[PATCH v9 05/24] v4l: fwnode: Support generic parsing of graph endpoints in a device

Sakari Ailus
2017-09-08T13:18:25Z

The current practice is that drivers iterate over their endpoints and
parse each endpoint separately. This is very similar in a number of
drivers, implement a generic function for the job. Driver specific matters
can be taken into account in the driver specific callback.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
drivers/media/v4l2-core/v4l2-async.c | 30 ++++++++
drivers/media/v4l2-core/v4l2-fwnode.c | 136 ++++++++++++++++++++++++++++++++++
include/media/v4l2-async.h | 24 +++++-
include/media/v4l2-fwnode.h | 56 ++++++++++++++
4 files changed, 244 insertions(+), 2 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 831f185ecd47..ad099b9bb71d 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -22,6 +22,7 @@

#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)
@@ -219,6 +220,35 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
}
EXPORT_SYMBOL(v4l2_async_notifier_unregister);

+void v4l2_async_notifier_release(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(1);
+ }
+
+ kfree(asd);
+ }
+
+ notifier->max_subdevs = 0;
+ notifier->num_subdevs = 0;
+
+ kvfree(notifier->subdevs);
+ notifier->subdevs = NULL;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_release);
+
int v4l2_async_register_subdev(struct v4l2_subdev *sd)
{
struct v4l2_async_notifier *notifier;
diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 706f9e7b90f1..d978f2d714ca 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -19,6 +19,7 @@
*/
#include <linux/acpi.h>
#include <linux/kernel.h>
+#include <linux/mm.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/property.h>
@@ -26,6 +27,7 @@
#include <linux/string.h>
#include <linux/types.h>

+#include <media/v4l2-async.h>
#include <media/v4l2-fwnode.h>

enum v4l2_fwnode_bus_type {
@@ -313,6 +315,140 @@ 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 = kvmalloc_array(
+ 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);
+
+ kvfree(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.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;
+ }
+
+ /* Ignore endpoints the parsing of which failed. */
+ 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 endpoint %u,%u\n", vep->base.port,
+ vep->base.id);
+ else if (ret < 0)
+ dev_warn(dev, "driver could not parse endpoint %u,%u (%d)\n",
+ vep->base.port, vep->base.id, ret);
+ v4l2_fwnode_endpoint_free(vep);
+ if (ret < 0)
+ goto out_err;
+
+ asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
+ 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;
+}
+
+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))
+{
+ 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)); )
+ if (fwnode_device_is_available(
+ fwnode_graph_get_port_parent(fwnode)))
+ 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)); ) {
+ if (!fwnode_device_is_available(
+ fwnode_graph_get_port_parent(fwnode)))
+ continue;
+
+ if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs)) {
+ ret = -EINVAL;
+ break;
+ }
+
+ 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;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
index c69d8c8a66d0..96fa1afc00dd 100644
--- a/include/media/v4l2-async.h
+++ b/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;
@@ -121,6 +126,21 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);

/**
+ * v4l2_async_notifier_release - release notifier resources
+ * @notifier: the notifier the resources of which are to be released
+ *
+ * Release memory resources related to a notifier, including the async
+ * sub-devices allocated for the purposes of the notifier. The user is
+ * responsible for releasing the notifier's resources after calling
+ * @v4l2_async_notifier_parse_fwnode_endpoints.
+ *
+ * There is no harm from calling v4l2_async_notifier_release in other
+ * cases as long as its memory has been zeroed after it has been
+ * allocated.
+ */
+void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier);
+
+/**
* v4l2_async_register_subdev - registers a sub-device to the asynchronous
* subdevice framework
*
diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
index 68eb22ba571b..3819a73c3c8a 100644
--- a/include/media/v4l2-fwnode.h
+++ b/include/media/v4l2-fwnode.h
@@ -25,6 +25,8 @@
#include <media/v4l2-mediabus.h>

struct fwnode_handle;
+struct v4l2_async_notifier;
+struct v4l2_async_subdev;

#define V4L2_FWNODE_CSI2_MAX_DATA_LANES 4

@@ -201,4 +203,58 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
*/
void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);

+/**
+ * v4l2_async_notifier_parse_fwnode_endpoints - Parse V4L2 fwnode endpoints in a
+ * device node
+ * @dev: the device the endpoints of which are to be parsed
+ * @notifier: notifier for @dev
+ * @asd_struct_size: size of the driver's async sub-device struct, including
+ * sizeof(struct v4l2_async_subdev). The &struct
+ * v4l2_async_subdev shall be the first member of
+ * the driver's async sub-device struct, i.e. both
+ * begin at the same memory address.
+ * @parse_endpoint: Driver's callback function called on each V4L2 fwnode
+ * endpoint. Optional.
+ * Return: %0 on success
+ * %-ENOTCONN if the endpoint is to be skipped but this
+ * should not be considered as an error
+ * %-EINVAL if the endpoint configuration is invalid
+ *
+ * Parse the fwnode endpoints of the @dev device and populate the async sub-
+ * devices array of the notifier. The @parse_endpoint callback function is
+ * called for each endpoint with the corresponding async sub-device pointer to
+ * let the caller initialize the driver-specific part of the async sub-device
+ * structure.
+ *
+ * The notifier memory shall be zeroed before this function is called on the
+ * notifier.
+ *
+ * This function may not be called on a registered notifier and may be called on
+ * a notifier only once.
+ *
+ * Do not change the notifier's subdevs array, take references to the subdevs
+ * array itself or change the notifier's num_subdevs field. This is because this
+ * function allocates and reallocates the subdevs array based on parsing
+ * endpoints.
+ *
+ * The @struct v4l2_fwnode_endpoint passed to the callback function
+ * @parse_endpoint is released once the function is finished. If there is a need
+ * to retain that configuration, the user needs to allocate memory for it.
+ *
+ * Any notifier populated using this function must be released with a call to
+ * v4l2_async_notifier_release() after it has been unregistered and the async
+ * sub-devices are no longer in use.
+ *
+ * Return: %0 on success, including when no async sub-devices are found
+ * %-ENOMEM if memory allocation failed
+ * %-EINVAL if graph or endpoint parsing failed
+ * Other error codes as returned by @parse_endpoint
+ */
+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));
+
#endif /* _V4L2_FWNODE_H */
--
2.11.0