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 | 10 +- drivers/media/media-devnode.c | 321 +++++++++++++++++++++++++++++++++++++++++ include/media/media-devnode.h | 97 +++++++++++++ 4 files changed, 439 insertions(+), 2 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 a28541b..6b946e6 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 499b081..3a08991 100644 --- a/drivers/media/Makefile +++ b/drivers/media/Makefile @@ -2,7 +2,13 @@ # 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/ IR/ video/

-obj-$(CONFIG_VIDEO_DEV) += radio/ -obj-$(CONFIG_DVB_CORE) += dvb/ +obj-$(CONFIG_VIDEO_DEV) += radio/ +obj-$(CONFIG_DVB_CORE) += dvb/ diff --git a/drivers/media/media-devnode.c b/drivers/media/media-devnode.c new file mode 100644 index 0000000..7804b70 --- /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@maxwell.research.nokia.com + * + * 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..01cd034 --- /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@maxwell.research.nokia.com + * + * 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@maxwell.research.nokia.com --- 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..b252cf9 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_INPUT indicates that the pad supports sinking data. + MEDIA_PAD_FL_OUTPUT indicates that the pad supports sourcing data. + +One and only one of MEDIA_PAD_FL_INPUT and MEDIA_PAD_FL_OUTPUT 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 019d3e0..b890248 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 57a9c6b..b8a3ace 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..e4ba2bc --- /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@maxwell.research.nokia.com + * + * 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 input and output 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 e11f01a..0b1ecf5 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..7cf9135 --- /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@maxwell.research.nokia.com + * + * 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_ENTITY_TYPE_SHIFT) +#define MEDIA_ENT_T_DEVNODE_V4L (MEDIA_ENTITY_T_DEVNODE + 1) +#define MEDIA_ENT_T_DEVNODE_FB (MEDIA_ENTITY_T_DEVNODE + 2) +#define MEDIA_ENT_T_DEVNODE_ALSA (MEDIA_ENTITY_T_DEVNODE + 3) +#define MEDIA_ENT_T_DEVNODE_DVB (MEDIA_ENTITY_T_DEVNODE + 4) + +#define MEDIA_ENT_T_V4L2_SUBDEV (2 << MEDIA_ENTITY_TYPE_SHIFT) +#define MEDIA_ENT_T_V4L2_SUBDEV_SENSOR (MEDIA_ENTITY_T_V4L2_SUBDEV + 1) +#define MEDIA_ENT_T_V4L2_SUBDEV_FLASH (MEDIA_ENTITY_T_V4L2_SUBDEV + 2) +#define MEDIA_ENT_T_V4L2_SUBDEV_LENS (MEDIA_ENTITY_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_INPUT (1 << 0) +#define MEDIA_PAD_FL_OUTPUT (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 input and output 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 | 5 ++++ 5 files changed, 69 insertions(+), 0 deletions(-)

diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt index 88fe379..9017a41 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 b8a3ace..e4c2157 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 a805f20..fe6bfd2 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 0b1ecf5..260d59c 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 b82f824..114541a 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -81,6 +81,8 @@ struct media_entity { struct media_pad *pads; /* Pads array (num_pads elements) */ struct media_link *links; /* Links array (max_links elements)*/

+ int use_count; /* Use count for the entity. */ + union { /* Node specifications */ struct { @@ -129,6 +131,9 @@ 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 ioctl and implement it at the media device level to query device information.

- MEDIA_IOC_DEVICE_INFO: Query media device information

The ioctl and its data structure are defined in the new kernel header linux/media.h available to userspace applications.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- Documentation/DocBook/media-entities.tmpl | 12 ++ Documentation/DocBook/v4l/media-controller.xml | 10 ++ Documentation/DocBook/v4l/media-func-close.xml | 59 +++++++++ Documentation/DocBook/v4l/media-func-ioctl.xml | 116 +++++++++++++++++ Documentation/DocBook/v4l/media-func-open.xml | 94 ++++++++++++++ .../DocBook/v4l/media-ioc-device-info.xml | 132 ++++++++++++++++++++ drivers/media/media-device.c | 57 +++++++++ include/linux/Kbuild | 1 + include/linux/media.h | 45 +++++++ 9 files changed, 526 insertions(+), 0 deletions(-) create mode 100644 Documentation/DocBook/v4l/media-func-close.xml create mode 100644 Documentation/DocBook/v4l/media-func-ioctl.xml create mode 100644 Documentation/DocBook/v4l/media-func-open.xml create mode 100644 Documentation/DocBook/v4l/media-ioc-device-info.xml create mode 100644 include/linux/media.h

