1 files changed, 320 insertions, 285 deletions

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index d3bf82c0de1d..118fcf27854d 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2012, The Linux Foundation. All rights reserved.
  */
 
+#include <linux/build_bug.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/types.h>
@@ -112,40 +113,24 @@ 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_outport; i++) {
-		conn = &parent->pdata->conns[i];
-		if (conn->child_dev == csdev)
-			return conn->child_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_outport; i++) {
-		conn = &csdev->pdata->conns[i];
-		if (conn->child_dev == child)
-			return conn->outport;
-	}
-
-	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)
@@ -252,63 +237,47 @@ void coresight_disclaim_device(struct coresight_device *csdev)
 }
 EXPORT_SYMBOL_GPL(coresight_disclaim_device);
 
-/* enable or disable an associated CTI device of the supplied CS device */
-static int
-coresight_control_assoc_ectdev(struct coresight_device *csdev, bool enable)
+/*
+ * Add a helper as an output device. This function takes the @coresight_mutex
+ * because it's assumed that it's called from the helper device, outside of the
+ * core code where the mutex would already be held. Don't add new calls to this
+ * from inside the core code, instead try to add the new helper to the DT and
+ * ACPI where it will be picked up and linked automatically.
+ */
+void coresight_add_helper(struct coresight_device *csdev,
+			  struct coresight_device *helper)
 {
-	int ect_ret = 0;
-	struct coresight_device *ect_csdev = csdev->ect_dev;
-	struct module *mod;
+	int i;
+	struct coresight_connection conn = {};
+	struct coresight_connection *new_conn;
 
-	if (!ect_csdev)
-		return 0;
-	if ((!ect_ops(ect_csdev)->enable) || (!ect_ops(ect_csdev)->disable))
-		return 0;
+	mutex_lock(&coresight_mutex);
+	conn.dest_fwnode = fwnode_handle_get(dev_fwnode(&helper->dev));
+	conn.dest_dev = helper;
+	conn.dest_port = conn.src_port = -1;
+	conn.src_dev = csdev;
 
-	mod = ect_csdev->dev.parent->driver->owner;
-	if (enable) {
-		if (try_module_get(mod)) {
-			ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
-			if (ect_ret) {
-				module_put(mod);
-			} else {
-				get_device(ect_csdev->dev.parent);
-				csdev->ect_enabled = true;
-			}
-		} else
-			ect_ret = -ENODEV;
-	} else {
-		if (csdev->ect_enabled) {
-			ect_ret = ect_ops(ect_csdev)->disable(ect_csdev);
-			put_device(ect_csdev->dev.parent);
-			module_put(mod);
-			csdev->ect_enabled = false;
-		}
-	}
+	/*
+	 * Check for duplicates because this is called every time a helper
+	 * device is re-loaded. Existing connections will get re-linked
+	 * automatically.
+	 */
+	for (i = 0; i < csdev->pdata->nr_outconns; ++i)
+		if (csdev->pdata->out_conns[i]->dest_fwnode == conn.dest_fwnode)
+			goto unlock;
 
-	/* output warning if ECT enable is preventing trace operation */
-	if (ect_ret)
-		dev_info(&csdev->dev, "Associated ECT device (%s) %s failed\n",
-			 dev_name(&ect_csdev->dev),
-			 enable ? "enable" : "disable");
-	return ect_ret;
-}
+	new_conn = coresight_add_out_conn(csdev->dev.parent, csdev->pdata,
+					  &conn);
+	if (!IS_ERR(new_conn))
+		coresight_add_in_conn(new_conn);
 
-/*
- * Set the associated ect / cti device while holding the coresight_mutex
- * to avoid a race with coresight_enable that may try to use this value.
- */
-void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
-				      struct coresight_device *ect_csdev)
-{
-	mutex_lock(&coresight_mutex);
-	csdev->ect_dev = ect_csdev;
+unlock:
 	mutex_unlock(&coresight_mutex);
 }
-EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
+EXPORT_SYMBOL_GPL(coresight_add_helper);
 
 static int coresight_enable_sink(struct coresight_device *csdev,
-				 u32 mode, void *data)
+				 enum cs_mode mode, void *data)
 {
 	int ret;
 
