FROMLIST: v4l: fwnode: Support generic parsing of graph endpoints in a device

Add two functions for parsing devices graph endpoints:
v4l2_async_notifier_parse_fwnode_endpoints and
v4l2_async_notifier_parse_fwnode_endpoints_by_port. The former iterates
over all endpoints whereas the latter only iterates over the endpoints in
a given port.

The former is mostly useful for existing drivers that currently implement
the iteration over all the endpoints themselves whereas the latter is
especially intended for devices with both sinks and sources: async
sub-devices for external devices connected to the device's sources will
have already been set up, or they are part of the master device.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
(cherry picked from commit 339b5569a4c60144ae8b4aae497080ceea9190fa)
https://git.linuxtv.org/sailus/media_tree.git/log/?h=010f7f4393fd
http://www.spinics.net/lists/linux-media/msg122688.html
Signed-off-by: Marc Herbert <marc.herbert@intel.com>

Conflicts:
	include/media/v4l2-fwnode.h
(purely contextual conflict)

BUG=b:64133998
TEST=media device topology shows subdevs registered successfully
TEST=no camera regression

Change-Id: I97772ddab949a86f4a0eb2e3610d72cba22709ef
Reviewed-on: https://chromium-review.googlesource.com/693688
Commit-Ready: Tomasz Figa <tfiga@chromium.org>
Tested-by: Hyungwoo Yang <hyungwoo.yang@intel.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Jacob Chen <jacob2.chen@rock-chips.com>

Author: Sakari Ailus

drivers/media/v4l2-core/v4l2-async.c

@@ -21,6 +21,7 @@
 
 #include <media/v4l2-async.h>
 #include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
 #include <media/v4l2-subdev.h>
 
 static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
@@ -225,6 +226,35 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
 }
 EXPORT_SYMBOL(v4l2_async_notifier_unregister);
 
+void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
+{
+	unsigned int i;
+
+	if (!notifier->max_subdevs)
+		return;
+
+	for (i = 0; i < notifier->num_subdevs; i++) {
+		struct v4l2_async_subdev *asd = notifier->subdevs[i];
+
+		switch (asd->match_type) {
+		case V4L2_ASYNC_MATCH_FWNODE:
+			fwnode_handle_put(asd->match.fwnode.fwnode);
+			break;
+		default:
+			WARN_ON_ONCE(true);
+		}
+
+		kfree(asd);
+	}
+
+	notifier->max_subdevs = 0;
+	notifier->num_subdevs = 0;
+
+	kvfree(notifier->subdevs);
+	notifier->subdevs = NULL;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup);
+
 int v4l2_async_register_subdev(struct v4l2_subdev *sd)
 {
 	struct v4l2_async_notifier *notifier;

drivers/media/v4l2-core/v4l2-fwnode.c

@@ -19,13 +19,15 @@
  */
 #include <linux/acpi.h>
 #include <linux/kernel.h>
+#include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/types.h>
 
+#include <media/v4l2-async.h>
 #include <media/v4l2-fwnode.h>
 
 static int v4l2_fwnode_endpoint_parse_csi_bus(struct fwnode_handle *fwnode,
@@ -264,6 +266,200 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
 }
 EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
 
