2019-06-10 16:21:08

by Codrin Ciubotariu

Subject: [PATCH] clk: at91: generated: Truncate divisor to GENERATED_MAX_DIV + 1

From: Codrin Ciubotariu <[email protected]>

In clk_generated_determine_rate(), if the divisor is greater than
GENERATED_MAX_DIV + 1, then the wrong best_rate will be returned.
If clk_generated_set_rate() will be called later with this wrong
rate, it will return -EINVAL, so the generated clock won't change
its value. Do no let the divisor be greater than GENERATED_MAX_DIV + 1.

Fixes: 8c7aa6328947 ("clk: at91: clk-generated: remove useless divisor loop")
Signed-off-by: Codrin Ciubotariu <[email protected]>
---
drivers/clk/at91/clk-generated.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
index 5f18847965c1..290cffe35deb 100644
--- a/drivers/clk/at91/clk-generated.c
+++ b/drivers/clk/at91/clk-generated.c
@@ -146,6 +146,8 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
continue;

div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
+ if (div > GENERATED_MAX_DIV + 1)
+ div = GENERATED_MAX_DIV + 1;

clk_generated_best_diff(req, parent, parent_rate, div,
&best_diff, &best_rate);
--
2.20.1

2019-06-12 18:00:42

by Nicolas Ferre

Subject: Re: [PATCH] clk: at91: generated: Truncate divisor to GENERATED_MAX_DIV + 1

On 10/06/2019 at 17:20, Codrin Ciubotariu - M19940 wrote:
> From: Codrin Ciubotariu <[email protected]>
>
> In clk_generated_determine_rate(), if the divisor is greater than
> GENERATED_MAX_DIV + 1, then the wrong best_rate will be returned.
> If clk_generated_set_rate() will be called later with this wrong
> rate, it will return -EINVAL, so the generated clock won't change
> its value. Do no let the divisor be greater than GENERATED_MAX_DIV + 1.
>
> Fixes: 8c7aa6328947 ("clk: at91: clk-generated: remove useless divisor loop")
> Signed-off-by: Codrin Ciubotariu <[email protected]>

Yes:
Acked-by: Nicolas Ferre <[email protected]>

Thanks for having fixed this Codrin. Best regards,
Nicolas

> ---
> drivers/clk/at91/clk-generated.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
> index 5f18847965c1..290cffe35deb 100644
> --- a/drivers/clk/at91/clk-generated.c
> +++ b/drivers/clk/at91/clk-generated.c
> @@ -146,6 +146,8 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
> continue;
>
> div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
> + if (div > GENERATED_MAX_DIV + 1)
> + div = GENERATED_MAX_DIV + 1;
>
> clk_generated_best_diff(req, parent, parent_rate, div,
> &best_diff, &best_rate);
>


--
Nicolas Ferre

2019-06-12 18:01:50

by Ludovic Desroches

Subject: Re: [PATCH] clk: at91: generated: Truncate divisor to GENERATED_MAX_DIV + 1

On Wed, Jun 12, 2019 at 03:54:00PM +0200, Nicolas Ferre - M43238 wrote:
> On 10/06/2019 at 17:20, Codrin Ciubotariu - M19940 wrote:
> > From: Codrin Ciubotariu <[email protected]>
> >
> > In clk_generated_determine_rate(), if the divisor is greater than
> > GENERATED_MAX_DIV + 1, then the wrong best_rate will be returned.
> > If clk_generated_set_rate() will be called later with this wrong
> > rate, it will return -EINVAL, so the generated clock won't change
> > its value. Do no let the divisor be greater than GENERATED_MAX_DIV + 1.
> >
> > Fixes: 8c7aa6328947 ("clk: at91: clk-generated: remove useless divisor loop")
> > Signed-off-by: Codrin Ciubotariu <[email protected]>
>
> Yes:
> Acked-by: Nicolas Ferre <[email protected]>

Acked-by: Ludovic Desroches <[email protected]>

Thanks

Ludovic

>
> Thanks for having fixed this Codrin. Best regards,
> Nicolas
>
> > ---
> > drivers/clk/at91/clk-generated.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
> > index 5f18847965c1..290cffe35deb 100644
> > --- a/drivers/clk/at91/clk-generated.c
> > +++ b/drivers/clk/at91/clk-generated.c
> > @@ -146,6 +146,8 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
> > continue;
> >
> > div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
> > + if (div > GENERATED_MAX_DIV + 1)
> > + div = GENERATED_MAX_DIV + 1;
> >
> > clk_generated_best_diff(req, parent, parent_rate, div,
> > &best_diff, &best_rate);
> >
>
>
> --
> Nicolas Ferre