[PATCH 1/1]mmc: fix division by zero when calculate mmc erase time

From: Chuanxiao Dong
Date: Thu Feb 24 2011 - 06:25:16 EST


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 <chuanxiao.dong@xxxxxxxxx>
---
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 34a7e8c..12d0eb8 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

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