From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chuanxiao Dong Subject: [PATCH v4 3/3]mmc: fix division by zero when cal erase timeout Date: Sat, 12 Feb 2011 14:22:26 +0800 Message-ID: <20110212062226.GD25519@intel.com> Reply-To: Chuanxiao Dong Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga11.intel.com ([192.55.52.93]:37203 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758657Ab1BLG27 (ORCPT ); Sat, 12 Feb 2011 01:28:59 -0500 Content-Disposition: inline Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: linux-mmc@vger.kernel.org, cjb@laptop.org Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, adrian.hunter@nokia.com Since if clock gating feature is enabled, the clock frequency may be zero when host clock is gated. In such scenario, mmc_set_mmc_erase_timeout() may have a division by zero bug. So this patch used mmc_host_clk_rate() to fix this. Signed-off-by: Chuanxiao Dong --- drivers/mmc/core/core.c | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 0eb27aa..2f4576d 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -1201,8 +1201,14 @@ static void mmc_set_mmc_erase_timeout(struct mmc_card *card, * less but not that much less, so fudge it by multiplying by 2. */ timeout_clks <<= 1; - timeout_us += (timeout_clks * 1000) / - (card->host->ios.clock / 1000); + + /* + * at this moment, host controller maybe clock gated, so make + * sure we can get a correct host clock freq. + */ + if (mmc_host_clk_rate(card->host)) + timeout_us += (timeout_clks * 1000) / + (mmc_host_clk_rate(card->host) / 1000); erase_timeout = timeout_us / 1000; -- 1.6.6.1