[PATCH v8 7/7] clk: Warn of unbalanced clk_prepare() calls

From: Tomeu Vizoso
Date: Mon Sep 01 2014 - 11:35:12 EST


The warning will display the clock user that is trying to unprepare the clock,
and the location of the last unprepare call.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>

---

v8: * Patch added
---
drivers/clk/clk.c | 22 ++++++++++++++++++++--
include/linux/clk-private.h | 3 +++
2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 13ee3dd..a3d2372 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -834,7 +834,17 @@ void clk_unprepare(struct clk *clk_user)
if (IS_ERR_OR_NULL(clk_user))
return;

- clk_provider_unprepare(clk_to_clk_core(clk_user));
+ clk_prepare_lock();
+ if (!WARN(clk_user->prepare_count == 0,
+ "incorrect unprepare clk dev %s con %s last caller of unprepare %pF\n",
+ clk_user->dev_id, clk_user->con_id, clk_user->last_unprepare)) {
+
+ clk_user->last_unprepare = __builtin_return_address(0);
+ clk_user->prepare_count--;
+
+ __clk_unprepare(clk_to_clk_core(clk_user));
+ }
+ clk_prepare_unlock();
}
EXPORT_SYMBOL_GPL(clk_unprepare);

@@ -890,10 +900,18 @@ EXPORT_SYMBOL_GPL(clk_provider_prepare);
*/
int clk_prepare(struct clk *clk_user)
{
+ int ret;
+
if (!clk_user)
return 0;

- return clk_provider_prepare(clk_to_clk_core(clk_user));
+ clk_prepare_lock();
+ ret = __clk_prepare(clk_to_clk_core(clk_user));
+ if (!ret)
+ clk_user->prepare_count++;
+ clk_prepare_unlock();
+
+ return ret;
}
EXPORT_SYMBOL_GPL(clk_prepare);

diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
index 8126046..cf93bde 100644
--- a/include/linux/clk-private.h
+++ b/include/linux/clk-private.h
@@ -64,6 +64,9 @@ struct clk {
unsigned int enable_count;
void *last_disable;

+ unsigned int prepare_count;
+ void *last_unprepare;
+
unsigned long floor_constraint;
unsigned long ceiling_constraint;
struct hlist_node child_node;
--
1.9.3

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