diff --git a/Documentation/DocBook/media-entities.tmpl b/Documentation/DocBook/media-entities.tmpl index 61d6f11..6af3375 100644 --- a/Documentation/DocBook/media-entities.tmpl +++ b/Documentation/DocBook/media-entities.tmpl @@ -11,6 +11,10 @@ <!ENTITY func-select "<link linkend='func-select'><function>select()</function></link>"> <!ENTITY func-write "<link linkend='func-write'><function>write()</function></link>">

+<!ENTITY media-func-close "<link linkend='media-func-close'><function>close()</function></link>"> +<!ENTITY media-func-ioctl "<link linkend='media-func-ioctl'><function>ioctl()</function></link>"> +<!ENTITY media-func-open "<link linkend='media-func-open'><function>open()</function></link>"> + <!-- Ioctls --> <!ENTITY VIDIOC-CROPCAP "<link linkend='vidioc-cropcap'><constant>VIDIOC_CROPCAP</constant></link>"> <!ENTITY VIDIOC-DBG-G-CHIP-IDENT "<link linkend='vidioc-dbg-g-chip-ident'><constant>VIDIOC_DBG_G_CHIP_IDENT</constant></link>"> @@ -87,6 +91,8 @@ <!ENTITY VIDIOC-TRY-FMT "<link linkend='vidioc-g-fmt'><constant>VIDIOC_TRY_FMT</constant></link>"> <!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>"> + <!-- Types --> <!ENTITY v4l2-std-id "<link linkend='v4l2-std-id'>v4l2_std_id</link>">

@@ -181,6 +187,8 @@ <!ENTITY v4l2-vbi-format "struct&nbsp;<link linkend='v4l2-vbi-format'>v4l2_vbi_format</link>"> <!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>"> + <!-- Error Codes --> <!ENTITY EACCES "<errorcode>EACCES</errorcode> error code"> <!ENTITY EAGAIN "<errorcode>EAGAIN</errorcode> error code"> @@ -322,6 +330,10 @@ <!ENTITY sub-media-indices SYSTEM "media-indices.tmpl">

<!ENTITY sub-media-controller SYSTEM "v4l/media-controller.xml"> +<!ENTITY sub-media-open SYSTEM "v4l/media-func-open.xml"> +<!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">

