Commit cdd6ed90 authored by Viresh Kumar's avatar Viresh Kumar
Browse files

OPP: Use a single mechanism to free the OPP table 



Currently there are two separate ways to free the OPP table based on how
it is created in the first place.

We call _dev_pm_opp_remove_table() to free the static and/or dynamic
OPP, OPP list devices, etc. This is done for the case where the OPP
table is added while initializing the OPPs, like via the path
dev_pm_opp_of_add_table().

We also call dev_pm_opp_put_opp_table() in some cases which eventually
frees the OPP table structure once the reference count reaches 0. This
is used by the first case as well as other cases like
dev_pm_opp_set_regulators() where the OPPs aren't necessarily
initialized at this point.

This whole thing is a bit unclear and messy and obstruct any further
cleanup/fixup of OPP core.

This patch tries to streamline this by keeping a single path for OPP
table destruction, i.e. dev_pm_opp_put_opp_table().

All the cleanup happens in _opp_table_kref_release() now after the
reference count reaches 0. _dev_pm_opp_remove_table() is removed as it
isn't required anymore.

We don't drop the reference to the OPP table after creating it from
_of_add_opp_table_v{1|2}() anymore and the same is dropped only when we
try to remove them.

Tested-by: default avatarNiklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
parent 2a4eb735

drivers/opp/core.c

+16 −38
Original line number Diff line number Diff line
@@ -867,23 +867,24 @@ struct opp_table *dev_pm_opp_get_opp_table_indexed(struct device *dev, 
static void _opp_table_kref_release(struct kref *kref)

{

	struct opp_table *opp_table = container_of(kref, struct opp_table, kref);

	struct opp_device *opp_dev;

	struct opp_device *opp_dev, *temp;



	/* Release clk */

	if (!IS_ERR(opp_table->clk))

		clk_put(opp_table->clk);



	WARN_ON(!list_empty(&opp_table->opp_list));



	list_for_each_entry_safe(opp_dev, temp, &opp_table->dev_list, node) {

		/*

	 * No need to take opp_table->lock here as we are guaranteed that no

	 * references to the OPP table are taken at this point.

		 * The OPP table is getting removed, drop the performance state

		 * constraints.

		 */

	opp_dev = list_first_entry(&opp_table->dev_list, struct opp_device,

				   node);

		if (opp_table->genpd_performance_state)

			dev_pm_genpd_set_performance_state((struct device *)(opp_dev->dev), 0);



		_remove_opp_dev(opp_dev, opp_table);



	/* dev_list must be empty now */

	WARN_ON(!list_empty(&opp_table->dev_list));

	}



	mutex_destroy(&opp_table->lock);

	list_del(&opp_table->node);
@@ -1758,33 +1759,6 @@ int dev_pm_opp_unregister_notifier(struct device *dev, 
}

EXPORT_SYMBOL(dev_pm_opp_unregister_notifier);



/*

 * Free OPPs either created using static entries present in DT.

 */

void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev)

{

	/* Protect dev_list */

	mutex_lock(&opp_table->lock);



	/* Find if opp_table manages a single device */

	if (list_is_singular(&opp_table->dev_list)) {

		/* Free static OPPs */

		_put_opp_list_kref(opp_table);



		/*

		 * The OPP table is getting removed, drop the performance state

		 * constraints.

		 */

		if (opp_table->genpd_performance_state)

			dev_pm_genpd_set_performance_state(dev, 0);

	} else {

		_put_opp_list_kref(opp_table);

		_remove_opp_dev(_find_opp_dev(dev, opp_table), opp_table);

	}



	mutex_unlock(&opp_table->lock);

}



void _dev_pm_opp_find_and_remove_table(struct device *dev)

{

	struct opp_table *opp_table;
@@ -1802,8 +1776,12 @@ void _dev_pm_opp_find_and_remove_table(struct device *dev) 
		return;

	}



	_dev_pm_opp_remove_table(opp_table, dev);

	_put_opp_list_kref(opp_table);



	/* Drop reference taken by _find_opp_table() */

	dev_pm_opp_put_opp_table(opp_table);



	/* Drop reference taken while the OPP table was added */

	dev_pm_opp_put_opp_table(opp_table);

}

drivers/opp/of.c

+18 −14
Original line number Diff line number Diff line
@@ -407,14 +407,17 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np, 
	opp_table = _managed_opp(opp_np);

	if (opp_table) {

		/* OPPs are already managed */

		if (!_add_opp_dev(dev, opp_table))

		if (!_add_opp_dev(dev, opp_table)) {

			ret = -ENOMEM;

		else if (!opp_table->parsed_static_opps)

			goto initialize_static_opps;

		else

			goto put_opp_table;

		}



		if (opp_table->parsed_static_opps) {

			kref_get(&opp_table->list_kref);

			return 0;

		}



		goto put_opp_table;

		goto initialize_static_opps;

	}



	opp_table = dev_pm_opp_get_opp_table_indexed(dev, index);
@@ -432,17 +435,15 @@ initialize_static_opps: 
		if (ret) {

			dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,

				ret);

			_dev_pm_opp_remove_table(opp_table, dev);

			of_node_put(np);

			goto put_opp_table;

			goto put_list_kref;

		}

	}



	/* There should be one of more OPP defined */

	if (WARN_ON(!count)) {

		ret = -ENOENT;

		_put_opp_list_kref(opp_table);

		goto put_opp_table;

		goto put_list_kref;

	}



	list_for_each_entry(opp, &opp_table->opp_list, node)
@@ -453,8 +454,7 @@ initialize_static_opps: 
		dev_err(dev, "Not all nodes have performance state set (%d: %d)\n",

			count, pstate_count);

		ret = -ENOENT;

		_dev_pm_opp_remove_table(opp_table, dev);

		goto put_opp_table;

		goto put_list_kref;

	}



	if (pstate_count)
@@ -462,6 +462,10 @@ initialize_static_opps: 


	opp_table->parsed_static_opps = true;



	return 0;



put_list_kref:

	_put_opp_list_kref(opp_table);

put_opp_table:

	dev_pm_opp_put_opp_table(opp_table);
@@ -507,13 +511,13 @@ static int _of_add_opp_table_v1(struct device *dev) 
		if (ret) {

			dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",

				__func__, freq, ret);

			_dev_pm_opp_remove_table(opp_table, dev);

			break;

			_put_opp_list_kref(opp_table);

			dev_pm_opp_put_opp_table(opp_table);

			return ret;

		}

		nr -= 2;

	}



	dev_pm_opp_put_opp_table(opp_table);

	return ret;

}

drivers/opp/opp.h

+1 −1
Original line number Diff line number Diff line
@@ -190,11 +190,11 @@ struct opp_table { 


/* Routines internal to opp core */

void dev_pm_opp_get(struct dev_pm_opp *opp);

void _opp_remove_all_static(struct opp_table *opp_table);

void _get_opp_table_kref(struct opp_table *opp_table);

int _get_opp_count(struct opp_table *opp_table);

struct opp_table *_find_opp_table(struct device *dev);

struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_table);

void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev);

void _dev_pm_opp_find_and_remove_table(struct device *dev);

struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table);

void _opp_free(struct dev_pm_opp *opp);

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