[PATCH v11 1/9] coresight: etm4x: prohibit modifying ss_status and cntr_val while session is enabled

[Yeoreum Yun]

ss_status and cntr_val are overwritten with the values read from the
corresponding registers by etm4_disable_hw() when the session is disabled.

This means that any changes to these values made while the session is
enabled would be lost when the session is disabled.

Therefore, prohibit modifying ss_status and cntr_val while the session is
enabled.

Signed-off-by: Yeoreum Yun <yeoreum.yun at arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index cc6cdd3ae29d5..8d73248b840a6 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -1613,6 +1613,8 @@ static ssize_t cntr_val_store(struct device *dev,
 		return -EINVAL;
 	if (val > ETM_CNTR_MAX_VAL)
 		return -EINVAL;
+	if (coresight_get_mode(drvdata->csdev))
+		return -EBUSY;
 
 	raw_spin_lock(&drvdata->spinlock);
 	idx = config->cntr_idx;
@@ -1797,6 +1799,8 @@ static ssize_t sshot_ctrl_store(struct device *dev,
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
+	if (coresight_get_mode(drvdata->csdev))
+		return -EBUSY;
 
 	raw_spin_lock(&drvdata->spinlock);
 	idx = config->ss_idx;
@@ -1847,6 +1851,8 @@ static ssize_t sshot_pe_ctrl_store(struct device *dev,
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
+	if (coresight_get_mode(drvdata->csdev))
+		return -EBUSY;
 
 	raw_spin_lock(&drvdata->spinlock);
 	idx = config->ss_idx;

-- 
2.43.0