<!-- 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 f89228d..a46b786 100644 --- a/Documentation/DocBook/v4l/media-controller.xml +++ b/Documentation/DocBook/v4l/media-controller.xml @@ -74,3 +74,13 @@ pad to a sink pad.</para> </section> </chapter> + +<appendix id="media-user-func"> + <title>Function Reference</title> + <!-- Keep this alphabetically sorted. --> + &sub-media-open; + &sub-media-close; + &sub-media-ioctl; + <!-- All ioctls go here. --> + &sub-media-ioc-device-info; +</appendix> diff --git a/Documentation/DocBook/v4l/media-func-close.xml b/Documentation/DocBook/v4l/media-func-close.xml new file mode 100644 index 0000000..be149c8 --- /dev/null +++ b/Documentation/DocBook/v4l/media-func-close.xml @@ -0,0 +1,59 @@ +<refentry id="media-func-close"> + <refmeta> + <refentrytitle>media close()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>media-close</refname> + <refpurpose>Close a media device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include &lt;unistd.h&gt;</funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>close</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>Closes the media device. Resources associated with the file descriptor + are freed. The device configuration remain unchanged.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para><function>close</function> returns 0 on success. On error, -1 is + returned, and <varname>errno</varname> is set appropriately. Possible error + codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid open file descriptor. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/v4l/media-func-ioctl.xml b/Documentation/DocBook/v4l/media-func-ioctl.xml new file mode 100644 index 0000000..bda8604 --- /dev/null +++ b/Documentation/DocBook/v4l/media-func-ioctl.xml @@ -0,0 +1,116 @@ +<refentry id="media-func-ioctl"> + <refmeta> + <refentrytitle>media ioctl()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>media-ioctl</refname> + <refpurpose>Control a media device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include &lt;sys/ioctl.h&gt;</funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>void *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>Media ioctl request code as defined in the media.h header file, + for example MEDIA_IOC_SETUP_LINK.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to a request-specific structure.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + <para>The <function>ioctl()</function> function manipulates media device + parameters. The argument <parameter>fd</parameter> must be an open file + descriptor.</para> + <para>The ioctl <parameter>request</parameter> code specifies the media + function to be called. It has encoded in it whether the argument is an + input, output or read/write parameter, and the size of the argument + <parameter>argp</parameter> in bytes.</para> + <para>Macros and structures definitions specifying media ioctl requests and + their parameters are located in the media.h header file. All media ioctl + requests, their respective function and parameters are specified in + <xref linkend="media-user-func" />.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para><function>ioctl()</function> returns <returnvalue>0</returnvalue> on + success. On failure, <returnvalue>-1</returnvalue> is returned, and the + <varname>errno</varname> variable is set appropriately. Generic error codes + are listed below, and request-specific error codes are listed in the + individual requests descriptions.</para> + <para>When an ioctl that takes an output or read/write parameter fails, + the parameter remains unmodified.</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid open file descriptor. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para><parameter>argp</parameter> references an inaccessible memory + area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>request</parameter> or the data pointed to by + <parameter>argp</parameter> is not valid. This is a very common error + code, see the individual ioctl requests listed in + <xref linkend="media-user-func" /> for actual causes.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Insufficient kernel memory was available to complete the + request.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOTTY</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not associated with a character + special device.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/v4l/media-func-open.xml b/Documentation/DocBook/v4l/media-func-open.xml new file mode 100644 index 0000000..f7df034 --- /dev/null +++ b/Documentation/DocBook/v4l/media-func-open.xml @@ -0,0 +1,94 @@ +<refentry id="media-func-open"> + <refmeta> + <refentrytitle>media open()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>media-open</refname> + <refpurpose>Open a media device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include &lt;fcntl.h&gt;</funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>open</function></funcdef> + <paramdef>const char *<parameter>device_name</parameter></paramdef> + <paramdef>int <parameter>flags</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>device_name</parameter></term> + <listitem> + <para>Device to be opened.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>flags</parameter></term> + <listitem> + <para>Open flags. Access mode must be either <constant>O_RDONLY</constant> + or <constant>O_RDWR</constant>. Other flags have no effect.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + <refsect1> + <title>Description</title> + <para>To open a media device applications call <function>open()</function> + with the desired device name. The function has no side effects; the device + configuration remain unchanged.</para> + <para>When the device is opened in read-only mode, attemps to modify its + configuration will result in an error, and <varname>errno</varname> will be + set to <errorcode>EBADF</errorcode>.</para> + </refsect1> + <refsect1> + <title>Return Value</title> + + <para><function>open</function> returns the new file descriptor on success. + On error, -1 is returned, and <varname>errno</varname> is set appropriately. + Possible error codes are:</para> + + <variablelist> + <varlistentry> + <term><errorcode>EACCES</errorcode></term> + <listitem> + <para>The requested access to the file is not allowed.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EMFILE</errorcode></term> + <listitem> + <para>The process already has the maximum number of files open. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENFILE</errorcode></term> + <listitem> + <para>The system limit on the total number of open files has been + reached.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Insufficient kernel memory was available.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENXIO</errorcode></term> + <listitem> + <para>No device corresponding to this device special file exists. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/DocBook/v4l/media-ioc-device-info.xml b/Documentation/DocBook/v4l/media-ioc-device-info.xml new file mode 100644 index 0000000..278a312 --- /dev/null +++ b/Documentation/DocBook/v4l/media-ioc-device-info.xml @@ -0,0 +1,132 @@ +<refentry id="media-ioc-device-info"> + <refmeta> + <refentrytitle>ioctl MEDIA_IOC_DEVICE_INFO</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>MEDIA_IOC_DEVICE_INFO</refname> + <refpurpose>Query device information</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_device_info *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>MEDIA_IOC_DEVICE_INFO</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>All media devices must support the <constant>MEDIA_IOC_DEVICE_INFO</constant> + ioctl. To query device information, applications call the ioctl with a + pointer to a &media-device-info;. The driver fills the structure and returns + the information to the application. + The ioctl never fails.</para> + + <table pgwide="1" frame="none" id="media-device-info"> + <title>struct <structname>media_device_info</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>char</entry> + <entry><structfield>driver</structfield>[16]</entry> + <entry><para>Name of the driver implementing the media API as a + NUL-terminated ASCII string. The driver version is stored in the + <structfield>driver_version</structfield> field.</para> + <para>Driver specific applications can use this information to + verify the driver identity. It is also useful to work around + known bugs, or to identify drivers in error reports.</para></entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>model</structfield>[32]</entry> + <entry>Device model name as a NUL-terminated UTF-8 string. The + device version is stored in the <structfield>device_version</structfield> + field and is not be appended to the model name.</entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>serial</structfield>[40]</entry> + <entry>Serial number as a NUL-terminated ASCII string.</entry> + </row> + <row> + <entry>char</entry> + <entry><structfield>bus_info</structfield>[32]</entry> + <entry>Location of the device in the system as a NUL-terminated + ASCII string. This includes the bus type name (PCI, USB, ...) and a + bus-specific identifier.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>media_version</structfield></entry> + <entry>Media API version, formatted with the + <constant>KERNEL_VERSION()</constant> macro.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>hw_revision</structfield></entry> + <entry>Hardware device revision in a driver-specific format.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>media_version</structfield></entry> + <entry>Media device driver version, formatted with the + <constant>KERNEL_VERSION()</constant> macro. Together with the + <structfield>driver</structfield> field this identifies a particular + driver.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[31]</entry> + <entry>Reserved for future extensions. Drivers and applications must + set this array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + <para>The <structfield>serial</structfield> and <structfield>bus_info</structfield> + fields can be used to distinguish between multiple instances of otherwise + identical hardware. The serial number takes precedence when provided and can + be assumed to be unique. If the serial number is an empty string, the + <structfield>bus_info</structfield> field can be used instead. The + <structfield>bus_info</structfield> field is guaranteed to be unique, but + can vary across reboots or device unplug/replug.</para> + </refsect1> + + <refsect1> + <title>Return value</title> + <para>This function doesn't return specific error codes.</para> + </refsect1> +</refentry> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index e4c2157..5c745be 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -22,13 +22,70 @@

