The media_devnode structure provides support for registering and unregistering character devices using a dynamic major number. Reference counting is handled internally, making device drivers easier to write without having to solve the open/disconnect race condition issue over and over again.

The code is based on video/v4l2-dev.c.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- drivers/media/Kconfig | 13 ++ drivers/media/Makefile | 6 + drivers/media/media-devnode.c | 321 +++++++++++++++++++++++++++++++++++++++++ include/media/media-devnode.h | 97 +++++++++++++ 4 files changed, 437 insertions(+), 0 deletions(-) create mode 100644 drivers/media/media-devnode.c create mode 100644 include/media/media-devnode.h

diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig index 81b3ba8..2466f2b 100644 --- a/drivers/media/Kconfig +++ b/drivers/media/Kconfig @@ -14,6 +14,19 @@ if MEDIA_SUPPORT comment "Multimedia core support"

# +# Media controller +# + +config MEDIA_CONTROLLER + bool "Media Controller API (EXPERIMENTAL)" + depends on EXPERIMENTAL + ---help--- + Enable the media controller API used to query media devices internal + topology and configure it dynamically. + + This API is mostly used by camera interfaces in embedded platforms. + +# # V4L core and enabled API's #

diff --git a/drivers/media/Makefile b/drivers/media/Makefile index b603ea6..d56349f 100644 --- a/drivers/media/Makefile +++ b/drivers/media/Makefile @@ -2,6 +2,12 @@ # Makefile for the kernel multimedia device drivers. #

+media-objs := media-devnode.o + +ifeq ($(CONFIG_MEDIA_CONTROLLER),y) + obj-$(CONFIG_MEDIA_SUPPORT) += media.o +endif + obj-y += common/ rc/ video/

obj-$(CONFIG_VIDEO_DEV) += radio/ diff --git a/drivers/media/media-devnode.c b/drivers/media/media-devnode.c new file mode 100644 index 0000000..5509984 --- /dev/null +++ b/drivers/media/media-devnode.c @@ -0,0 +1,321 @@ +/* + * Media device node + * + * Copyright (C) 2010 Nokia Corporation + * + * Based on drivers/media/video/v4l2_dev.c code authored by + * Mauro Carvalho Chehab mchehab@infradead.org (version 2) + * Alan Cox, alan@lxorguk.ukuu.org.uk (version 1) + * + * Contacts: Laurent Pinchart laurent.pinchart@ideasonboard.com + * Sakari Ailus sakari.ailus@iki.fi + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * -- + * + * Generic media device node infrastructure to register and unregister + * character devices using a dynamic major number and proper reference + * counting. + */ + +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/kmod.h> +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/smp_lock.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/uaccess.h> +#include <asm/system.h> + +#include <media/media-devnode.h> + +#define MEDIA_NUM_DEVICES 256 +#define MEDIA_NAME "media" + +static dev_t media_dev_t; + +/* + * Active devices + */ +static DEFINE_MUTEX(media_devnode_lock); +static DECLARE_BITMAP(media_devnode_nums, MEDIA_NUM_DEVICES); + +/* Called when the last user of the media device exits. */ +static void media_devnode_release(struct device *cd) +{ + struct media_devnode *mdev = to_media_devnode(cd); + + mutex_lock(&media_devnode_lock); + + /* Delete the cdev on this minor as well */ + cdev_del(&mdev->cdev); + + /* Mark device node number as free */ + clear_bit(mdev->minor, media_devnode_nums); + + mutex_unlock(&media_devnode_lock); + + /* Release media_devnode and perform other cleanups as needed. */ + if (mdev->release) + mdev->release(mdev); +} + +static struct bus_type media_bus_type = { + .name = MEDIA_NAME, +}; + +static ssize_t media_read(struct file *filp, char __user *buf, + size_t sz, loff_t *off) +{ + struct media_devnode *mdev = media_devnode_data(filp); + + if (!mdev->fops->read) + return -EINVAL; + if (!media_devnode_is_registered(mdev)) + return -EIO; + return mdev->fops->read(filp, buf, sz, off); +} + +static ssize_t media_write(struct file *filp, const char __user *buf, + size_t sz, loff_t *off) +{ + struct media_devnode *mdev = media_devnode_data(filp); + + if (!mdev->fops->write) + return -EINVAL; + if (!media_devnode_is_registered(mdev)) + return -EIO; + return mdev->fops->write(filp, buf, sz, off); +} + +static unsigned int media_poll(struct file *filp, + struct poll_table_struct *poll) +{ + struct media_devnode *mdev = media_devnode_data(filp); + + if (!media_devnode_is_registered(mdev)) + return POLLERR | POLLHUP; + if (!mdev->fops->poll) + return DEFAULT_POLLMASK; + return mdev->fops->poll(filp, poll); +} + +static long media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + struct media_devnode *mdev = media_devnode_data(filp); + + if (!mdev->fops->ioctl) + return -ENOTTY; + + if (!media_devnode_is_registered(mdev)) + return -EIO; + + return mdev->fops->ioctl(filp, cmd, arg); +} + +/* Override for the open function */ +static int media_open(struct inode *inode, struct file *filp) +{ + struct media_devnode *mdev; + int ret; + + /* Check if the media device is available. This needs to be done with + * the media_devnode_lock held to prevent an open/unregister race: + * without the lock, the device could be unregistered and freed between + * the media_devnode_is_registered() and get_device() calls, leading to + * a crash. + */ + mutex_lock(&media_devnode_lock); + mdev = container_of(inode->i_cdev, struct media_devnode, cdev); + /* return ENXIO if the media device has been removed + already or if it is not registered anymore. */ + if (!media_devnode_is_registered(mdev)) { + mutex_unlock(&media_devnode_lock); + return -ENXIO; + } + /* and increase the device refcount */ + get_device(&mdev->dev); + mutex_unlock(&media_devnode_lock); + + filp->private_data = mdev; + + if (mdev->fops->open) { + ret = mdev->fops->open(filp); + if (ret) { + put_device(&mdev->dev); + return ret; + } + } + + return 0; +} + +/* Override for the release function */ +static int media_release(struct inode *inode, struct file *filp) +{ + struct media_devnode *mdev = media_devnode_data(filp); + int ret = 0; + + if (mdev->fops->release) + mdev->fops->release(filp); + + /* decrease the refcount unconditionally since the release() + return value is ignored. */ + put_device(&mdev->dev); + filp->private_data = NULL; + return ret; +} + +static const struct file_operations media_devnode_fops = { + .owner = THIS_MODULE, + .read = media_read, + .write = media_write, + .open = media_open, + .unlocked_ioctl = media_ioctl, + .release = media_release, + .poll = media_poll, + .llseek = no_llseek, +}; + +/** + * media_devnode_register - register a media device node + * @mdev: media device node structure we want to register + * + * The registration code assigns minor numbers and registers the new device node + * with the kernel. An error is returned if no free minor number can be found, + * or if the registration of the device node fails. + * + * Zero is returned on success. + * + * Note that if the media_devnode_register call fails, the release() callback of + * the media_devnode structure is *not* called, so the caller is responsible for + * freeing any data. + */ +int __must_check media_devnode_register(struct media_devnode *mdev) +{ + int minor; + int ret; + + /* Part 1: Find a free minor number */ + mutex_lock(&media_devnode_lock); + minor = find_next_zero_bit(media_devnode_nums, 0, MEDIA_NUM_DEVICES); + if (minor == MEDIA_NUM_DEVICES) { + mutex_unlock(&media_devnode_lock); + printk(KERN_ERR "could not get a free minor\n"); + return -ENFILE; + } + + set_bit(mdev->minor, media_devnode_nums); + mutex_unlock(&media_devnode_lock); + + mdev->minor = minor; + + /* Part 2: Initialize and register the character device */ + cdev_init(&mdev->cdev, &media_devnode_fops); + mdev->cdev.owner = mdev->fops->owner; + + ret = cdev_add(&mdev->cdev, MKDEV(MAJOR(media_dev_t), mdev->minor), 1); + if (ret < 0) { + printk(KERN_ERR "%s: cdev_add failed\n", __func__); + goto error; + } + + /* Part 3: Register the media device */ + mdev->dev.bus = &media_bus_type; + mdev->dev.devt = MKDEV(MAJOR(media_dev_t), mdev->minor); + mdev->dev.release = media_devnode_release; + if (mdev->parent) + mdev->dev.parent = mdev->parent; + dev_set_name(&mdev->dev, "media%d", mdev->minor); + ret = device_register(&mdev->dev); + if (ret < 0) { + printk(KERN_ERR "%s: device_register failed\n", __func__); + goto error; + } + + /* Part 4: Activate this minor. The char device can now be used. */ + set_bit(MEDIA_FLAG_REGISTERED, &mdev->flags); + + return 0; + +error: + cdev_del(&mdev->cdev); + clear_bit(mdev->minor, media_devnode_nums); + return ret; +} + +/** + * media_devnode_unregister - unregister a media device node + * @mdev: the device node to unregister + * + * This unregisters the passed device. Future open calls will be met with + * errors. + * + * This function can safely be called if the device node has never been + * registered or has already been unregistered. + */ +void media_devnode_unregister(struct media_devnode *mdev) +{ + /* Check if mdev was ever registered at all */ + if (!media_devnode_is_registered(mdev)) + return; + + mutex_lock(&media_devnode_lock); + clear_bit(MEDIA_FLAG_REGISTERED, &mdev->flags); + mutex_unlock(&media_devnode_lock); + device_unregister(&mdev->dev); +} + +/* + * Initialise media for linux + */ +static int __init media_devnode_init(void) +{ + int ret; + + printk(KERN_INFO "Linux media interface: v0.10\n"); + ret = alloc_chrdev_region(&media_dev_t, 0, MEDIA_NUM_DEVICES, + MEDIA_NAME); + if (ret < 0) { + printk(KERN_WARNING "media: unable to allocate major\n"); + return ret; + } + + ret = bus_register(&media_bus_type); + if (ret < 0) { + unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES); + printk(KERN_WARNING "media: bus_register failed\n"); + return -EIO; + } + + return 0; +} + +static void __exit media_devnode_exit(void) +{ + bus_unregister(&media_bus_type); + unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES); +} + +module_init(media_devnode_init) +module_exit(media_devnode_exit) + +MODULE_AUTHOR("Laurent Pinchart laurent.pinchart@ideasonboard.com"); +MODULE_DESCRIPTION("Device node registration for media drivers"); +MODULE_LICENSE("GPL"); diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h new file mode 100644 index 0000000..f6caafc --- /dev/null +++ b/include/media/media-devnode.h @@ -0,0 +1,97 @@ +/* + * Media device node + * + * Copyright (C) 2010 Nokia Corporation + * + * Contacts: Laurent Pinchart laurent.pinchart@ideasonboard.com + * Sakari Ailus sakari.ailus@iki.fi + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * -- + * + * Common functions for media-related drivers to register and unregister media + * device nodes. + */ + +#ifndef _MEDIA_DEVNODE_H +#define _MEDIA_DEVNODE_H + +#include <linux/poll.h> +#include <linux/fs.h> +#include <linux/device.h> +#include <linux/cdev.h> + +/* + * Flag to mark the media_devnode struct as registered. Drivers must not touch + * this flag directly, it will be set and cleared by media_devnode_register and + * media_devnode_unregister. + */ +#define MEDIA_FLAG_REGISTERED 0 + +struct media_file_operations { + struct module *owner; + ssize_t (*read) (struct file *, char __user *, size_t, loff_t *); + ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); + unsigned int (*poll) (struct file *, struct poll_table_struct *); + long (*ioctl) (struct file *, unsigned int, unsigned long); + int (*open) (struct file *); + int (*release) (struct file *); +}; + +/** + * struct media_devnode - Media device node + * @parent: parent device + * @minor: device node minor number + * @flags: flags, combination of the MEDIA_FLAG_* constants + * + * This structure represents a media-related device node. + * + * The @parent is a physical device. It must be set by core or device drivers + * before registering the node. + */ +struct media_devnode { + /* device ops */ + const struct media_file_operations *fops; + + /* sysfs */ + struct device dev; /* media device */ + struct cdev cdev; /* character device */ + struct device *parent; /* device parent */ + + /* device info */ + int minor; + unsigned long flags; /* Use bitops to access flags */ + + /* callbacks */ + void (*release)(struct media_devnode *mdev); +}; + +/* dev to media_devnode */ +#define to_media_devnode(cd) container_of(cd, struct media_devnode, dev) + +int __must_check media_devnode_register(struct media_devnode *mdev); +void media_devnode_unregister(struct media_devnode *mdev); + +static inline struct media_devnode *media_devnode_data(struct file *filp) +{ + return filp->private_data; +} + +static inline int media_devnode_is_registered(struct media_devnode *mdev) +{ + return test_bit(MEDIA_FLAG_REGISTERED, &mdev->flags); +} + +#endif /* _MEDIA_DEVNODE_H */

