[PATCH 1/2] OPP: Use _set_opp_level() for single genpd case

Viresh Kumar
2023-10-19T10:22:18Z

There are two genpd (as required-opp) cases that we need to handle,
devices with a single genpd and ones with multiple genpds.

The multiple genpds case is clear, where the OPP core calls
dev_pm_domain_attach_by_name() for them and uses the virtual devices
returned by this helper to call dev_pm_domain_set_performance_state()
later to change the performance state.

The single genpd case however requires special handling as we need to
use the same `dev` structure (instead of a virtual one provided by genpd
core) for setting the performance state via
dev_pm_domain_set_performance_state().

As we move towards more generic code to take care of the required OPPs,
where we will recursively call dev_pm_opp_set_opp() for all the required
OPPs, the above special case becomes a problem.

Eventually we want to handle all performance state changes via
_set_opp_level(), so lets move the single genpd case to that right away.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/opp/core.c | 6 ++++--
drivers/opp/of.c | 25 ++++++++++++++++++++++---
2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 84f345c69ea5..aab8c8e79146 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1074,10 +1074,12 @@ static int _opp_set_required_opps_generic(struct device *dev,
static int _opp_set_required_opps_genpd(struct device *dev,
struct opp_table *opp_table, struct dev_pm_opp *opp, bool scaling_down)
{
- struct device **genpd_virt_devs =
- opp_table->genpd_virt_devs ? opp_table->genpd_virt_devs : &dev;
+ struct device **genpd_virt_devs = opp_table->genpd_virt_devs;
int index, target, delta, ret;

+ if (!genpd_virt_devs)
+ return 0;
+
/* Scaling up? Set required OPPs in normal order, else reverse */
if (!scaling_down) {
index = 0;
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 81fa27599d58..e056f31a48b5 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -296,7 +296,7 @@ void _of_clear_opp(struct opp_table *opp_table, struct dev_pm_opp *opp)
of_node_put(opp->np);
}

-static int _link_required_opps(struct dev_pm_opp *opp,
+static int _link_required_opps(struct dev_pm_opp *opp, struct opp_table *opp_table,
struct opp_table *required_table, int index)
{
struct device_node *np;
@@ -314,6 +314,25 @@ static int _link_required_opps(struct dev_pm_opp *opp,
return -ENODEV;
}

+ /*
+ * There are two genpd (as required-opp) cases that we need to handle,
+ * devices with a single genpd and ones with multiple genpds.
+ *
+ * The single genpd case requires special handling as we need to use the
+ * same `dev` structure (instead of a virtual one provided by genpd
+ * core) for setting the performance state. Lets treat this as a case
+ * where the OPP's level is directly available without required genpd
+ * link in the DT.
+ *
+ * Just update the `level` with the right value, which
+ * dev_pm_opp_set_opp() will take care of in the normal path itself.
+ */
+ if (required_table->is_genpd && opp_table->required_opp_count == 1 &&
+ !opp_table->genpd_virt_devs) {
+ if (!WARN_ON(opp->level))
+ opp->level = opp->required_opps[0]->level;
+ }
+
return 0;
}

@@ -338,7 +357,7 @@ static int _of_opp_alloc_required_opps(struct opp_table *opp_table,
if (IS_ERR_OR_NULL(required_table))
continue;

- ret = _link_required_opps(opp, required_table, i);
+ ret = _link_required_opps(opp, opp_table, required_table, i);
if (ret)
goto free_required_opps;
}
@@ -359,7 +378,7 @@ static int lazy_link_required_opps(struct opp_table *opp_table,
int ret;

list_for_each_entry(opp, &opp_table->opp_list, node) {
- ret = _link_required_opps(opp, new_table, index);
+ ret = _link_required_opps(opp, opp_table, new_table, index);
if (ret)
return ret;
}
--
2.31.1.272.g89b43f80a514