#include <linux/types.h> #include <linux/ioctl.h> +#include <linux/media.h>

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

+/* ----------------------------------------------------------------------------- + * Userspace API + */ + +static int media_device_open(struct file *filp) +{ + return 0; +} + +static int media_device_close(struct file *filp) +{ + return 0; +} + +static int media_device_get_info(struct media_device *dev, + struct media_device_info __user *__info) +{ + struct media_device_info info; + + memset(&info, 0, sizeof(info)); + + strlcpy(info.driver, dev->dev->driver->name, sizeof(info.driver)); + strlcpy(info.model, dev->model, sizeof(info.model)); + strlcpy(info.serial, dev->serial, sizeof(info.serial)); + strlcpy(info.bus_info, dev->bus_info, sizeof(info.bus_info)); + + info.media_version = MEDIA_API_VERSION; + info.hw_revision = dev->hw_revision; + info.driver_version = dev->driver_version; + + return copy_to_user(__info, &info, sizeof(*__info)); +} + +static long media_device_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct media_devnode *devnode = media_devnode_data(filp); + struct media_device *dev = to_media_device(devnode); + long ret; + + switch (cmd) { + case MEDIA_IOC_DEVICE_INFO: + ret = media_device_get_info(dev, + (struct media_device_info __user *)arg); + break; + + default: + ret = -ENOIOCTLCMD; + } + + return ret; +} + static const struct media_file_operations media_device_fops = { .owner = THIS_MODULE, + .open = media_device_open, + .ioctl = media_device_ioctl, + .release = media_device_close, };

/* ----------------------------------------------------------------------------- diff --git a/include/linux/Kbuild b/include/linux/Kbuild index 97319a8..26e0a7f 100644 --- a/include/linux/Kbuild +++ b/include/linux/Kbuild @@ -228,6 +228,7 @@ header-y += magic.h header-y += major.h header-y += map_to_7segment.h header-y += matroxfb.h +header-y += media.h header-y += mempolicy.h header-y += meye.h header-y += mii.h diff --git a/include/linux/media.h b/include/linux/media.h new file mode 100644 index 0000000..4c52f08 --- /dev/null +++ b/include/linux/media.h @@ -0,0 +1,45 @@ +/* + * Multimedia device API + * + * Copyright (C) 2010 Nokia Corporation + * + * Contacts: Laurent Pinchart laurent.pinchart@ideasonboard.com + * Sakari Ailus sakari.ailus@maxwell.research.nokia.com + * + * 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 __LINUX_MEDIA_H +#define __LINUX_MEDIA_H + +#include <linux/ioctl.h> +#include <linux/types.h> +#include <linux/version.h> + +#define MEDIA_API_VERSION KERNEL_VERSION(0, 1, 0) + +struct media_device_info { + char driver[16]; + char model[32]; + char serial[40]; + char bus_info[32]; + __u32 media_version; + __u32 hw_revision; + __u32 driver_version; + __u32 reserved[31]; +}; + +#define MEDIA_IOC_DEVICE_INFO _IOWR('M', 1, struct media_device_info) + +#endif /* __LINUX_MEDIA_H */

