From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: [PATCH v2] tmio_mmc_pio: prevent endless loop in tmio_mmc_set_clock() Date: Sat, 06 Sep 2014 01:42:29 +0400 Message-ID: <2535223.qa7H57Aml3@wasted.cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from mail-la0-f45.google.com ([209.85.215.45]:59006 "EHLO mail-la0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751470AbaIEVmd (ORCPT ); Fri, 5 Sep 2014 17:42:33 -0400 Received: by mail-la0-f45.google.com with SMTP id pn19so14680188lab.18 for ; Fri, 05 Sep 2014 14:42:31 -0700 (PDT) Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: linux-mmc@vger.kernel.org, ian.molton@codethink.co.uk, chris@printf.net, ulf.hansson@linaro.org Cc: linux-sh@vger.kernel.org I spent a couple of days with the driver just hanging due to me forgetting to specify the external crystal frequency, so that clk_get_rate() returned 0 and thus the loop in tmio_mmc_set_clock() never ended. I don't think that's an acceptable behavior, so I suggest that the minimum frequency is checked for 0 in tmio_mmc_host_probe(). Signed-off-by: Sergei Shtylyov --- The patch is against Ulf Hansson's 'mmc.git' repo's 'fixes' branch. Changes in version 2: - fixed grammar in the changelog. drivers/mmc/host/tmio_mmc_pio.c | 9 +++++++++ 1 file changed, 9 insertions(+) Index: mmc/drivers/mmc/host/tmio_mmc_pio.c =================================================================== --- mmc.orig/drivers/mmc/host/tmio_mmc_pio.c +++ mmc/drivers/mmc/host/tmio_mmc_pio.c @@ -1044,6 +1044,15 @@ int tmio_mmc_host_probe(struct tmio_mmc_ } /* + * Check the sanity of mmc->f_min to prevent tmio_mmc_set_clock() from + * looping forever... + */ + if (mmc->f_min == 0) { + ret = -EINVAL; + goto pm_disable; + } + + /* * There are 4 different scenarios for the card detection: * 1) an external gpio irq handles the cd (best for power savings) * 2) internal sdhi irq handles the cd