+static int v4l2_async_notifier_realloc(struct v4l2_async_notifier *notifier,
+				       unsigned int max_subdevs)
+{
+	struct v4l2_async_subdev **subdevs;
+
+	if (max_subdevs <= notifier->max_subdevs)
+		return 0;
+
+	subdevs = kcalloc(
+		max_subdevs, sizeof(*notifier->subdevs),
+		GFP_KERNEL | __GFP_ZERO);
+	if (!subdevs)
+		return -ENOMEM;
+
+	if (notifier->subdevs) {
+		memcpy(subdevs, notifier->subdevs,
+		       sizeof(*subdevs) * notifier->num_subdevs);
+
+		kfree(notifier->subdevs);
+	}
+
+	notifier->subdevs = subdevs;
+	notifier->max_subdevs = max_subdevs;
+
+	return 0;
+}
+
+static int v4l2_async_notifier_fwnode_parse_endpoint(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	struct fwnode_handle *endpoint, unsigned int asd_struct_size,
+	int (*parse_endpoint)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	struct v4l2_async_subdev *asd;
+	struct v4l2_fwnode_endpoint *vep;
+	int ret = 0;
+
+	asd = kzalloc(asd_struct_size, GFP_KERNEL);
+	if (!asd)
+		return -ENOMEM;
+
+	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
+	asd->match.fwnode.fwnode =
+		fwnode_graph_get_remote_port_parent(endpoint);
+	if (!asd->match.fwnode.fwnode) {
+		dev_warn(dev, "bad remote port parent\n");
+		ret = -EINVAL;
+		goto out_err;
+	}
+
+	vep = v4l2_fwnode_endpoint_alloc_parse(endpoint);
+	if (IS_ERR(vep)) {
+		ret = PTR_ERR(vep);
+		dev_warn(dev, "unable to parse V4L2 fwnode endpoint (%d)\n",
+			 ret);
+		goto out_err;
+	}
+
+	ret = parse_endpoint ? parse_endpoint(dev, vep, asd) : 0;
+	if (ret == -ENOTCONN)
+		dev_dbg(dev, "ignoring port@%u/endpoint@%u\n", vep->base.port,
+			vep->base.id);
+	else if (ret < 0)
+		dev_warn(dev,
+			 "driver could not parse port@%u/endpoint@%u (%d)\n",
+			 vep->base.port, vep->base.id, ret);
+	v4l2_fwnode_endpoint_free(vep);
+	if (ret < 0)
+		goto out_err;
+
+	notifier->subdevs[notifier->num_subdevs] = asd;
+	notifier->num_subdevs++;
+
+	return 0;
+
+out_err:
+	fwnode_handle_put(asd->match.fwnode.fwnode);
+	kfree(asd);
+
+	return ret == -ENOTCONN ? 0 : ret;
+}
+
+static int __v4l2_async_notifier_parse_fwnode_endpoints(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	size_t asd_struct_size, unsigned int port, bool has_port,
+	int (*parse_endpoint)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	struct fwnode_handle *fwnode = NULL;
+	unsigned int max_subdevs = notifier->max_subdevs;
+	int ret;
+
+	if (WARN_ON(asd_struct_size < sizeof(struct v4l2_async_subdev)))
+		return -EINVAL;
+
+	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
+				     dev_fwnode(dev), fwnode)); ) {
+		struct fwnode_handle *dev_fwnode;
+		bool is_available;
+
+		dev_fwnode = fwnode_graph_get_port_parent(fwnode);
+		is_available = fwnode_device_is_available(dev_fwnode);
+		fwnode_handle_put(dev_fwnode);
+		if (!is_available)
+			continue;
+
+		if (has_port) {
+			struct fwnode_endpoint ep;
+
+			ret = fwnode_graph_parse_endpoint(fwnode, &ep);
+			if (ret) {
+				fwnode_handle_put(fwnode);
+				return ret;
+			}
+
+			if (ep.port != port)
+				continue;
+		}
+		max_subdevs++;
+	}
+
+	/* No subdevs to add? Return here. */
+	if (max_subdevs == notifier->max_subdevs)
+		return 0;
+
+	ret = v4l2_async_notifier_realloc(notifier, max_subdevs);
+	if (ret)
+		return ret;
+
+	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
+				     dev_fwnode(dev), fwnode)); ) {
+		struct fwnode_handle *dev_fwnode;
+		bool is_available;
+
+		dev_fwnode = fwnode_graph_get_port_parent(fwnode);
+		is_available = fwnode_device_is_available(dev_fwnode);
+		fwnode_handle_put(dev_fwnode);
+
+		if (!fwnode_device_is_available(dev_fwnode))
+			continue;
+
+		if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs)) {
+			ret = -EINVAL;
+			break;
+		}
+
+		if (has_port) {
+			struct fwnode_endpoint ep;
+
+			ret = fwnode_graph_parse_endpoint(fwnode, &ep);
+			if (ret)
+				break;
+
+			if (ep.port != port)
+				continue;
+		}
+
+		ret = v4l2_async_notifier_fwnode_parse_endpoint(
+			dev, notifier, fwnode, asd_struct_size, parse_endpoint);
+		if (ret < 0)
+			break;
+	}
+
+	fwnode_handle_put(fwnode);
+
+	return ret;
+}
+
+int v4l2_async_notifier_parse_fwnode_endpoints(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	size_t asd_struct_size,
+	int (*parse_endpoint)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	return __v4l2_async_notifier_parse_fwnode_endpoints(
+		dev, notifier, asd_struct_size, 0, false, parse_endpoint);
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
+
+int v4l2_async_notifier_parse_fwnode_endpoints_by_port(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	size_t asd_struct_size, unsigned int port,
+	int (*parse_endpoint)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	return __v4l2_async_notifier_parse_fwnode_endpoints(
+		dev, notifier, asd_struct_size, port, true, parse_endpoint);
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints_by_port);
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
 MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");

