From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965325Ab2DKXXc (ORCPT ); Wed, 11 Apr 2012 19:23:32 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:58738 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965309Ab2DKXX2 (ORCPT ); Wed, 11 Apr 2012 19:23:28 -0400 Message-Id: <20120411231042.452525315@linuxfoundation.org> User-Agent: quilt/0.60-19.1 Date: Wed, 11 Apr 2012 16:11:16 -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: [ 41/59] mmc: atmel-mci: correct data timeout computation In-Reply-To: <20120411231213.GA13124@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-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 @@ -480,7 +480,14 @@ err: static inline unsigned int atmci_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,