[media] media-device.h: Improve documentation and update it
Now that we moved the content of the media-framework.txt into the kerneldoc documentation, move the per-function specific documentation to the corresponding functions and clean it up. It would be good if we had already the markdown kernel-doc patches merged upstream, but, while we doesn't have it, let's make it less ugly at device-drivers.xml. Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Mauro Carvalho Chehab
parent
f1fd3289e8
commit
db7ee32aa1
@ -33,23 +33,11 @@
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/**
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* DOC: Media Controller
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*
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* Linux kernel media framework
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* ============================
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*
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* This document describes the Linux kernel media framework, its data structures,
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* functions and their usage.
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*
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*
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* Introduction
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* ------------
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*
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* The media controller API is documented in DocBook format in
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* Documentation/DocBook/media/v4l/media-controller.xml. This document will focus
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* The media controller userspace API is documented in DocBook format in
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* Documentation/DocBook/media/v4l/media-controller.xml. This document focus
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* on the kernel-side implementation of the media framework.
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*
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*
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* Abstract media device model
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* ---------------------------
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* * Abstract media device model:
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*
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* Discovering a device internal topology, and configuring it at runtime, is one
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* of the goals of the media framework. To achieve this, hardware devices are
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@ -72,195 +60,104 @@
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* pad to a sink pad.
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*
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*
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* Media device
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* ------------
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* * Media device:
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*
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* A media device is represented by a struct media_device instance, defined in
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* A media device is represented by a struct &media_device instance, defined in
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* include/media/media-device.h. Allocation of the structure is handled by the
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* media device driver, usually by embedding the media_device instance in a
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* media device driver, usually by embedding the &media_device instance in a
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* larger driver-specific structure.
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*
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* Drivers register media device instances by calling
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* __media_device_register() via the macro media_device_register()
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* and unregistered by calling
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* media_device_unregister().
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*
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* media_device_register(struct media_device *mdev);
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*
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* The caller is responsible for initializing the media_device structure before
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* registration. The following fields must be set:
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*
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* - dev must point to the parent device (usually a pci_dev, usb_interface or
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* platform_device instance).
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*
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* - model must be filled with the device model name as a NUL-terminated UTF-8
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* string. The device/model revision must not be stored in this field.
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*
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* The following fields are optional:
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*
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* - serial is a unique serial number stored as a NUL-terminated ASCII string.
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* The field is big enough to store a GUID in text form. If the hardware
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* doesn't provide a unique serial number this field must be left empty.
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*
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* - bus_info represents the location of the device in the system as a
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* NUL-terminated ASCII string. For PCI/PCIe devices bus_info must be set to
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* "PCI:" (or "PCIe:") followed by the value of pci_name(). For USB devices,
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* the usb_make_path() function must be used. This field is used by
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* applications to distinguish between otherwise identical devices that don't
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* provide a serial number.
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*
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* - hw_revision is the hardware device revision in a driver-specific format.
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* When possible the revision should be formatted with the KERNEL_VERSION
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* macro.
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*
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* - driver_version is formatted with the KERNEL_VERSION macro. The version
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* minor must be incremented when new features are added to the userspace API
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* without breaking binary compatibility. The version major must be
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* incremented when binary compatibility is broken.
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*
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* Upon successful registration a character device named media[0-9]+ is created.
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* The device major and minor numbers are dynamic. The model name is exported as
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* a sysfs attribute.
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*
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* Drivers unregister media device instances by calling
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*
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* media_device_unregister(struct media_device *mdev);
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*
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* Unregistering a media device that hasn't been registered is *NOT* safe.
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*
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*
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* Entities, pads and links
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* ------------------------
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* * Entities, pads and links:
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*
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* - Entities
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*
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* Entities are represented by a struct media_entity instance, defined in
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* Entities are represented by a struct &media_entity instance, defined in
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* include/media/media-entity.h. The structure is usually embedded into a
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* higher-level structure, such as a v4l2_subdev or video_device instance,
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* although drivers can allocate entities directly.