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 --- Documentation/DocBook/v4l/media-controller.xml | 20 +++ Documentation/media-framework.txt | 151 ++++++++++++++++++++++++ drivers/media/Makefile | 2 +- drivers/media/media-device.c | 56 +++++++++ drivers/media/media-entity.c | 147 +++++++++++++++++++++++ include/media/media-device.h | 19 +++ include/media/media-entity.h | 122 +++++++++++++++++++ 7 files changed, 516 insertions(+), 1 deletions(-) create mode 100644 drivers/media/media-entity.c create mode 100644 include/media/media-entity.h

diff --git a/Documentation/DocBook/v4l/media-controller.xml b/Documentation/DocBook/v4l/media-controller.xml index 253ddb4..f89228d 100644 --- a/Documentation/DocBook/v4l/media-controller.xml +++ b/Documentation/DocBook/v4l/media-controller.xml @@ -53,4 +53,24 @@ implementing policies that belong to userspace.</para> <para>The media controller API aims at solving those problems.</para> </section> + + <section id="media-controller-model"> + <title>Media device model</title> + <para>Discovering a device internal topology, and configuring it at runtime, + is one of the goals of the media controller API. To achieve this, hardware + devices are modelled as an oriented graph of building blocks called entities + connected through pads.</para> + <para>An entity is a basic media hardware or software 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.</para> + <para>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.</para> + <para>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.</para> + </section> </chapter> diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt index 1844c3f..0257bad 100644 --- a/Documentation/media-framework.txt +++ b/Documentation/media-framework.txt @@ -13,6 +13,30 @@ Documentation/DocBook/v4l/media-controller.xml. This document will focus on the kernel-side implementation of the media framework.

+Abstract media device model +--------------------------- + +Discovering a device internal topology, and configuring it at runtime, is one +of the goals of the media framework. To achieve this, hardware devices are +modeled as an oriented graph of building blocks called entities connected +through pads. + +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. + + Media device ------------

@@ -65,3 +89,130 @@ Drivers unregister media device instances by calling media_device_unregister(struct media_device *mdev);

Unregistering a media device that hasn't been registered is *NOT* safe. + + +Entities, pads and links +------------------------ + +- Entities + +Entities are represented by a struct media_entity instance, defined in +include/media/media-entity.h. The structure is usually embedded into a +higher-level structure, such as a v4l2_subdev or video_device instance, +although drivers can allocate entities directly. + +Drivers initialize entities by calling + + media_entity_init(struct media_entity *entity, u16 num_pads, + struct media_pad *pads, u16 extra_links); + +The media_entity name, type, flags, revision and group_id fields can be +initialized before or after calling media_entity_init. Entities embedded in +higher-level standard structures can have some of those fields set by the +higher-level framework. + +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_init. The function will initialize the other pads fields. + +Unlike the number of pads, the total number of links isn't always known in +advance by the entity driver. As an initial estimate, media_entity_init +pre-allocates a number of links equal to the number of pads plus an optional +number of extra links. The links array will be reallocated if it grows beyond +the initial estimate. + +Drivers register entities with a media device by calling + + media_device_register_entity(struct media_device *mdev, + struct media_entity *entity); + +Entities are identified by a unique positive integer ID. Drivers can provide an +ID by filling the media_entity id field prior to registration, or request the +media controller framework to assign an ID automatically. Drivers that provide +IDs manually must ensure that all IDs are unique. IDs are not guaranteed to be +contiguous even when they are all assigned automatically by the framework. + +Drivers unregister entities by calling + + media_device_unregister_entity(struct media_entity *entity); + +Unregistering an entity will not change the IDs of the other entities, and the +ID will never be reused for a newly registered entity. + +When a media device is unregistered, all its entities are unregistered +automatically. No manual entities unregistration is then required. + +Drivers free resources associated with an entity by calling + + media_entity_cleanup(struct media_entity *entity); + +This function must be called during the cleanup phase after unregistering the +entity. Note that the media_entity instance itself must be freed explicitly by +the driver if required. + +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. + +Logical entity groups can be defined by setting the group ID of all member +entities to the same non-zero value. An entity group serves no purpose in the +kernel, but is reported to userspace during entities enumeration. The group_id +field belongs to the media device driver and must not by touched by entity +drivers. + +Media device drivers should define groups if several entities are logically +bound together. Example usages include reporting + + - ALSA, VBI and video nodes that carry the same media stream + - lens and flash controllers associated with a sensor + +- Pads + +Pads are represented by a struct media_pad instance, defined in +include/media/media-entity.h. Each entity stores its pads in a pads array +managed by the entity driver. Drivers usually embed the array in a +driver-specific structure. + +Pads are identified by their entity and their 0-based index in the pads array. +Both information are stored in the media_pad structure, making the media_pad +pointer the canonical way to store and pass link references. + +Pads have flags that describe the pad capabilities and state. + + MEDIA_PAD_FL_SINK indicates that the pad supports sinking data. + MEDIA_PAD_FL_SOURCE indicates that the pad supports sourcing data. + +One and only one of MEDIA_PAD_FL_SINK and MEDIA_PAD_FL_SOURCE must be set for +each pad. + +- Links + +Links are represented by a struct media_link instance, defined in +include/media/media-entity.h. Each entity stores all links originating at or +targetting any of its pads in a links array. A given link is thus stored +twice, once in the source entity and once in the target entity. The array is +pre-allocated and grows dynamically as needed. + +Drivers create links by calling + + media_entity_create_link(struct media_entity *source, u16 source_pad, + struct media_entity *sink, u16 sink_pad, + u32 flags); + +An entry in the link array of each entity is allocated and stores pointers +to source and sink pads. + +Links have flags that describe the link capabilities and state. + + MEDIA_LNK_FL_ENABLED 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. + MEDIA_LNK_FL_IMMUTABLE 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. diff --git a/drivers/media/Makefile b/drivers/media/Makefile index 36731aa..64755c9 100644 --- a/drivers/media/Makefile +++ b/drivers/media/Makefile @@ -2,7 +2,7 @@ # Makefile for the kernel multimedia device drivers. #

-media-objs := media-device.o media-devnode.o +media-objs := media-device.o media-devnode.o media-entity.o

ifeq ($(CONFIG_MEDIA_CONTROLLER),y) obj-$(CONFIG_MEDIA_SUPPORT) += media.o diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index bcd3985..a36509a 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -25,6 +25,7 @@

#include <media/media-device.h> #include <media/media-devnode.h> +#include <media/media-entity.h>

static const struct media_file_operations media_device_fops = { .owner = THIS_MODULE, @@ -69,6 +70,10 @@ int __must_check media_device_register(struct media_device *mdev) if (WARN_ON(mdev->dev == NULL || mdev->model[0] == 0)) return -EINVAL;

