OPP: Call dev_pm_opp_set_opp() for required OPPs

Configuring the required OPP was never properly implemented, we just
took an exception for genpds and configured them directly, while leaving
out all other required OPP types.

Now that a standard call to dev_pm_opp_set_opp() takes care of
configuring the opp->level too, the special handling for genpds can be
avoided by simply calling dev_pm_opp_set_opp() for the required OPPs,
which shall eventually configure the corresponding level for genpds.

This also makes it possible for us to configure other type of required
OPPs (no concrete users yet though), via the same path. This is how
other frameworks take care of parent nodes, like clock, regulators, etc,
where we recursively call the same helper.

In order to call dev_pm_opp_set_opp() for the virtual genpd devices,
they must share the OPP table of the genpd. Call _add_opp_dev() for them
to get that done.

This commit also extends the struct dev_pm_opp_config to pass required
devices, for non-genpd cases, which can be used to call
dev_pm_opp_set_opp() for the non-genpd required devices.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

1 files changed, 82 insertions, 86 deletions

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index aeb216f7e978..e08375ed50aa 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1054,48 +1054,22 @@ static int _set_opp_bw(const struct opp_table *opp_table,
 	return 0;
 }
 
-static int _set_performance_state(struct device *dev, struct device *pd_dev,
-				  struct dev_pm_opp *opp, int i)
-{
-	unsigned int pstate = 0;
-	int ret;
-
-	if (!pd_dev)
-		return 0;
-
-	if (likely(opp)) {
-		pstate = opp->required_opps[i]->level;
-		if (pstate == OPP_LEVEL_UNSET)
-			return 0;
-	}
-
-	ret = dev_pm_domain_set_performance_state(pd_dev, pstate);
-	if (ret) {
-		dev_err(dev, "Failed to set performance state of %s: %d (%d)\n",
-			dev_name(pd_dev), pstate, ret);
-	}
-
-	return ret;
-}
-
-static int _opp_set_required_opps_generic(struct device *dev,
-	struct opp_table *opp_table, struct dev_pm_opp *opp, bool scaling_down)
-{
-	dev_err(dev, "setting required-opps isn't supported for non-genpd devices\n");
-	return -ENOENT;
-}
-
-static int _opp_set_required_opps_genpd(struct device *dev,
-	struct opp_table *opp_table, struct dev_pm_opp *opp, bool scaling_down)
+/* This is only called for PM domain for now */
+static int _set_required_opps(struct device *dev, struct opp_table *opp_table,
+			      struct dev_pm_opp *opp, bool up)
 {
-	struct device **genpd_virt_devs = opp_table->genpd_virt_devs;
+	struct device **devs = opp_table->required_devs;
 	int index, target, delta, ret;
 
-	if (!genpd_virt_devs)
+	if (!devs)
 		return 0;
 
+	/* required-opps not fully initialized yet */
+	if (lazy_linking_pending(opp_table))
+		return -EBUSY;
+
 	/* Scaling up? Set required OPPs in normal order, else reverse */
-	if (!scaling_down) {
+	if (up) {
 		index = 0;
 		target = opp_table->required_opp_count;
 		delta = 1;
@@ -1106,9 +1080,11 @@ static int _opp_set_required_opps_genpd(struct device *dev,
 	}
 
 	while (index != target) {
-		ret = _set_performance_state(dev, genpd_virt_devs[index], opp, index);
-		if (ret)
-			return ret;
+		if (devs[index]) {
+			ret = dev_pm_opp_set_opp(devs[index], opp->required_opps[index]);
+			if (ret)
+				return ret;
+		}
 
 		index += delta;
 	}
@@ -1116,34 +1092,6 @@ static int _opp_set_required_opps_genpd(struct device *dev,
 	return 0;
 }
 
-/* This is only called for PM domain for now */
-static int _set_required_opps(struct device *dev, struct opp_table *opp_table,
-			      struct dev_pm_opp *opp, bool up)
-{
-	/* required-opps not fully initialized yet */
-	if (lazy_linking_pending(opp_table))
-		return -EBUSY;
-
-	if (opp_table->set_required_opps)
-		return opp_table->set_required_opps(dev, opp_table, opp, up);
-
-	return 0;
-}
-
-/* Update set_required_opps handler */
-void _update_set_required_opps(struct opp_table *opp_table)
-{
-	/* Already set */
-	if (opp_table->set_required_opps)
-		return;
-
-	/* All required OPPs will belong to genpd or none */
-	if (opp_table->required_opp_tables[0]->is_genpd)
-		opp_table->set_required_opps = _opp_set_required_opps_genpd;
-	else
-		opp_table->set_required_opps = _opp_set_required_opps_generic;
-}
-
 static int _set_opp_level(struct device *dev, struct opp_table *opp_table,
 			  struct dev_pm_opp *opp)
 {
@@ -2406,19 +2354,13 @@ static void _opp_detach_genpd(struct opp_table *opp_table)
 {
 	int index;
 