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*
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* Drivers initialize entity pads by calling
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*
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* media_entity_pads_init(struct media_entity *entity, u16 num_pads,
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* struct media_pad *pads);
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*
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* If no pads are needed, drivers could directly fill entity->num_pads
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* with 0 and entity->pads with NULL or to call the above function that
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* will do the same.
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*
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* The media_entity name, type and flags fields should be initialized before
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* calling media_device_register_entity(). Entities embedded in higher-level
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* standard structures can have some of those fields set by the higher-level
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* framework.
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*
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* As the number of pads is known in advance, the pads array is not allocated
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* dynamically but is managed by the entity driver. Most drivers will embed the
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* pads array in a driver-specific structure, avoiding dynamic allocation.
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*
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* Drivers must set the direction of every pad in the pads array before calling
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* media_entity_pads_init. The function will initialize the other pads fields.
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*
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* Unlike the number of pads, the total number of links isn't always known in
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* advance by the entity driver. As an initial estimate, media_entity_pads_init
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* pre-allocates a number of links equal to the number of pads. The links array
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* will be reallocated if it grows beyond the initial estimate.
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* media_entity_pads_init().
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*
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* Drivers register entities with a media device by calling
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* media_device_register_entity()
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* and unregistred by calling
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* media_device_unregister_entity().
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*
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* media_device_register_entity(struct media_device *mdev,
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* struct media_entity *entity);
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* - Interfaces
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*
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* Entities are identified by a unique positive integer ID. Drivers can provide an
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* ID by filling the media_entity id field prior to registration, or request the
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* media controller framework to assign an ID automatically. Drivers that provide
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* IDs manually must ensure that all IDs are unique. IDs are not guaranteed to be
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* contiguous even when they are all assigned automatically by the framework.
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* Interfaces are represented by a struct &media_interface instance, defined in
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* include/media/media-entity.h. Currently, only one type of interface is
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* defined: a device node. Such interfaces are represented by a struct
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* &media_intf_devnode.
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*
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* Drivers unregister entities by calling
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*
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* media_device_unregister_entity(struct media_entity *entity);
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*
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* Unregistering an entity will not change the IDs of the other entities, and the
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* ID will never be reused for a newly registered entity.
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*
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* When a media device is unregistered, all its entities are unregistered
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* automatically. No manual entities unregistration is then required.
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*
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* Drivers free resources associated with an entity by calling
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*
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* media_entity_cleanup(struct media_entity *entity);
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*
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* This function must be called during the cleanup phase after unregistering the
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* entity. Note that the media_entity instance itself must be freed explicitly by
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* the driver if required.
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*
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* Entities have flags that describe the entity capabilities and state.
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*
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* MEDIA_ENT_FL_DEFAULT indicates the default entity for a given type.
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* This can be used to report the default audio and video devices or the
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* default camera sensor.
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*
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* Logical entity groups can be defined by setting the group ID of all member
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* entities to the same non-zero value. An entity group serves no purpose in the
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* kernel, but is reported to userspace during entities enumeration.
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*
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* Media device drivers should define groups if several entities are logically
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* bound together. Example usages include reporting
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*
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* - ALSA, VBI and video nodes that carry the same media stream
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* - lens and flash controllers associated with a sensor
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* Drivers initialize and create device node interfaces by calling
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* media_devnode_create()
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* and remove them by calling:
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* media_devnode_remove().
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*
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* - Pads
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*
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* Pads are represented by a struct media_pad instance, defined in
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* Pads are represented by a struct &media_pad instance, defined in
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* include/media/media-entity.h. Each entity stores its pads in a pads array
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* managed by the entity driver. Drivers usually embed the array in a
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* driver-specific structure.
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*
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* Pads are identified by their entity and their 0-based index in the pads array.
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* Both information are stored in the media_pad structure, making the media_pad
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* pointer the canonical way to store and pass link references.
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* Pads are identified by their entity and their 0-based index in the pads
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* array.
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* Both information are stored in the &media_pad structure, making the
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* &media_pad pointer the canonical way to store and pass link references.
