Viresh Kumar viresh.kumar@linaro.org writes:
Some platforms have the capability to configure the performance state of their Power Domains. The performance levels are represented by positive integer values, a lower value represents lower performance state.
This patch registers the power domain framework for PM QOS performance notifier in order to manage performance state of power domains.
It seems to me it doesm't just register, but actually keeps track of the performance_state by always tracking the max.
This also allows the power domain drivers to implement a ->set_performance_state() callback, which will be called by the power domain core from the notifier routine.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
drivers/base/power/domain.c | 98 ++++++++++++++++++++++++++++++++++++++++++++- include/linux/pm_domain.h | 5 +++ 2 files changed, 101 insertions(+), 2 deletions(-)
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index a73d79670a64..1158a07f92de 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -367,6 +367,88 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb, return NOTIFY_DONE; } +static void update_domain_performance_state(struct generic_pm_domain *genpd,
int depth)+{
- struct generic_pm_domain_data *pd_data;
- struct generic_pm_domain *subdomain;
- struct pm_domain_data *pdd;
- unsigned int state = 0;
- struct gpd_link *link;
- /* Traverse all devices within the domain */
- list_for_each_entry(pdd, &genpd->dev_list, list_node) {
pd_data = to_gpd_data(pdd);if (pd_data->performance_state > state)state = pd_data->performance_state;- }
This seems to only update the state if it's bigger. Maybe I'm missing something here, but it seems like won't be able to lower the performance_state after it's been raised?
- /* Traverse all subdomains within the domain */
- list_for_each_entry(link, &genpd->master_links, master_node) {
subdomain = link->slave;if (subdomain->performance_state > state)state = subdomain->performance_state;- }
So subdomains are always assumed to influence the performance_state of the parent domains? Is that always the case? I suspect this should be probably be a reasonable default assumption, but maybe controlled with a flag.
- if (genpd->performance_state == state)
return;- genpd->performance_state = state;
- if (genpd->set_performance_state) {
genpd->set_performance_state(genpd, state);return;- }
So is zero not a valid performance_state? That doesn't seem quite right to me, but either way, it should be documented.
- /* Propagate only if this domain has a single parent */
Why? This limitation should be explained in the cover letter and changelog. I would also expect some sort of WARN here since this could otherwise be a rather silent failures.
[...]
Kevin