frequency is host->bus_hz/2 */ + return us * (DIV_ROUND_UP(host->bus_hz, 2000000)); } static void atmci_set_timeout(struct atmel_mci *host,