On 7/17/2021 1:49 AM, Stephen Boyd wrote:

Quoting Rajendra Nayak (2021-07-16 03:00:57)

quoted

Some devics within power domains with performance states do not

devices

quoted

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 <redacted>
---
  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.

quoted

                 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.

quoted

+                       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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