+ mdev->entity_id = 1; + INIT_LIST_HEAD(&mdev->entities); + spin_lock_init(&mdev->lock); + /* Register the device node. */ mdev->devnode.fops = &media_device_fops; mdev->devnode.parent = mdev->dev; @@ -94,7 +99,58 @@ EXPORT_SYMBOL_GPL(media_device_register); */ void media_device_unregister(struct media_device *mdev) { + struct media_entity *entity; + struct media_entity *next; + + list_for_each_entry_safe(entity, next, &mdev->entities, list) + media_device_unregister_entity(entity); + device_remove_file(&mdev->devnode.dev, &dev_attr_model); media_devnode_unregister(&mdev->devnode); } EXPORT_SYMBOL_GPL(media_device_unregister); + +/** + * media_device_register_entity - Register an entity with a media device + * @mdev: The media device + * @entity: The entity + */ +int __must_check media_device_register_entity(struct media_device *mdev, + struct media_entity *entity) +{ + /* Warn if we apparently re-register an entity */ + WARN_ON(entity->parent != NULL); + entity->parent = mdev; + + spin_lock(&mdev->lock); + if (entity->id == 0) + entity->id = mdev->entity_id++; + else + mdev->entity_id = max(entity->id + 1, mdev->entity_id); + list_add_tail(&entity->list, &mdev->entities); + spin_unlock(&mdev->lock); + + return 0; +} +EXPORT_SYMBOL_GPL(media_device_register_entity); + +/** + * media_device_unregister_entity - Unregister an entity + * @entity: The entity + * + * If the entity has never been registered this function will return + * immediately. + */ +void media_device_unregister_entity(struct media_entity *entity) +{ + struct media_device *mdev = entity->parent; + + if (mdev == NULL) + return; + + spin_lock(&mdev->lock); + list_del(&entity->list); + spin_unlock(&mdev->lock); + entity->parent = NULL; +} +EXPORT_SYMBOL_GPL(media_device_unregister_entity); diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c new file mode 100644 index 0000000..5c31df9 --- /dev/null +++ b/drivers/media/media-entity.c @@ -0,0 +1,147 @@ +/* + * Media entity + * + * Copyright (C) 2010 Nokia Corporation + * + * Contacts: Laurent Pinchart laurent.pinchart@ideasonboard.com + * Sakari Ailus sakari.ailus@iki.fi + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <media/media-entity.h> + +/** + * media_entity_init - Initialize a media entity + * + * @num_pads: Total number of sink and source pads. + * @extra_links: Initial estimate of the number of extra links. + * @pads: Array of 'num_pads' pads. + * + * The total number of pads is an intrinsic property of entities known by the + * entity driver, while the total number of links depends on hardware design + * and is an extrinsic property unknown to the entity driver. However, in most + * use cases the entity driver can guess the number of links which can safely + * be assumed to be equal to or larger than the number of pads. + * + * For those reasons the links array can be preallocated based on the entity + * driver guess and will be reallocated later if extra links need to be + * created. + * + * This function allocates a links array with enough space to hold at least + * 'num_pads' + 'extra_links' elements. The media_entity::max_links field will + * be set to the number of allocated elements. + * + * The pads array is managed by the entity driver and passed to + * media_entity_init() where its pointer will be stored in the entity structure. + */ +int +media_entity_init(struct media_entity *entity, u16 num_pads, + struct media_pad *pads, u16 extra_links) +{ + struct media_link *links; + unsigned int max_links = num_pads + extra_links; + unsigned int i; + + links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL); + if (links == NULL) + return -ENOMEM; + + entity->group_id = 0; + entity->max_links = max_links; + entity->num_links = 0; + entity->num_backlinks = 0; + entity->num_pads = num_pads; + entity->pads = pads; + entity->links = links; + + for (i = 0; i < num_pads; i++) { + pads[i].entity = entity; + pads[i].index = i; + } + + return 0; +} +EXPORT_SYMBOL_GPL(media_entity_init); + +void +media_entity_cleanup(struct media_entity *entity) +{ + kfree(entity->links); +} +EXPORT_SYMBOL_GPL(media_entity_cleanup); + +static struct media_link *media_entity_add_link(struct media_entity *entity) +{ + if (entity->num_links >= entity->max_links) { + struct media_link *links = entity->links; + unsigned int max_links = entity->max_links + 2; + unsigned int i; + + links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL); + if (links == NULL) + return NULL; + + for (i = 0; i < entity->num_links; i++) + links[i].reverse->reverse = &links[i]; + + entity->max_links = max_links; + entity->links = links; + } + + return &entity->links[entity->num_links++]; +} + +int +media_entity_create_link(struct media_entity *source, u16 source_pad, + struct media_entity *sink, u16 sink_pad, u32 flags) +{ + struct media_link *link; + struct media_link *backlink; + + BUG_ON(source == NULL || sink == NULL); + BUG_ON(source_pad >= source->num_pads); + BUG_ON(sink_pad >= sink->num_pads); + + link = media_entity_add_link(source); + if (link == NULL) + return -ENOMEM; + + link->source = &source->pads[source_pad]; + link->sink = &sink->pads[sink_pad]; + link->flags = flags; + + /* Create the backlink. Backlinks are used to help graph traversal and + * are not reported to userspace. + */ + backlink = media_entity_add_link(sink); + if (backlink == NULL) { + source->num_links--; + return -ENOMEM; + } + + backlink->source = &source->pads[source_pad]; + backlink->sink = &sink->pads[sink_pad]; + backlink->flags = flags; + + link->reverse = backlink; + backlink->reverse = link; + + sink->num_backlinks++; + + return 0; +} +EXPORT_SYMBOL_GPL(media_entity_create_link); diff --git a/include/media/media-device.h b/include/media/media-device.h index 30857f7..a8390fe 100644 --- a/include/media/media-device.h +++ b/include/media/media-device.h @@ -25,8 +25,10 @@

#include <linux/device.h> #include <linux/list.h> +#include <linux/spinlock.h>

#include <media/media-devnode.h> +#include <media/media-entity.h>

/** * struct media_device - Media device @@ -37,6 +39,9 @@ * @bus_info: Unique and stable device location identifier * @hw_revision: Hardware device revision * @driver_version: Device driver version + * @entity_id: ID of the next entity to be registered + * @entities: List of registered entities + * @lock: Entities list lock * * This structure represents an abstract high-level media device. It allows easy * access to entities and provides basic media device-level support. The @@ -58,6 +63,12 @@ struct media_device { char bus_info[32]; u32 hw_revision; u32 driver_version; + + u32 entity_id; + struct list_head entities; + + /* Protects the entities list */ + spinlock_t lock; };

/* media_devnode to media_device */ @@ -66,4 +77,12 @@ struct media_device { int __must_check media_device_register(struct media_device *mdev); void media_device_unregister(struct media_device *mdev);

+int __must_check media_device_register_entity(struct media_device *mdev, + struct media_entity *entity); +void media_device_unregister_entity(struct media_entity *entity); + +/* Iterate over all entities. */ +#define media_device_for_each_entity(entity, mdev) \ + list_for_each_entry(entity, &(mdev)->entities, list) + #endif diff --git a/include/media/media-entity.h b/include/media/media-entity.h new file mode 100644 index 0000000..f6c856c --- /dev/null +++ b/include/media/media-entity.h @@ -0,0 +1,122 @@ +/* + * Media entity + * + * Copyright (C) 2010 Nokia Corporation + * + * Contacts: Laurent Pinchart laurent.pinchart@ideasonboard.com + * Sakari Ailus sakari.ailus@iki.fi + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef _MEDIA_ENTITY_H +#define _MEDIA_ENTITY_H + +#include <linux/list.h> + +#define MEDIA_ENT_TYPE_SHIFT 16 +#define MEDIA_ENT_TYPE_MASK 0x00ff0000 +#define MEDIA_ENT_SUBTYPE_MASK 0x0000ffff + +#define MEDIA_ENT_T_DEVNODE (1 << MEDIA_ENT_TYPE_SHIFT) +#define MEDIA_ENT_T_DEVNODE_V4L (MEDIA_ENT_T_DEVNODE + 1) +#define MEDIA_ENT_T_DEVNODE_FB (MEDIA_ENT_T_DEVNODE + 2) +#define MEDIA_ENT_T_DEVNODE_ALSA (MEDIA_ENT_T_DEVNODE + 3) +#define MEDIA_ENT_T_DEVNODE_DVB (MEDIA_ENT_T_DEVNODE + 4) + +#define MEDIA_ENT_T_V4L2_SUBDEV (2 << MEDIA_ENT_TYPE_SHIFT) +#define MEDIA_ENT_T_V4L2_SUBDEV_SENSOR (MEDIA_ENT_T_V4L2_SUBDEV + 1) +#define MEDIA_ENT_T_V4L2_SUBDEV_FLASH (MEDIA_ENT_T_V4L2_SUBDEV + 2) +#define MEDIA_ENT_T_V4L2_SUBDEV_LENS (MEDIA_ENT_T_V4L2_SUBDEV + 3) + +#define MEDIA_ENT_FL_DEFAULT (1 << 0) + +#define MEDIA_LNK_FL_ENABLED (1 << 0) +#define MEDIA_LNK_FL_IMMUTABLE (1 << 1) + +#define MEDIA_PAD_FL_SINK (1 << 0) +#define MEDIA_PAD_FL_SOURCE (1 << 1) + +struct media_link { + struct media_pad *source; /* Source pad */ + struct media_pad *sink; /* Sink pad */ + struct media_link *reverse; /* Link in the reverse direction */ + unsigned long flags; /* Link flags (MEDIA_LNK_FL_*) */ +}; + +struct media_pad { + struct media_entity *entity; /* Entity this pad belongs to */ + u16 index; /* Pad index in the entity pads array */ + unsigned long flags; /* Pad flags (MEDIA_PAD_FL_*) */ +}; + +struct media_entity { + struct list_head list; + struct media_device *parent; /* Media device this entity belongs to*/ + u32 id; /* Entity ID, unique in the parent media + * device context */ + const char *name; /* Entity name */ + u32 type; /* Entity type (MEDIA_ENT_T_*) */ + u32 revision; /* Entity revision, driver specific */ + unsigned long flags; /* Entity flags (MEDIA_ENT_FL_*) */ + u32 group_id; /* Entity group ID */ + + u16 num_pads; /* Number of sink and source pads */ + u16 num_links; /* Number of existing links, both + * enabled and disabled */ + u16 num_backlinks; /* Number of backlinks */ + u16 max_links; /* Maximum number of links */ + + struct media_pad *pads; /* Pads array (num_pads elements) */ + struct media_link *links; /* Links array (max_links elements)*/ + + union { + /* Node specifications */ + struct { + u32 major; + u32 minor; + } v4l; + struct { + u32 major; + u32 minor; + } fb; + struct { + u32 card; + u32 device; + u32 subdevice; + } alsa; + int dvb; + + /* Sub-device specifications */ + /* Nothing needed yet */ + }; +}; + +static inline u32 media_entity_type(struct media_entity *entity) +{ + return entity->type & MEDIA_ENT_TYPE_MASK; +} + +static inline u32 media_entity_subtype(struct media_entity *entity) +{ + return entity->type & MEDIA_ENT_SUBTYPE_MASK; +} + +int media_entity_init(struct media_entity *entity, u16 num_pads, + struct media_pad *pads, u16 extra_links); +void media_entity_cleanup(struct media_entity *entity); +int media_entity_create_link(struct media_entity *source, u16 source_pad, + struct media_entity *sink, u16 sink_pad, u32 flags); + +#endif

