coresight: cti: Move resource release to cti_remove()

Currently, CTI driver releases resource by deferring
cti_device_release() to the device unregistration:

  cti_remove()
   `> coresight_unregister()
       `> cti_remove_assoc_from_csdev()
       `> device_unregister()
           `> cti_device_release()
               `> mutex_lock(&ect_mutex)
               `> release CTI resource
               `> mutex_unlock(&ect_mutex)

In the above flow, two different CTI release callbacks are involved:
cti_remove_assoc_from_csdev() and cti_device_release().  The former is
used by a CoreSight device to unbind its associated CTI helper device,
while the latter releases resources for the CTI device itself.  Since
there is no dependency between them, it is unnecessary to defer the CTI
resource release until device unregistration.

This commit releases the resources directly in cti_remove() and remove
the injected release callback.

Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Mike Leach <mike.leach@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260224-arm_coresight_refactor_cti_resource_release-v1-1-ff1b2bca9176@arm.com

2 files changed, 3 insertions, 23 deletions

diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
index bfbc365bb2ef..7a8f1ef6b94e 100644
--- a/drivers/hwtracing/coresight/coresight-cti-core.c
+++ b/drivers/hwtracing/coresight/coresight-cti-core.c
@@ -823,16 +823,13 @@ static const struct coresight_ops cti_ops = {
 	.helper_ops = &cti_ops_ect,
 };
 
-/*
- * Free up CTI specific resources
- * called by dev->release, need to call down to underlying csdev release.
- */
-static void cti_device_release(struct device *dev)
+static void cti_remove(struct amba_device *adev)
 {
-	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	struct cti_drvdata *drvdata = dev_get_drvdata(&adev->dev);
 	struct cti_drvdata *ect_item, *ect_tmp;
 
 	mutex_lock(&ect_mutex);
+	cti_remove_conn_xrefs(drvdata);
 	cti_pm_release(drvdata);
 
 	/* remove from the list */
@@ -844,17 +841,6 @@ static void cti_device_release(struct device *dev)
 	}
 	mutex_unlock(&ect_mutex);
 
-	if (drvdata->csdev_release)
-		drvdata->csdev_release(dev);
-}
-static void cti_remove(struct amba_device *adev)
-{
-	struct cti_drvdata *drvdata = dev_get_drvdata(&adev->dev);
-
-	mutex_lock(&ect_mutex);
-	cti_remove_conn_xrefs(drvdata);
-	mutex_unlock(&ect_mutex);
-
 	coresight_unregister(drvdata->csdev);
 }
 
@@ -947,10 +933,6 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
 	cti_update_conn_xrefs(drvdata);
 	mutex_unlock(&ect_mutex);
 
-	/* set up release chain */
-	drvdata->csdev_release = drvdata->csdev->dev.release;
-	drvdata->csdev->dev.release = cti_device_release;
-
 	/* all done - dec pm refcount */
 	pm_runtime_put(&adev->dev);
 	dev_info(&drvdata->csdev->dev, "CTI initialized\n");
diff --git a/drivers/hwtracing/coresight/coresight-cti.h b/drivers/hwtracing/coresight/coresight-cti.h
index 4f89091ee93f..daff9e32a6da 100644
--- a/drivers/hwtracing/coresight/coresight-cti.h
+++ b/drivers/hwtracing/coresight/coresight-cti.h
@@ -170,7 +170,6 @@ struct cti_config {
  * @spinlock:	Control data access to one at a time.
  * @config:	Configuration data for this CTI device.
  * @node:	List entry of this device in the list of CTI devices.
- * @csdev_release: release function for underlying coresight_device.
  */
 struct cti_drvdata {
 	void __iomem *base;
@@ -179,7 +178,6 @@ struct cti_drvdata {
 	raw_spinlock_t spinlock;
 	struct cti_config config;
 	struct list_head node;
-	void (*csdev_release)(struct device *dev);
 };
 
 /*