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*
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* Pads have flags that describe the pad capabilities and state.
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*
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* MEDIA_PAD_FL_SINK indicates that the pad supports sinking data.
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* MEDIA_PAD_FL_SOURCE indicates that the pad supports sourcing data.
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* %MEDIA_PAD_FL_SINK indicates that the pad supports sinking data.
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* %MEDIA_PAD_FL_SOURCE indicates that the pad supports sourcing data.
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*
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* One and only one of MEDIA_PAD_FL_SINK and MEDIA_PAD_FL_SOURCE must be set for
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* each pad.
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* NOTE: One and only one of %MEDIA_PAD_FL_SINK and %MEDIA_PAD_FL_SOURCE must
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* be set for each pad.
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*
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* - Links
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*
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* Links are represented by a struct media_link instance, defined in
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* include/media/media-entity.h. Each entity stores all links originating at or
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* targeting any of its pads in a links array. A given link is thus stored
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* twice, once in the source entity and once in the target entity. The array is
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* pre-allocated and grows dynamically as needed.
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* Links are represented by a struct &media_link instance, defined in
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* include/media/media-entity.h. There are two types of links:
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*
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* Drivers create links by calling
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* 1. pad to pad links:
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*
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* media_create_pad_link(struct media_entity *source, u16 source_pad,
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* struct media_entity *sink, u16 sink_pad,
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* u32 flags);
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* Associate two entities via their PADs. Each entity has a list that points
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* to all links originating at or targeting any of its pads.
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* A given link is thus stored twice, once in the source entity and once in
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* the target entity.
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*
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* An entry in the link array of each entity is allocated and stores pointers
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* to source and sink pads.
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* Drivers create pad to pad links by calling:
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* media_create_pad_link() and remove with media_entity_remove_links().
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*
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* Links have flags that describe the link capabilities and state.
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* 2. interface to entity links:
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*
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* MEDIA_LNK_FL_ENABLED indicates that the link is enabled and can be used
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* to transfer media data. When two or more links target a sink pad, only
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* one of them can be enabled at a time.
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* MEDIA_LNK_FL_IMMUTABLE indicates that the link enabled state can't be
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* modified at runtime. If MEDIA_LNK_FL_IMMUTABLE is set, then
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* MEDIA_LNK_FL_ENABLED must also be set since an immutable link is always
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* enabled.
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* Associate one interface to a Link.
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*
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* Drivers create interface to entity links by calling:
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* media_create_intf_link() and remove with media_remove_intf_links().
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*
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* Graph traversal
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* ---------------
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* NOTE:
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*
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* Links can only be created after having both ends already created.
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*
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* Links have flags that describe the link capabilities and state. The
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* valid values are described at media_create_pad_link() and
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* media_create_intf_link().
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*
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* Graph traversal:
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*
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* The media framework provides APIs to iterate over entities in a graph.
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*
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* To iterate over all entities belonging to a media device, drivers can use the
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* media_device_for_each_entity macro, defined in include/media/media-device.h.
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* To iterate over all entities belonging to a media device, drivers can use
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* the media_device_for_each_entity macro, defined in
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* include/media/media-device.h.
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*
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* struct media_entity *entity;
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*
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@ -279,126 +176,82 @@
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* currently defined as 16.
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*
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* Drivers initiate a graph traversal by calling
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*
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* media_entity_graph_walk_start(struct media_entity_graph *graph,
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* struct media_entity *entity);
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* media_entity_graph_walk_start()
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*
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* The graph structure, provided by the caller, is initialized to start graph
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* traversal at the given entity.
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*
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* Drivers can then retrieve the next entity by calling
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*
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* media_entity_graph_walk_next(struct media_entity_graph *graph);
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* media_entity_graph_walk_next()
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*
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* When the graph traversal is complete the function will return NULL.
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*
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* Graph traversal can be interrupted at any moment. No cleanup function call is
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* required and the graph structure can be freed normally.
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* Graph traversal can be interrupted at any moment. No cleanup function call
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* is required and the graph structure can be freed normally.