Due to the wide differences between drivers regarding power management needs, the media controller does not implement power management. However, the media_entity structure includes a use_count field that media drivers can use to track the number of users of every entity for power management needs.

The use_count field is owned by media drivers and must not be touched by entity drivers. Access to the field must be protected by the media device graph_mutex lock.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- Documentation/media-framework.txt | 13 ++++++++++ drivers/media/media-device.c | 1 + drivers/media/media-entity.c | 46 +++++++++++++++++++++++++++++++++++++ include/media/media-device.h | 4 +++ include/media/media-entity.h | 9 +++++++ 5 files changed, 73 insertions(+), 0 deletions(-)

diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt index ab17f33..78ae020 100644 --- a/Documentation/media-framework.txt +++ b/Documentation/media-framework.txt @@ -258,3 +258,16 @@ When the graph traversal is complete the function will return NULL.

Graph traversal can be interrupted at any moment. No cleanup function call is required and the graph structure can be freed normally. + + +Use count and power handling +---------------------------- + +Due to the wide differences between drivers regarding power management needs, +the media controller does not implement power management. However, the +media_entity structure includes a use_count field that media drivers can use to +track the number of users of every entity for power management needs. + +The use_count field is owned by media drivers and must not be touched by entity +drivers. Access to the field must be protected by the media device graph_mutex +lock. diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index a36509a..d2bc809 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -73,6 +73,7 @@ int __must_check media_device_register(struct media_device *mdev) mdev->entity_id = 1; INIT_LIST_HEAD(&mdev->entities); spin_lock_init(&mdev->lock); + mutex_init(&mdev->graph_mutex);

/* Register the device node. */ mdev->devnode.fops = &media_device_fops; diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c index 166f2b5..3e7e2d5 100644 --- a/drivers/media/media-entity.c +++ b/drivers/media/media-entity.c @@ -23,6 +23,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <media/media-entity.h> +#include <media/media-device.h>

/** * media_entity_init - Initialize a media entity @@ -196,6 +197,51 @@ media_entity_graph_walk_next(struct media_entity_graph *graph) EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);

/* ----------------------------------------------------------------------------- + * Module use count + */ + +/* + * media_entity_get - Get a reference to the parent module + * @entity: The entity + * + * Get a reference to the parent media device module. + * + * The function will return immediately if @entity is NULL. + * + * Return a pointer to the entity on success or NULL on failure. + */ +struct media_entity *media_entity_get(struct media_entity *entity) +{ + if (entity == NULL) + return NULL; + + if (entity->parent->dev && + !try_module_get(entity->parent->dev->driver->owner)) + return NULL; + + return entity; +} +EXPORT_SYMBOL_GPL(media_entity_get); + +/* + * media_entity_put - Release the reference to the parent module + * @entity: The entity + * + * Release the reference count acquired by media_entity_get(). + * + * The function will return immediately if @entity is NULL. + */ +void media_entity_put(struct media_entity *entity) +{ + if (entity == NULL) + return; + + if (entity->parent->dev) + module_put(entity->parent->dev->driver->owner); +} +EXPORT_SYMBOL_GPL(media_entity_put); + +/* ----------------------------------------------------------------------------- * Links management */

diff --git a/include/media/media-device.h b/include/media/media-device.h index a8390fe..5d2bff4 100644 --- a/include/media/media-device.h +++ b/include/media/media-device.h @@ -25,6 +25,7 @@

#include <linux/device.h> #include <linux/list.h> +#include <linux/mutex.h> #include <linux/spinlock.h>

#include <media/media-devnode.h> @@ -42,6 +43,7 @@ * @entity_id: ID of the next entity to be registered * @entities: List of registered entities * @lock: Entities list lock + * @graph_mutex: Entities graph operation lock * * This structure represents an abstract high-level media device. It allows easy * access to entities and provides basic media device-level support. The @@ -69,6 +71,8 @@ struct media_device {

/* Protects the entities list */ spinlock_t lock; + /* Serializes graph operations. */ + struct mutex graph_mutex; };

/* media_devnode to media_device */ diff --git a/include/media/media-entity.h b/include/media/media-entity.h index 28f61f6..a9b31d9 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -81,6 +81,12 @@ struct media_entity { struct media_pad *pads; /* Pads array (num_pads elements) */ struct media_link *links; /* Links array (max_links elements)*/

+ /* Reference counts must never be negative, but are signed integers on + * purpose: a simple WARN_ON(<0) check can be used to detect reference + * count bugs that would make them negative. + */ + int use_count; /* Use count for the entity. */ + union { /* Node specifications */ struct { @@ -129,6 +135,9 @@ void media_entity_cleanup(struct media_entity *entity); int media_entity_create_link(struct media_entity *source, u16 source_pad, struct media_entity *sink, u16 sink_pad, u32 flags);

+struct media_entity *media_entity_get(struct media_entity *entity); +void media_entity_put(struct media_entity *entity); + void media_entity_graph_walk_start(struct media_entity_graph *graph, struct media_entity *entity); struct media_entity *

Create the following two ioctls and implement them at the media device level to enumerate entities, pads and links.

- MEDIA_IOC_ENUM_ENTITIES: Enumerate entities and their properties - MEDIA_IOC_ENUM_LINKS: Enumerate all pads and links for a given entity

Entity IDs can be non-contiguous. Userspace applications should enumerate entities using the MEDIA_ENT_ID_FLAG_NEXT flag. When the flag is set in the entity ID, the MEDIA_IOC_ENUM_ENTITIES will return the next entity with an ID bigger than the requested one.

Only forward links that originate at one of the entity's source pads are returned during the enumeration process.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Sakari Ailus sakari.ailus@iki.fi --- Documentation/DocBook/media-entities.tmpl | 8 + Documentation/DocBook/v4l/media-controller.xml | 2 + .../DocBook/v4l/media-ioc-device-info.xml | 3 +- .../DocBook/v4l/media-ioc-enum-entities.xml | 308 ++++++++++++++++++++ Documentation/DocBook/v4l/media-ioc-enum-links.xml | 202 +++++++++++++ drivers/media/media-device.c | 123 ++++++++ include/linux/media.h | 85 ++++++ include/media/media-entity.h | 24 +-- 8 files changed, 731 insertions(+), 24 deletions(-) create mode 100644 Documentation/DocBook/v4l/media-ioc-enum-entities.xml create mode 100644 Documentation/DocBook/v4l/media-ioc-enum-links.xml

diff --git a/Documentation/DocBook/media-entities.tmpl b/Documentation/DocBook/media-entities.tmpl index 6af3375..6e7dae4 100644 --- a/Documentation/DocBook/media-entities.tmpl +++ b/Documentation/DocBook/media-entities.tmpl @@ -92,6 +92,8 @@ <!ENTITY VIDIOC-UNSUBSCRIBE-EVENT "<link linkend='vidioc-subscribe-event'><constant>VIDIOC_UNSUBSCRIBE_EVENT</constant></link>">

<!ENTITY MEDIA-IOC-DEVICE-INFO "<link linkend='media-ioc-device-info'><constant>MEDIA_IOC_DEVICE_INFO</constant></link>"> +<!ENTITY MEDIA-IOC-ENUM-ENTITIES "<link linkend='media-ioc-enum-entities'><constant>MEDIA_IOC_ENUM_ENTITIES</constant></link>"> +<!ENTITY MEDIA-IOC-ENUM-LINKS "<link linkend='media-ioc-enum-links'><constant>MEDIA_IOC_ENUM_LINKS</constant></link>">

<!-- Types --> <!ENTITY v4l2-std-id "<link linkend='v4l2-std-id'>v4l2_std_id</link>"> @@ -188,6 +190,10 @@ <!ENTITY v4l2-window "struct&nbsp;<link linkend='v4l2-window'>v4l2_window</link>">

