Re: [PATCH 03/31] media: Media Controller register/unregister entity_notify API
From: Shuah Khan
Date: Thu Jan 28 2016 - 12:10:22 EST
On 01/28/2016 08:13 AM, Mauro Carvalho Chehab wrote:
> Em Wed, 6 Jan 2016 13:26:52 -0700
> Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> escreveu:
>
>> Add new interfaces to register and unregister entity_notify
>> hook to media device to allow drivers to take appropriate
>> actions when as new entities get added to the shared media
>> device.When a new entity is registered, all registered
>> entity_notify hooks are invoked to allow drivers or modules
>> that registered hook to take appropriate action. For example,
>> ALSA driver registers an entity_notify hook to parse the list
>> of registered entities to determine if decoder has been linked
>> to ALSA entity. au0828 bridge driver registers an entity_notify
>> hook to create media graph for the device.
>>
>> Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
>> ---
>> drivers/media/media-device.c | 61 ++++++++++++++++++++++++++++++++++++++++++++
>> include/media/media-device.h | 25 ++++++++++++++++++
>> 2 files changed, 86 insertions(+)
>>
>> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
>> index b786b10..20c85a9 100644
>> --- a/drivers/media/media-device.c
>> +++ b/drivers/media/media-device.c
>> @@ -536,6 +536,7 @@ static void media_device_release(struct media_devnode *mdev)
>> int __must_check media_device_register_entity(struct media_device *mdev,
>> struct media_entity *entity)
>> {
>> + struct media_entity_notify *notify, *next;
>> unsigned int i;
>> int ret;
>>
>> @@ -575,6 +576,11 @@ int __must_check media_device_register_entity(struct media_device *mdev,
>> media_gobj_create(mdev, MEDIA_GRAPH_PAD,
>> &entity->pads[i].graph_obj);
>>
>> + /* invoke entity_notify callbacks */
>> + list_for_each_entry_safe(notify, next, &mdev->entity_notify, list) {
>> + (notify)->notify(entity, notify->notify_data);
>> + }
>> +
>> spin_unlock(&mdev->lock);
>>
>> return 0;
>> @@ -608,6 +614,8 @@ static void __media_device_unregister_entity(struct media_entity *entity)
>> /* Remove the entity */
>> media_gobj_destroy(&entity->graph_obj);
>>
>> + /* invoke entity_notify callbacks to handle entity removal?? */
>> +
>> entity->graph_obj.mdev = NULL;
>> }
>>
>> @@ -633,6 +641,7 @@ int __must_check media_device_init(struct media_device *mdev)
>> INIT_LIST_HEAD(&mdev->interfaces);
>> INIT_LIST_HEAD(&mdev->pads);
>> INIT_LIST_HEAD(&mdev->links);
>> + INIT_LIST_HEAD(&mdev->entity_notify);
>> spin_lock_init(&mdev->lock);
>> mutex_init(&mdev->graph_mutex);
>> ida_init(&mdev->entity_internal_idx);
>> @@ -680,11 +689,59 @@ int __must_check __media_device_register(struct media_device *mdev,
>> }
>> EXPORT_SYMBOL_GPL(__media_device_register);
>>
>> +/**
>> + * media_device_register_entity_notify - Register a media entity notify
>> + * callback with a media device. When a new entity is registered, all
>> + * the registered media_entity_notify callbacks are invoked.
>> + * @mdev: The media device
>> + * @nptr: The media_entity_notify
>> + */
>
> Please put the documentation only at the header files. Please mention that
> it locks the addition using the mdev->lock spinlock.
>
> Also, please follow the format that we're using with other KernelDoc
> tags:
>
> /**
> * function() - short description
> *
> * @foo: foo description
> * @bar: bar description
> *
> * detailed description
> */
>
> In case of doubts, please check Documentation/kernel-doc-nano-HOWTO.txt.
>
> Don't forget to check if the documentation looks sane by compiling it
> with:
> make cleandocs
> make DOCBOOKS=device-drivers.xml htmldocs
>
> Same applies to other documentation below and on other patches in this
> series.
>
>> +int __must_check media_device_register_entity_notify(struct media_device *mdev,
>> + struct media_entity_notify *nptr)
>> +{
>> + spin_lock(&mdev->lock);
>> + list_add_tail(&nptr->list, &mdev->entity_notify);
>> + spin_unlock(&mdev->lock);
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(media_device_register_entity_notify);
>> +
>> +/**
>> + * __media_device_unregister_entity_notify - Unregister a media entity notify
>> + * callback with a media device. When a new entity is registered, all
>> + * the registered media_entity_notify callbacks are invoked.
