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As video hardware pipelines become increasingly complex and configurable, the current hardware description through v4l2 subdevices reaches its limits. In addition to enumerating and configuring subdevices, video camera drivers need a way to discover and modify at runtime how those subdevices are connected. This is done through new elements called entities, pads and links. An entity is a basic media hardware building block. It can correspond to a large variety of logical blocks such as physical hardware devices (CMOS sensor for instance), logical hardware devices (a building block in a System-on-Chip image processing pipeline), DMA channels or physical connectors. A pad is a connection endpoint through which an entity can interact with other entities. Data (not restricted to video) produced by an entity flows from the entity's output to one or more entity inputs. Pads should not be confused with physical pins at chip boundaries. A link is a point-to-point oriented connection between two pads, either on the same entity or on different entities. Data flows from a source pad to a sink pad. Links are stored in the source entity. To make backwards graph walk faster, a copy of all links is also stored in the sink entity. The copy is known as a backlink and is only used to help graph traversal. The entity API is made of three functions: - media_entity_init() initializes an entity. The caller must provide an array of pads as well as an estimated number of links. The links array is allocated dynamically and will be reallocated if it grows beyond the initial estimate. - media_entity_cleanup() frees resources allocated for an entity. It must be called during the cleanup phase after unregistering the entity and before freeing it. - media_entity_create_link() creates a link between two entities. An entry in the link array of each entity is allocated and stores pointers to source and sink pads. When a media device is unregistered, all its entities are unregistered automatically. The code is based on Hans Verkuil <hverkuil@xs4all.nl> initial work. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
88 lines
2.7 KiB
C
88 lines
2.7 KiB
C
/*
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* Media device
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*
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* Copyright (C) 2010 Nokia Corporation
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*
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* Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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* Sakari Ailus <sakari.ailus@iki.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _MEDIA_DEVICE_H
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#define _MEDIA_DEVICE_H
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#include <linux/device.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <media/media-devnode.h>
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#include <media/media-entity.h>
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/**
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* struct media_device - Media device
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* @dev: Parent device
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* @devnode: Media device node
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* @model: Device model name
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* @serial: Device serial number (optional)
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* @bus_info: Unique and stable device location identifier
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* @hw_revision: Hardware device revision
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* @driver_version: Device driver version
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* @entity_id: ID of the next entity to be registered
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* @entities: List of registered entities
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* @lock: Entities list lock
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*
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* This structure represents an abstract high-level media device. It allows easy
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* access to entities and provides basic media device-level support. The
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* structure can be allocated directly or embedded in a larger structure.
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*
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* The parent @dev is a physical device. It must be set before registering the
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* media device.
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*
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* @model is a descriptive model name exported through sysfs. It doesn't have to
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* be unique.
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*/
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struct media_device {
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/* dev->driver_data points to this struct. */
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struct device *dev;
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struct media_devnode devnode;
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char model[32];
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char serial[40];
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char bus_info[32];
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u32 hw_revision;
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u32 driver_version;
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u32 entity_id;
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struct list_head entities;
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/* Protects the entities list */
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spinlock_t lock;
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};
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/* media_devnode to media_device */
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#define to_media_device(node) container_of(node, struct media_device, devnode)
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int __must_check media_device_register(struct media_device *mdev);
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void media_device_unregister(struct media_device *mdev);
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int __must_check media_device_register_entity(struct media_device *mdev,
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struct media_entity *entity);
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void media_device_unregister_entity(struct media_entity *entity);
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/* Iterate over all entities. */
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#define media_device_for_each_entity(entity, mdev) \
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list_for_each_entry(entity, &(mdev)->entities, list)
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#endif
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