Re: [PATCH 1/7] clk: actions: Fix factor clk struct member access

Andreas Färber
2019-06-10T13:36:50Z

Hi Mani,

Am 08.06.19 um 21:53 schrieb Manivannan Sadhasivam:
> Since the helper "owl_factor_helper_round_rate" is shared between factor
> and composite clocks, using the factor clk specific helper function
> like "hw_to_owl_factor" to access its members will create issues when
> called from composite clk specific code. Hence, pass the "factor_hw"
> struct pointer directly instead of fetching it using factor clk specific
> helpers.
>
> This issue has been observed when a composite clock like "sd0_clk" tried
> to call "owl_factor_helper_round_rate" resulting in pointer dereferencing
> error.
>
> Fixes: 4bb78fc9744a ("clk: actions: Add factor clock support")
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
> drivers/clk/actions/owl-factor.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/clk/actions/owl-factor.c b/drivers/clk/actions/owl-factor.c
> index 317d4a9e112e..f419dfdd334f 100644
> --- a/drivers/clk/actions/owl-factor.c
> +++ b/drivers/clk/actions/owl-factor.c
> @@ -64,11 +64,10 @@ static unsigned int _get_table_val(const struct clk_factor_table *table,
> return val;
> }
>
> -static int clk_val_best(struct clk_hw *hw, unsigned long rate,
> +static int clk_val_best(const struct owl_factor_hw *factor_hw,
> + struct clk_hw *hw, unsigned long rate,
> unsigned long *best_parent_rate)
> {
> - struct owl_factor *factor = hw_to_owl_factor(hw);
> - struct owl_factor_hw *factor_hw = &factor->factor_hw;
> const struct clk_factor_table *clkt = factor_hw->table;
> unsigned long parent_rate, try_parent_rate, best = 0, cur_rate;
> unsigned long parent_rate_saved = *best_parent_rate;
> @@ -126,7 +125,7 @@ long owl_factor_helper_round_rate(struct owl_clk_common *common,
> const struct clk_factor_table *clkt = factor_hw->table;
> unsigned int val, mul = 0, div = 1;
>
> - val = clk_val_best(&common->hw, rate, parent_rate);
> + val = clk_val_best(factor_hw, &common->hw, rate, parent_rate);
> _get_table_div_mul(clkt, val, &mul, &div);
>
> return *parent_rate * mul / div;

While at it, I think it would be a good idea to rename it to
owl_clk_val_best. Pretty confusing that you're touching only owl files
for a clk_ refactoring, which sounds like common clk code.

Regards,
Andreas

--
SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)