<!ENTITY media-device-info "struct&nbsp;<link linkend='media-device-info'>media_device_info</link>"> +<!ENTITY media-entity-desc "struct&nbsp;<link linkend='media-entity-desc'>media_entity_desc</link>"> +<!ENTITY media-links-enum "struct&nbsp;<link linkend='media-links-enum'>media_links_enum</link>"> +<!ENTITY media-pad-desc "struct&nbsp;<link linkend='media-pad-desc'>media_pad_desc</link>"> +<!ENTITY media-link-desc "struct&nbsp;<link linkend='media-link-desc'>media_link_desc</link>">

<!-- Error Codes --> <!ENTITY EACCES "<errorcode>EACCES</errorcode> error code"> @@ -334,6 +340,8 @@ <!ENTITY sub-media-close SYSTEM "v4l/media-func-close.xml"> <!ENTITY sub-media-ioctl SYSTEM "v4l/media-func-ioctl.xml"> <!ENTITY sub-media-ioc-device-info SYSTEM "v4l/media-ioc-device-info.xml"> +<!ENTITY sub-media-ioc-enum-entities SYSTEM "v4l/media-ioc-enum-entities.xml"> +<!ENTITY sub-media-ioc-enum-links SYSTEM "v4l/media-ioc-enum-links.xml">

<!-- Function Reference --> <!ENTITY close SYSTEM "v4l/func-close.xml"> diff --git a/Documentation/DocBook/v4l/media-controller.xml b/Documentation/DocBook/v4l/media-controller.xml index a46b786..2c4fd2b 100644 --- a/Documentation/DocBook/v4l/media-controller.xml +++ b/Documentation/DocBook/v4l/media-controller.xml @@ -83,4 +83,6 @@ &sub-media-ioctl; <!-- All ioctls go here. --> &sub-media-ioc-device-info; + &sub-media-ioc-enum-entities; + &sub-media-ioc-enum-links; </appendix> diff --git a/Documentation/DocBook/v4l/media-ioc-device-info.xml b/Documentation/DocBook/v4l/media-ioc-device-info.xml index 278a312..1f32373 100644 --- a/Documentation/DocBook/v4l/media-ioc-device-info.xml +++ b/Documentation/DocBook/v4l/media-ioc-device-info.xml @@ -27,7 +27,8 @@ <varlistentry> <term><parameter>fd</parameter></term> <listitem> - <para>&fd;</para> + <para>File descriptor returned by + <link linkend='media-func-open'><function>open()</function></link>.</para> </listitem> </varlistentry> <varlistentry> diff --git a/Documentation/DocBook/v4l/media-ioc-enum-entities.xml b/Documentation/DocBook/v4l/media-ioc-enum-entities.xml new file mode 100644 index 0000000..13d0cc4 --- /dev/null +++ b/Documentation/DocBook/v4l/media-ioc-enum-entities.xml @@ -0,0 +1,308 @@ +<refentry id="media-ioc-enum-entities"> + <refmeta> + <refentrytitle>ioctl MEDIA_IOC_ENUM_ENTITIES</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>MEDIA_IOC_ENUM_ENTITIES</refname> + <refpurpose>Enumerate entities and their properties</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct media_entity_desc *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>File descriptor returned by + <link linkend='media-func-open'><function>open()</function></link>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>MEDIA_IOC_ENUM_ENTITIES</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + <para>To query the attributes of an entity, applications set the id field + of a &media-entity-desc; structure and call the MEDIA_IOC_ENUM_ENTITIES + ioctl with a pointer to this structure. The driver fills the rest of the + structure or returns an &EINVAL; when the id is invalid.</para> + <para>Entities can be enumerated by or'ing the id with the + <constant>MEDIA_ENT_ID_FLAG_NEXT</constant> flag. The driver will return + information about the entity with the smallest id strictly larger than the + requested one ('next entity'), or the &EINVAL; if there is none.</para> + <para>Entity IDs can be non-contiguous. Applications must + <emphasis>not</emphasis> try to enumerate entities by calling + MEDIA_IOC_ENUM_ENTITIES with increasing id's until they get an error.</para> + <para>Two or more entities that share a common non-zero + <structfield>group_id</structfield> value are considered as logically + grouped. Groups are used to report + <itemizedlist> + <listitem>ALSA, VBI and video nodes that carry the same media + stream</listitem> + <listitem>lens and flash controllers associated with a sensor</listitem> + </itemizedlist> + </para> + + <table pgwide="1" frame="none" id="media-entity-desc"> + <title>struct <structname>media_entity_desc</structname></title> + <tgroup cols="5"> + <colspec colname="c1" /> + <colspec colname="c2" /> + <colspec colname="c3" /> + <colspec colname="c4" /> + <colspec colname="c5" /> + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>id</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity id, set by the application. When the id is or'ed with + <constant>MEDIA_ENT_ID_FLAG_NEXT</constant>, the driver clears the + flag and returns the first entity with a larger id.</entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry></entry> + <entry></entry> + <entry>Entity name as an UTF-8 NULL-terminated string.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>type</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity type, see <xref linkend="media-entity-type" /> for details.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>revision</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity revision in a driver/hardware specific format.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity flags, see <xref linkend="media-entity-flag" /> for details.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>group_id</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Entity group ID</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>pads</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Number of pads</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>links</structfield></entry> + <entry></entry> + <entry></entry> + <entry>Total number of outbound links. Inbound links are not counted + in this field.</entry> + </row> + <row> + <entry>union</entry> + </row> + <row> + <entry></entry> + <entry>struct</entry> + <entry><structfield>v4l</structfield></entry> + <entry></entry> + <entry>Valid for V4L sub-devices and nodes only.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>major</structfield></entry> + <entry>V4L device node major number. For V4L sub-devices with no + device node, set by the driver to 0.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>minor</structfield></entry> + <entry>V4L device node minor number. For V4L sub-devices with no + device node, set by the driver to 0.</entry> + </row> + <row> + <entry></entry> + <entry>struct</entry> + <entry><structfield>fb</structfield></entry> + <entry></entry> + <entry>Valid for frame buffer nodes only.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>major</structfield></entry> + <entry>Frame buffer device node major number.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>minor</structfield></entry> + <entry>Frame buffer device node minor number.</entry> + </row> + <row> + <entry></entry> + <entry>struct</entry> + <entry><structfield>alsa</structfield></entry> + <entry></entry> + <entry>Valid for ALSA devices only.</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>card</structfield></entry> + <entry>ALSA card number</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>device</structfield></entry> + <entry>ALSA device number</entry> + </row> + <row> + <entry></entry> + <entry></entry> + <entry>__u32</entry> + <entry><structfield>subdevice</structfield></entry> + <entry>ALSA sub-device number</entry> + </row> + <row> + <entry></entry> + <entry>int</entry> + <entry><structfield>dvb</structfield></entry> + <entry></entry> + <entry>DVB card number</entry> + </row> + <row> + <entry></entry> + <entry>__u8</entry> + <entry><structfield>raw</structfield>[180]</entry> + <entry></entry> + <entry></entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="media-entity-type"> + <title>Media entity types</title> + <tgroup cols="2"> + <colspec colname="c1"/> + <colspec colname="c2"/> + <tbody valign="top"> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE</constant></entry> + <entry>Unknown device node</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE_V4L</constant></entry> + <entry>V4L video, radio or vbi device node</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE_FB</constant></entry> + <entry>Frame buffer device node</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE_ALSA</constant></entry> + <entry>ALSA card</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_DEVNODE_DVB</constant></entry> + <entry>DVB card</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV</constant></entry> + <entry>Unknown V4L sub-device</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_SENSOR</constant></entry> + <entry>Video sensor</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_FLASH</constant></entry> + <entry>Flash controller</entry> + </row> + <row> + <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_LENS</constant></entry> + <entry>Lens controller</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="media-entity-flag"> + <title>Media entity flags</title> + <tgroup cols="2"> + <colspec colname="c1"/> + <colspec colname="c2"/> + <tbody valign="top"> + <row> + <entry><constant>MEDIA_ENT_FL_DEFAULT</constant></entry> + <entry>Default entity for its type. Used to discover the default + audio, VBI and video devices, the default camera sensor, ...</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &media-entity-desc; <structfield>id</structfield> references + a non-existing entity.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/v4l/media-ioc-enum-links.xml b/Documentation/DocBook/v4l/media-ioc-enum-links.xml new file mode 100644 index 0000000..4b08e55 --- /dev/null +++ b/Documentation/DocBook/v4l/media-ioc-enum-links.xml @@ -0,0 +1,202 @@ +<refentry id="media-ioc-enum-links"> + <refmeta> + <refentrytitle>ioctl MEDIA_IOC_ENUM_LINKS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>MEDIA_IOC_ENUM_LINKS</refname> + <refpurpose>Enumerate all pads and links for a given entity</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>struct media_links_enum *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>File descriptor returned by + <link linkend='media-func-open'><function>open()</function></link>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>MEDIA_IOC_ENUM_LINKS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To enumerate pads and/or links for a given entity, applications set + the entity field of a &media-links-enum; structure and initialize the + &media-pad-desc; and &media-link-desc; structure arrays pointed by the + <structfield>pads</structfield> and <structfield>links</structfield> fields. + They then call the MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this + structure.</para> + <para>If the <structfield>pads</structfield> field is not NULL, the driver + fills the <structfield>pads</structfield> array with information about the + entity's pads. The array must have enough room to store all the entity's + pads. The number of pads can be retrieved with the &MEDIA-IOC-ENUM-ENTITIES; + ioctl.</para> + <para>If the <structfield>links</structfield> field is not NULL, the driver + fills the <structfield>links</structfield> array with information about the + entity's outbound links. The array must have enough room to store all the + entity's outbound links. The number of outbound links can be retrieved with + the &MEDIA-IOC-ENUM-ENTITIES; ioctl.</para> + <para>Only forward links that originate at one of the entity's source pads + are returned during the enumeration process.</para> + + <table pgwide="1" frame="none" id="media-links-enum"> + <title>struct <structname>media_links_enum</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>entity</structfield></entry> + <entry>Entity id, set by the application.</entry> + </row> + <row> + <entry>struct &media-pad-desc;</entry> + <entry>*<structfield>pads</structfield></entry> + <entry>Pointer to a pads array allocated by the application. Ignored + if NULL.</entry> + </row> + <row> + <entry>struct &media-link-desc;</entry> + <entry>*<structfield>links</structfield></entry> + <entry>Pointer to a links array allocated by the application. Ignored + if NULL.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="media-pad-desc"> + <title>struct <structname>media_pad_desc</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>entity</structfield></entry> + <entry>ID of the entity this pad belongs to.</entry> + </row> + <row> + <entry>__u16</entry> + <entry><structfield>index</structfield></entry> + <entry>0-based pad index.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Pad flags, see <xref linkend="media-pad-flag" /> for more details.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="media-pad-flag"> + <title>Media pad flags</title> + <tgroup cols="2"> + <colspec colname="c1"/> + <colspec colname="c2"/> + <tbody valign="top"> + <row> + <entry><constant>MEDIA_PAD_FL_SINK</constant></entry> + <entry>Input pad, relative to the entity. Input pads sink data and + are targets of links.</entry> + </row> + <row> + <entry><constant>MEDIA_PAD_FL_SOURCE</constant></entry> + <entry>Output pad, relative to the entity. Output pads source data + and are origins of links.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table pgwide="1" frame="none" id="media-link-desc"> + <title>struct <structname>media_links_desc</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>struct &media-pad-desc;</entry> + <entry><structfield>source</structfield></entry> + <entry>Pad at the origin of this link.</entry> + </row> + <row> + <entry>struct &media-pad-desc;</entry> + <entry><structfield>sink</structfield></entry> + <entry>Pad at the target of this link.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>flags</structfield></entry> + <entry>Link flags, see <xref linkend="media-link-flag" /> for more details.</entry> + </row> + </tbody> + </tgroup> + </table> + + <table frame="none" pgwide="1" id="media-link-flag"> + <title>Media link flags</title> + <tgroup cols="2"> + <colspec colname="c1"/> + <colspec colname="c2"/> + <tbody valign="top"> + <row> + <entry><constant>MEDIA_LNK_FL_ENABLED</constant></entry> + <entry>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.</entry> + </row> + <row> + <entry><constant>MEDIA_LNK_FL_IMMUTABLE</constant></entry> + <entry>The link enabled state can't be modified at runtime. An + immutable link is always enabled.</entry> + </row> + </tbody> + </tgroup> + </table> + <para>One and only one of <constant>MEDIA_PAD_FL_SINK</constant> and + <constant>MEDIA_PAD_FL_SOURCE</constant> must be set for every pad.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &media-links-enum; <structfield>id</structfield> references + a non-existing entity.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index 92e0d4e..648a9d8 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -61,6 +61,117 @@ static int media_device_get_info(struct media_device *dev, return copy_to_user(__info, &info, sizeof(*__info)); }

