| Message ID | 20230526-topic-opp_bw-v1-1-e881091363af@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | opp: Provide a function for just setting bandwidth | expand |
On 26-05-23, 12:59, Konrad Dybcio wrote: > There are some users which have tight power sequencing requirements, > like the Qualcomm Adreno GPU. > > Dropping the entire OPP kills clocks, bw and required-opps at once, > but on certain Adrenos we need something like: > > > disable memory clock (clk) > disable all other clocks, including the opp-managed core clock (clk_bulk) > kill one, fully manually controlled genpd (manual runtime pm) > remove bus vote (func proposed in this patch) > kill another genpd (manual runtime pm) > kill the opp-managed genpd (automatic pm calls) > > Changing the order kills the chip until you reboot the whole board and > setting freq=0 using dev_pm_opp_set_rate doesn't drop the bw vote. I am a bit confused now. What's the exact problem with dev_pm_opp_set_rate(dev, 0) ? It does set the bandwidth too, from what I can see.
On 29.05.2023 06:58, Viresh Kumar wrote: > On 26-05-23, 12:59, Konrad Dybcio wrote: >> There are some users which have tight power sequencing requirements, >> like the Qualcomm Adreno GPU. >> >> Dropping the entire OPP kills clocks, bw and required-opps at once, >> but on certain Adrenos we need something like: >> >> >> disable memory clock (clk) >> disable all other clocks, including the opp-managed core clock (clk_bulk) >> kill one, fully manually controlled genpd (manual runtime pm) >> remove bus vote (func proposed in this patch) >> kill another genpd (manual runtime pm) >> kill the opp-managed genpd (automatic pm calls) >> >> Changing the order kills the chip until you reboot the whole board and >> setting freq=0 using dev_pm_opp_set_rate doesn't drop the bw vote. > > I am a bit confused now. > > What's the exact problem with dev_pm_opp_set_rate(dev, 0) ? It does set the > bandwidth too, from what I can see. I think I didn't state my intentions correctly.. The proposed function would set *just* the bandwidth through OPP, so it'd be essentially equal to loop over num_paths { icc_get(...) icc_set(...) icc_put(...) } but since OPP already picked up these interconnect paths, it makes little sense to mess with them through raw APIs. Konrad >
Hi Konrad, On 26.05.23 12:17, Konrad Dybcio wrote: > Currently it's not possible to set just the bandwidth if the OPP > describes other properties (required-opps, opp-hz etc.). > > Introduce dev_pm_opp_set_bw() to solve this problem. > Who is going to use this? BR, Georgi
On 29.05.2023 12:38, Georgi Djakov wrote: > Hi Konrad, > > On 26.05.23 12:17, Konrad Dybcio wrote: >> Currently it's not possible to set just the bandwidth if the OPP >> describes other properties (required-opps, opp-hz etc.). >> >> Introduce dev_pm_opp_set_bw() to solve this problem. >> > > Who is going to use this? I wanted to use it with Adreno for fine-grained control during system suspend/resume. It turned out that I was essentially then trying to power on the hardware without its power supply. https://lore.kernel.org/linux-kernel/8b7f4b22-76e2-e812-92ed-35e5ecdd6309@kernel.org/T/#t Konrad > > BR, > Georgi >
diff --git a/drivers/opp/core.c b/drivers/opp/core.c index 85cbc8de407c..00d7f7c20189 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -1278,6 +1278,34 @@ int dev_pm_opp_set_opp(struct device *dev, struct dev_pm_opp *opp) } EXPORT_SYMBOL_GPL(dev_pm_opp_set_opp); +/** + * dev_pm_opp_set_bw() - Configure device's interconnect bandwidth from OPP + * @dev: device for which we do this operation + * @opp: OPP to get the bandwidth data from + * + * This configures the interconnect bandwidth based on the properties of the + * OPP passed to this routine. + * + * Return: 0 on success, a negative error number otherwise. + */ +int dev_pm_opp_set_bw(struct device *dev, struct dev_pm_opp *opp) +{ + struct opp_table *opp_table; + int ret; + + opp_table = _find_opp_table(dev); + if (IS_ERR(opp_table)) { + dev_err(dev, "%s: device opp doesn't exist\n", __func__); + return PTR_ERR(opp_table); + } + + ret = _set_opp_bw(opp_table, opp, dev); + dev_pm_opp_put_opp_table(opp_table); + + return ret; +} +EXPORT_SYMBOL_GPL(dev_pm_opp_set_bw); + /* OPP-dev Helpers */ static void _remove_opp_dev(struct opp_device *opp_dev, struct opp_table *opp_table) diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h index dc1fb5890792..5e074ac7a68e 100644 --- a/include/linux/pm_opp.h +++ b/include/linux/pm_opp.h @@ -167,6 +167,7 @@ struct dev_pm_opp *dev_pm_opp_xlate_required_opp(struct opp_table *src_table, st int dev_pm_opp_xlate_performance_state(struct opp_table *src_table, struct opp_table *dst_table, unsigned int pstate); int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq); int dev_pm_opp_set_opp(struct device *dev, struct dev_pm_opp *opp); +int dev_pm_opp_set_bw(struct device *dev, struct dev_pm_opp *opp); int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, const struct cpumask *cpumask); int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask); void dev_pm_opp_remove_table(struct device *dev); @@ -373,6 +374,11 @@ static inline int dev_pm_opp_set_opp(struct device *dev, struct dev_pm_opp *opp) return -EOPNOTSUPP; } +static inline int dev_pm_opp_set_bw(struct device *dev, struct dev_pm_opp *opp) +{ + return -EOPNOTSUPP; +} + static inline int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, const struct cpumask *cpumask) { return -EOPNOTSUPP;
Currently it's not possible to set just the bandwidth if the OPP describes other properties (required-opps, opp-hz etc.). Introduce dev_pm_opp_set_bw() to solve this problem. Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org> --- drivers/opp/core.c | 28 ++++++++++++++++++++++++++++ include/linux/pm_opp.h | 6 ++++++ 2 files changed, 34 insertions(+) --- base-commit: 6a3d37b4d885129561e1cef361216f00472f7d2e change-id: 20230526-topic-opp_bw-8d04a85a93a8 Best regards,