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SubjectRe: [PATCH v3 1/2] PM / Domains: Add support for 'required-opps' to set default perf state
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On 7/16/2021 10:43 AM, Rajendra Nayak wrote:
> Some devics within power domains with performance states do not
> support DVFS, but still need to vote on a default/static state
> while they are active. They can express this using the 'required-opps'
> property in device tree, which points to the phandle of the OPP
> supported by the corresponding power-domains.
>
> Add support to parse this information from DT and then set the
> specified performance state during attach and drop it on detach.
> Also drop/set as part of runtime suspend/resume callbacks.
>
> Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
> ---
> drivers/base/power/domain.c | 29 ++++++++++++++++++++++++++++-
> include/linux/pm_domain.h | 1 +
> 2 files changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index a934c67..eef5507 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -917,6 +917,10 @@ static int genpd_runtime_suspend(struct device *dev)
> if (irq_safe_dev_in_no_sleep_domain(dev, genpd))
> return 0;
>
> + /* Drop the default performance state */
> + if (dev_gpd_data(dev)->default_pstate)
> + dev_pm_genpd_set_performance_state(dev, 0);
> +
> genpd_lock(genpd);
> gpd_data->rpm_pstate = genpd_drop_performance_state(dev);
> genpd_power_off(genpd, true, 0);
> @@ -937,6 +941,7 @@ static int genpd_runtime_resume(struct device *dev)
> {
> struct generic_pm_domain *genpd;
> struct generic_pm_domain_data *gpd_data = dev_gpd_data(dev);
> + unsigned int default_pstate = gpd_data->default_pstate;
> struct gpd_timing_data *td = &gpd_data->td;
> bool runtime_pm = pm_runtime_enabled(dev);
> ktime_t time_start;
> @@ -968,6 +973,9 @@ static int genpd_runtime_resume(struct device *dev)
> if (ret)
> return ret;
>
> + /* Set the default performance state */
> + if (default_pstate)
> + dev_pm_genpd_set_performance_state(dev, default_pstate);
> out:
> /* Measure resume latency. */
> time_start = 0;
> @@ -1000,6 +1008,8 @@ static int genpd_runtime_resume(struct device *dev)
> genpd_stop_dev(genpd, dev);
> err_poweroff:
> if (!pm_runtime_is_irq_safe(dev) || genpd_is_irq_safe(genpd)) {
> + if (default_pstate)
> + dev_pm_genpd_set_performance_state(dev, 0);
> genpd_lock(genpd);
> gpd_data->rpm_pstate = genpd_drop_performance_state(dev);
> genpd_power_off(genpd, true, 0);
> @@ -2598,6 +2608,12 @@ static void genpd_dev_pm_detach(struct device *dev, bool power_off)
>
> dev_dbg(dev, "removing from PM domain %s\n", pd->name);
>
> + /* Drop the default performance state */
> + if (dev_gpd_data(dev)->default_pstate) {
> + dev_pm_genpd_set_performance_state(dev, 0);
> + dev_gpd_data(dev)->default_pstate = 0;
> + }
> +
> for (i = 1; i < GENPD_RETRY_MAX_MS; i <<= 1) {
> ret = genpd_remove_device(pd, dev);
> if (ret != -EAGAIN)
> @@ -2635,9 +2651,10 @@ static void genpd_dev_pm_sync(struct device *dev)
> static int __genpd_dev_pm_attach(struct device *dev, struct device *base_dev,
> unsigned int index, bool power_on)
> {
> + struct device_node *np;
> struct of_phandle_args pd_args;
> struct generic_pm_domain *pd;
> - int ret;
> + int ret, pstate;
>
> ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
> "#power-domain-cells", index, &pd_args);
> @@ -2678,6 +2695,16 @@ static int __genpd_dev_pm_attach(struct device *dev, struct device *base_dev,
> if (ret)
> genpd_remove_device(pd, dev);
>
> + /* Set the default performance state */
> + np = base_dev->of_node;
> + if (of_parse_phandle(np, "required-opps", index)) {
> + pstate = of_get_required_opp_performance_state(np, index);
> + if (pstate > 0) {
> + dev_pm_genpd_set_performance_state(dev, pstate);
> + dev_gpd_data(dev)->default_pstate = pstate;
> + }
> + }

I realized this needs better error handling after I sent it out,
I'll fix and respin.

> +
> return ret ? -EPROBE_DEFER : 1;
> }
>
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 21a0577..67017c9 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -198,6 +198,7 @@ struct generic_pm_domain_data {
> struct notifier_block *power_nb;
> int cpu;
> unsigned int performance_state;
> + unsigned int default_pstate;
> unsigned int rpm_pstate;
> ktime_t next_wakeup;
> void *data;
>

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