summaryrefslogtreecommitdiffstats
path: root/drivers/clk/clk.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/clk/clk.c')
-rw-r--r--drivers/clk/clk.c201
1 files changed, 158 insertions, 43 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 9004e0718..fe1d45eac 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -37,6 +37,10 @@ static HLIST_HEAD(clk_root_list);
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,
@@ -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;
@@ -122,6 +127,89 @@ 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)
{
@@ -1310,9 +1398,6 @@ 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)
@@ -1321,8 +1406,6 @@ 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)
@@ -1338,9 +1421,6 @@ 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)
@@ -1365,8 +1445,6 @@ 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);
}
@@ -1382,12 +1460,22 @@ __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)
@@ -1404,6 +1492,8 @@ static int __init clk_disable_unused(void)
clk_prepare_unlock();
+ clk_pm_runtime_put_all();
+
return 0;
}
late_initcall_sync(clk_disable_unused);
@@ -3115,28 +3205,41 @@ static void clk_summary_show_one(struct seq_file *s, struct clk_core *c,
int level)
{
int phase;
+ struct clk *clk_user;
+ int multi_node = 0;
- seq_printf(s, "%*s%-*s %7d %8d %8d %11lu %10lu ",
+ seq_printf(s, "%*s%-*s %-7d %-8d %-8d %-11lu %-10lu ",
level * 3 + 1, "",
- 30 - level * 3, c->name,
+ 35 - level * 3, c->name,
c->enable_count, c->prepare_count, c->protect_count,
clk_core_get_rate_recalc(c),
clk_core_get_accuracy_recalc(c));
phase = clk_core_get_phase(c);
if (phase >= 0)
- seq_printf(s, "%5d", phase);
+ seq_printf(s, "%-5d", phase);
else
seq_puts(s, "-----");
- seq_printf(s, " %6d", clk_core_get_scaled_duty_cycle(c, 100000));
+ seq_printf(s, " %-6d", clk_core_get_scaled_duty_cycle(c, 100000));
if (c->ops->is_enabled)
- seq_printf(s, " %9c\n", clk_core_is_enabled(c) ? 'Y' : 'N');
+ seq_printf(s, " %5c ", clk_core_is_enabled(c) ? 'Y' : 'N');
else if (!c->ops->enable)
- seq_printf(s, " %9c\n", 'Y');
+ seq_printf(s, " %5c ", 'Y');
else
- seq_printf(s, " %9c\n", '?');
+ seq_printf(s, " %5c ", '?');
+
+ hlist_for_each_entry(clk_user, &c->clks, clks_node) {
+ seq_printf(s, "%*s%-*s %-25s\n",
+ level * 3 + 2 + 105 * multi_node, "",
+ 30,
+ clk_user->dev_id ? clk_user->dev_id : "deviceless",
+ clk_user->con_id ? clk_user->con_id : "no_connection_id");
+
+ multi_node = 1;
+ }
+
}
static void clk_summary_show_subtree(struct seq_file *s, struct clk_core *c,
@@ -3144,9 +3247,7 @@ static void clk_summary_show_subtree(struct seq_file *s, struct clk_core *c,
{
struct clk_core *child;
- clk_pm_runtime_get(c);
clk_summary_show_one(s, c, level);
- clk_pm_runtime_put(c);
hlist_for_each_entry(child, &c->children, child_node)
clk_summary_show_subtree(s, child, level + 1);
@@ -3155,11 +3256,16 @@ static void clk_summary_show_subtree(struct seq_file *s, struct clk_core *c,
static int clk_summary_show(struct seq_file *s, void *data)
{
struct clk_core *c;
- struct hlist_head **lists = (struct hlist_head **)s->private;
+ struct hlist_head **lists = s->private;
+ int ret;
- seq_puts(s, " enable prepare protect duty hardware\n");
- seq_puts(s, " clock count count count rate accuracy phase cycle enable\n");
- seq_puts(s, "-------------------------------------------------------------------------------------------------------\n");
+ seq_puts(s, " enable prepare protect duty hardware connection\n");
+ seq_puts(s, " clock count count count rate accuracy phase cycle enable consumer id\n");
+ seq_puts(s, "---------------------------------------------------------------------------------------------------------------------------------------------\n");
+
+ ret = clk_pm_runtime_get_all();
+ if (ret)
+ return ret;
clk_prepare_lock();
@@ -3168,6 +3274,7 @@ static int clk_summary_show(struct seq_file *s, void *data)
clk_summary_show_subtree(s, c, 0);
clk_prepare_unlock();
+ clk_pm_runtime_put_all();
return 0;
}
@@ -3214,9 +3321,15 @@ static int clk_dump_show(struct seq_file *s, void *data)
{
struct clk_core *c;
bool first_node = true;
- struct hlist_head **lists = (struct hlist_head **)s->private;
+ struct hlist_head **lists = s->private;
+ int ret;
+
+ ret = clk_pm_runtime_get_all();
+ if (ret)
+ return ret;
seq_putc(s, '{');
+
clk_prepare_lock();
for (; *lists; lists++) {
@@ -3229,6 +3342,7 @@ static int clk_dump_show(struct seq_file *s, void *data)
}
clk_prepare_unlock();
+ clk_pm_runtime_put_all();
seq_puts(s, "}\n");
return 0;
@@ -3836,8 +3950,6 @@ 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:
@@ -4066,6 +4178,22 @@ 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)
{
@@ -4086,6 +4214,8 @@ __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;
@@ -4098,9 +4228,8 @@ __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;
@@ -4140,12 +4269,10 @@ __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);
}
@@ -4225,18 +4352,6 @@ 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