[PATCH 19/32] coresight: Properly address errors in sink::disable() functions

[Mathieu Poirier]

When disabling a sink the reference counter ensures the operation goes
through if nobody else is using it.  As such if drvdata::mode is already
set do CS_MODE_DISABLED, it is an error and should be reported as such.

Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Tested-by: Leo Yan <leo.yan@xxxxxxxxxx>
Tested-by: Robert Walker <robert.walker@xxxxxxx>
---
 drivers/hwtracing/coresight/coresight-etb10.c   | 9 ++++-----
 drivers/hwtracing/coresight/coresight-tmc-etf.c | 9 ++++-----
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 9 ++++-----
 3 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 8e63863cf950..6b73bc2e0dbd 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -333,11 +333,10 @@ static int etb_disable(struct coresight_device *csdev)
 		return -EBUSY;
 	}
 
-	/* Disable the ETB only if it needs to */
-	if (drvdata->mode != CS_MODE_DISABLED) {
-		etb_disable_hw(drvdata);
-		drvdata->mode = CS_MODE_DISABLED;
-	}
+	/* Complain if we (somehow) got out of sync */
+	WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
+	etb_disable_hw(drvdata);
+	drvdata->mode = CS_MODE_DISABLED;
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	dev_dbg(drvdata->dev, "ETB disabled\n");
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index d50a608a60f1..30f868676540 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -297,11 +297,10 @@ static int tmc_disable_etf_sink(struct coresight_device *csdev)
 		return -EBUSY;
 	}
 
-	/* Disable the TMC only if it needs to */
-	if (drvdata->mode != CS_MODE_DISABLED) {
-		tmc_etb_disable_hw(drvdata);
-		drvdata->mode = CS_MODE_DISABLED;
-	}
+	/* Complain if we (somehow) got out of sync */
+	WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
+	tmc_etb_disable_hw(drvdata);
+	drvdata->mode = CS_MODE_DISABLED;
 
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 6a8f39d03de3..9a0b346be58b 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1417,11 +1417,10 @@ static int tmc_disable_etr_sink(struct coresight_device *csdev)
 		return -EBUSY;
 	}
 
-	/* Disable the TMC only if it needs to */
-	if (drvdata->mode != CS_MODE_DISABLED) {
-		tmc_etr_disable_hw(drvdata);
-		drvdata->mode = CS_MODE_DISABLED;
-	}
+	/* Complain if we (somehow) got out of sync */
+	WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
+	tmc_etr_disable_hw(drvdata);
+	drvdata->mode = CS_MODE_DISABLED;
 
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
-- 
2.17.1