Patch "coresight: cti: Add PM runtime call in enable_store" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    coresight: cti: Add PM runtime call in enable_store

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     coresight-cti-add-pm-runtime-call-in-enable_store.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit fc01e33265cd56ea4083221c5d2e4f928f8c4eb2
Author: Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
Date:   Tue Jan 10 11:07:35 2023 +0000

    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@xxxxxxxxxxx>
    [Change to only call pm_runtime_put if a disable happened]
    Tested-by: Jinlong Mao <quic_jinlmao@xxxxxxxxxxx>
    Signed-off-by: James Clark <james.clark@xxxxxxx>
    Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
    Link: https://lore.kernel.org/r/20230110110736.2709917-3-james.clark@xxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
index 7ff7e7780bbfb..92fc3000872a1 100644
--- 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;