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OPP: Use a single mechanism to free the OPP table

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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: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
This commit is contained in:
Viresh Kumar 2018-09-12 12:35:19 +05:30
parent 2a4eb7358a
commit cdd6ed90cd
3 changed files with 36 additions and 54 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

54
drivers/opp/core.c
View file

@ -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);
/*
* No need to take opp_table->lock here as we are guaranteed that no
* references to the OPP table are taken at this point.
*/
opp_dev = list_first_entry(&opp_table->dev_list, struct opp_device,
node);
WARN_ON(!list_empty(&opp_table->opp_list));
_remove_opp_dev(opp_dev, opp_table);
list_for_each_entry_safe(opp_dev, temp, &opp_table->dev_list, node) {
/*
* The OPP table is getting removed, drop the performance state
* constraints.
*/
if (opp_table->genpd_performance_state)
dev_pm_genpd_set_performance_state((struct device *)(opp_dev->dev), 0);
/* dev_list must be empty now */
WARN_ON(!list_empty(&opp_table->dev_list));
_remove_opp_dev(opp_dev, opp_table);
}
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);
}

34
drivers/opp/of.c
View file

@ -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
kref_get(&opp_table->list_kref);
goto put_opp_table;
}
goto put_opp_table;
if (opp_table->parsed_static_opps) {
kref_get(&opp_table->list_kref);
return 0;
}
goto initialize_static_opps;
}
opp_table = dev_pm_opp_get_opp_table_indexed(dev, index);
@ -432,17 +435,15 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np,
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 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np,
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 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np,
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;
}

2
drivers/opp/opp.h
View file

@ -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);