[PATCH v3 1/2] coresight: Fix clock refcount imbalance on platform remove

[Jie Gan]

coresight_get_enable_clocks() enables the programming clock and the
optional AT clock through devm_clk_get_optional_enabled(), which also
registers a devm action to call clk_disable_unprepare() when the driver
detaches.

After probe, pm_runtime_put() allows the device to suspend and the
runtime suspend callback disables the same clocks. During remove the
device is left runtime suspended, so pm_runtime_disable() freezes it
with the clocks already disabled. The devm cleanup that runs afterwards
calls clk_disable_unprepare() a second time, underflowing the clock
enable refcount.

Resume the device with pm_runtime_get_sync() before tearing it down so
the clocks are enabled again and balance the devm-managed disable. Then
pm_runtime_set_suspended() and pm_runtime_put_noidle() leave the device
in a coherent runtime PM state (suspended, usage count balanced) once
the devm action has disabled the clocks.

This affects all CoreSight platform drivers that obtain their clocks
through coresight_get_enable_clocks(): catu, cpu-debug, ctcu, etm4x,
funnel, replicator, stm, tmc and tpiu.

Fixes: 1abc1b212eff ("coresight: Appropriately disable programming clocks")
Reviewed-by: Yeoreum Yun <yeoreum.yun@xxxxxxx>
Reviewed-by: Leo Yan <leo.yan@xxxxxxx>
Signed-off-by: Jie Gan <jie.gan@xxxxxxxxxxxxxxxx>
---
 drivers/hwtracing/coresight/coresight-catu.c       |  8 ++++++++
 drivers/hwtracing/coresight/coresight-cpu-debug.c  |  8 ++++++++
 drivers/hwtracing/coresight/coresight-ctcu-core.c  |  8 ++++++++
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 13 +++++++++++--
 drivers/hwtracing/coresight/coresight-funnel.c     |  8 ++++++++
 drivers/hwtracing/coresight/coresight-replicator.c |  8 ++++++++
 drivers/hwtracing/coresight/coresight-stm.c        |  8 ++++++++
 drivers/hwtracing/coresight/coresight-tmc-core.c   |  8 ++++++++
 drivers/hwtracing/coresight/coresight-tpiu.c       |  8 ++++++++
 9 files changed, 75 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
index ad8dafea7d2f..b72fa7f4bdeb 100644
--- a/drivers/hwtracing/coresight/coresight-catu.c
+++ b/drivers/hwtracing/coresight/coresight-catu.c
@@ -646,8 +646,16 @@ static void catu_platform_remove(struct platform_device *pdev)
 	if (WARN_ON(!drvdata))
 		return;
 
+	/*
+	 * Resume the device so its clocks are enabled again, balancing the
+	 * clk_disable_unprepare() that devm runs when the driver detaches.
+	 * Then mark it suspended and drop the usage count taken here.
+	 */
+	pm_runtime_get_sync(&pdev->dev);
 	__catu_remove(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 
 #ifdef CONFIG_PM
diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c
index 3a806c1d50ea..87b39874461e 100644
--- a/drivers/hwtracing/coresight/coresight-cpu-debug.c
+++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c
@@ -710,8 +710,16 @@ static void debug_platform_remove(struct platform_device *pdev)
 	if (WARN_ON(!drvdata))
 		return;
 
+	/*
+	 * Resume the device so its clocks are enabled again, balancing the
+	 * clk_disable_unprepare() that devm runs when the driver detaches.
+	 * Then mark it suspended and drop the usage count taken here.
+	 */
+	pm_runtime_get_sync(&pdev->dev);
 	__debug_remove(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 
 #ifdef CONFIG_ACPI
diff --git a/drivers/hwtracing/coresight/coresight-ctcu-core.c b/drivers/hwtracing/coresight/coresight-ctcu-core.c
index 9043cad42f01..e0e33e3ca5bf 100644
--- a/drivers/hwtracing/coresight/coresight-ctcu-core.c
+++ b/drivers/hwtracing/coresight/coresight-ctcu-core.c
@@ -265,8 +265,16 @@ static void ctcu_platform_remove(struct platform_device *pdev)
 	if (WARN_ON(!drvdata))
 		return;
 
