Messages in this thread | | | Date | Wed, 26 Jul 2017 11:25:06 +0300 | From | Peter De Schrijver <> | Subject | Re: [PATCH] clk: Don't write error code into divider register |
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On Tue, Jul 25, 2017 at 05:32:08PM -0700, Stephen Boyd wrote: > On 07/25, Peter De Schrijver wrote: > > From: Alex Frid <afrid@nvidia.com> > > > > Add a check for error returned by divider value calculation to avoid > > writing error code into hw register. > > > > Signed-off-by: Alex Frid <afrid@nvidia.com> > > Reviewed-by: Peter De Schrijver <pdeschrijver@nvidia.com> > > Reviewed-by: Jon Mayo <jmayo@nvidia.com> > > --- > > Fixes: bca9690b9426 ("clk: divider: Make generic for usage elsewhere") > > perhaps? > > Also, curious how this got triggered? Presumably round_rate would > have failed before a set_rate call with something invalid came > through so that's why nobody has reported anything so far. >
I don't really know. Aleks do you remember?
> > drivers/clk/clk-divider.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c > > index 9bb472c..4ed516c 100644 > > --- a/drivers/clk/clk-divider.c > > +++ b/drivers/clk/clk-divider.c > > @@ -385,12 +385,14 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate, > > unsigned long parent_rate) > > { > > struct clk_divider *divider = to_clk_divider(hw); > > - unsigned int value; > > + int value; > > unsigned long flags = 0; > > u32 val; > > > > value = divider_get_val(rate, parent_rate, divider->table, > > divider->width, divider->flags); > > + if (value < 0) > > Perhaps value should be an s32 if we're doing a writel with it > shifted so much. And then, we could declare it as a u32 and test > it with > > if ((s32)value < 0) > > to see if there was an error. Sort of annoying that we've limited > the available space of divider_get_val() by combining the value > with the error code number space. We may want to not do that in > case people have huge dividers. >
Yes. It would have been better to return the divider in a separate variable. There seem to be few users though, only 6.
Peter.
> -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > a Linux Foundation Collaborative Project
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