lkml.org 
[lkml]   [2021]   [Aug]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v5 1/2] PM / Domains: Add support for 'required-opps' to set default perf state
From
Date

On 8/2/2021 6:29 PM, Ulf Hansson wrote:
> On Tue, 20 Jul 2021 at 09:12, Rajendra Nayak <rnayak@codeaurora.org> wrote:
>>
>> Some devices 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.
>> runtime suspend/resume callbacks already have logic to drop/set
>> the vote as needed and should take care of dropping the default
>> perf state vote on runtime suspend and restore it back on runtime
>> resume.
>>
>> Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
>> ---
>> drivers/base/power/domain.c | 28 +++++++++++++++++++++++++---
>> include/linux/pm_domain.h | 1 +
>> 2 files changed, 26 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index a934c67..f454031 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -2598,6 +2598,12 @@ 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 +2641,10 @@ 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);
>> @@ -2675,10 +2682,25 @@ 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;
>
> Please use dev->of_node instead (it is set to the same of_node as
> base_dev by the callers of __genpd_dev_pm_attach) as it's more
> consistent with existing code.
>
>> + if (of_parse_phandle(np, "required-opps", index)) {
>> + pstate = of_get_required_opp_performance_state(np, index);
>> + if (pstate < 0) {
>> + ret = pstate;
>> + dev_err(dev, "failed to set required performance state for power-domain %s: %d\n",
>> + pd->name, ret);
>> + }
>> + dev_pm_genpd_set_performance_state(dev, pstate);
>> + dev_gpd_data(dev)->default_pstate = pstate;
>
> This doesn't look entirely correct to me. If we fail to translate a
> required opp to a performance state, we shouldn't try to set it.

yeah, that does not seem right at all :(

> Perhaps it's also easier to call
> of_get_required_opp_performance_state() unconditionally of whether a
> "required-opps" specifier exists. If it fails with the translation,
> then we just skip setting a default state and continue with returning
> 1.
>
> Would that work?

I think it should, I'll redo the error handling, hopefully right this time,
and re-post. Thanks for the review.

>
>> + }
>>
>> - return ret ? -EPROBE_DEFER : 1;
>> + return ret ? ret : 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;
>> --
>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
>> of Code Aurora Forum, hosted by The Linux Foundation
>>
>
> Kind regards
> Uffe
>

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

\
 
 \ /
  Last update: 2021-08-03 06:39    [W:2.280 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site