On 09/03/2017 07:49 PM, Sakari Ailus wrote:
> 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@xxxxxxxxxxxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-async.c | 16 ++++
> drivers/media/v4l2-core/v4l2-fwnode.c | 136 ++++++++++++++++++++++++++++++++++
> include/media/v4l2-async.h | 24 +++++-
> include/media/v4l2-fwnode.h | 53 +++++++++++++
> 4 files changed, 227 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index 851f128eba22..6740a241d4a1 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)
> @@ -278,6 +279,21 @@ 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;
> +
> + for (i = 0; i < notifier->num_subdevs; i++)
> + kfree(notifier->subdevs[i]);
> +
> + 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..f8c7a9bc6a58 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;
How likely is it that parse_endpoint will be NULL? I ask because if it is
common, then you could put everything from v4l2_fwnode_endpoint_alloc_parse
until just before 'asd->match_type = V4L2_ASYNC_MATCH_FWNODE;' under
'if (parse_endpoint) {'.
The disadvantage is that you won't see parse errors, but on the other hand
nobody apparently needs it, so why bother. I'm not sure what is the right thing
to do here.
> + v4l2_fwnode_endpoint_free(vep);
Here vep is freed,
> + if (ret == -ENOTCONN) {
> + dev_dbg(dev, "ignoring endpoint %u,%u\n", vep->base.port,
> + vep->base.id);
but still used here
> + kfree(asd);
> + return 0;
> + } else if (ret < 0) {
> + dev_warn(dev, "driver could not parse endpoint %u,%u (%d)\n",
> + vep->base.port, vep->base.id, ret);
and here.
> + 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;
> +}
> +
> +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 (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))
> + break;
I think you should return an error here. I feel that if this happens, then
something very strange is going on and you are better off returning -EINVAL
or something like that.
> +
> + 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@xxxxxxxxxxxxxxx>");
> MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>");
> 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..6d125f26ec84 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 +203,55 @@ 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. When using this function, the user may not access the
> + * notifier's subdevs array nor change notifier's num_subdevs field, these are
> + * reserved for the framework's internal use only.
I don't think the sentence "When using...only" makes any sense. How would you
even be able to access any of the notifier fields? You don't have access to it
from the parse_endpoint callback.
I think it can just be dropped.
> + *
> + * 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 */
>
Regards,
Hans