+	/*
+	 * Resume the device so its clocks are enabled again, balancing the
+	 * clk_disable_unprepare() that devm runs when the driver detaches.
+	 * Then mark it suspended and drop the usage count taken here.
+	 */
+	pm_runtime_get_sync(&pdev->dev);
 	ctcu_remove(pdev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 
 #ifdef CONFIG_PM
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 14bb31bd6a0b..dd5d26717f15 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -2414,9 +2414,18 @@ static void etm4_remove_platform_dev(struct platform_device *pdev)
 {
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(&pdev->dev);
 
-	if (drvdata)
-		etm4_remove_dev(drvdata);
+	if (WARN_ON(!drvdata))
+		return;
+	/*
+	 * Resume the device so its clocks are enabled again, balancing the
+	 * clk_disable_unprepare() that devm runs when the driver detaches.
+	 * Then mark it suspended and drop the usage count taken here.
+	 */
+	pm_runtime_get_sync(&pdev->dev);
+	etm4_remove_dev(drvdata);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 
 static const struct amba_id etm4_ids[] = {
diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c
index 0abc11f0690c..d69cd66e8394 100644
--- a/drivers/hwtracing/coresight/coresight-funnel.c
+++ b/drivers/hwtracing/coresight/coresight-funnel.c
@@ -333,8 +333,16 @@ static void funnel_platform_remove(struct platform_device *pdev)
 	if (WARN_ON(!drvdata))
 		return;
 
+	/*
+	 * Resume the device so its clocks are enabled again, balancing the
+	 * clk_disable_unprepare() that devm runs when the driver detaches.
+	 * Then mark it suspended and drop the usage count taken here.
+	 */
+	pm_runtime_get_sync(&pdev->dev);
 	funnel_remove(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 
 static const struct of_device_id funnel_match[] = {
diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
index 2f382de357ee..1df01deb2f69 100644
--- a/drivers/hwtracing/coresight/coresight-replicator.c
+++ b/drivers/hwtracing/coresight/coresight-replicator.c
@@ -312,8 +312,16 @@ static void replicator_platform_remove(struct platform_device *pdev)
 	if (WARN_ON(!drvdata))
 		return;
 
+	/*
+	 * Resume the device so its clocks are enabled again, balancing the
+	 * clk_disable_unprepare() that devm runs when the driver detaches.
+	 * Then mark it suspended and drop the usage count taken here.
+	 */
+	pm_runtime_get_sync(&pdev->dev);
 	replicator_remove(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 
 #ifdef CONFIG_PM
diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
index 4e860519a73f..a75b1c56a867 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -1025,8 +1025,16 @@ static void stm_platform_remove(struct platform_device *pdev)
 	if (WARN_ON(!drvdata))
 		return;
 
+	/*
+	 * Resume the device so its clocks are enabled again, balancing the
+	 * clk_disable_unprepare() that devm runs when the driver detaches.
+	 * Then mark it suspended and drop the usage count taken here.
+	 */
+	pm_runtime_get_sync(&pdev->dev);
 	__stm_remove(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 
 #ifdef CONFIG_ACPI
diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index bc5a133ada3e..ed40bfea32f9 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -988,8 +988,16 @@ static void tmc_platform_remove(struct platform_device *pdev)
 	if (WARN_ON(!drvdata))
 		return;
 
+	/*
+	 * Resume the device so its clocks are enabled again, balancing the
+	 * clk_disable_unprepare() that devm runs when the driver detaches.
+	 * Then mark it suspended and drop the usage count taken here.
+	 */
+	pm_runtime_get_sync(&pdev->dev);
 	__tmc_remove(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 
 #ifdef CONFIG_PM
diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
index 7b029d2eb389..775507d0bb36 100644
--- a/drivers/hwtracing/coresight/coresight-tpiu.c
+++ b/drivers/hwtracing/coresight/coresight-tpiu.c
@@ -285,8 +285,16 @@ static void tpiu_platform_remove(struct platform_device *pdev)
 	if (WARN_ON(!drvdata))
 		return;
 
+	/*
+	 * Resume the device so its clocks are enabled again, balancing the
+	 * clk_disable_unprepare() that devm runs when the driver detaches.
+	 * Then mark it suspended and drop the usage count taken here.
+	 */
+	pm_runtime_get_sync(&pdev->dev);
 	__tpiu_remove(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 
 #ifdef CONFIG_ACPI

-- 
2.34.1