Create the following ioctl and implement it at the media device level to setup links.

- MEDIA_IOC_SETUP_LINK: Modify the properties of a given link

The only property that can currently be modified is the ENABLED link flag to enable/disable a link. Links marked with the IMMUTABLE link flag can not be enabled or disabled.

Enabling or disabling a link has effects on entities' use count. Those changes are automatically propagated through the graph.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Stanimir Varbanov svarbanov@mm-sol.com Signed-off-by: Sakari Ailus sakari.ailus@maxwell.research.nokia.com --- Documentation/DocBook/media-entities.tmpl | 2 + Documentation/DocBook/v4l/media-controller.xml | 1 + Documentation/DocBook/v4l/media-ioc-setup-link.xml | 90 +++++++++++ Documentation/media-framework.txt | 42 ++++++ drivers/media/media-device.c | 45 ++++++ drivers/media/media-entity.c | 155 ++++++++++++++++++++ include/linux/media.h | 1 + include/media/media-device.h | 3 + include/media/media-entity.h | 17 ++ 9 files changed, 356 insertions(+), 0 deletions(-) create mode 100644 Documentation/DocBook/v4l/media-ioc-setup-link.xml

diff --git a/Documentation/DocBook/media-entities.tmpl b/Documentation/DocBook/media-entities.tmpl index 6e7dae4..679c585 100644 --- a/Documentation/DocBook/media-entities.tmpl +++ b/Documentation/DocBook/media-entities.tmpl @@ -94,6 +94,7 @@ <!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>"> +<!ENTITY MEDIA-IOC-SETUP-LINK "<link linkend='media-ioc-setup-link'><constant>MEDIA_IOC_SETUP_LINK</constant></link>">

<!-- Types --> <!ENTITY v4l2-std-id "<link linkend='v4l2-std-id'>v4l2_std_id</link>"> @@ -342,6 +343,7 @@ <!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"> +<!ENTITY sub-media-ioc-setup-link SYSTEM "v4l/media-ioc-setup-link.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 2c4fd2b..2dc25e1 100644 --- a/Documentation/DocBook/v4l/media-controller.xml +++ b/Documentation/DocBook/v4l/media-controller.xml @@ -85,4 +85,5 @@ &sub-media-ioc-device-info; &sub-media-ioc-enum-entities; &sub-media-ioc-enum-links; + &sub-media-ioc-setup-link; </appendix> diff --git a/Documentation/DocBook/v4l/media-ioc-setup-link.xml b/Documentation/DocBook/v4l/media-ioc-setup-link.xml new file mode 100644 index 0000000..09ab3d2 --- /dev/null +++ b/Documentation/DocBook/v4l/media-ioc-setup-link.xml @@ -0,0 +1,90 @@ +<refentry id="media-ioc-setup-link"> + <refmeta> + <refentrytitle>ioctl MEDIA_IOC_SETUP_LINK</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>MEDIA_IOC_SETUP_LINK</refname> + <refpurpose>Modify the properties of a link</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_link_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_LINKS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To change link properties applications fill a &media-link-desc; with + link identification information (source and sink pad) and the new requested + link flags. They then call the MEDIA_IOC_SETUP_LINK ioctl with a pointer to + that structure.</para> + <para>The only configurable property is the <constant>ENABLED</constant> + link flag to enable/disable a link. Links marked with the + <constant>IMMUTABLE</constant> link flag can not be enabled or disabled. + </para> + <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>If the specified link can't be found the driver returns with an + &EINVAL;.</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>The link properties can't be changed because the link is + currently busy. This can be caused, for instance, by an active media + stream (audio or video) on the link. The ioctl shouldn't be retried if + no other action is performed before to fix the problem.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &media-link-desc; references a non-existing link, or the + link is immutable and an attempt to modify its configuration was made. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt index 9017a41..634845e 100644 --- a/Documentation/media-framework.txt +++ b/Documentation/media-framework.txt @@ -259,6 +259,16 @@ 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.