@@ -319,14 +288,10 @@ static int coresight_enable_sink(struct coresight_device *csdev,
 	if (!sink_ops(csdev)->enable)
 		return -EINVAL;
 
-	ret = coresight_control_assoc_ectdev(csdev, true);
-	if (ret)
-		return ret;
 	ret = sink_ops(csdev)->enable(csdev, mode, data);
-	if (ret) {
-		coresight_control_assoc_ectdev(csdev, false);
+	if (ret)
 		return ret;
-	}
+
 	csdev->enable = true;
 
 	return 0;
@@ -342,7 +307,6 @@ static void coresight_disable_sink(struct coresight_device *csdev)
 	ret = sink_ops(csdev)->disable(csdev);
 	if (ret)
 		return;
-	coresight_control_assoc_ectdev(csdev, false);
 	csdev->enable = false;
 }
 
@@ -352,32 +316,26 @@ 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);
-			if (ret)
-				coresight_control_assoc_ectdev(csdev, false);
-		}
+		ret = link_ops(csdev)->enable(csdev, inconn, outconn);
+		if (!ret)
+			csdev->enable = true;
 	}
 
-	if (!ret)
-		csdev->enable = true;
-
 	return ret;
 }
 
@@ -385,78 +343,125 @@ 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->nr_inport;
-	} else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
-		nr_conns = csdev->pdata->nr_outport;
-	} else {
-		nr_conns = 1;
-	}
-
 	if (link_ops(csdev)->disable) {
-		link_ops(csdev)->disable(csdev, inport, outport);
-		coresight_control_assoc_ectdev(csdev, false);
+		link_ops(csdev)->disable(csdev, inconn, outconn);
 	}
 
-	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;
 }
 
-static int coresight_enable_source(struct coresight_device *csdev, u32 mode)
+int coresight_enable_source(struct coresight_device *csdev, enum cs_mode mode,
+			    void *data)
 {
 	int ret;
 
 	if (!csdev->enable) {
 		if (source_ops(csdev)->enable) {
-			ret = coresight_control_assoc_ectdev(csdev, true);
+			ret = source_ops(csdev)->enable(csdev, data, mode);
 			if (ret)
 				return ret;
-			ret = source_ops(csdev)->enable(csdev, NULL, mode);
-			if (ret) {
-				coresight_control_assoc_ectdev(csdev, false);
-				return ret;
-			}
 		}
 		csdev->enable = true;
 	}
 
-	atomic_inc(csdev->refcnt);
+	atomic_inc(&csdev->refcnt);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(coresight_enable_source);
+
+static bool coresight_is_helper(struct coresight_device *csdev)
+{
+	return csdev->type == CORESIGHT_DEV_TYPE_HELPER;
+}
+
+static int coresight_enable_helper(struct coresight_device *csdev,
+				   enum cs_mode mode, void *data)
+{
+	int ret;
+
+	if (!helper_ops(csdev)->enable)
+		return 0;
+	ret = helper_ops(csdev)->enable(csdev, mode, data);
+	if (ret)
+		return ret;
 
