coresight: Make refcount a property of the connection

This removes the need to do an additional lookup for the total number
of ports used and also removes the need to allocate an array of
refcounts which is just another representation of a connection array.

This was only used for link type devices, for regular devices a single
refcount on the coresight device is used.

There is a both an input and output refcount in case two link type
devices are connected together so that they don't overwrite each other's
counts.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
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/20230425143542.2305069-11-james.clark@arm.com

1 files changed, 40 insertions, 76 deletions

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index a0a0ea2c626b..939b7fb751b5 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -112,40 +112,24 @@ struct coresight_device *coresight_get_percpu_sink(int cpu)
 }
 EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
 
-static int coresight_find_link_inport(struct coresight_device *csdev,
-				      struct coresight_device *parent)
+static struct coresight_connection *
+coresight_find_out_connection(struct coresight_device *src_dev,
+			      struct coresight_device *dest_dev)
 {
 	int i;
 	struct coresight_connection *conn;
 
-	for (i = 0; i < parent->pdata->nr_outconns; i++) {
-		conn = parent->pdata->out_conns[i];
-		if (conn->dest_dev == csdev)
-			return conn->dest_port;
+	for (i = 0; i < src_dev->pdata->nr_outconns; i++) {
+		conn = src_dev->pdata->out_conns[i];
+		if (conn->dest_dev == dest_dev)
+			return conn;
 	}
 
-	dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s\n",
-		dev_name(&parent->dev), dev_name(&csdev->dev));
+	dev_err(&src_dev->dev,
+		"couldn't find output connection, src_dev: %s, dest_dev: %s\n",
+		dev_name(&src_dev->dev), dev_name(&dest_dev->dev));
 
-	return -ENODEV;
-}
-
-static int coresight_find_link_outport(struct coresight_device *csdev,
-				       struct coresight_device *child)
-{
-	int i;
-	struct coresight_connection *conn;
-
-	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
-		conn = csdev->pdata->out_conns[i];
-		if (conn->dest_dev == child)
-			return conn->src_port;
-	}
-
-	dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s\n",
-		dev_name(&csdev->dev), dev_name(&child->dev));
-
-	return -ENODEV;
+	return ERR_PTR(-ENODEV);
 }
 
 static inline u32 coresight_read_claim_tags(struct coresight_device *csdev)
@@ -352,24 +336,24 @@ static int coresight_enable_link(struct coresight_device *csdev,
 {
 	int ret = 0;
 	int link_subtype;
-	int inport, outport;
+	struct coresight_connection *inconn, *outconn;
 
 	if (!parent || !child)
 		return -EINVAL;
 
-	inport = coresight_find_link_inport(csdev, parent);
-	outport = coresight_find_link_outport(csdev, child);
+	inconn = coresight_find_out_connection(parent, csdev);
+	outconn = coresight_find_out_connection(csdev, child);
 	link_subtype = csdev->subtype.link_subtype;
 
-	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG && inport < 0)
-		return inport;
-	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT && outport < 0)
-		return outport;
+	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG && IS_ERR(inconn))
+		return PTR_ERR(inconn);
+	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT && IS_ERR(outconn))
+		return PTR_ERR(outconn);
 
 	if (link_ops(csdev)->enable) {
 		ret = coresight_control_assoc_ectdev(csdev, true);
 		if (!ret) {
-			ret = link_ops(csdev)->enable(csdev, inport, outport);
+			ret = link_ops(csdev)->enable(csdev, inconn, outconn);
 			if (ret)
 				coresight_control_assoc_ectdev(csdev, false);
 		}
@@ -385,33 +369,36 @@ static void coresight_disable_link(struct coresight_device *csdev,
 				   struct coresight_device *parent,
 				   struct coresight_device *child)
 {
-	int i, nr_conns;
+	int i;
 	int link_subtype;
-	int inport, outport;
+	struct coresight_connection *inconn, *outconn;
 
 	if (!parent || !child)
 		return;
 