include/media/v4l2-async.h

@@ -18,7 +18,6 @@ struct device;
 struct device_node;
 struct v4l2_device;
 struct v4l2_subdev;
-struct v4l2_async_notifier;
 
 /* A random max subdevice number, used to allocate an array on stack */
 #define V4L2_MAX_SUBDEVS 128U
@@ -50,6 +49,10 @@ enum v4l2_async_match_type {
  * @match:	union of per-bus type matching data sets
  * @list:	used to link struct v4l2_async_subdev objects, waiting to be
  *		probed, to a notifier->waiting list
+ *
+ * When this struct is used as a member in a driver specific struct,
+ * the driver specific struct shall contain the &struct
+ * v4l2_async_subdev as its first member.
  */
 struct v4l2_async_subdev {
 	enum v4l2_async_match_type match_type;
@@ -78,7 +81,8 @@ struct v4l2_async_subdev {
 /**
  * struct v4l2_async_notifier - v4l2_device notifier data
  *
- * @num_subdevs: number of subdevices
+ * @num_subdevs: number of subdevices used in the subdevs array
+ * @max_subdevs: number of subdevices allocated in the subdevs array
  * @subdevs:	array of pointers to subdevice descriptors
  * @v4l2_dev:	pointer to struct v4l2_device
  * @waiting:	list of struct v4l2_async_subdev, waiting for their drivers
@@ -90,6 +94,7 @@ struct v4l2_async_subdev {
  */
 struct v4l2_async_notifier {
 	unsigned int num_subdevs;
+	unsigned int max_subdevs;
 	struct v4l2_async_subdev **subdevs;
 	struct v4l2_device *v4l2_dev;
 	struct list_head waiting;
@@ -104,9 +109,50 @@ struct v4l2_async_notifier {
 		       struct v4l2_async_subdev *asd);
 };
 
+/**
+ * v4l2_async_notifier_register - registers a subdevice asynchronous notifier
+ *
+ * @v4l2_dev: pointer to &struct v4l2_device
+ * @notifier: pointer to &struct v4l2_async_notifier
+ */
 int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
 				 struct v4l2_async_notifier *notifier);
+
+/**
+ * v4l2_async_notifier_unregister - unregisters a subdevice asynchronous notifier
+ *
+ * @notifier: pointer to &struct v4l2_async_notifier
+ */
 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
+
+/**
+ * v4l2_async_notifier_cleanup - clean up notifier resources
+ * @notifier: the notifier the resources of which are to be cleaned up
+ *
+ * Release memory resources related to a notifier, including the async
+ * sub-devices allocated for the purposes of the notifier but not the notifier
+ * itself. The user is responsible for calling this function to clean up the
+ * notifier after calling @v4l2_async_notifier_parse_fwnode_endpoints.
+ *
+ * There is no harm from calling v4l2_async_notifier_cleanup in other
+ * cases as long as its memory has been zeroed after it has been
+ * allocated.
+ */
+void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier);
+
+/**
+ * v4l2_async_register_subdev - registers a sub-device to the asynchronous
+ * 	subdevice framework
+ *
+ * @sd: pointer to &struct v4l2_subdev
+ */
 int v4l2_async_register_subdev(struct v4l2_subdev *sd);
+
+/**
+ * v4l2_async_unregister_subdev - unregisters a sub-device to the asynchronous
+ * 	subdevice framework
+ *
+ * @sd: pointer to &struct v4l2_subdev
+ */
 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
 #endif