+Helper functions can be used to find a link between two given pads, or a pad +connected to another pad through an enabled link + + media_entity_find_link(struct media_pad *source, + struct media_pad *sink); + + media_entity_remote_source(struct media_pad *pad); + +Refer to the kerneldoc documentation for more information. +

Use count and power handling ---------------------------- @@ -271,3 +281,35 @@ 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. + + +Links setup +----------- + +Link properties can be modified at runtime by calling + + media_entity_setup_link(struct media_link *link, u32 flags); + +The flags argument contains the requested new link flags. + +The only configurable property is the ENABLED link flag to enable/disable a +link. Links marked with the IMMUTABLE link flag can not be enabled or disabled. + +When a link is enabled or disabled, the media framework calls the +link_setup operation for the two entities at the source and sink of the link, +in that order. If the second link_setup call fails, another link_setup call is +made on the first entity to restore the original link flags. + +Media device drivers can be notified of link setup operations by setting the +media_device::link_notify pointer to a callback function. If provided, the +notification callback will be called before enabling and after disabling +links. + +Entity drivers must implement the link_setup operation if any of their links +is non-immutable. The operation must either configure the hardware or store +the configuration information to be applied later. + +Link configuration must not have any side effect on other links. If an enabled +link at a sink pad prevents another link at the same pad from being disabled, +the link_setup operation must return -EBUSY and can't implicitly disable the +first enabled link. diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index 1f46acb..719deba 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -172,6 +172,44 @@ static long media_device_enum_links(struct media_device *mdev, return 0; }

+static long media_device_setup_link(struct media_device *mdev, + struct media_link_desc __user *_ulink) +{ + struct media_link *link = NULL; + struct media_link_desc ulink; + struct media_entity *source; + struct media_entity *sink; + int ret; + + if (copy_from_user(&ulink, _ulink, sizeof(ulink))) + return -EFAULT; + + /* Find the source and sink entities and link. + */ + source = find_entity(mdev, ulink.source.entity); + sink = find_entity(mdev, ulink.sink.entity); + + if (source == NULL || sink == NULL) + return -EINVAL; + + if (ulink.source.index >= source->num_pads || + ulink.sink.index >= sink->num_pads) + return -EINVAL; + + link = media_entity_find_link(&source->pads[ulink.source.index], + &sink->pads[ulink.sink.index]); + if (link == NULL) + return -EINVAL; + + /* Setup the link on both entities. */ + ret = __media_entity_setup_link(link, ulink.flags); + + if (copy_to_user(_ulink, &ulink, sizeof(ulink))) + return -EFAULT; + + return ret; +} + static long media_device_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { @@ -197,6 +235,13 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd, mutex_unlock(&dev->graph_mutex); break;

