2018-12-24 19:01:51

by Aditya Pakki

Subject: [PATCH] clk: Fix a missing check on regmap_bulk_read

Currently, vc5_pll_recalc_rate() may produce incorrect output when
regmap_bulk_read() fails. The fix checks the return value of the
latter function and returns 0 in case of failure.

Signed-off-by: Aditya Pakki <[email protected]>
---
drivers/clk/clk-versaclock5.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
index decffb3826ec..cd76a893c594 100644
--- a/drivers/clk/clk-versaclock5.c
+++ b/drivers/clk/clk-versaclock5.c
@@ -413,7 +413,8 @@ static unsigned long vc5_pll_recalc_rate(struct clk_hw *hw,
u32 div_int, div_frc;
u8 fb[5];

- regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);
+ if (regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5))
+ return 0;

div_int = (fb[0] << 4) | (fb[1] >> 4);
div_frc = (fb[2] << 16) | (fb[3] << 8) | fb[4];
--
2.17.1

2019-01-09 18:57:35

by Stephen Boyd

Subject: Re: [PATCH] clk: Fix a missing check on regmap_bulk_read

Quoting Aditya Pakki (2018-12-24 11:00:32)
> Currently, vc5_pll_recalc_rate() may produce incorrect output when
> regmap_bulk_read() fails. The fix checks the return value of the
> latter function and returns 0 in case of failure.
>
> Signed-off-by: Aditya Pakki <[email protected]>
> ---
> drivers/clk/clk-versaclock5.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
> index decffb3826ec..cd76a893c594 100644
> --- a/drivers/clk/clk-versaclock5.c
> +++ b/drivers/clk/clk-versaclock5.c
> @@ -413,7 +413,8 @@ static unsigned long vc5_pll_recalc_rate(struct clk_hw *hw,
> u32 div_int, div_frc;
> u8 fb[5];
>
> - regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);
> + if (regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5))
> + return 0;

There are a bunch of other regmap_*() APIs in here that "could fail".
Why has this one been chosen but the other ones not?

2019-01-09 22:39:34

by Marek Vasut

Subject: Re: [PATCH] clk: Fix a missing check on regmap_bulk_read

On 12/24/18 8:00 PM, Aditya Pakki wrote:
> Currently, vc5_pll_recalc_rate() may produce incorrect output when
> regmap_bulk_read() fails. The fix checks the return value of the
> latter function and returns 0 in case of failure.
>
> Signed-off-by: Aditya Pakki <[email protected]>
> ---
> drivers/clk/clk-versaclock5.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
> index decffb3826ec..cd76a893c594 100644
> --- a/drivers/clk/clk-versaclock5.c
> +++ b/drivers/clk/clk-versaclock5.c
> @@ -413,7 +413,8 @@ static unsigned long vc5_pll_recalc_rate(struct clk_hw *hw,
> u32 div_int, div_frc;
> u8 fb[5];
>
> - regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);
> + if (regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5))
> + return 0;

Shouldn't this return ret on failure ?

> div_int = (fb[0] << 4) | (fb[1] >> 4);
> div_frc = (fb[2] << 16) | (fb[3] << 8) | fb[4];
>


--
Best regards,
Marek Vasut