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*
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* Helper functions can be used to find a link between two given pads, or a pad
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* connected to another pad through an enabled link
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* media_entity_find_link() and media_entity_remote_pad()
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*
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* media_entity_find_link(struct media_pad *source,
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* struct media_pad *sink);
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* Use count and power handling:
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*
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* media_entity_remote_pad(struct media_pad *pad);
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* Due to the wide differences between drivers regarding power management
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* needs, the media controller does not implement power management. However,
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* the &media_entity structure includes a use_count field that media drivers
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* can use to track the number of users of every entity for power management
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* needs.
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*
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* Refer to the kerneldoc documentation for more information.
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* The &media_entity.@use_count field is owned by media drivers and must not be
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* touched by entity drivers. Access to the field must be protected by the
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* &media_device.@graph_mutex lock.
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*
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*
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* Use count and power handling
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* ----------------------------
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*
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* Due to the wide differences between drivers regarding power management needs,
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* the media controller does not implement power management. However, the
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* media_entity structure includes a use_count field that media drivers can use to
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* track the number of users of every entity for power management needs.
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*
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* The use_count field is owned by media drivers and must not be touched by entity
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* drivers. Access to the field must be protected by the media device graph_mutex
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* lock.
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*
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*
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* Links setup
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* -----------
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* Links setup:
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*
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* Link properties can be modified at runtime by calling
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* media_entity_setup_link()
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*
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* media_entity_setup_link(struct media_link *link, u32 flags);
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*
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* The flags argument contains the requested new link flags.
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*
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* The only configurable property is the ENABLED link flag to enable/disable a
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* link. Links marked with the IMMUTABLE link flag can not be enabled or disabled.
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*
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* When a link is enabled or disabled, the media framework calls the
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* link_setup operation for the two entities at the source and sink of the link,
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* in that order. If the second link_setup call fails, another link_setup call is
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* made on the first entity to restore the original link flags.
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*
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* Media device drivers can be notified of link setup operations by setting the
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* media_device::link_notify pointer to a callback function. If provided, the
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* notification callback will be called before enabling and after disabling
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* links.
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*
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* Entity drivers must implement the link_setup operation if any of their links
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* is non-immutable. The operation must either configure the hardware or store
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* the configuration information to be applied later.
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*
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* Link configuration must not have any side effect on other links. If an enabled
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* link at a sink pad prevents another link at the same pad from being enabled,
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* the link_setup operation must return -EBUSY and can't implicitly disable the
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* first enabled link.
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*
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*
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* Pipelines and media streams
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* ---------------------------
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* Pipelines and media streams:
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*
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* When starting streaming, drivers must notify all entities in the pipeline to
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* prevent link states from being modified during streaming by calling
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*
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* media_entity_pipeline_start(struct media_entity *entity,
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* struct media_pipeline *pipe);
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* media_entity_pipeline_start().
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*
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* The function will mark all entities connected to the given entity through
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* enabled links, either directly or indirectly, as streaming.
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*
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* The media_pipeline instance pointed to by the pipe argument will be stored in
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* every entity in the pipeline. Drivers should embed the media_pipeline structure
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* in higher-level pipeline structures and can then access the pipeline through
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* the media_entity pipe field.
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* The &media_pipeline instance pointed to by the pipe argument will be stored
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* in every entity in the pipeline. Drivers should embed the &media_pipeline
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* structure in higher-level pipeline structures and can then access the
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* pipeline through the &media_entity pipe field.
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*
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* Calls to media_entity_pipeline_start() can be nested. The pipeline pointer must
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* be identical for all nested calls to the function.
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* Calls to media_entity_pipeline_start() can be nested. The pipeline pointer
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* must be identical for all nested calls to the function.
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*
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* media_entity_pipeline_start() may return an error. In that case, it will
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* clean up any of the changes it did by itself.
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*
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* When stopping the stream, drivers must notify the entities with
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*
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* media_entity_pipeline_stop(struct media_entity *entity);
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* media_entity_pipeline_stop().