+	csdev->enable = true;
 	return 0;
 }
 
+static void coresight_disable_helper(struct coresight_device *csdev)
+{
+	int ret;
+
+	if (!helper_ops(csdev)->disable)
+		return;
+
+	ret = helper_ops(csdev)->disable(csdev, NULL);
+	if (ret)
+		return;
+	csdev->enable = false;
+}
+
+static void coresight_disable_helpers(struct coresight_device *csdev)
+{
+	int i;
+	struct coresight_device *helper;
+
+	for (i = 0; i < csdev->pdata->nr_outconns; ++i) {
+		helper = csdev->pdata->out_conns[i]->dest_dev;
+		if (helper && coresight_is_helper(helper))
+			coresight_disable_helper(helper);
+	}
+}
+
 /**
  *  coresight_disable_source - Drop the reference count by 1 and disable
  *  the device if there are no users left.
  *
  *  @csdev: The coresight device to disable
+ *  @data: Opaque data to pass on to the disable function of the source device.
+ *         For example in perf mode this is a pointer to the struct perf_event.
  *
  *  Returns true if the device has been disabled.
  */
-static bool coresight_disable_source(struct coresight_device *csdev)
+bool coresight_disable_source(struct coresight_device *csdev, void *data)
 {
-	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);
+			source_ops(csdev)->disable(csdev, data);
+		coresight_disable_helpers(csdev);
 		csdev->enable = false;
 	}
 	return !csdev->enable;
 }
+EXPORT_SYMBOL_GPL(coresight_disable_source);
 
 /*
  * coresight_disable_path_from : Disable components in the given path beyond
@@ -507,6 +512,9 @@ static void coresight_disable_path_from(struct list_head *path,
 		default:
 			break;
 		}
+
+		/* Disable all helpers adjacent along the path last */
+		coresight_disable_helpers(csdev);
 	}
 }
 
@@ -516,9 +524,28 @@ void coresight_disable_path(struct list_head *path)
 }
 EXPORT_SYMBOL_GPL(coresight_disable_path);
 
-int coresight_enable_path(struct list_head *path, u32 mode, void *sink_data)
+static int coresight_enable_helpers(struct coresight_device *csdev,
+				    enum cs_mode mode, void *data)
 {
+	int i, ret = 0;
+	struct coresight_device *helper;
 
+	for (i = 0; i < csdev->pdata->nr_outconns; ++i) {
+		helper = csdev->pdata->out_conns[i]->dest_dev;
+		if (!helper || !coresight_is_helper(helper))
+			continue;
+
+		ret = coresight_enable_helper(helper, mode, data);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+int coresight_enable_path(struct list_head *path, enum cs_mode mode,
+			  void *sink_data)
+{
 	int ret = 0;
 	u32 type;
 	struct coresight_node *nd;
@@ -528,6 +555,10 @@ int coresight_enable_path(struct list_head *path, u32 mode, void *sink_data)
 		csdev = nd->csdev;
 		type = csdev->type;
 
+		/* Enable all helpers adjacent to the path first */
+		ret = coresight_enable_helpers(csdev, mode, sink_data);
+		if (ret)
+			goto err;
 		/*
 		 * ETF devices are tricky... They can be a link or a sink,
 		 * depending on how they are configured.  If an ETF has been
@@ -602,10 +633,10 @@ coresight_find_enabled_sink(struct coresight_device *csdev)
 	/*
 	 * Recursively explore each port found on this element.
 	 */
-	for (i = 0; i < csdev->pdata->nr_outport; i++) {
+	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
 		struct coresight_device *child_dev;
 
-		child_dev = csdev->pdata->conns[i].child_dev;
+		child_dev = csdev->pdata->out_conns[i]->dest_dev;
 		if (child_dev)
 			sink = coresight_find_enabled_sink(child_dev);
 		if (sink)
@@ -718,11 +749,11 @@ static int coresight_grab_device(struct coresight_device *csdev)
 {
 	int i;
 
-	for (i = 0; i < csdev->pdata->nr_outport; i++) {
+	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
 		struct coresight_device *child;
 
-		child  = csdev->pdata->conns[i].child_dev;
-		if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
+		child = csdev->pdata->out_conns[i]->dest_dev;
+		if (child && coresight_is_helper(child))
 			if (!coresight_get_ref(child))
 				goto err;
 	}
@@ -732,8 +763,8 @@ err:
 	for (i--; i >= 0; i--) {
 		struct coresight_device *child;
 