-	inport = coresight_find_link_inport(csdev, parent);
-	outport = coresight_find_link_outport(csdev, child);
+	inconn = coresight_find_out_connection(parent, csdev);
+	outconn = coresight_find_out_connection(csdev, child);
 	link_subtype = csdev->subtype.link_subtype;
 
-	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
-		nr_conns = csdev->pdata->high_inport;
-	} else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
-		nr_conns = csdev->pdata->high_outport;
-	} else {
-		nr_conns = 1;
-	}
-
 	if (link_ops(csdev)->disable) {
-		link_ops(csdev)->disable(csdev, inport, outport);
+		link_ops(csdev)->disable(csdev, inconn, outconn);
 		coresight_control_assoc_ectdev(csdev, false);
 	}
 
-	for (i = 0; i < nr_conns; i++)
-		if (atomic_read(&csdev->refcnt[i]) != 0)
+	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
+		for (i = 0; i < csdev->pdata->nr_inconns; i++)
+			if (atomic_read(&csdev->pdata->in_conns[i]->dest_refcnt) !=
+			    0)
+				return;
+	} else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
+		for (i = 0; i < csdev->pdata->nr_outconns; i++)
+			if (atomic_read(&csdev->pdata->out_conns[i]->src_refcnt) !=
+			    0)
+				return;
+	} else {
+		if (atomic_read(&csdev->refcnt) != 0)
 			return;
+	}
 
 	csdev->enable = false;
 }
@@ -435,7 +422,7 @@ static int coresight_enable_source(struct coresight_device *csdev,
 		csdev->enable = true;
 	}
 
-	atomic_inc(csdev->refcnt);
+	atomic_inc(&csdev->refcnt);
 
 	return 0;
 }
@@ -450,7 +437,7 @@ static int coresight_enable_source(struct coresight_device *csdev,
  */
 static bool coresight_disable_source(struct coresight_device *csdev)
 {
-	if (atomic_dec_return(csdev->refcnt) == 0) {
+	if (atomic_dec_return(&csdev->refcnt) == 0) {
 		if (source_ops(csdev)->disable)
 			source_ops(csdev)->disable(csdev, NULL);
 		coresight_control_assoc_ectdev(csdev, false);
@@ -1094,7 +1081,7 @@ int coresight_enable(struct coresight_device *csdev)
 		 * source is already enabled.
 		 */
 		if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE)
-			atomic_inc(csdev->refcnt);
+			atomic_inc(&csdev->refcnt);
 		goto out;
 	}
 
@@ -1308,7 +1295,6 @@ static void coresight_device_release(struct device *dev)
 	struct coresight_device *csdev = to_coresight_device(dev);
 
 	fwnode_handle_put(csdev->dev.fwnode);
-	kfree(csdev->refcnt);
 	kfree(csdev);
 }
 
@@ -1537,9 +1523,6 @@ void coresight_release_platform_data(struct coresight_device *csdev,
 struct coresight_device *coresight_register(struct coresight_desc *desc)
 {
 	int ret;
-	int link_subtype;
-	int nr_refcnts = 1;
-	atomic_t *refcnts = NULL;
 	struct coresight_device *csdev;
 	bool registered = false;
 
@@ -1549,25 +1532,6 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
 		goto err_out;
 	}
 
-	if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
-	    desc->type == CORESIGHT_DEV_TYPE_LINKSINK) {
-		link_subtype = desc->subtype.link_subtype;
-
-		if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
-			nr_refcnts = desc->pdata->high_inport;
-		else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
-			nr_refcnts = desc->pdata->high_outport;
-	}
-
-	refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
-	if (!refcnts) {
-		ret = -ENOMEM;
-		kfree(csdev);
-		goto err_out;
-	}
-
-	csdev->refcnt = refcnts;
-
 	csdev->pdata = desc->pdata;
 
 	csdev->type = desc->type;