>> + * @mdev: The media device
>> + * @nptr: The media_entity_notify
>> + * Non-locking version. Should be called with mdev->lock held.
>> + */
>> +static void __media_device_unregister_entity_notify(struct media_device *mdev,
>> + struct media_entity_notify *nptr)
>
> __must_check
Thanks for the catch. Will fix it.
>
>> +{
>> + list_del(&nptr->list);
>> +}
>> +
>> +/**
>> + * media_device_unregister_entity_notify - Unregister a media entity notify
>> + * callback with a media device. When a new entity is registered, all
>> + * the registered media_entity_notify callbacks are invoked.
>> + * @mdev: The media device
>> + * @nptr: The media_entity_notify
>> + */
>> +void media_device_unregister_entity_notify(struct media_device *mdev,
>> + struct media_entity_notify *nptr)
>> +{
>> + spin_lock(&mdev->lock);
>> + __media_device_unregister_entity_notify(mdev, nptr);
>> + spin_unlock(&mdev->lock);
>> +}
>> +EXPORT_SYMBOL_GPL(media_device_unregister_entity_notify);
>> +
>> void media_device_unregister(struct media_device *mdev)
>> {
>> struct media_entity *entity;
>> struct media_entity *next;
>> struct media_interface *intf, *tmp_intf;
>> + struct media_entity_notify *notify, *nextp;
>>
>> if (mdev == NULL)
>> return;
>> @@ -701,6 +758,10 @@ void media_device_unregister(struct media_device *mdev)
>> list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list)
>> __media_device_unregister_entity(entity);
>>
>> + /* Remove all entity_notify callbacks from the media device */
>> + list_for_each_entry_safe(notify, nextp, &mdev->entity_notify, list)
>> + __media_device_unregister_entity_notify(mdev, notify);
>> +
>> /* Remove all interfaces from the media device */
>> list_for_each_entry_safe(intf, tmp_intf, &mdev->interfaces,
>> graph_obj.list) {
>> diff --git a/include/media/media-device.h b/include/media/media-device.h
>> index 122963a..6520d1c 100644
>> --- a/include/media/media-device.h
>> +++ b/include/media/media-device.h
>> @@ -264,6 +264,12 @@
>> struct ida;
>> struct device;
>>
>> +struct media_entity_notify {
>> + struct list_head list;
>> + void *notify_data;
>> + void (*notify)(struct media_entity *entity, void *notify_data);
>> +};
>
> Please document the structure.
>
>> +
>> /**
>> * struct media_device - Media device
>> * @dev: Parent device
>> @@ -319,6 +325,9 @@ struct media_device {
>> struct list_head pads;
>> struct list_head links;
>>
>> + /* notify callback list invoked when a new entity is registered */
>> + struct list_head entity_notify;
>> +
>
> Please document the new field at the Kernel-doc header.
>
>> /* Protects the graph objects creation/removal */
>> spinlock_t lock;
>> /* Serializes graph operations. */
>> @@ -497,6 +506,11 @@ int __must_check media_device_register_entity(struct media_device *mdev,
>> */
>> void media_device_unregister_entity(struct media_entity *entity);
>>
>> +int __must_check media_device_register_entity_notify(struct media_device *mdev,
>> + struct media_entity_notify *nptr);
>> +void media_device_unregister_entity_notify(struct media_device *mdev,
>> + struct media_entity_notify *nptr);
>> +
>
> Documentation?
I would like to add documentation as an add-on to the series,
as I explained in response to [PATCH 04/31]
Hope that is okay for this patch as well.
thanks,
-- Shuah
>
>> /**
>> * media_device_get_devres() - get media device as device resource
>> * creates if one doesn't exist
>> @@ -552,6 +566,17 @@ static inline int media_device_register_entity(struct media_device *mdev,
>> static inline void media_device_unregister_entity(struct media_entity *entity)
>> {
>> }
>> +static inline int media_device_register_entity_notify(
>> + struct media_device *mdev,
>> + struct media_entity_notify *nptr)
>> +{
>> + return 0;
>> +}
>> +static inline void media_device_unregister_entity_notify(
>> + struct media_device *mdev,
>> + struct media_entity_notify *nptr)
>> +{
>> +}
>> static inline struct media_device *media_device_get_devres(struct device *dev)
>> {
>> return NULL;
>
> Documentation?
>
> Regards,
> Mauro
>
--
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@xxxxxxxxxxxxxxx | (970) 217-8978