+ case MEDIA_IOC_SETUP_LINK: + mutex_lock(&dev->graph_mutex); + ret = media_device_setup_link(dev, + (struct media_link_desc __user *)arg); + mutex_unlock(&dev->graph_mutex); + break; + default: ret = -ENOIOCTLCMD; } diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c index fe6bfd2..d703ce8 100644 --- a/drivers/media/media-entity.c +++ b/drivers/media/media-entity.c @@ -306,3 +306,158 @@ media_entity_create_link(struct media_entity *source, u16 source_pad, return 0; } EXPORT_SYMBOL_GPL(media_entity_create_link); + +static int __media_entity_setup_link_notify(struct media_link *link, u32 flags) +{ + const u32 mask = MEDIA_LNK_FL_ENABLED; + int ret; + + /* Notify both entities. */ + ret = media_entity_call(link->source->entity, link_setup, + link->source, link->sink, flags); + if (ret < 0 && ret != -ENOIOCTLCMD) + return ret; + + ret = media_entity_call(link->sink->entity, link_setup, + link->sink, link->source, flags); + if (ret < 0 && ret != -ENOIOCTLCMD) { + media_entity_call(link->source->entity, link_setup, + link->source, link->sink, link->flags); + return ret; + } + + link->flags = (link->flags & ~mask) | (flags & mask); + link->reverse->flags = link->flags; + + return 0; +} + +/** + * __media_entity_setup_link - Configure a media link + * @link: The link being configured + * @flags: Link configuration flags + * + * The bulk of link setup is handled by the two entities connected through the + * link. This function notifies both entities of the link configuration change. + * + * If the link is immutable or if the current and new configuration are + * identical, return immediately. + * + * The user is expected to hold link->source->parent->mutex. If not, + * media_entity_setup_link() should be used instead. + */ +int __media_entity_setup_link(struct media_link *link, u32 flags) +{ + struct media_device *mdev; + struct media_entity *source, *sink; + int ret = -EBUSY; + + if (link == NULL) + return -EINVAL; + + if (link->flags & MEDIA_LNK_FL_IMMUTABLE) + return link->flags == flags ? 0 : -EINVAL; + + if (link->flags == flags) + return 0; + + source = link->source->entity; + sink = link->sink->entity; + + mdev = source->parent; + + if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) { + ret = mdev->link_notify(link->source, link->sink, + MEDIA_LNK_FL_ENABLED); + if (ret < 0) + return ret; + } + + ret = __media_entity_setup_link_notify(link, flags); + if (ret < 0) + goto err; + + if (!(flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) + mdev->link_notify(link->source, link->sink, 0); + + return 0; + +err: + if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) + mdev->link_notify(link->source, link->sink, 0); + + return ret; +} + +int media_entity_setup_link(struct media_link *link, u32 flags) +{ + int ret; + + mutex_lock(&link->source->entity->parent->graph_mutex); + ret = __media_entity_setup_link(link, flags); + mutex_unlock(&link->source->entity->parent->graph_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(media_entity_setup_link); + +/** + * media_entity_find_link - Find a link between two pads + * @source: Source pad + * @sink: Sink pad + * + * Return a pointer to the link between the two entities. If no such link + * exists, return NULL. + */ +struct media_link * +media_entity_find_link(struct media_pad *source, struct media_pad *sink) +{ + struct media_link *link; + unsigned int i; + + for (i = 0; i < source->entity->num_links; ++i) { + link = &source->entity->links[i]; + + if (link->source->entity == source->entity && + link->source->index == source->index && + link->sink->entity == sink->entity && + link->sink->index == sink->index) + return link; + } + + return NULL; +} +EXPORT_SYMBOL_GPL(media_entity_find_link); + +/** + * media_entity_remote_source - Find the source pad at the remote end of a link + * @pad: Sink pad at the local end of the link + * + * Search for a remote source pad connected to the given sink pad by iterating + * over all links originating or terminating at that pad until an enabled link + * is found. + * + * Return a pointer to the pad at the remote end of the first found enabled + * link, or NULL if no enabled link has been found. + */ +struct media_pad *media_entity_remote_source(struct media_pad *pad) +{ + unsigned int i; + + for (i = 0; i < pad->entity->num_links; i++) { + struct media_link *link = &pad->entity->links[i]; + + if (!(link->flags & MEDIA_LNK_FL_ENABLED)) + continue; + + if (link->source == pad) + return link->sink; + + if (link->sink == pad) + return link->source; + } + + return NULL; + +} +EXPORT_SYMBOL_GPL(media_entity_remote_source); diff --git a/include/linux/media.h b/include/linux/media.h index 64c0313..2f67ed2 100644 --- a/include/linux/media.h +++ b/include/linux/media.h @@ -126,5 +126,6 @@ struct media_links_enum { #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) +#define MEDIA_IOC_SETUP_LINK _IOWR('M', 4, struct media_link_desc)

#endif /* __LINUX_MEDIA_H */ diff --git a/include/media/media-device.h b/include/media/media-device.h index 260d59c..ad93e66 100644 --- a/include/media/media-device.h +++ b/include/media/media-device.h @@ -73,6 +73,9 @@ struct media_device { spinlock_t lock; /* Serializes graph operations. */ struct mutex graph_mutex; + + int (*link_notify)(struct media_pad *source, + struct media_pad *sink, u32 flags); };

/* media_devnode to media_device */ diff --git a/include/media/media-entity.h b/include/media/media-entity.h index 0954490..60fc7bd 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -39,6 +39,12 @@ struct media_pad { unsigned long flags; /* Pad flags (MEDIA_PAD_FL_*) */ };

+struct media_entity_operations { + int (*link_setup)(struct media_entity *entity, + const struct media_pad *local, + const struct media_pad *remote, u32 flags); +}; + struct media_entity { struct list_head list; struct media_device *parent; /* Media device this entity belongs to*/ @@ -59,6 +65,8 @@ struct media_entity { struct media_pad *pads; /* Pads array (num_pads elements) */ struct media_link *links; /* Links array (max_links elements)*/

