From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Ferre Subject: Re: [PATCH v2 1/3] mmc: atmel-mci: correct data timeout computation Date: Wed, 28 Mar 2012 13:44:37 +0200 Message-ID: <4F72F9A5.60900@atmel.com> References: <1332344483-3915-2-git-send-email-ludovic.desroches@atmel.com> <1332930513-14893-1-git-send-email-ludovic.desroches@atmel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from newsmtp5.atmel.com ([204.2.163.5]:52238 "EHLO sjogate2.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932285Ab2C1Lou (ORCPT ); Wed, 28 Mar 2012 07:44:50 -0400 In-Reply-To: <1332930513-14893-1-git-send-email-ludovic.desroches@atmel.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: ludovic.desroches@atmel.com Cc: linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org On 03/28/2012 12:28 PM, ludovic.desroches@atmel.com : > From: Ludovic Desroches > > 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 > Cc: stable > --- > drivers/mmc/host/atmel-mci.c | 9 ++++++++- > 1 files changed, 8 insertions(+), 1 deletions(-) > > diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c > index e4449a5..3a57964 100644 > --- 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, -- Nicolas Ferre