On 09/19/2017 10:20 AM, Sakari Ailus wrote:
> Hi Hans,
>
> Thank you for the review.
>
> On Tue, Sep 19, 2017 at 10:03:27AM +0200, Hans Verkuil wrote:
>> On 09/15/2017 04:17 PM, Sakari Ailus wrote:
>>> 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@xxxxxxxxxxxxxxx>
>>> ---
>>> drivers/media/v4l2-core/v4l2-async.c | 30 ++++++
>>> drivers/media/v4l2-core/v4l2-fwnode.c | 185 ++++++++++++++++++++++++++++++++++
>>> include/media/v4l2-async.h | 24 ++++-
>>> include/media/v4l2-fwnode.h | 117 +++++++++++++++++++++
>>> 4 files changed, 354 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
>>> index 831f185ecd47..bf0215dde616 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(true);
>>
>> Please add a break here.
>
> Yes.
>
>>
>>> + }
>>> +
>>> + 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..44ee35f6aad5 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 +315,189 @@ 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;
>>> +}
>>> +
>>> +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)); ) {
>>
>> You can replace this by:
>>
>> while ((fwnode = fwnode_graph_get_next_endpoint(dev_fwnode(dev), fwnode))) {
>>
>>> + if (!fwnode_device_is_available(
>>> + fwnode_graph_get_port_parent(fwnode)))
>>> + 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)); ) {
>>
>> Same here: this can be a 'while'.
>
> The fwnode = NULL assignment still needs to be done. A for loop has a
> natural initialiser for the loop, I think it's cleaner than using while
> here.
After the previous while fwnode is NULL again (since that's when the while
stops).
>
> The macro would be implemented this way as well.
>
> For the loop above this one, I'd use for for consistency: it's the same
> loop after all.
>
> This reminds me --- I'll send the patch for the macro.
If this is going to be replaced by a macro, then disregard my comment.
>
>>
>>> + if (!fwnode_device_is_available(
>>> + fwnode_graph_get_port_parent(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@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..83afac48ea6b 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 +203,119 @@ 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, even if the function returned an error.
>>> + *
>>> + * 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));
>>> +
>>> +/**
>>> + * v4l2_async_notifier_parse_fwnode_endpoints_by_port - Parse V4L2 fwnode
>>> + * endpoints of a port 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.
>>> + * @port: port number where endpoints are to be parsed
>>> + * @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
>>> + *
>>> + * This function is just like @v4l2_async_notifier_parse_fwnode_endpoints with
>>> + * the exception that it only parses endpoints in a given port. This is useful
>>> + * on devices that have both sinks and sources: the async sub-devices connected
>>
>> on -> for
>>
>>> + * to sources have already been set up by another driver (on capture devices).
>>
>> on -> for
>
> Agreed on both.
>
>>
>> So if I understand this correctly for devices with both sinks and sources you use
>> this function to just parse the sink ports. And you have to give explicit port
>> numbers since you can't tell from parsing the device tree if a port is a sink or
>> source port, right? Only the driver knows this.
>
> Correct. The graph data structure in DT isn't directed, so this is only
> known by the driver.
I think this should be clarified.
I wonder if there is any way around it. I don't have time to dig into this, but
isn't it possible to tell that the source ports are already configured?
Anyway, that can be looked at later.
Regards,
Hans
>
>>
>>> + *
>>> + * Parse the fwnode endpoints of the @dev device on a given @port 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 the first time.
>>> + *
>>> + * This function may not be called on a registered notifier and may be called on
>>> + * a notifier only once per port.
>>> + *
>>> + * 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, even if the function returned an error.
>>> + *
>>> + * 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_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));
>>> +
>>> #endif /* _V4L2_FWNODE_H */
>>>
>>
>
