Messages in this thread | | | Date | Tue, 21 Nov 2023 12:01:15 +0530 | Subject | Re: [PATCH v6 2/3] clk: qcom: clk-rcg2: add support for rcg2 freq multi ops | From | Devi Priya <> |
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On 11/20/2023 11:44 PM, Christian Marangi wrote: > On Mon, Nov 20, 2023 at 03:51:50PM +0530, Devi Priya wrote: >> >> >> On 9/16/2023 7:30 PM, 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. >>> If a conf can't be found due to parent not reachable, a WARN is printed >>> and -EINVAL is returned. >>> >>> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> >>> --- >>> drivers/clk/qcom/clk-rcg.h | 1 + >>> drivers/clk/qcom/clk-rcg2.c | 167 ++++++++++++++++++++++++++++++++++++ >>> drivers/clk/qcom/common.c | 18 ++++ >>> drivers/clk/qcom/common.h | 2 + >>> 4 files changed, 188 insertions(+) >>> >>> diff --git a/drivers/clk/qcom/clk-rcg.h b/drivers/clk/qcom/clk-rcg.h >>> index c81458db6ce4..dc9a77965e68 100644 >>> --- a/drivers/clk/qcom/clk-rcg.h >>> +++ b/drivers/clk/qcom/clk-rcg.h >>> @@ -190,6 +190,7 @@ 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 e22baf3a7112..617e7ff0f6a3 100644 >>> --- a/drivers/clk/qcom/clk-rcg2.c >>> +++ b/drivers/clk/qcom/clk-rcg2.c >>> @@ -266,6 +266,116 @@ 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 rate_diff, best_rate_diff = ULONG_MAX; >>> + const struct freq_conf *conf, *best_conf; >>> + struct clk_rcg2 *rcg = to_clk_rcg2(hw); >>> + const char *name = clk_hw_get_name(hw); >>> + unsigned long parent_rate, rate; >>> + struct clk_hw *p; >>> + int index, i; >>> + >>> + /* Init best_conf to the first conf */ >>> + best_conf = f->confs; >>> + >>> + /* Exit early if only one config is defined */ >>> + if (f->num_confs == 1) >>> + goto exit; >>> + >>> + /* 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; >>> + goto exit; >>> + } >>> + >>> + rate_diff = abs(req_rate - rate); >>> + if (rate_diff < best_rate_diff) { >>> + best_rate_diff = rate_diff; >>> + best_conf = conf; >>> + } >>> + } >>> + >>> + /* >>> + * Very unlikely. Warn if we couldn't find a correct config >>> + * due to parent not found in every config. >>> + */ >>> + if (unlikely(i == f->num_confs)) { >>> + WARN(1, "%s: can't find a configuration for rate %lu.", >>> + name, req_rate); >>> + return ERR_PTR(-EINVAL); >>> + } >> Hi Christian, >> >> Thanks a lot for the patch! >> We have incorporated these changes along with the corresponding clock driver >> changes & tested it on IPQ9574 & IPQ5332 targets. >> >> When setting the clk rate for the nss port clocks, for the requested >> frequency the correct config gets selected and the >> clk rate is set properly. >> We see the WARN getting printed for other frequencies (rate * i where >> i=2 to maxdiv) that is requested by the clk_hw_round_rate function. >> >> Upon analysis, we see that the for loop in clk_divider_bestdiv iterates >> until the maxdiv value and requests (rate*i) via the clk_hw_round_rate >> API to find the bestdiv and best_parent_rate. For frequencies which are >> multiples of the requested frequency (rate*i where i=2 to maxdiv), it >> seems unlikely to see the WARN being printed. >> >> Can you please help us understand when the WARN is likely to be printed >> & Looking forward to your suggestions on how this WARN could >> be suppressed in the afore mentioned scenario! >> > > Hi, > > thanks a lot for testing this. Maybe was a small oversight by me. > > I attached an alternative patch. Can you test it and tell me if the WARN > is still printed? (the WARN must be printed only when the parent is not > found, I don't think it's your case) > Hi Christian,
WARN does not get printed with the attached patchset. Thanks much!
Regards, Devi Priya
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