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*
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* If multiple calls to media_entity_pipeline_start() have been made the same
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* number of media_entity_pipeline_stop() calls are required to stop streaming. The
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* media_entity pipe field is reset to NULL on the last nested stop call.
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* number of media_entity_pipeline_stop() calls are required to stop streaming.
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* The &media_entity pipe field is reset to NULL on the last nested stop call.
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*
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* Link configuration will fail with -EBUSY by default if either end of the link is
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* a streaming entity. Links that can be modified while streaming must be marked
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* with the MEDIA_LNK_FL_DYNAMIC flag.
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* Link configuration will fail with -%EBUSY by default if either end of the
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* link is a streaming entity. Links that can be modified while streaming must
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* be marked with the %MEDIA_LNK_FL_DYNAMIC flag.
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*
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* If other operations need to be disallowed on streaming entities (such as
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* changing entities configuration parameters) drivers can explicitly check the
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* media_entity stream_count field to find out if an entity is streaming. This
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* operation must be done with the media_device graph_mutex held.
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*
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*
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* Link validation
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* ---------------
|
||||
* Link validation:
|
||||
*
|
||||
* Link validation is performed by media_entity_pipeline_start() for any
|
||||
* entity which has sink pads in the pipeline. The
|
||||
* media_entity::link_validate() callback is used for that purpose. In
|
||||
* link_validate() callback, entity driver should check that the properties of
|
||||
* &media_entity.@link_validate() callback is used for that purpose. In
|
||||
* @link_validate() callback, entity driver should check that the properties of
|
||||
* the source pad of the connected entity and its own sink pad match. It is up
|
||||
* to the type of the entity (and in the end, the properties of the hardware)
|
||||
* what matching actually means.
|
||||
@ -484,13 +337,113 @@ struct media_device {
|
||||
/* media_devnode to media_device */
|
||||
#define to_media_device(node) container_of(node, struct media_device, devnode)
|
||||
|
||||
/**
|
||||
* __media_device_register() - Registers a media device element
|
||||
*
|
||||
* @mdev: pointer to struct &media_device
|
||||
* @owner: should be filled with %THIS_MODULE
|
||||
*
|
||||
* Users, should, instead, call the media_device_register() macro.
|
||||
*
|
||||
* The caller is responsible for initializing the media_device structure before
|
||||
* registration. The following fields must be set:
|
||||
*
|
||||
* - dev must point to the parent device (usually a &pci_dev, &usb_interface or
|
||||
* &platform_device instance).
|
||||
*
|
||||
* - model must be filled with the device model name as a NUL-terminated UTF-8
|
||||
* string. The device/model revision must not be stored in this field.
|
||||
*
|
||||
* The following fields are optional:
|
||||
*
|
||||
* - serial is a unique serial number stored as a NUL-terminated ASCII string.
|
||||
* The field is big enough to store a GUID in text form. If the hardware
|
||||
* doesn't provide a unique serial number this field must be left empty.
|
||||
*
|
||||
* - bus_info represents the location of the device in the system as a
|
||||
* NUL-terminated ASCII string. For PCI/PCIe devices bus_info must be set to
|
||||
* "PCI:" (or "PCIe:") followed by the value of pci_name(). For USB devices,
|
||||
* the usb_make_path() function must be used. This field is used by
|
||||
* applications to distinguish between otherwise identical devices that don't
|
||||
* provide a serial number.
|
||||
*
|
||||
* - hw_revision is the hardware device revision in a driver-specific format.
|
||||
* When possible the revision should be formatted with the KERNEL_VERSION
|
||||
* macro.
|
||||
*
|
||||
* - driver_version is formatted with the KERNEL_VERSION macro. The version
|
||||
* minor must be incremented when new features are added to the userspace API
|
||||
* without breaking binary compatibility. The version major must be
|
||||
* incremented when binary compatibility is broken.
|
||||
*
|
||||
* Notes:
|
||||
*
|
||||
* Upon successful registration a character device named media[0-9]+ is created.
|
||||
* The device major and minor numbers are dynamic. The model name is exported as
|
||||
* a sysfs attribute.
