[PATCH 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 pm_runtime_disable()
so the clocks are enabled again and balance the devm-managed disable.

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")
Signed-off-by: Jie Gan <jie.gan at oss.qualcomm.com>
---
 drivers/hwtracing/coresight/coresight-catu.c       | 1 +
 drivers/hwtracing/coresight/coresight-cpu-debug.c  | 1 +
 drivers/hwtracing/coresight/coresight-ctcu-core.c  | 1 +
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 1 +
 drivers/hwtracing/coresight/coresight-funnel.c     | 1 +
 drivers/hwtracing/coresight/coresight-replicator.c | 1 +
 drivers/hwtracing/coresight/coresight-stm.c        | 1 +
 drivers/hwtracing/coresight/coresight-tmc-core.c   | 1 +
 drivers/hwtracing/coresight/coresight-tpiu.c       | 1 +
 9 files changed, 9 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
index ad8dafea7d2f..f7e501e6cbd7 100644
--- a/drivers/hwtracing/coresight/coresight-catu.c
+++ b/drivers/hwtracing/coresight/coresight-catu.c
@@ -647,6 +647,7 @@ static void catu_platform_remove(struct platform_device *pdev)
 		return;
 
 	__catu_remove(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c
index 3a806c1d50ea..f7efae5b5ce5 100644
--- a/drivers/hwtracing/coresight/coresight-cpu-debug.c
+++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c
@@ -711,6 +711,7 @@ static void debug_platform_remove(struct platform_device *pdev)
 		return;
 
 	__debug_remove(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-ctcu-core.c b/drivers/hwtracing/coresight/coresight-ctcu-core.c
index 9043cad42f01..9b6da29d9735 100644
--- a/drivers/hwtracing/coresight/coresight-ctcu-core.c
+++ b/drivers/hwtracing/coresight/coresight-ctcu-core.c
@@ -266,6 +266,7 @@ static void ctcu_platform_remove(struct platform_device *pdev)
 		return;
 
 	ctcu_remove(pdev);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 14bb31bd6a0b..147761024c0f 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -2416,6 +2416,7 @@ static void etm4_remove_platform_dev(struct platform_device *pdev)
 
 	if (drvdata)
 		etm4_remove_dev(drvdata);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c
index 0abc11f0690c..4c5b94640e6a 100644
--- a/drivers/hwtracing/coresight/coresight-funnel.c
+++ b/drivers/hwtracing/coresight/coresight-funnel.c
@@ -334,6 +334,7 @@ static void funnel_platform_remove(struct platform_device *pdev)
 		return;
 
 	funnel_remove(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
index 2f382de357ee..2d765f1f73b3 100644
--- a/drivers/hwtracing/coresight/coresight-replicator.c
+++ b/drivers/hwtracing/coresight/coresight-replicator.c
@@ -313,6 +313,7 @@ static void replicator_platform_remove(struct platform_device *pdev)
 		return;
 
 	replicator_remove(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
index 4e860519a73f..a653f1eebeca 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -1026,6 +1026,7 @@ static void stm_platform_remove(struct platform_device *pdev)
 		return;
 
 	__stm_remove(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index bc5a133ada3e..c9cf486873e2 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -989,6 +989,7 @@ static void tmc_platform_remove(struct platform_device *pdev)
 		return;
 
 	__tmc_remove(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
index 7b029d2eb389..72ac93749be1 100644
--- a/drivers/hwtracing/coresight/coresight-tpiu.c
+++ b/drivers/hwtracing/coresight/coresight-tpiu.c
@@ -286,6 +286,7 @@ static void tpiu_platform_remove(struct platform_device *pdev)
 		return;
 
 	__tpiu_remove(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 

-- 
2.34.1