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authorViresh Kumar <viresh.kumar@linaro.org>2018-11-02 12:10:19 +0300
committerViresh Kumar <viresh.kumar@linaro.org>2018-12-14 13:58:18 +0300
commit18edf49c45544cfb93002b3b31fe8fc7fc14d95c (patch)
treec1c9a9e3ebd03fb7185540598adc9d80aba197e8 /drivers/base
parentcd50c6d3eb91bdff9ac37ee645c49ae274385d35 (diff)
downloadlinux-18edf49c45544cfb93002b3b31fe8fc7fc14d95c.tar.xz
PM / Domains: Propagate performance state updates
Currently a genpd only handles the performance state requirements from the devices under its control. This commit extends that to also handle the performance state requirement(s) put on the master genpd by its sub-domains. There is a separate value required for each master that the genpd has and so a new field is added to the struct gpd_link (link->performance_state), which represents the link between a genpd and its master. The struct gpd_link also got another field prev_performance_state, which is used by genpd core as a temporary variable during transitions. On a call to dev_pm_genpd_set_performance_state(), the genpd core first updates the performance state of the masters of the device's genpd and then updates the performance state of the genpd. The masters do the same and propagate performance state updates to their masters before updating their own. The performance state transition from genpd to its master is done with the help of dev_pm_opp_xlate_performance_state(), which looks at the OPP tables of both the domains to translate the state. Tested-by: Rajendra Nayak <rnayak@codeaurora.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/power/domain.c93
1 files changed, 82 insertions, 11 deletions
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 808ba41b6580..611c0ccbad5f 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -244,6 +244,7 @@ static int _genpd_reeval_performance_state(struct generic_pm_domain *genpd,
{
struct generic_pm_domain_data *pd_data;
struct pm_domain_data *pdd;
+ struct gpd_link *link;
/* New requested state is same as Max requested state */
if (state == genpd->performance_state)
@@ -262,31 +263,101 @@ static int _genpd_reeval_performance_state(struct generic_pm_domain *genpd,
}
/*
- * We aren't propagating performance state changes of a subdomain to its
- * masters as we don't have hardware that needs it. Over that, the
- * performance states of subdomain and its masters may not have
- * one-to-one mapping and would require additional information. We can
- * get back to this once we have hardware that needs it. For that
- * reason, we don't have to consider performance state of the subdomains
- * of genpd here.
+ * Traverse all sub-domains within the domain. This can be
+ * done without any additional locking as the link->performance_state
+ * field is protected by the master genpd->lock, which is already taken.
+ *
+ * Also note that link->performance_state (subdomain's performance state
+ * requirement to master domain) is different from
+ * link->slave->performance_state (current performance state requirement
+ * of the devices/sub-domains of the subdomain) and so can have a
+ * different value.
+ *
+ * Note that we also take vote from powered-off sub-domains into account
+ * as the same is done for devices right now.
*/
+ list_for_each_entry(link, &genpd->master_links, master_node) {
+ if (link->performance_state > state)
+ state = link->performance_state;
+ }
+
return state;
}
static int _genpd_set_performance_state(struct generic_pm_domain *genpd,
- unsigned int state)
+ unsigned int state, int depth)
{
- int ret;
+ struct generic_pm_domain *master;
+ struct gpd_link *link;
+ int master_state, ret;
if (state == genpd->performance_state)
return 0;
+ /* Propagate to masters of genpd */
+ list_for_each_entry(link, &genpd->slave_links, slave_node) {
+ master = link->master;
+
+ if (!master->set_performance_state)
+ continue;
+
+ /* Find master's performance state */
+ ret = dev_pm_opp_xlate_performance_state(genpd->opp_table,
+ master->opp_table,
+ state);
+ if (unlikely(ret < 0))
+ goto err;
+
+ master_state = ret;
+
+ genpd_lock_nested(master, depth + 1);
+
+ link->prev_performance_state = link->performance_state;
+ link->performance_state = master_state;
+ master_state = _genpd_reeval_performance_state(master,
+ master_state);
+ ret = _genpd_set_performance_state(master, master_state, depth + 1);
+ if (ret)
+ link->performance_state = link->prev_performance_state;
+
+ genpd_unlock(master);
+
+ if (ret)
+ goto err;
+ }
+
ret = genpd->set_performance_state(genpd, state);
if (ret)
- return ret;
+ goto err;
genpd->performance_state = state;
return 0;
+
+err:
+ /* Encountered an error, lets rollback */
+ list_for_each_entry_continue_reverse(link, &genpd->slave_links,
+ slave_node) {
+ master = link->master;
+
+ if (!master->set_performance_state)
+ continue;
+
+ genpd_lock_nested(master, depth + 1);
+
+ master_state = link->prev_performance_state;
+ link->performance_state = master_state;
+
+ master_state = _genpd_reeval_performance_state(master,
+ master_state);
+ if (_genpd_set_performance_state(master, master_state, depth + 1)) {
+ pr_err("%s: Failed to roll back to %d performance state\n",
+ master->name, master_state);
+ }
+
+ genpd_unlock(master);
+ }
+
+ return ret;
}
/**
@@ -331,7 +402,7 @@ int dev_pm_genpd_set_performance_state(struct device *dev, unsigned int state)
gpd_data->performance_state = state;
state = _genpd_reeval_performance_state(genpd, state);
- ret = _genpd_set_performance_state(genpd, state);
+ ret = _genpd_set_performance_state(genpd, state, 0);
if (ret)
gpd_data->performance_state = prev;