commit: e9b86841b372de01ae865080118e29159d8b7c39
From: Linus Walleij <[email protected]>
Date: Wed, 5 Jan 2011 00:44:32 +0100
Subject: [PATCH] mmc: fix division by zero in MMC core

The card is not always clocked and the clock frequency zero is perfectly
legal, thus this code in mmc_set_data_timeout() may cause a division by
zero. It will be triggered more often if you're using software clock
gating but can be triggered under other conditions too.

Reported-by: Pierre Tardy <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Reviewed-by: Chris Ball <[email protected]>
Cc: <[email protected]>
Signed-off-by: Chris Ball <[email protected]>
---
 drivers/mmc/core/core.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 4b1d8fb..6625c05 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -299,8 +299,9 @@ void mmc_set_data_timeout(struct mmc_data *data, const 
struct mmc_card *card)
                unsigned int timeout_us, limit_us;
 
                timeout_us = data->timeout_ns / 1000;
-               timeout_us += data->timeout_clks * 1000 /
-                       (mmc_host_clk_rate(card->host) / 1000);
+               if (mmc_host_clk_rate(card->host))
+                       timeout_us += data->timeout_clks * 1000 /
+                               (mmc_host_clk_rate(card->host) / 1000);
 
                if (data->flags & MMC_DATA_WRITE)
                        /*

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