summaryrefslogtreecommitdiffstats
path: root/drivers/clk/clk.c
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-08 17:45:37 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-08 17:45:37 +0000
commit1c134c659904809d1ca3baf2bb295ca1c7107aee (patch)
treec55c18153612f7df8e54d15aa52db97552d7eb78 /drivers/clk/clk.c
parentReleasing progress-linux version 5.10.209-2progress6u1. (diff)
downloadlinux-1c134c659904809d1ca3baf2bb295ca1c7107aee.tar.xz
linux-1c134c659904809d1ca3baf2bb295ca1c7107aee.zip
Merging upstream version 5.10.216.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/clk/clk.c')
-rw-r--r--drivers/clk/clk.c157
1 files changed, 125 insertions, 32 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 62572d59e..a0927c7f8 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -37,7 +37,11 @@ static HLIST_HEAD(clk_root_list);
static HLIST_HEAD(clk_orphan_list);
static LIST_HEAD(clk_notifier_list);
-static struct hlist_head *all_lists[] = {
+/* 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,
NULL,
@@ -59,6 +63,7 @@ struct clk_core {
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;
@@ -129,6 +134,89 @@ static void clk_pm_runtime_put(struct clk_core *core)
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)
{
@@ -425,6 +513,9 @@ static struct clk_core *clk_core_get(struct clk_core *core, u8 p_index)
if (IS_ERR(hw))
return ERR_CAST(hw);
+ if (!hw)
+ return NULL;
+
return hw->core;
}
@@ -1228,9 +1319,6 @@ static void __init clk_unprepare_unused_subtree(struct clk_core *core)
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)
@@ -1239,8 +1327,6 @@ static void __init clk_unprepare_unused_subtree(struct clk_core *core)
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)
@@ -1256,9 +1342,6 @@ 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)
@@ -1283,8 +1366,6 @@ static void __init clk_disable_unused_subtree(struct clk_core *core)
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);
}
@@ -1300,12 +1381,22 @@ __setup("clk_ignore_unused", clk_ignore_unused_setup);
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");
return 0;
}
+ 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)
@@ -1322,6 +1413,8 @@ static int __init clk_disable_unused(void)
clk_prepare_unlock();
+ clk_pm_runtime_put_all();
+
return 0;
}
late_initcall_sync(clk_disable_unused);
@@ -3627,9 +3720,6 @@ static int __clk_core_init(struct clk_core *core)
}
clk_core_reparent_orphans_nolock();
-
-
- kref_init(&core->ref);
out:
clk_pm_runtime_put(core);
unlock:
@@ -3839,6 +3929,22 @@ static void clk_core_free_parent_map(struct clk_core *core)
kfree(core->parents);
}
+/* Free memory allocated for a struct clk_core */
+static void __clk_release(struct kref *ref)
+{
+ 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);
+}
+
static struct clk *
__clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw)
{
@@ -3859,6 +3965,8 @@ __clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw)
goto fail_out;
}
+ kref_init(&core->ref);
+
core->name = kstrdup_const(init->name, GFP_KERNEL);
if (!core->name) {
ret = -ENOMEM;
@@ -3871,9 +3979,8 @@ __clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw)
}
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;
@@ -3913,12 +4020,10 @@ __clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw)
hw->clk = NULL;
fail_create_clk:
- clk_core_free_parent_map(core);
fail_parents:
fail_ops:
- kfree_const(core->name);
fail_name:
- kfree(core);
+ kref_put(&core->ref, __clk_release);
fail_out:
return ERR_PTR(ret);
}
@@ -3998,18 +4103,6 @@ int of_clk_hw_register(struct device_node *node, struct clk_hw *hw)
}
EXPORT_SYMBOL_GPL(of_clk_hw_register);
-/* Free memory allocated for a clock. */
-static void __clk_release(struct kref *ref)
-{
- struct clk_core *core = container_of(ref, struct clk_core, ref);
-
- lockdep_assert_held(&prepare_lock);
-
- clk_core_free_parent_map(core);
- kfree_const(core->name);
- kfree(core);
-}
-
/*
* Empty clk_ops for unregistered clocks. These are used temporarily
* after clk_unregister() was called on a clock and until last clock
@@ -4062,7 +4155,7 @@ static void clk_core_evict_parent_cache_subtree(struct clk_core *root,
/* Remove this clk from all parent caches */
static void clk_core_evict_parent_cache(struct clk_core *core)
{
- struct hlist_head **lists;
+ const struct hlist_head **lists;
struct clk_core *root;
lockdep_assert_held(&prepare_lock);