-		child  = csdev->pdata->conns[i].child_dev;
-		if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
+		child = csdev->pdata->out_conns[i]->dest_dev;
+		if (child && coresight_is_helper(child))
 			coresight_put_ref(child);
 	}
 	return -ENODEV;
@@ -748,11 +779,11 @@ static void coresight_drop_device(struct coresight_device *csdev)
 	int i;
 
 	coresight_put_ref(csdev);
-	for (i = 0; i < csdev->pdata->nr_outport; i++) {
+	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
 		struct coresight_device *child;
 
-		child  = csdev->pdata->conns[i].child_dev;
-		if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
+		child = csdev->pdata->out_conns[i]->dest_dev;
+		if (child && coresight_is_helper(child))
 			coresight_put_ref(child);
 	}
 }
@@ -790,10 +821,10 @@ static int _coresight_build_path(struct coresight_device *csdev,
 	}
 
 	/* Not a sink - recursively explore each port found on this element */
-	for (i = 0; i < csdev->pdata->nr_outport; i++) {
+	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
 		struct coresight_device *child_dev;
 
-		child_dev = csdev->pdata->conns[i].child_dev;
+		child_dev = csdev->pdata->out_conns[i]->dest_dev;
 		if (child_dev &&
 		    _coresight_build_path(child_dev, sink, path) == 0) {
 			found = true;
@@ -959,11 +990,11 @@ coresight_find_sink(struct coresight_device *csdev, int *depth)
 	 * Not a sink we want - or possible child sink may be better.
 	 * recursively explore each port found on this element.
 	 */
-	for (i = 0; i < csdev->pdata->nr_outport; i++) {
+	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
 		struct coresight_device *child_dev, *sink = NULL;
 		int child_depth = curr_depth;
 
-		child_dev = csdev->pdata->conns[i].child_dev;
+		child_dev = csdev->pdata->out_conns[i]->dest_dev;
 		if (child_dev)
 			sink = coresight_find_sink(child_dev, &child_depth);
 
@@ -1093,7 +1124,7 @@ 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;
 	}
 
@@ -1114,7 +1145,7 @@ int coresight_enable(struct coresight_device *csdev)
 	if (ret)
 		goto err_path;
 
-	ret = coresight_enable_source(csdev, CS_MODE_SYSFS);
+	ret = coresight_enable_source(csdev, CS_MODE_SYSFS, NULL);
 	if (ret)
 		goto err_source;
 
@@ -1171,7 +1202,7 @@ void coresight_disable(struct coresight_device *csdev)
 	if (ret)
 		goto out;
 
-	if (!csdev->enable || !coresight_disable_source(csdev))
+	if (!csdev->enable || !coresight_disable_source(csdev, NULL))
 		goto out;
 
 	switch (csdev->subtype.source_subtype) {
@@ -1296,18 +1327,16 @@ static struct device_type coresight_dev_type[] = {
 	},
 	{
 		.name = "helper",
-	},
-	{
-		.name = "ect",
-	},
+	}
 };
+/* Ensure the enum matches the names and groups */
+static_assert(ARRAY_SIZE(coresight_dev_type) == CORESIGHT_DEV_TYPE_MAX);
 
 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);
 }
 
@@ -1315,45 +1344,57 @@ static int coresight_orphan_match(struct device *dev, void *data)
 {
 	int i, ret = 0;
 	bool still_orphan = false;
-	struct coresight_device *csdev, *i_csdev;
+	struct coresight_device *dst_csdev = data;
+	struct coresight_device *src_csdev = to_coresight_device(dev);
 	struct coresight_connection *conn;
-
-	csdev = data;
-	i_csdev = to_coresight_device(dev);
-
-	/* No need to check oneself */
-	if (csdev == i_csdev)
-		return 0;
+	bool fixup_self = (src_csdev == dst_csdev);
 