-	if (!opp_table->genpd_virt_devs)
-		return;
-
 	for (index = 0; index < opp_table->required_opp_count; index++) {
-		if (!opp_table->genpd_virt_devs[index])
+		if (!opp_table->required_devs[index])
 			continue;
 
-		dev_pm_domain_detach(opp_table->genpd_virt_devs[index], false);
-		opp_table->genpd_virt_devs[index] = NULL;
+		dev_pm_domain_detach(opp_table->required_devs[index], false);
+		opp_table->required_devs[index] = NULL;
 	}
-
-	kfree(opp_table->genpd_virt_devs);
-	opp_table->genpd_virt_devs = NULL;
 }
 
 /*
@@ -2445,14 +2387,14 @@ static int _opp_attach_genpd(struct opp_table *opp_table, struct device *dev,
 	int index = 0, ret = -EINVAL;
 	const char * const *name = names;
 
-	if (opp_table->genpd_virt_devs)
-		return 0;
+	if (!opp_table->required_devs) {
+		dev_err(dev, "Required OPPs not available, can't attach genpd\n");
+		return -EINVAL;
+	}
 
-	opp_table->genpd_virt_devs = kcalloc(opp_table->required_opp_count,
-					     sizeof(*opp_table->genpd_virt_devs),
-					     GFP_KERNEL);
-	if (!opp_table->genpd_virt_devs)
-		return -ENOMEM;
+	/* Checking only the first one is enough ? */
+	if (opp_table->required_devs[0])
+		return 0;
 
 	while (*name) {
 		if (index >= opp_table->required_opp_count) {
@@ -2468,13 +2410,25 @@ static int _opp_attach_genpd(struct opp_table *opp_table, struct device *dev,
 			goto err;
 		}
 
-		opp_table->genpd_virt_devs[index] = virt_dev;
+		/*
+		 * Add the virtual genpd device as a user of the OPP table, so
+		 * we can call dev_pm_opp_set_opp() on it directly.
+		 *
+		 * This will be automatically removed when the OPP table is
+		 * removed, don't need to handle that here.
+		 */
+		if (!_add_opp_dev(virt_dev, opp_table->required_opp_tables[index])) {
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		opp_table->required_devs[index] = virt_dev;
 		index++;
 		name++;
 	}
 
 	if (virt_devs)
-		*virt_devs = opp_table->genpd_virt_devs;
+		*virt_devs = opp_table->required_devs;
 
 	return 0;
 
@@ -2484,10 +2438,42 @@ err:
 
 }
 
+static int _opp_set_required_devs(struct opp_table *opp_table,
+				  struct device *dev,
+				  struct device **required_devs)
+{
+	int i;
+
+	if (!opp_table->required_devs) {
+		dev_err(dev, "Required OPPs not available, can't set required devs\n");
+		return -EINVAL;
+	}
+
+	/* Another device that shares the OPP table has set the required devs ? */
+	if (opp_table->required_devs[0])
+		return 0;
+
+	for (i = 0; i < opp_table->required_opp_count; i++)
+		opp_table->required_devs[i] = required_devs[i];
+
+	return 0;
+}
+
+static void _opp_put_required_devs(struct opp_table *opp_table)
+{
+	int i;
+
+	for (i = 0; i < opp_table->required_opp_count; i++)
+		opp_table->required_devs[i] = NULL;
+}
+
 static void _opp_clear_config(struct opp_config_data *data)
 {
-	if (data->flags & OPP_CONFIG_GENPD)
+	if (data->flags & OPP_CONFIG_REQUIRED_DEVS)
+		_opp_put_required_devs(data->opp_table);
+	else if (data->flags & OPP_CONFIG_GENPD)
 		_opp_detach_genpd(data->opp_table);
+
 	if (data->flags & OPP_CONFIG_REGULATOR)
 		_opp_put_regulators(data->opp_table);
 	if (data->flags & OPP_CONFIG_SUPPORTED_HW)
@@ -2601,12 +2587,22 @@ int dev_pm_opp_set_config(struct device *dev, struct dev_pm_opp_config *config)
 
 	/* Attach genpds */
 	if (config->genpd_names) {
+		if (config->required_devs)
+			goto err;
+
 		ret = _opp_attach_genpd(opp_table, dev, config->genpd_names,
 					config->virt_devs);
 		if (ret)
 			goto err;
 
 		data->flags |= OPP_CONFIG_GENPD;
+	} else if (config->required_devs) {
+		ret = _opp_set_required_devs(opp_table, dev,
+					     config->required_devs);
+		if (ret)
+			goto err;
+
+		data->flags |= OPP_CONFIG_REQUIRED_DEVS;
 	}
 
 	ret = xa_alloc(&opp_configs, &id, data, XA_LIMIT(1, INT_MAX),