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SubjectRe: [PATCH v4 1/2] PM / Domains: Add support for 'required-opps' to set default perf state
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On 7/17/2021 1:49 AM, Stephen Boyd wrote:
> Quoting Rajendra Nayak (2021-07-16 03:00:57)
>> Some devics within power domains with performance states do not
>
> devices
>
>> 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 | 37 ++++++++++++++++++++++++++++++++++---
>> include/linux/pm_domain.h | 1 +
>> 2 files changed, 35 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index a934c67..dcc0b71 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -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);
>
> Maybe this should be
>
> prev_state = genpd_drop_performance_state(dev);
> if (!default_pstate)
> gdp_data->rpm_pstate = prev_state;
>
> so we don't call dev_pm_genpd_set_performance_state() effectively twice?
> Also it would make sure we call dev_pm_genpd_set_performance_state()
> underneath the genpd_lock() if that is important. Similarly do that on
> suspend path.

looking through this more, I think I can completely drop any special
handling for default_pstate in runtime suspend and resume. The existing
drop/restore login Ulf has added should take care of it.
I'll test and respin soon.

>
>> 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)
>> @@ -2675,10 +2692,24 @@ static int __genpd_dev_pm_attach(struct device *dev, struct device *base_dev,
>> genpd_unlock(pd);
>> }
>>
>> - if (ret)
>> + if (ret) {
>> genpd_remove_device(pd, dev);
>> + return -EPROBE_DEFER;
>> + }
>> +
>> + /* 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_err(dev, "failed to set pstate:%d", pstate);
>
> Missing newline on printk. Also can we spell out pstate as "failed to
> set required performance state %d for power-domain %d"?

thanks, will fix when I respin.
Thanks for the review.

>
>> + ret = pstate;
>> + }
>> + dev_pm_genpd_set_performance_state(dev, pstate);
>> + dev_gpd_data(dev)->default_pstate = pstate;
>> + }
>>
>> - return ret ? -EPROBE_DEFER : 1;
>> + return ret ? ret : 1;
>> }
>>
>> /**

--
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