+static struct media_entity *find_entity(struct media_device *mdev, u32 id) +{ + struct media_entity *entity; + int next = id & MEDIA_ENT_ID_FLAG_NEXT; + + id &= ~MEDIA_ENT_ID_FLAG_NEXT; + + spin_lock(&mdev->lock); + + media_device_for_each_entity(entity, mdev) { + if ((entity->id == id && !next) || + (entity->id > id && next)) { + spin_unlock(&mdev->lock); + return entity; + } + } + + spin_unlock(&mdev->lock); + + return NULL; +} + +static long media_device_enum_entities(struct media_device *mdev, + struct media_entity_desc __user *uent) +{ + struct media_entity *ent; + struct media_entity_desc u_ent; + + if (copy_from_user(&u_ent.id, &uent->id, sizeof(u_ent.id))) + return -EFAULT; + + ent = find_entity(mdev, u_ent.id); + + if (ent == NULL) + return -EINVAL; + + u_ent.id = ent->id; + u_ent.name[0] = '\0'; + if (ent->name) + strlcpy(u_ent.name, ent->name, sizeof(u_ent.name)); + u_ent.type = ent->type; + u_ent.revision = ent->revision; + u_ent.flags = ent->flags; + u_ent.group_id = ent->group_id; + u_ent.pads = ent->num_pads; + u_ent.links = ent->num_links - ent->num_backlinks; + u_ent.v4l.major = ent->v4l.major; + u_ent.v4l.minor = ent->v4l.minor; + if (copy_to_user(uent, &u_ent, sizeof(u_ent))) + return -EFAULT; + return 0; +} + +static void media_device_kpad_to_upad(const struct media_pad *kpad, + struct media_pad_desc *upad) +{ + upad->entity = kpad->entity->id; + upad->index = kpad->index; + upad->flags = kpad->flags; +} + +static long media_device_enum_links(struct media_device *mdev, + struct media_links_enum __user *ulinks) +{ + struct media_entity *entity; + struct media_links_enum links; + + if (copy_from_user(&links, ulinks, sizeof(links))) + return -EFAULT; + + entity = find_entity(mdev, links.entity); + if (entity == NULL) + return -EINVAL; + + if (links.pads) { + unsigned int p; + + for (p = 0; p < entity->num_pads; p++) { + struct media_pad_desc pad; + media_device_kpad_to_upad(&entity->pads[p], &pad); + if (copy_to_user(&links.pads[p], &pad, sizeof(pad))) + return -EFAULT; + } + } + + if (links.links) { + struct media_link_desc __user *ulink; + unsigned int l; + + for (l = 0, ulink = links.links; l < entity->num_links; l++) { + struct media_link_desc link; + + /* Ignore backlinks. */ + if (entity->links[l].source->entity != entity) + continue; + + media_device_kpad_to_upad(entity->links[l].source, + &link.source); + media_device_kpad_to_upad(entity->links[l].sink, + &link.sink); + link.flags = entity->links[l].flags; + if (copy_to_user(ulink, &link, sizeof(*ulink))) + return -EFAULT; + ulink++; + } + } + if (copy_to_user(ulinks, &links, sizeof(*ulinks))) + return -EFAULT; + return 0; +} + static long media_device_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { @@ -74,6 +185,18 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd, (struct media_device_info __user *)arg); break;

+ case MEDIA_IOC_ENUM_ENTITIES: + ret = media_device_enum_entities(dev, + (struct media_entity_desc __user *)arg); + break; + + case MEDIA_IOC_ENUM_LINKS: + mutex_lock(&dev->graph_mutex); + ret = media_device_enum_links(dev, + (struct media_links_enum __user *)arg); + mutex_unlock(&dev->graph_mutex); + break; + default: ret = -ENOIOCTLCMD; } diff --git a/include/linux/media.h b/include/linux/media.h index 64090db..17c93a4 100644 --- a/include/linux/media.h +++ b/include/linux/media.h @@ -40,6 +40,91 @@ struct media_device_info { __u32 reserved[31]; };

+#define MEDIA_ENT_ID_FLAG_NEXT (1 << 31) + +#define MEDIA_ENT_TYPE_SHIFT 16 +#define MEDIA_ENT_TYPE_MASK 0x00ff0000 +#define MEDIA_ENT_SUBTYPE_MASK 0x0000ffff + +#define MEDIA_ENT_T_DEVNODE (1 << MEDIA_ENT_TYPE_SHIFT) +#define MEDIA_ENT_T_DEVNODE_V4L (MEDIA_ENT_T_DEVNODE + 1) +#define MEDIA_ENT_T_DEVNODE_FB (MEDIA_ENT_T_DEVNODE + 2) +#define MEDIA_ENT_T_DEVNODE_ALSA (MEDIA_ENT_T_DEVNODE + 3) +#define MEDIA_ENT_T_DEVNODE_DVB (MEDIA_ENT_T_DEVNODE + 4) + +#define MEDIA_ENT_T_V4L2_SUBDEV (2 << MEDIA_ENT_TYPE_SHIFT) +#define MEDIA_ENT_T_V4L2_SUBDEV_SENSOR (MEDIA_ENT_T_V4L2_SUBDEV + 1) +#define MEDIA_ENT_T_V4L2_SUBDEV_FLASH (MEDIA_ENT_T_V4L2_SUBDEV + 2) +#define MEDIA_ENT_T_V4L2_SUBDEV_LENS (MEDIA_ENT_T_V4L2_SUBDEV + 3) + +#define MEDIA_ENT_FL_DEFAULT (1 << 0) + +struct media_entity_desc { + __u32 id; + char name[32]; + __u32 type; + __u32 revision; + __u32 flags; + __u32 group_id; + __u16 pads; + __u16 links; + + __u32 reserved[4]; + + union { + /* Node specifications */ + struct { + __u32 major; + __u32 minor; + } v4l; + struct { + __u32 major; + __u32 minor; + } fb; + struct { + __u32 card; + __u32 device; + __u32 subdevice; + } alsa; + int dvb; + + /* Sub-device specifications */ + /* Nothing needed yet */ + __u8 raw[184]; + }; +}; + +#define MEDIA_PAD_FL_SINK (1 << 0) +#define MEDIA_PAD_FL_SOURCE (1 << 1) + +struct media_pad_desc { + __u32 entity; /* entity ID */ + __u16 index; /* pad index */ + __u32 flags; /* pad flags */ + __u32 reserved[2]; +}; + +#define MEDIA_LNK_FL_ENABLED (1 << 0) +#define MEDIA_LNK_FL_IMMUTABLE (1 << 1) + +struct media_link_desc { + struct media_pad_desc source; + struct media_pad_desc sink; + __u32 flags; + __u32 reserved[2]; +}; + +struct media_links_enum { + __u32 entity; + /* Should have enough room for pads elements */ + struct media_pad_desc __user *pads; + /* Should have enough room for links elements */ + struct media_link_desc __user *links; + __u32 reserved[4]; +}; + #define MEDIA_IOC_DEVICE_INFO _IOWR('M', 1, struct media_device_info) +#define MEDIA_IOC_ENUM_ENTITIES _IOWR('M', 2, struct media_entity_desc) +#define MEDIA_IOC_ENUM_LINKS _IOWR('M', 3, struct media_links_enum)

