[PATCH v2 09/10] coresight: Cleanup coresight DT bindings

[Suzuki K Poulose <suzuki.poulose@arm.com>]

The coresight drivers relied on default bindings for graph
in DT, while reusing the "reg" field of the "ports" to indicate
the actual hardware port number for the connections. This can
cause duplicate ports with same addresses, but different
direction. However, with the rules getting stricter w.r.t to the
address mismatch with the label, it is no longer possible to use
the port address field for the hardware port number.

This patch introduces new DT binding rules for coresight
components, based on the same generic DT graph bindings, but
avoiding the address duplication.

- All output ports must be specified under a child node with
  name "out-ports".
- All input ports must be specified under a childe node with
  name "in-ports".
- Port address should match the hardware port number.

The support for legacy bindings is retained, with a warning.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 .../devicetree/bindings/arm/coresight.txt          | 91 ++++++++++----------
 drivers/hwtracing/coresight/of_coresight.c         | 97 +++++++++++++++++++---
 2 files changed, 129 insertions(+), 59 deletions(-)

diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
index 8e21512..f39d2c6 100644
--- a/Documentation/devicetree/bindings/arm/coresight.txt
+++ b/Documentation/devicetree/bindings/arm/coresight.txt
@@ -104,19 +104,9 @@ The connections must be described via generic DT graph bindings as described
 by the "bindings/graph.txt", where each "port" along with an "endpoint"
 component represents a hardware port and the connection.
 
-Since it is possible to have multiple connections for any coresight component
-with a specific direction of data flow, each connection must define the
-following properties to uniquely identify the connection details.
-
- * Direction of the data flow w.r.t the component :
-   Each input port must have the following property defined at the "endpoint"
-   for the port.
-	"slave-mode"
-
- * Hardware Port number at the component:
-     -  The hardware port number is assumed to be the address of the "port"
-         component.
-
+ * All output ports must be listed inside a child node named "out-ports"
+ * All input ports must be listed inside a child node named "in-ports".
+ * Port address must match the hardware port number.
 
 Example:
 
@@ -127,10 +117,11 @@ Example:
 
 		clocks = <&oscclk6a>;
 		clock-names = "apb_pclk";
-		port {
-			etb_in_port: endpoint@0 {
-				slave-mode;
-				remote-endpoint = <&replicator_out_port0>;
+		in-ports {
+			port {
+				etb_in_port: endpoint@0 {
+					remote-endpoint = <&replicator_out_port0>;
+				};
 			};
 		};
 	};
@@ -141,10 +132,11 @@ Example:
 
 		clocks = <&oscclk6a>;
 		clock-names = "apb_pclk";
-		port {
-			tpiu_in_port: endpoint@0 {
-				slave-mode;
-				remote-endpoint = <&replicator_out_port1>;
+		out-ports {
+			port {
+				tpiu_in_port: endpoint@0 {
+					remote-endpoint = <&replicator_out_port1>;
+				};
 			};
 		};
 	};
@@ -185,7 +177,7 @@ Example:
 		 */
 		compatible = "arm,coresight-replicator";
 
-		ports {
+		out-ports {
 			#address-cells = <1>;
 			#size-cells = <0>;
 
@@ -203,12 +195,11 @@ Example:
 					remote-endpoint = <&tpiu_in_port>;
 				};
 			};
+		};
 
-			/* replicator input port */
-			port@2 {
-				reg = <0>;
+		in-ports {
+			port {
 				replicator_in_port0: endpoint {
-					slave-mode;
 					remote-endpoint = <&funnel_out_port0>;
 				};
 			};
@@ -221,40 +212,36 @@ Example:
 
 		clocks = <&oscclk6a>;
 		clock-names = "apb_pclk";
-		ports {
-			#address-cells = <1>;
-			#size-cells = <0>;
-
-			/* funnel output port */
-			port@0 {
-				reg = <0>;
+		out-ports {
+			port {
 				funnel_out_port0: endpoint {
 					remote-endpoint =
 							<&replicator_in_port0>;
 				};
 			};
+		};
 
-			/* funnel input ports */
-			port@1 {
+		in-ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 {
 				reg = <0>;
 				funnel_in_port0: endpoint {
-					slave-mode;
 					remote-endpoint = <&ptm0_out_port>;
 				};
 			};
 
-			port@2 {
+			port@1 {
 				reg = <1>;
 				funnel_in_port1: endpoint {
-					slave-mode;
 					remote-endpoint = <&ptm1_out_port>;
 				};
 			};
 
-			port@3 {
+			port@2 {
 				reg = <2>;
 				funnel_in_port2: endpoint {
-					slave-mode;
 					remote-endpoint = <&etm0_out_port>;
 				};
 			};
@@ -270,9 +257,11 @@ Example:
 		cpu = <&cpu0>;
 		clocks = <&oscclk6a>;
 		clock-names = "apb_pclk";
-		port {
-			ptm0_out_port: endpoint {
-				remote-endpoint = <&funnel_in_port0>;
+		out-ports {
+			port {
+				ptm0_out_port: endpoint {
+					remote-endpoint = <&funnel_in_port0>;
+				};
 			};
 		};
 	};
@@ -284,9 +273,11 @@ Example:
 		cpu = <&cpu1>;
 		clocks = <&oscclk6a>;
 		clock-names = "apb_pclk";
-		port {
-			ptm1_out_port: endpoint {
-				remote-endpoint = <&funnel_in_port1>;
+		out-ports {
+			port {
+				ptm1_out_port: endpoint {
+					remote-endpoint = <&funnel_in_port1>;
+				};
 			};
 		};
 	};
@@ -300,9 +291,11 @@ Example:
 
 		clocks = <&soc_smc50mhz>;
 		clock-names = "apb_pclk";
-		port {
-			stm_out_port: endpoint {
-				remote-endpoint = <&main_funnel_in_port2>;
+		out-ports {
+			port {
+				stm_out_port: endpoint {
+					remote-endpoint = <&main_funnel_in_port2>;
+				};
 			};
 		};
 	};
diff --git a/drivers/hwtracing/coresight/of_coresight.c b/drivers/hwtracing/coresight/of_coresight.c
index f9e2169..2178734 100644
--- a/drivers/hwtracing/coresight/of_coresight.c
+++ b/drivers/hwtracing/coresight/of_coresight.c
@@ -45,13 +45,13 @@ of_coresight_get_endpoint_device(struct device_node *endpoint)
 			       endpoint, of_dev_node_match);
 }
 