 	/* Move on to another component if no connection is orphan */
-	if (!i_csdev->orphan)
+	if (!src_csdev->orphan)
 		return 0;
 	/*
-	 * Circle throuch all the connection of that component.  If we find
-	 * an orphan connection whose name matches @csdev, link it.
+	 * Circle through all the connections of that component.  If we find
+	 * an orphan connection whose name matches @dst_csdev, link it.
 	 */
-	for (i = 0; i < i_csdev->pdata->nr_outport; i++) {
-		conn = &i_csdev->pdata->conns[i];
+	for (i = 0; i < src_csdev->pdata->nr_outconns; i++) {
+		conn = src_csdev->pdata->out_conns[i];
 
-		/* Skip the port if FW doesn't describe it */
-		if (!conn->child_fwnode)
+		/* Skip the port if it's already connected. */
+		if (conn->dest_dev)
 			continue;
-		/* We have found at least one orphan connection */
-		if (conn->child_dev == NULL) {
-			/* Does it match this newly added device? */
-			if (conn->child_fwnode == csdev->dev.fwnode) {
-				ret = coresight_make_links(i_csdev,
-							   conn, csdev);
-				if (ret)
-					return ret;
-			} else {
-				/* This component still has an orphan */
-				still_orphan = true;
-			}
+
+		/*
+		 * If we are at the "new" device, which triggered this search,
+		 * we must find the remote device from the fwnode in the
+		 * connection.
+		 */
+		if (fixup_self)
+			dst_csdev = coresight_find_csdev_by_fwnode(
+				conn->dest_fwnode);
+
+		/* Does it match this newly added device? */
+		if (dst_csdev && conn->dest_fwnode == dst_csdev->dev.fwnode) {
+			ret = coresight_make_links(src_csdev, conn, dst_csdev);
+			if (ret)
+				return ret;
+
+			/*
+			 * Install the device connection. This also indicates that
+			 * the links are operational on both ends.
+			 */
+			conn->dest_dev = dst_csdev;
+			conn->src_dev = src_csdev;
+
+			ret = coresight_add_in_conn(conn);
+			if (ret)
+				return ret;
+		} else {
+			/* This component still has an orphan */
+			still_orphan = true;
 		}
 	}
 
-	i_csdev->orphan = still_orphan;
+	src_csdev->orphan = still_orphan;
 
 	/*
 	 * Returning '0' in case we didn't encounter any error,
@@ -1368,91 +1409,43 @@ static int coresight_fixup_orphan_conns(struct coresight_device *csdev)
 			 csdev, coresight_orphan_match);
 }
 
-
-static int coresight_fixup_device_conns(struct coresight_device *csdev)
-{
-	int i, ret = 0;
-
-	for (i = 0; i < csdev->pdata->nr_outport; i++) {
-		struct coresight_connection *conn = &csdev->pdata->conns[i];
-
-		if (!conn->child_fwnode)
-			continue;
-		conn->child_dev =
-			coresight_find_csdev_by_fwnode(conn->child_fwnode);
-		if (conn->child_dev && conn->child_dev->has_conns_grp) {
-			ret = coresight_make_links(csdev, conn,
-						   conn->child_dev);
-			if (ret)
-				break;
-		} else {
-			csdev->orphan = true;
-		}
-	}
-
-	return ret;
-}
-
-static int coresight_remove_match(struct device *dev, void *data)
+/* coresight_remove_conns - Remove other device's references to this device */
+static void coresight_remove_conns(struct coresight_device *csdev)
 {
-	int i;
-	struct coresight_device *csdev, *iterator;
+	int i, j;
 	struct coresight_connection *conn;
 
-	csdev = data;
-	iterator = to_coresight_device(dev);
-
-	/* No need to check oneself */
-	if (csdev == iterator)
-		return 0;
-
 	/*
-	 * Circle throuch all the connection of that component.  If we find
-	 * a connection whose name matches @csdev, remove it.
+	 * Remove the input connection references from the destination device
+	 * for each output connection.
 	 */
-	for (i = 0; i < iterator->pdata->nr_outport; i++) {
-		conn = &iterator->pdata->conns[i];
-
-		if (conn->child_dev == NULL || conn->child_fwnode == NULL)
+	for (i = 0; i < csdev->pdata->nr_outconns; i++) {
+		conn = csdev->pdata->out_conns[i];
+		if (!conn->dest_dev)
 			continue;
 