#endif /* __LINUX_MEDIA_H */ diff --git a/include/media/media-entity.h b/include/media/media-entity.h index a9b31d9..51bdafc 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -24,29 +24,7 @@ #define _MEDIA_ENTITY_H

#include <linux/list.h> - -#define MEDIA_ENT_TYPE_SHIFT 16 -#define MEDIA_ENT_TYPE_MASK 0x00ff0000 -#define MEDIA_ENT_SUBTYPE_MASK 0x0000ffff - -#define MEDIA_ENT_T_DEVNODE (1 << MEDIA_ENT_TYPE_SHIFT) -#define MEDIA_ENT_T_DEVNODE_V4L (MEDIA_ENT_T_DEVNODE + 1) -#define MEDIA_ENT_T_DEVNODE_FB (MEDIA_ENT_T_DEVNODE + 2) -#define MEDIA_ENT_T_DEVNODE_ALSA (MEDIA_ENT_T_DEVNODE + 3) -#define MEDIA_ENT_T_DEVNODE_DVB (MEDIA_ENT_T_DEVNODE + 4) - -#define MEDIA_ENT_T_V4L2_SUBDEV (2 << MEDIA_ENT_TYPE_SHIFT) -#define MEDIA_ENT_T_V4L2_SUBDEV_SENSOR (MEDIA_ENT_T_V4L2_SUBDEV + 1) -#define MEDIA_ENT_T_V4L2_SUBDEV_FLASH (MEDIA_ENT_T_V4L2_SUBDEV + 2) -#define MEDIA_ENT_T_V4L2_SUBDEV_LENS (MEDIA_ENT_T_V4L2_SUBDEV + 3) - -#define MEDIA_ENT_FL_DEFAULT (1 << 0) - -#define MEDIA_LNK_FL_ENABLED (1 << 0) -#define MEDIA_LNK_FL_IMMUTABLE (1 << 1) - -#define MEDIA_PAD_FL_SINK (1 << 0) -#define MEDIA_PAD_FL_SOURCE (1 << 1) +#include <linux/media.h>

struct media_link { struct media_pad *source; /* Source pad */

Drivers often need to associate pipeline objects to entities, and to take stream state into account when configuring entities and links. The pipeline API helps drivers manage that information.

When starting streaming, drivers call media_entity_pipeline_start(). The function marks all entities connected to the given entity through enabled links, either directly or indirectly, as streaming. Similarly, when stopping the stream, drivers call media_entity_pipeline_stop().

The media_entity_pipeline_start() function takes a pointer to a media pipeline and stores it in every entity in the graph. Drivers should embed the media_pipeline structure in higher-level pipeline structures and can then access the pipeline through the media_entity structure.

Link configuration will fail with -EBUSY by default if either end of the link is a streaming entity, unless the link is marked with the MEDIA_LNK_FL_DYNAMIC flag.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- Documentation/DocBook/v4l/media-ioc-enum-links.xml | 5 ++ Documentation/DocBook/v4l/media-ioc-setup-link.xml | 3 + Documentation/media-framework.txt | 38 ++++++++++ drivers/media/media-entity.c | 73 ++++++++++++++++++++ include/linux/media.h | 1 + include/media/media-entity.h | 10 +++ 6 files changed, 130 insertions(+), 0 deletions(-)

diff --git a/Documentation/DocBook/v4l/media-ioc-enum-links.xml b/Documentation/DocBook/v4l/media-ioc-enum-links.xml index 4b08e55..ca968bc 100644 --- a/Documentation/DocBook/v4l/media-ioc-enum-links.xml +++ b/Documentation/DocBook/v4l/media-ioc-enum-links.xml @@ -179,6 +179,11 @@ <entry>The link enabled state can't be modified at runtime. An immutable link is always enabled.</entry> </row> + <row> + <entry><constant>MEDIA_LNK_FL_DYNAMIC</constant></entry> + <entry>The link enabled state can be modified during streaming. This + flag is set by drivers and is read-only for applications.</entry> + </row> </tbody> </tgroup> </table> diff --git a/Documentation/DocBook/v4l/media-ioc-setup-link.xml b/Documentation/DocBook/v4l/media-ioc-setup-link.xml index 09ab3d2..2331e76 100644 --- a/Documentation/DocBook/v4l/media-ioc-setup-link.xml +++ b/Documentation/DocBook/v4l/media-ioc-setup-link.xml @@ -60,6 +60,9 @@ <para>Link configuration has no side effect on other links. If an enabled link at the sink pad prevents the link from being enabled, the driver returns with an &EBUSY;.</para> + <para>Only links marked with the <constant>DYNAMIC</constant> link flag can + be enabled/disabled while streaming media data. Attempting to enable or + disable a streaming non-dynamic link will return an &EBUSY;.</para> <para>If the specified link can't be found the driver returns with an &EINVAL;.</para> </refsect1> diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt index 4809221..fd48add 100644 --- a/Documentation/media-framework.txt +++ b/Documentation/media-framework.txt @@ -313,3 +313,41 @@ 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 disabled, the link_setup operation must return -EBUSY and can't implicitly disable the first enabled link. + + +Pipelines and media streams +--------------------------- + +When starting streaming, drivers must notify all entities in the pipeline to +prevent link states from being modified during streaming by calling + + media_entity_pipeline_start(struct media_entity *entity, + struct media_pipeline *pipe); + +The function will mark all entities connected to the given entity through +enabled links, either directly or indirectly, as streaming. + +The media_pipeline instance pointed to by the pipe argument will be stored in +every entity in the pipeline. Drivers should embed the media_pipeline structure +in higher-level pipeline structures and can then access the pipeline through +the media_entity pipe field. + +Calls to media_entity_pipeline_start() can be nested. The pipeline pointer must +be identical for all nested calls to the function. + +When stopping the stream, drivers must notify the entities with + + media_entity_pipeline_stop(struct media_entity *entity); + +If multiple calls to media_entity_pipeline_start() have been made the same +number of media_entity_pipeline_stop() calls are required to stop streaming. The +media_entity pipe field is reset to NULL on the last nested stop call. + +Link configuration will fail with -EBUSY by default if either end of the link is +a streaming entity. Links that can be modified while streaming must be marked +with the MEDIA_LNK_FL_DYNAMIC flag. + +If other operations need to be disallowed on streaming entities (such as +changing entities configuration parameters) drivers can explictly check the +media_entity stream_count field to find out if an entity is streaming. This +operation must be done with the media_device graph_mutex held. diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c index 6795c92..23640ed 100644 --- a/drivers/media/media-entity.c +++ b/drivers/media/media-entity.c @@ -197,6 +197,75 @@ media_entity_graph_walk_next(struct media_entity_graph *graph) EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);

/* ----------------------------------------------------------------------------- + * Pipeline management + */ + +/** + * media_entity_pipeline_start - Mark a pipeline as streaming + * @entity: Starting entity + * @pipe: Media pipeline to be assigned to all entities in the pipeline. + * + * Mark all entities connected to a given entity through enabled links, either + * directly or indirectly, as streaming. The given pipeline object is assigned to + * every entity in the pipeline and stored in the media_entity pipe field. + * + * Calls to this function can be nested, in which case the same number of + * media_entity_pipeline_stop() calls will be required to stop streaming. The + * pipeline pointer must be identical for all nested calls to + * media_entity_pipeline_start(). + */ +void media_entity_pipeline_start(struct media_entity *entity, + struct media_pipeline *pipe) +{ + struct media_device *mdev = entity->parent; + struct media_entity_graph graph; + + mutex_lock(&mdev->graph_mutex); + + media_entity_graph_walk_start(&graph, entity); + + while ((entity = media_entity_graph_walk_next(&graph))) { + entity->stream_count++; + WARN_ON(entity->pipe && entity->pipe != pipe); + entity->pipe = pipe; + } + + mutex_unlock(&mdev->graph_mutex); +} +EXPORT_SYMBOL_GPL(media_entity_pipeline_start); + +/** + * media_entity_pipeline_stop - Mark a pipeline as not streaming + * @entity: Starting entity + * + * Mark all entities connected to a given entity through enabled links, either + * directly or indirectly, as not streaming. The media_entity pipe field is + * reset to NULL. + * + * If multiple calls to media_entity_pipeline_start() have been made, the same + * number of calls to this function are required to mark the pipeline as not + * streaming. + */ +void media_entity_pipeline_stop(struct media_entity *entity) +{ + struct media_device *mdev = entity->parent; + struct media_entity_graph graph; + + mutex_lock(&mdev->graph_mutex); + + media_entity_graph_walk_start(&graph, entity); + + while ((entity = media_entity_graph_walk_next(&graph))) { + entity->stream_count--; + if (entity->stream_count == 0) + entity->pipe = NULL; + } + + mutex_unlock(&mdev->graph_mutex); +} +EXPORT_SYMBOL_GPL(media_entity_pipeline_stop); + +/* ----------------------------------------------------------------------------- * Module use count */

@@ -364,6 +433,10 @@ int __media_entity_setup_link(struct media_link *link, u32 flags) source = link->source->entity; sink = link->sink->entity;