-static inline bool of_coresight_ep_is_input(struct device_node *ep)
+static inline bool of_coresight_legacy_ep_is_input(struct device_node *ep)
 {
 	return of_property_read_bool(ep, "slave-mode");
 }
 
-static void of_coresight_get_ports(const struct device_node *node,
-				   int *nr_inport, int *nr_outport)
+static void of_coresight_get_ports_legacy(const struct device_node *node,
+					  int *nr_inport, int *nr_outport)
 {
 	struct device_node *ep = NULL;
 	int in = 0, out = 0;
@@ -61,7 +61,7 @@ static void of_coresight_get_ports(const struct device_node *node,
 		if (!ep)
 			break;
 
-		if (of_coresight_ep_is_input(ep))
+		if (of_coresight_legacy_ep_is_input(ep))
 			in++;
 		else
 			out++;
@@ -72,6 +72,67 @@ static void of_coresight_get_ports(const struct device_node *node,
 	*nr_outport = out;
 }
 
+static struct device_node *of_coresight_get_port_parent(struct device_node *ep)
+{
+	struct device_node *parent = of_graph_get_port_parent(ep);
+
+	/*
+	 * Skip one-level up to the real device node, if we
+	 * are using the new bindings.
+	 */
+	if (!of_node_cmp(parent->name, "in-ports") ||
+	    !of_node_cmp(parent->name, "out-ports"))
+		parent = of_get_next_parent(parent);
+
+	return parent;
+}
+
+static inline struct device_node *
+of_coresight_get_input_ports_node(const struct device_node *node)
+{
+	return of_get_child_by_name(node, "in-ports");
+}
+
+static inline struct device_node *
+of_coresight_get_output_ports_node(const struct device_node *node)
+{
+	return of_get_child_by_name(node, "out-ports");
+}
+
+static inline int
+of_coresight_count_ports(struct device_node *port_parent)
+{
+	int i = 0;
+	struct device_node *ep = NULL;
+
+	while ((ep = of_graph_get_next_endpoint(port_parent, ep)))
+		i++;
+	return i;
+}
+
+static void of_coresight_get_ports(const struct device_node *node,
+				   int *nr_inport, int *nr_outport)
+{
+	struct device_node *input_ports = NULL, *output_ports = NULL;
+
+	input_ports = of_coresight_get_input_ports_node(node);
+	output_ports = of_coresight_get_output_ports_node(node);
+
+	if (input_ports || output_ports) {
+		if (input_ports) {
+			*nr_inport = of_coresight_count_ports(input_ports);
+			of_node_put(input_ports);
+		}
+		if (output_ports) {
+			*nr_outport = of_coresight_count_ports(output_ports);
+			of_node_put(output_ports);
+		}
+	} else {
+		/* Fall back to legacy DT bindings parsing */
+		of_coresight_get_ports_legacy(node, nr_inport, nr_outport);
+	}
+}
+
 static int of_coresight_alloc_memory(struct device *dev,
 			struct coresight_platform_data *pdata)
 {
@@ -136,7 +197,7 @@ static int of_coresight_parse_endpoint(struct device *dev,
 		rep = of_graph_get_remote_endpoint(ep);
 		if (!rep)
 			break;
-		rparent = of_graph_get_port_parent(rep);
+		rparent = of_coresight_get_port_parent(rep);
 		if (!rparent)
 			break;
 		if (of_graph_parse_endpoint(rep, &rendpoint))
@@ -176,6 +237,8 @@ of_get_coresight_platform_data(struct device *dev,
 	struct coresight_platform_data *pdata;
 	struct coresight_connection *conn;
 	struct device_node *ep = NULL;
+	const struct device_node *parent = NULL;
+	bool legacy_binding = false;
 
 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
@@ -196,14 +259,28 @@ of_get_coresight_platform_data(struct device *dev,
 	if (ret)
 		return ERR_PTR(ret);
 
+	parent = of_coresight_get_output_ports_node(node);
+	/*
+	 * If the DT uses obsoleted bindings, the ports are listed
+	 * under the device and we need to filter out the input
+	 * ports.
+	 */
+	if (!parent) {
+		legacy_binding = true;
+		parent = node;
+		dev_warn_once(dev, "Uses obsolete Coresight DT bindings\n");
+	}
+
 	conn = pdata->conns;
-	/* Iterate through each port to discover topology */
-	while ((ep = of_graph_get_next_endpoint(node, ep))) {
+
+	/* Iterate through each output port to discover topology */
+	while ((ep = of_graph_get_next_endpoint(parent, ep))) {
 		/*
-		 * No need to deal with input ports, processing for as
-		 * processing for output ports will deal with them.
+		 * Legacy binding mixes input/output ports under the
+		 * same parent. So, skip the input ports if we are dealing
+		 * with legacy binding.
 		 */
-		if (of_coresight_ep_is_input(ep))
+		if (legacy_binding && of_coresight_legacy_ep_is_input(ep))
 			continue;
 
 		ret = of_coresight_parse_endpoint(dev, ep, &conn);
-- 
2.7.4