coresight: cti: Add PM runtime call in enable_store

[ Upstream commit eff674a9b86a6ffdd10c3af3863545acf7f1ce4f ]

In commit 6746eae4bbad ("coresight: cti: Fix hang in cti_disable_hw()")
PM runtime calls are removed from cti_enable_hw/cti_disable_hw. When
enabling CTI by writing enable sysfs node, clock for accessing CTI
register won't be enabled. Device will crash due to register access
issue. Add PM runtime call in enable_store to fix this issue.

Fixes: 6746eae4bbad ("coresight: cti: Fix hang in cti_disable_hw()")
Signed-off-by: Mao Jinlong <quic_jinlmao@quicinc.com>
[Change to only call pm_runtime_put if a disable happened]
Tested-by: Jinlong Mao <quic_jinlmao@quicinc.com>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230110110736.2709917-3-james.clark@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
index 6d59c81..71e7a82 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
@@ -108,10 +108,19 @@ static ssize_t enable_store(struct device *dev,
        if (ret)
                return ret;
 
-       if (val)
+       if (val) {
+               ret = pm_runtime_resume_and_get(dev->parent);
+               if (ret)
+                       return ret;
                ret = cti_enable(drvdata->csdev);
-       else
+               if (ret)
+                       pm_runtime_put(dev->parent);
+       } else {
                ret = cti_disable(drvdata->csdev);
+               if (!ret)
+                       pm_runtime_put(dev->parent);
+       }
+
        if (ret)
                return ret;
        return size;