+ if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) && + (source->stream_count || sink->stream_count)) + return -EBUSY; + mdev = source->parent;

if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) { diff --git a/include/linux/media.h b/include/linux/media.h index 7c69913..7ed23b4 100644 --- a/include/linux/media.h +++ b/include/linux/media.h @@ -106,6 +106,7 @@ struct media_pad_desc {

#define MEDIA_LNK_FL_ENABLED (1 << 0) #define MEDIA_LNK_FL_IMMUTABLE (1 << 1) +#define MEDIA_LNK_FL_DYNAMIC (1 << 2)

struct media_link_desc { struct media_pad_desc source; diff --git a/include/media/media-entity.h b/include/media/media-entity.h index d889dcc..cd8bca6 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -26,6 +26,9 @@ #include <linux/list.h> #include <linux/media.h>

+struct media_pipeline { +}; + struct media_link { struct media_pad *source; /* Source pad */ struct media_pad *sink; /* Sink pad */ @@ -71,8 +74,11 @@ struct media_entity { * purpose: a simple WARN_ON(<0) check can be used to detect reference * count bugs that would make them negative. */ + int stream_count; /* Stream count for the entity. */ int use_count; /* Use count for the entity. */

+ struct media_pipeline *pipe; /* Pipeline this entity belongs to. */ + union { /* Node specifications */ struct { @@ -118,6 +124,7 @@ struct media_entity_graph { int media_entity_init(struct media_entity *entity, u16 num_pads, struct media_pad *pads, u16 extra_links); void media_entity_cleanup(struct media_entity *entity); + int media_entity_create_link(struct media_entity *source, u16 source_pad, struct media_entity *sink, u16 sink_pad, u32 flags); int __media_entity_setup_link(struct media_link *link, u32 flags); @@ -133,6 +140,9 @@ void media_entity_graph_walk_start(struct media_entity_graph *graph, struct media_entity *entity); struct media_entity * media_entity_graph_walk_next(struct media_entity_graph *graph); +void media_entity_pipeline_start(struct media_entity *entity, + struct media_pipeline *pipe); +void media_entity_pipeline_stop(struct media_entity *entity);

#define media_entity_call(entity, operation, args...) \ (((entity)->ops && (entity)->ops->operation) ? \

V4L2 devices are media entities. As such they need to inherit from (include) the media_entity structure.

When registering/unregistering the device, the media entity is automatically registered/unregistered. The entity is acquired on device open and released on device close.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Sakari Ailus sakari.ailus@iki.fi --- Documentation/video4linux/v4l2-framework.txt | 38 ++++++++++++++++++-- drivers/media/video/v4l2-dev.c | 49 +++++++++++++++++++++++-- include/media/v4l2-dev.h | 7 ++++ 3 files changed, 87 insertions(+), 7 deletions(-)

diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index 7de55cf..0627081 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -71,6 +71,10 @@ sub-device instances, the video_device struct stores V4L2 device node data and in the future a v4l2_fh struct will keep track of filehandle instances (this is not yet implemented).

+The V4L2 framework also optionally integrates with the media framework. If a +driver sets the struct v4l2_device mdev field, sub-devices and video nodes +will automatically appear in the media framework as entities. +

struct v4l2_device ------------------ @@ -84,11 +88,14 @@ You must register the device instance: v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);

Registration will initialize the v4l2_device struct. If the dev->driver_data -field is NULL, it will be linked to v4l2_dev. Drivers that use the media -device framework in addition to the V4L2 framework need to set +field is NULL, it will be linked to v4l2_dev. + +Drivers that want integration with the media device framework need to set dev->driver_data manually to point to the driver-specific device structure that embed the struct v4l2_device instance. This is achieved by a -dev_set_drvdata() call before registering the V4L2 device instance. +dev_set_drvdata() call before registering the V4L2 device instance. They must +also set the struct v4l2_device mdev field to point to a properly initialized +and registered media_device instance.

If v4l2_dev->name is empty then it will be set to a value derived from dev (driver name followed by the bus_id, to be precise). If you set it up before @@ -530,6 +537,21 @@ If you use v4l2_ioctl_ops, then you should set either .unlocked_ioctl or The v4l2_file_operations struct is a subset of file_operations. The main difference is that the inode argument is omitted since it is never used.

+If integration with the media framework is needed, you must initialize the +media_entity struct embedded in the video_device struct (entity field) by +calling media_entity_init(): + + struct media_pad *pad = &my_vdev->pad; + int err; + + err = media_entity_init(&vdev->entity, 1, pad, 0); + +The pads array must have been previously initialized. There is no need to +manually set the struct media_entity type and name fields. + +A reference to the entity will be automatically acquired/released when the +video device is opened/closed. + v4l2_file_operations and locking --------------------------------

@@ -559,6 +581,9 @@ for you. return err; }

+If the v4l2_device parent device has a non-NULL mdev field, the video device +entity will be automatically registered with the media device. + Which device is registered depends on the type argument. The following types exist:

@@ -634,6 +659,13 @@ release, of course) will return an error as well. When the last user of the video device node exits, then the vdev->release() callback is called and you can do the final cleanup there.

+Don't forget to cleanup the media entity associated with the video device if +it has been initialized: + + media_entity_cleanup(&vdev->entity); + +This can be done from the release callback. +

video_device helper functions ----------------------------- diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c index abe04ef..e405b80 100644 --- a/drivers/media/video/v4l2-dev.c +++ b/drivers/media/video/v4l2-dev.c @@ -303,6 +303,9 @@ static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm) static int v4l2_open(struct inode *inode, struct file *filp) { struct video_device *vdev; +#if defined(CONFIG_MEDIA_CONTROLLER) + struct media_entity *entity = NULL; +#endif int ret = 0;

/* Check if the video device is available */ @@ -316,6 +319,16 @@ static int v4l2_open(struct inode *inode, struct file *filp) /* and increase the device refcount */ video_get(vdev); mutex_unlock(&videodev_lock); +#if defined(CONFIG_MEDIA_CONTROLLER) + if (vdev->v4l2_dev && vdev->v4l2_dev->mdev) { + entity = media_entity_get(&vdev->entity); + if (!entity) { + ret = -EBUSY; + video_put(vdev); + return ret; + } + } +#endif if (vdev->fops->open) { if (vdev->lock && mutex_lock_interruptible(vdev->lock)) { ret = -ERESTARTSYS; @@ -331,8 +344,13 @@ static int v4l2_open(struct inode *inode, struct file *filp)

err: /* decrease the refcount in case of an error */ - if (ret) + if (ret) { +#if defined(CONFIG_MEDIA_CONTROLLER) + if (vdev->v4l2_dev && vdev->v4l2_dev->mdev) + media_entity_put(entity); +#endif video_put(vdev); + } return ret; }

@@ -349,7 +367,10 @@ static int v4l2_release(struct inode *inode, struct file *filp) if (vdev->lock) mutex_unlock(vdev->lock); } - +#if defined(CONFIG_MEDIA_CONTROLLER) + if (vdev->v4l2_dev && vdev->v4l2_dev->mdev) + media_entity_put(&vdev->entity); +#endif /* decrease the refcount unconditionally since the release() return value is ignored. */ video_put(vdev); @@ -585,12 +606,27 @@ int __video_register_device(struct video_device *vdev, int type, int nr, if (nr != -1 && nr != vdev->num && warn_if_nr_in_use) printk(KERN_WARNING "%s: requested %s%d, got %s\n", __func__, name_base, nr, video_device_node_name(vdev)); - - /* Part 5: Activate this minor. The char device can now be used. */ +#if defined(CONFIG_MEDIA_CONTROLLER) + /* Part 5: Register the entity. */ + if (vdev->v4l2_dev && vdev->v4l2_dev->mdev) { + vdev->entity.type = MEDIA_ENT_T_DEVNODE_V4L; + vdev->entity.name = vdev->name; + vdev->entity.v4l.major = VIDEO_MAJOR; + vdev->entity.v4l.minor = vdev->minor; + ret = media_device_register_entity(vdev->v4l2_dev->mdev, + &vdev->entity); + if (ret < 0) + printk(KERN_WARNING + "%s: media_device_register_entity failed\n", + __func__); + } +#endif + /* Part 6: Activate this minor. The char device can now be used. */ set_bit(V4L2_FL_REGISTERED, &vdev->flags); mutex_lock(&videodev_lock); video_device[vdev->minor] = vdev; mutex_unlock(&videodev_lock); + return 0;

cleanup: @@ -618,6 +654,11 @@ void video_unregister_device(struct video_device *vdev) if (!vdev || !video_is_registered(vdev)) return;

+#if defined(CONFIG_MEDIA_CONTROLLER) + if (vdev->v4l2_dev && vdev->v4l2_dev->mdev) + media_device_unregister_entity(&vdev->entity); +#endif + mutex_lock(&videodev_lock); /* This must be in a critical section to prevent a race with v4l2_open. * Once this bit has been cleared video_get may never be called again. diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h index 4fe6831..51b2c51 100644 --- a/include/media/v4l2-dev.h +++ b/include/media/v4l2-dev.h @@ -16,6 +16,8 @@ #include <linux/mutex.h> #include <linux/videodev2.h>

+#include <media/media-entity.h> + #define VIDEO_MAJOR 81

#define VFL_TYPE_GRABBER 0 @@ -55,6 +57,9 @@ struct v4l2_file_operations {

struct video_device { +#if defined(CONFIG_MEDIA_CONTROLLER) + struct media_entity entity; +#endif /* device ops */ const struct v4l2_file_operations *fops;

@@ -100,6 +105,8 @@ struct video_device struct mutex *lock; };

+#define media_entity_to_video_device(entity) \ + container_of(entity, struct video_device, entity) /* dev to video-device */ #define to_video_device(cd) container_of(cd, struct video_device, dev)