-		if (csdev->dev.fwnode == conn->child_fwnode) {
-			iterator->orphan = true;
-			coresight_remove_links(iterator, conn);
-			/*
-			 * Drop the reference to the handle for the remote
-			 * device acquired in parsing the connections from
-			 * platform data.
-			 */
-			fwnode_handle_put(conn->child_fwnode);
-			conn->child_fwnode = NULL;
-			/* No need to continue */
-			break;
-		}
+		for (j = 0; j < conn->dest_dev->pdata->nr_inconns; ++j)
+			if (conn->dest_dev->pdata->in_conns[j] == conn) {
+				conn->dest_dev->pdata->in_conns[j] = NULL;
+				break;
+			}
 	}
 
 	/*
-	 * Returning '0' ensures that all known component on the
-	 * bus will be checked.
+	 * For all input connections, remove references to this device.
+	 * Connection objects are shared so modifying this device's input
+	 * connections affects the other device's output connection.
 	 */
-	return 0;
-}
+	for (i = 0; i < csdev->pdata->nr_inconns; ++i) {
+		conn = csdev->pdata->in_conns[i];
+		/* Input conns array is sparse */
+		if (!conn)
+			continue;
 
-/*
- * coresight_remove_conns - Remove references to this given devices
- * from the connections of other devices.
- */
-static void coresight_remove_conns(struct coresight_device *csdev)
-{
-	/*
-	 * Another device will point to this device only if there is
-	 * an output port connected to this one. i.e, if the device
-	 * doesn't have at least one input port, there is no point
-	 * in searching all the devices.
-	 */
-	if (csdev->pdata->nr_inport)
-		bus_for_each_dev(&coresight_bustype, NULL,
-				 csdev, coresight_remove_match);
+		conn->src_dev->orphan = true;
+		coresight_remove_links(conn->src_dev, conn);
+		conn->dest_dev = NULL;
+	}
 }
 
 /**
@@ -1544,24 +1537,27 @@ void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset)
  * to the output port of this device.
  */
 void coresight_release_platform_data(struct coresight_device *csdev,
+				     struct device *dev,
 				     struct coresight_platform_data *pdata)
 {
 	int i;
-	struct coresight_connection *conns = pdata->conns;
+	struct coresight_connection **conns = pdata->out_conns;
 
-	for (i = 0; i < pdata->nr_outport; i++) {
+	for (i = 0; i < pdata->nr_outconns; i++) {
 		/* If we have made the links, remove them now */
-		if (csdev && conns[i].child_dev)
-			coresight_remove_links(csdev, &conns[i]);
+		if (csdev && conns[i]->dest_dev)
+			coresight_remove_links(csdev, conns[i]);
 		/*
 		 * Drop the refcount and clear the handle as this device
 		 * is going away
 		 */
-		if (conns[i].child_fwnode) {
-			fwnode_handle_put(conns[i].child_fwnode);
-			pdata->conns[i].child_fwnode = NULL;
-		}
+		fwnode_handle_put(conns[i]->dest_fwnode);
+		conns[i]->dest_fwnode = NULL;
+		devm_kfree(dev, conns[i]);
 	}
+	devm_kfree(dev, pdata->out_conns);
+	devm_kfree(dev, pdata->in_conns);
+	devm_kfree(dev, pdata);
 	if (csdev)
 		coresight_remove_conns_sysfs_group(csdev);
 }
@@ -1569,9 +1565,6 @@ 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;
 