|
||||
*
|
||||
* Unregistering a media device that hasn't been registered is *NOT* safe.
|
||||
*/
|
||||
int __must_check __media_device_register(struct media_device *mdev,
|
||||
struct module *owner);
|
||||
#define media_device_register(mdev) __media_device_register(mdev, THIS_MODULE)
|
||||
|
||||
/**
|
||||
* __media_device_unregister() - Unegisters a media device element
|
||||
*
|
||||
* @mdev: pointer to struct &media_device
|
||||
*/
|
||||
void media_device_unregister(struct media_device *mdev);
|
||||
|
||||
/**
|
||||
* media_device_register_entity() - registers a media entity inside a
|
||||
* previously registered media device.
|
||||
*
|
||||
* @mdev: pointer to struct &media_device
|
||||
* @entity: pointer to struct &media_entity to be registered
|
||||
*
|
||||
* Entities are identified by a unique positive integer ID. The media
|
||||
* controller framework will such ID automatically. IDs are not guaranteed
|
||||
* to be contiguous, and the ID number can change on newer Kernel versions.
|
||||
* So, neither the driver nor userspace should hardcode ID numbers to refer
|
||||
* to the entities, but, instead, use the framework to find the ID, when
|
||||
* needed.
|
||||
*
|
||||
* The media_entity name, type and flags fields should be initialized before
|
||||
* calling media_device_register_entity(). Entities embedded in higher-level
|
||||
* standard structures can have some of those fields set by the higher-level
|
||||
* framework.
|
||||
*
|
||||
* If the device has pads, media_entity_pads_init() should be called before
|
||||
* this function. Otherwise, the &media_entity.@pad and &media_entity.@num_pads
|
||||
* should be zeroed before calling this function.
|
||||
*
|
||||
* Entities have flags that describe the entity capabilities and state:
|
||||
*
|
||||
* %MEDIA_ENT_FL_DEFAULT indicates the default entity for a given type.
|
||||
* This can be used to report the default audio and video devices or the
|
||||
* default camera sensor.
|
||||
*/
|
||||
int __must_check media_device_register_entity(struct media_device *mdev,
|
||||
struct media_entity *entity);
|
||||
|
||||
/*
|
||||
* media_device_unregister_entity() - unregisters a media entity.
|
||||
*
|
||||
* @entity: pointer to struct &media_entity to be unregistered
|
||||
*
|
||||
* All links associated with the entity and all PADs are automatically
|
||||
* unregistered from the media_device when this function is called.
|
||||
*
|
||||
* Unregistering an entity will not change the IDs of the other entities and
|
||||
* the previoully used ID will never be reused for a newly registered entities.
|
||||
*
|
||||
* When a media device is unregistered, all its entities are unregistered
|
||||
* automatically. No manual entities unregistration is then required.
|
||||
*
|
||||
* Note: the media_entity instance itself must be freed explicitly by
|
||||
* the driver if required.
|
||||
*/
|
||||
void media_device_unregister_entity(struct media_entity *entity);
|
||||
struct media_device *media_device_get_devres(struct device *dev);
|
||||
struct media_device *media_device_find_devres(struct device *dev);
|
||||
|
||||
@ -343,18 +343,112 @@ void media_gobj_init(struct media_device *mdev,
|
||||
struct media_gobj *gobj);
|
||||
void media_gobj_remove(struct media_gobj *gobj);
|
||||
|
||||
/**
|
||||
* media_entity_pads_init() - Initialize the entity pads
|
||||
*
|
||||
* @entity: entity where the pads belong
|
||||
* @num_pads: number of pads to be initialized
|
||||
* @pads: pads array
|
||||
*
|
||||
* If no pads are needed, drivers could either directly fill
|
||||
* &media_entity->@num_pads with 0 and &media_entity->@pads with NULL or call
|
||||
* this function that will do the same.
|
||||
*
|
||||
* As the number of pads is known in advance, the pads array is not allocated
|
||||
* dynamically but is managed by the entity driver. Most drivers will embed the
|
||||
* pads array in a driver-specific structure, avoiding dynamic allocation.
