coresight: platform: Refactor graph endpoint parsing

Refactor the of graph endpoint parsing code, to make the error
handling easier.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hwtracing/coresight/of_coresight.c b/drivers/hwtracing/coresight/of_coresight.c
index 6880bee..70205f3 100644 (file)
--- a/drivers/hwtracing/coresight/of_coresight.c
+++ b/drivers/hwtracing/coresight/of_coresight.c
@@ -114,17 +114,70 @@ int of_coresight_get_cpu(const struct device_node *node)
 }
 EXPORT_SYMBOL_GPL(of_coresight_get_cpu);
 
+/*
+ * of_coresight_parse_endpoint : Parse the given output endpoint @ep
+ * and fill the connection information in @pdata[@i].
+ *
+ * Parses the local port, remote device name and the remote port.
+ *
+ * Returns :
+ *      1      - If the parsing is successful and a connection record
+ *               was created for an output connection.
+ *      0      - If the parsing completed without any fatal errors.
+ *     -Errno  - Fatal error, abort the scanning.
+ */
+static int of_coresight_parse_endpoint(struct device *dev,
+                                      struct device_node *ep,
+                                      struct coresight_platform_data *pdata,
+                                      int i)
+{
+       int ret = 0;
+       struct of_endpoint endpoint, rendpoint;
+       struct device_node *rparent = NULL;
+       struct device_node *rport = NULL;
+       struct device *rdev = NULL;
+
+       do {
+               /* Parse the local port details */
+               if (of_graph_parse_endpoint(ep, &endpoint))
+                       break;
+               /*
+                * Get a handle on the remote port and parent
+                * attached to it.
+                */
+               rparent = of_graph_get_remote_port_parent(ep);
+               if (!rparent)
+                       break;
+               rport = of_graph_get_remote_port(ep);
+               if (!rport)
+                       break;
+               if (of_graph_parse_endpoint(rport, &rendpoint))
+                       break;
+
+               /* If the remote device is not available, defer probing */
+               rdev = of_coresight_get_endpoint_device(rparent);
+               if (!rdev) {
+                       ret = -EPROBE_DEFER;
+                       break;
+               }
+
+               pdata->outports[i] = endpoint.port;
+               pdata->child_names[i] = dev_name(rdev);
+               pdata->child_ports[i] = rendpoint.id;
+               /* Connection record updated */
+               ret = 1;
+       } while (0);
+
+       return ret;
+}
+
 struct coresight_platform_data *
 of_get_coresight_platform_data(struct device *dev,
                               const struct device_node *node)
 {
        int i = 0, ret = 0;
        struct coresight_platform_data *pdata;
-       struct of_endpoint endpoint, rendpoint;
-       struct device *rdev;
        struct device_node *ep = NULL;
-       struct device_node *rparent = NULL;
-       struct device_node *rport = NULL;
 
        pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata)
@@ -132,64 +185,39 @@ of_get_coresight_platform_data(struct device *dev,
 
        /* Use device name as sysfs handle */
        pdata->name = dev_name(dev);
+       pdata->cpu = of_coresight_get_cpu(node);
 
        /* Get the number of input and output port for this component */
        of_coresight_get_ports(node, &pdata->nr_inport, &pdata->nr_outport);
 
-       if (pdata->nr_outport) {
-               ret = of_coresight_alloc_memory(dev, pdata);
-               if (ret)
+       /* If there are no output connections, we are done */
+       if (!pdata->nr_outport)
+               return pdata;
+
+       ret = of_coresight_alloc_memory(dev, pdata);
+       if (ret)
+               return ERR_PTR(ret);
+
+       /* Iterate through each port to discover topology */
+       while ((ep = of_graph_get_next_endpoint(node, ep))) {
+               /*
+                * No need to deal with input ports, as processing the
+                * output ports connected to them will process the details.
+                */
+               if (of_find_property(ep, "slave-mode", NULL))
+                       continue;
+
+               ret = of_coresight_parse_endpoint(dev, ep, pdata, i);
+               switch (ret) {
+               case 1:
+                       i++;            /* Fall through */
+               case 0:
+                       break;
+               default:
                        return ERR_PTR(ret);
-
-               /* Iterate through each port to discover topology */
-               do {
-                       /* Get a handle on a port */
-                       ep = of_graph_get_next_endpoint(node, ep);
-                       if (!ep)
-                               break;
-
-                       /*
-                        * No need to deal with input ports, processing for as
-                        * processing for output ports will deal with them.
-                        */
-                       if (of_find_property(ep, "slave-mode", NULL))
-                               continue;
-
-                       /* Get a handle on the local endpoint */
-                       ret = of_graph_parse_endpoint(ep, &endpoint);
-
-                       if (ret)
-                               continue;
-
-                       /* The local out port number */
-                       pdata->outports[i] = endpoint.port;
-
-                       /*
-                        * Get a handle on the remote port and parent
-                        * attached to it.
-                        */
-                       rparent = of_graph_get_remote_port_parent(ep);
-                       rport = of_graph_get_remote_port(ep);
-
-                       if (!rparent || !rport)
-                               continue;
-
-                       if (of_graph_parse_endpoint(rport, &rendpoint))
-                               continue;
-
-                       rdev = of_coresight_get_endpoint_device(rparent);
-                       if (!rdev)
-                               return ERR_PTR(-EPROBE_DEFER);
-
-                       pdata->child_names[i] = dev_name(rdev);
-                       pdata->child_ports[i] = rendpoint.id;
-
-                       i++;
-               } while (ep);
+               }
        }
 
-       pdata->cpu = of_coresight_get_cpu(node);
-
        return pdata;
 }
 EXPORT_SYMBOL_GPL(of_get_coresight_platform_data);