@@ -1581,32 +1574,13 @@ 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->nr_inport;
-		else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
-			nr_refcnts = desc->pdata->nr_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;
 	csdev->subtype = desc->subtype;
 	csdev->ops = desc->ops;
 	csdev->access = desc->access;
-	csdev->orphan = false;
+	csdev->orphan = true;
 
 	csdev->dev.type = &coresight_dev_type[desc->type];
 	csdev->dev.groups = desc->groups;
@@ -1657,8 +1631,6 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
 
 	ret = coresight_create_conns_sysfs_group(csdev);
 	if (!ret)
-		ret = coresight_fixup_device_conns(csdev);
-	if (!ret)
 		ret = coresight_fixup_orphan_conns(csdev);
 
 out_unlock:
@@ -1678,7 +1650,7 @@ out_unlock:
 
 err_out:
 	/* Cleanup the connection information */
-	coresight_release_platform_data(NULL, desc->pdata);
+	coresight_release_platform_data(NULL, desc->dev, desc->pdata);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(coresight_register);
@@ -1691,7 +1663,7 @@ void coresight_unregister(struct coresight_device *csdev)
 		cti_assoc_ops->remove(csdev);
 	coresight_remove_conns(csdev);
 	coresight_clear_default_sink(csdev);
-	coresight_release_platform_data(csdev, csdev->pdata);
+	coresight_release_platform_data(csdev, csdev->dev.parent, csdev->pdata);
 	device_unregister(&csdev->dev);
 }
 EXPORT_SYMBOL_GPL(coresight_unregister);
@@ -1714,6 +1686,69 @@ static inline int coresight_search_device_idx(struct coresight_dev_list *dict,
 	return -ENOENT;
 }
 
+static bool coresight_compare_type(enum coresight_dev_type type_a,
+				   union coresight_dev_subtype subtype_a,
+				   enum coresight_dev_type type_b,
+				   union coresight_dev_subtype subtype_b)
+{
+	if (type_a != type_b)
+		return false;
+
+	switch (type_a) {
+	case CORESIGHT_DEV_TYPE_SINK:
+		return subtype_a.sink_subtype == subtype_b.sink_subtype;
+	case CORESIGHT_DEV_TYPE_LINK:
+		return subtype_a.link_subtype == subtype_b.link_subtype;
+	case CORESIGHT_DEV_TYPE_LINKSINK:
+		return subtype_a.link_subtype == subtype_b.link_subtype &&
+		       subtype_a.sink_subtype == subtype_b.sink_subtype;
+	case CORESIGHT_DEV_TYPE_SOURCE:
+		return subtype_a.source_subtype == subtype_b.source_subtype;
+	case CORESIGHT_DEV_TYPE_HELPER:
+		return subtype_a.helper_subtype == subtype_b.helper_subtype;
+	default:
+		return false;
+	}
+}
+
+struct coresight_device *
+coresight_find_input_type(struct coresight_platform_data *pdata,
+			  enum coresight_dev_type type,
+			  union coresight_dev_subtype subtype)
+{
+	int i;
+	struct coresight_connection *conn;
+
+	for (i = 0; i < pdata->nr_inconns; ++i) {
+		conn = pdata->in_conns[i];
+		if (conn &&
+		    coresight_compare_type(type, subtype, conn->src_dev->type,
+					   conn->src_dev->subtype))
+			return conn->src_dev;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(coresight_find_input_type);
+
+struct coresight_device *
+coresight_find_output_type(struct coresight_platform_data *pdata,
+			   enum coresight_dev_type type,
+			   union coresight_dev_subtype subtype)
+{
+	int i;
+	struct coresight_connection *conn;
+
+	for (i = 0; i < pdata->nr_outconns; ++i) {
+		conn = pdata->out_conns[i];
+		if (conn->dest_dev &&
+		    coresight_compare_type(type, subtype, conn->dest_dev->type,
+					   conn->dest_dev->subtype))
+			return conn->dest_dev;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(coresight_find_output_type);
+
 bool coresight_loses_context_with_cpu(struct device *dev)
 {
 	return fwnode_property_present(dev_fwnode(dev),