On 27.04.2023 17:07, Christian Marangi wrote:
> Some RCG frequency can be reached by multiple configuration.
>
> Add clk_rcg2_fm_ops ops to support these special RCG configurations.
>
> These alternative ops will select the frequency using a CEIL policy.
>
> When the correct frequency is found, the correct config is selected by
> calculating the final rate (by checking the defined parent and values
> in the config that is being checked) and deciding based on the one that
> is less different than the requested one.
>
> These check are skipped if there is just on config for the requested
> freq.
>
> qcom_find_freq_multi is added to search the freq with the new struct
> freq_multi_tbl.
> __clk_rcg2_select_conf is used to select the correct conf by simulating
> the final clock.
>
> Signed-off-by: Christian Marangi <ansuelsmth@xxxxxxxxx>
> ---
> drivers/clk/qcom/clk-rcg.h | 1 +
> drivers/clk/qcom/clk-rcg2.c | 152 ++++++++++++++++++++++++++++++++++++
> drivers/clk/qcom/common.c | 18 +++++
> drivers/clk/qcom/common.h | 2 +
> 4 files changed, 173 insertions(+)
>
> diff --git a/drivers/clk/qcom/clk-rcg.h b/drivers/clk/qcom/clk-rcg.h
> index dc85b46b0d79..f8ec989ed3d9 100644
> --- a/drivers/clk/qcom/clk-rcg.h
> +++ b/drivers/clk/qcom/clk-rcg.h
> @@ -188,6 +188,7 @@ struct clk_rcg2_gfx3d {
>
> extern const struct clk_ops clk_rcg2_ops;
> extern const struct clk_ops clk_rcg2_floor_ops;
> +extern const struct clk_ops clk_rcg2_fm_ops;
> extern const struct clk_ops clk_rcg2_mux_closest_ops;
> extern const struct clk_ops clk_edp_pixel_ops;
> extern const struct clk_ops clk_byte_ops;
> diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
> index 76551534f10d..4f2fe012ef5f 100644
> --- a/drivers/clk/qcom/clk-rcg2.c
> +++ b/drivers/clk/qcom/clk-rcg2.c
> @@ -266,6 +266,104 @@ static int _freq_tbl_determine_rate(struct clk_hw *hw, const struct freq_tbl *f,
> return 0;
> }
>
> +static const struct freq_conf *
> +__clk_rcg2_select_conf(struct clk_hw *hw, const struct freq_multi_tbl *f,
> + unsigned long req_rate)
> +{
> + unsigned long best_rate = 0, parent_rate, rate;
> + const struct freq_conf *conf, *best_conf;
> + struct clk_rcg2 *rcg = to_clk_rcg2(hw);
> + struct clk_hw *p;
> + int index, i;
> +
> + /* Exit early if only one config is defined */
> + if (f->num_confs == 1)
> + return f->confs;
> +
> + /* Search in each provided config the one that is near the wanted rate */
> + for (i = 0, conf = f->confs; i < f->num_confs; i++, conf++) {
> + index = qcom_find_src_index(hw, rcg->parent_map, conf->src);
> + if (index < 0)
> + continue;
> +
> + p = clk_hw_get_parent_by_index(hw, index);
> + if (!p)
> + continue;
> +
> + parent_rate = clk_hw_get_rate(p);
> + rate = calc_rate(parent_rate, conf->n, conf->m, conf->n, conf->pre_div);
> +
> + if (rate == req_rate) {
> + best_conf = conf;
> + break;
> + }
> +
> + if (abs(req_rate - rate) < abs(best_rate - rate)) {
Shouldn't this be:
if (abs(req_rate - rate) < abs(best_rate - req_rate)
?
this way it'd say
"if this iteration's rate is closer to the requested one than the
best one we've found yet, it's better"
> + best_rate = rate;
> + best_conf = conf;
> + }
> + }
> +
> + /*
> + * Very unlikely.
> + * Force the first conf if we can't find a correct config.
> + */
> + if (unlikely(i == f->num_confs))
> + best_conf = f->confs;
Is that a supported scenario or would it be a device driver / clock
driver error?
> +
> + return best_conf;
> +}
> +
> +static int _freq_tbl_fm_determine_rate(struct clk_hw *hw, const struct freq_multi_tbl *f,
> + struct clk_rate_request *req)
> +{
> + unsigned long clk_flags, rate = req->rate;
> + const struct freq_conf *conf;
> + struct clk_hw *p;
> + struct clk_rcg2 *rcg = to_clk_rcg2(hw);
swap lines 2, 3, 4 to 4, 2, 3 and you'll get a revers-Christmas-tree!
Konrad
