From: Ludovic Desroches Date: Wed, 28 Mar 2012 10:28:33 +0000 (+0200) Subject: mmc: atmel-mci: correct data timeout computation X-Git-Tag: next-20120402~27^2~9 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=17befa685141cff960995ac8b6ca3f9571fbaa19;p=karo-tx-linux.git mmc: atmel-mci: correct data timeout computation 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: Signed-off-by: Chris Ball --- diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c index 9819dc09ce08..34080f590f69 100644 --- a/drivers/mmc/host/atmel-mci.c +++ b/drivers/mmc/host/atmel-mci.c @@ -482,7 +482,14 @@ 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,