> -----Original Message----- > From: Marc Koschewski [mailto:[email protected]] > Sent: Thursday, February 24, 2011 7:38 PM > To: Dong, Chuanxiao > Cc: [email protected]; [email protected]; [email protected]; > [email protected]; [email protected] > Subject: Re: [PATCH 1/1]mmc: fix division by zero when calculate mmc erase > time > > Hi, > > * Chuanxiao Dong <[email protected]> [2011-02-24 19:18:01 +0800]: > > > 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 <[email protected]> > > --- > > 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); > > Why don't you just reuse mmc_host_clk_rate()'s result instead of calling it > twice? This is a incline function and just return host->ios.clock. Reuse mmc_host_clk_rate()'s result need to add a new variable to save the value.
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