|
||||
*
|
||||
* Drivers must set the direction of every pad in the pads array before calling
|
||||
* media_entity_pads_init(). The function will initialize the other pads fields.
|
||||
*/
|
||||
int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
|
||||
struct media_pad *pads);
|
||||
|
||||
/**
|
||||
* media_entity_cleanup() - free resources associated with an entity
|
||||
*
|
||||
* @entity: entity where the pads belong
|
||||
*
|
||||
* This function must be called during the cleanup phase after unregistering
|
||||
* the entity (currently, it does nothing).
|
||||
*/
|
||||
static inline void media_entity_cleanup(struct media_entity *entity) {};
|
||||
|
||||
/**
|
||||
* media_create_pad_link() - creates a link between two entities.
|
||||
*
|
||||
* @source: pointer to &media_entity of the source pad.
|
||||
* @source_pad: number of the source pad in the pads array
|
||||
* @sink: pointer to &media_entity of the sink pad.
|
||||
* @sink_pad: number of the sink pad in the pads array.
|
||||
* @flags: Link flags, as defined in include/uapi/linux/media.h.
|
||||
*
|
||||
* Valid values for flags:
|
||||
* A %MEDIA_LNK_FL_ENABLED flag indicates that the link is enabled and can be
|
||||
* used to transfer media data. When two or more links target a sink pad,
|
||||
* only one of them can be enabled at a time.
|
||||
*
|
||||
* A %MEDIA_LNK_FL_IMMUTABLE flag indicates that the link enabled state can't
|
||||
* be modified at runtime. If %MEDIA_LNK_FL_IMMUTABLE is set, then
|
||||
* %MEDIA_LNK_FL_ENABLED must also be set since an immutable link is
|
||||
* always enabled.
|
||||
*
|
||||
* NOTE:
|
||||
*
|
||||
* Before calling this function, media_entity_pads_init() and
|
||||
* media_device_register_entity() should be called previously for both ends.
|
||||
*/
|
||||
__must_check int media_create_pad_link(struct media_entity *source,
|
||||
u16 source_pad, struct media_entity *sink,
|
||||
u16 sink_pad, u32 flags);
|
||||
void __media_entity_remove_links(struct media_entity *entity);
|
||||
|
||||
/**
|
||||
* media_entity_remove_links() - remove all links associated with an entity
|
||||
*
|
||||
* @entity: pointer to &media_entity
|
||||
*
|
||||
* Note: this is called automatically when an entity is unregistered via
|
||||
* media_device_register_entity().
|
||||
*/
|
||||
void media_entity_remove_links(struct media_entity *entity);
|
||||
|
||||
int __media_entity_setup_link(struct media_link *link, u32 flags);
|
||||
|
||||
/**
|
||||
* media_entity_setup_link() - changes the link flags properties in runtime
|
||||
*
|
||||
* @link: pointer to &media_link
|
||||
* @flags: the requested new link flags
|
||||
*
|
||||
* The only configurable property is the %MEDIA_LNK_FL_ENABLED link flag
|
||||
* flag to enable/disable a link. Links marked with the
|
||||
* %MEDIA_LNK_FL_IMMUTABLE link flag can not be enabled or disabled.
|
||||
*
|
||||
* When a link is enabled or disabled, the media framework calls the
|
||||
* link_setup operation for the two entities at the source and sink of the
|
||||
* link, in that order. If the second link_setup call fails, another
|
||||
* link_setup call is made on the first entity to restore the original link
|
||||
* flags.
|
||||
*
|
||||
* Media device drivers can be notified of link setup operations by setting the
|
||||
* media_device::link_notify pointer to a callback function. If provided, the
|
||||
* notification callback will be called before enabling and after disabling
|
||||
* links.
|
||||
*
|
||||
* Entity drivers must implement the link_setup operation if any of their links
|
||||
* is non-immutable. The operation must either configure the hardware or store
|
||||
* the configuration information to be applied later.
