static HLIST_HEAD(clk_orphan_list);
static LIST_HEAD(clk_notifier_list);
+/* List of registered clks that use runtime PM */
+static HLIST_HEAD(clk_rpm_list);
+static DEFINE_MUTEX(clk_rpm_list_lock);
+
static const struct hlist_head *all_lists[] = {
&clk_root_list,
&clk_orphan_list,
struct clk_hw *hw;
struct module *owner;
struct device *dev;
+ struct hlist_node rpm_node;
struct device_node *of_node;
struct clk_core *parent;
struct clk_parent_map *parents;
pm_runtime_put_sync(core->dev);
}
+/**
+ * clk_pm_runtime_get_all() - Runtime "get" all clk provider devices
+ *
+ * Call clk_pm_runtime_get() on all runtime PM enabled clks in the clk tree so
+ * that disabling unused clks avoids a deadlock where a device is runtime PM
+ * resuming/suspending and the runtime PM callback is trying to grab the
+ * prepare_lock for something like clk_prepare_enable() while
+ * clk_disable_unused_subtree() holds the prepare_lock and is trying to runtime
+ * PM resume/suspend the device as well.
+ *
+ * Context: Acquires the 'clk_rpm_list_lock' and returns with the lock held on
+ * success. Otherwise the lock is released on failure.
+ *
+ * Return: 0 on success, negative errno otherwise.
+ */
+static int clk_pm_runtime_get_all(void)
+{
+ int ret;
+ struct clk_core *core, *failed;
+
+ /*
+ * Grab the list lock to prevent any new clks from being registered
+ * or unregistered until clk_pm_runtime_put_all().
+ */
+ mutex_lock(&clk_rpm_list_lock);
+
+ /*
+ * Runtime PM "get" all the devices that are needed for the clks
+ * currently registered. Do this without holding the prepare_lock, to
+ * avoid the deadlock.
+ */
+ hlist_for_each_entry(core, &clk_rpm_list, rpm_node) {
+ ret = clk_pm_runtime_get(core);
+ if (ret) {
+ failed = core;
+ pr_err("clk: Failed to runtime PM get '%s' for clk '%s'\n",
+ dev_name(failed->dev), failed->name);
+ goto err;
+ }
+ }
+
+ return 0;
+
+err:
+ hlist_for_each_entry(core, &clk_rpm_list, rpm_node) {
+ if (core == failed)
+ break;
+
+ clk_pm_runtime_put(core);
+ }
+ mutex_unlock(&clk_rpm_list_lock);
+
+ return ret;
+}
+
+/**
+ * clk_pm_runtime_put_all() - Runtime "put" all clk provider devices
+ *
+ * Put the runtime PM references taken in clk_pm_runtime_get_all() and release
+ * the 'clk_rpm_list_lock'.
+ */
+static void clk_pm_runtime_put_all(void)
+{
+ struct clk_core *core;
+
+ hlist_for_each_entry(core, &clk_rpm_list, rpm_node)
+ clk_pm_runtime_put(core);
+ mutex_unlock(&clk_rpm_list_lock);
+}
+
+static void clk_pm_runtime_init(struct clk_core *core)
+{
+ struct device *dev = core->dev;
+
+ if (dev && pm_runtime_enabled(dev)) {
+ core->rpm_enabled = true;
+
+ mutex_lock(&clk_rpm_list_lock);
+ hlist_add_head(&core->rpm_node, &clk_rpm_list);
+ mutex_unlock(&clk_rpm_list_lock);
+ }
+}
+
/*** locking ***/
static void clk_prepare_lock(void)
{
if (core->flags & CLK_IGNORE_UNUSED)
return;
- if (clk_pm_runtime_get(core))
- return;
-
if (clk_core_is_prepared(core)) {
trace_clk_unprepare(core);
if (core->ops->unprepare_unused)
core->ops->unprepare(core->hw);
trace_clk_unprepare_complete(core);
}
-
- clk_pm_runtime_put(core);
}
static void __init clk_disable_unused_subtree(struct clk_core *core)
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_prepare_enable(core->parent);
- if (clk_pm_runtime_get(core))
- goto unprepare_out;
-
flags = clk_enable_lock();
if (core->enable_count)
unlock_out:
clk_enable_unlock(flags);
- clk_pm_runtime_put(core);
-unprepare_out:
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_disable_unprepare(core->parent);
}
static int __init clk_disable_unused(void)
{
struct clk_core *core;
+ int ret;
if (clk_ignore_unused) {
pr_warn("clk: Not disabling unused clocks\n");
pr_info("clk: Disabling unused clocks\n");
+ ret = clk_pm_runtime_get_all();
+ if (ret)
+ return ret;
+ /*
+ * Grab the prepare lock to keep the clk topology stable while iterating
+ * over clks.
+ */
clk_prepare_lock();
hlist_for_each_entry(core, &clk_root_list, child_node)
clk_prepare_unlock();
+ clk_pm_runtime_put_all();
+
return 0;
}
late_initcall_sync(clk_disable_unused);
{
struct clk_core *core = container_of(ref, struct clk_core, ref);
+ if (core->rpm_enabled) {
+ mutex_lock(&clk_rpm_list_lock);
+ hlist_del(&core->rpm_node);
+ mutex_unlock(&clk_rpm_list_lock);
+ }
+
clk_core_free_parent_map(core);
kfree_const(core->name);
kfree(core);
}
core->ops = init->ops;
- if (dev && pm_runtime_enabled(dev))
- core->rpm_enabled = true;
core->dev = dev;
+ clk_pm_runtime_init(core);
core->of_node = np;
if (dev && dev->driver)
core->owner = dev->driver->owner;