|
||||
*
|
||||
* Link configuration must not have any side effect on other links. If an
|
||||
* enabled link at a sink pad prevents another link at the same pad from
|
||||
* being enabled, the link_setup operation must return -EBUSY and can't
|
||||
* implicitly disable the first enabled link.
|
||||
*
|
||||
* NOTE: the valid values of the flags for the link is the same as described
|
||||
* on media_create_pad_link(), for pad to pad links or the same as described
|
||||
* on media_create_intf_link(), for interface to entity links.
|
||||
*/
|
||||
int media_entity_setup_link(struct media_link *link, u32 flags);
|
||||
struct media_link *media_entity_find_link(struct media_pad *source,
|
||||
struct media_pad *sink);
|
||||
@ -371,18 +465,72 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
|
||||
struct media_pipeline *pipe);
|
||||
void media_entity_pipeline_stop(struct media_entity *entity);
|
||||
|
||||
/**
|
||||
* media_devnode_create() - creates and initializes a device node interface
|
||||
*
|
||||
* @mdev: pointer to struct &media_device
|
||||
* @type: type of the interface, as given by MEDIA_INTF_T_* macros
|
||||
* as defined in the uapi/media/media.h header.
|
||||
* @flags: Interface flags as defined in uapi/media/media.h.
|
||||
* @major: Device node major number.
|
||||
* @minor: Device node minor number.
|
||||
*
|
||||
* Return: if succeeded, returns a pointer to the newly allocated
|
||||
* &media_intf_devnode pointer.
|
||||
*/
|
||||
struct media_intf_devnode *
|
||||
__must_check media_devnode_create(struct media_device *mdev,
|
||||
u32 type, u32 flags,
|
||||
u32 major, u32 minor);
|
||||
/**
|
||||
* media_devnode_remove() - removes a device node interface
|
||||
*
|
||||
* @devnode: pointer to &media_intf_devnode to be freed.
|
||||
*
|
||||
* When a device node interface is removed, all links to it are automatically
|
||||
* removed.
|
||||
*/
|
||||
void media_devnode_remove(struct media_intf_devnode *devnode);
|
||||
struct media_link *
|
||||
|
||||
/**
|
||||
* media_create_intf_link() - creates a link between an entity and an interface
|
||||
*
|
||||
* @entity: pointer to %media_entity
|
||||
* @intf: pointer to %media_interface
|
||||
* @flags: Link flags, as defined in include/uapi/linux/media.h.
|
||||
*
|
||||
*
|
||||
* Valid values for flags:
|
||||
* The %MEDIA_LNK_FL_ENABLED flag indicates that the interface is connected to
|
||||
* the entity hardware. That's the default value for interfaces. An
|
||||
* interface may be disabled if the hardware is busy due to the usage
|
||||
* of some other interface that it is currently controlling the hardware.
|
||||
* A typical example is an hybrid TV device that handle only one type of
|
||||
* stream on a given time. So, when the digital TV is streaming,
|
||||
* the V4L2 interfaces won't be enabled, as such device is not able to
|
||||
* also stream analog TV or radio.
|
||||
*
|
||||
* Note:
|
||||
*
|
||||
* Before calling this function, media_devnode_create() should be called for
|
||||
* the interface and media_device_register_entity() should be called for the
|
||||
* interface that will be part of the link.
|
||||
*/
|
||||
__must_check media_create_intf_link(struct media_entity *entity,
|
||||
struct media_interface *intf,
|
||||
u32 flags);
|
||||
void __media_remove_intf_link(struct media_link *link);
|
||||
void media_remove_intf_link(struct media_link *link);
|
||||
void __media_remove_intf_links(struct media_interface *intf);
|
||||
/**
|
||||
* media_remove_intf_links() - remove all links associated with an interface
|
||||
*
|
||||
* @intf: pointer to &media_interface
|
||||
*
|
||||
* Note: this is called automatically when an entity is unregistered via
|
||||
* media_device_register_entity() and by media_devnode_remove().
|
||||
*/
|
||||
void media_remove_intf_links(struct media_interface *intf);
|
||||
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user