+ const struct media_entity_operations *ops; /* Entity operations */ + int use_count; /* Use count for the entity. */

union { @@ -108,6 +116,11 @@ int media_entity_init(struct media_entity *entity, u16 num_pads, 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); +int media_entity_setup_link(struct media_link *link, u32 flags); +struct media_link *media_entity_find_link(struct media_pad *source, + struct media_pad *sink); +struct media_pad *media_entity_remote_source(struct media_pad *pad);

struct media_entity *media_entity_get(struct media_entity *entity); void media_entity_put(struct media_entity *entity); @@ -117,4 +130,8 @@ void media_entity_graph_walk_start(struct media_entity_graph *graph, struct media_entity * media_entity_graph_walk_next(struct media_entity_graph *graph);

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

The pointer will later be used to register/unregister media entities when registering/unregistering a v4l2_subdev or a video_device.

With the introduction of media devices, device drivers need to store a pointer to a driver-specific structure in the device's drvdata. v4l2_device can't claim ownership of the drvdata anymore.

To maintain compatibility with drivers that rely on v4l2_device storing a pointer to itself in the device's drvdata, v4l2_device_register() will keep doing so if the drvdata is NULL.

Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- Documentation/video4linux/v4l2-framework.txt | 17 ++++++++++++----- drivers/media/video/v4l2-device.c | 13 +++++++------ include/media/v4l2-device.h | 4 ++++ 3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index 4db1def..aeb2a22 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -83,11 +83,17 @@ You must register the device instance:

v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);

-Registration will initialize the v4l2_device struct and link dev->driver_data -to v4l2_dev. 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 calling v4l2_device_register then it will be untouched. If dev is -NULL, then you *must* setup v4l2_dev->name before calling v4l2_device_register. +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 +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. + +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 +calling v4l2_device_register then it will be untouched. If dev is NULL, then +you *must* setup v4l2_dev->name before calling v4l2_device_register.

You can use v4l2_device_set_name() to set the name based on a driver name and a driver-global atomic_t instance. This will generate names like ivtv0, ivtv1, @@ -108,6 +114,7 @@ You unregister with:

v4l2_device_unregister(struct v4l2_device *v4l2_dev);

+If the dev->driver_data field points to v4l2_dev, it will be reset to NULL. Unregistering will also automatically unregister all subdevs from the device.

If you have a hotpluggable device (e.g. a USB device), then when a disconnect diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c index 97e84df..5c16a12 100644 --- a/drivers/media/video/v4l2-device.c +++ b/drivers/media/video/v4l2-device.c @@ -47,9 +47,8 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) if (!v4l2_dev->name[0]) snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s", dev->driver->name, dev_name(dev)); - if (dev_get_drvdata(dev)) - v4l2_warn(v4l2_dev, "Non-NULL drvdata on register\n"); - dev_set_drvdata(dev, v4l2_dev); + if (!dev_get_drvdata(dev)) + dev_set_drvdata(dev, v4l2_dev); return 0; } EXPORT_SYMBOL_GPL(v4l2_device_register); @@ -72,10 +71,12 @@ EXPORT_SYMBOL_GPL(v4l2_device_set_name);

void v4l2_device_disconnect(struct v4l2_device *v4l2_dev) { - if (v4l2_dev->dev) { + if (v4l2_dev->dev == NULL) + return; + + if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev) dev_set_drvdata(v4l2_dev->dev, NULL); - v4l2_dev->dev = NULL; - } + v4l2_dev->dev = NULL; } EXPORT_SYMBOL_GPL(v4l2_device_disconnect);

diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h index b16f307..759db73 100644 --- a/include/media/v4l2-device.h +++ b/include/media/v4l2-device.h @@ -21,6 +21,7 @@ #ifndef _V4L2_DEVICE_H #define _V4L2_DEVICE_H

+#include <media/media-device.h> #include <media/v4l2-subdev.h>

/* Each instance of a V4L2 device should create the v4l2_device struct, @@ -39,6 +40,9 @@ struct v4l2_device { Note: dev might be NULL if there is no parent device as is the case with e.g. ISA devices. */ struct device *dev; +#if defined(CONFIG_MEDIA_CONTROLLER) + struct media_device *mdev; +#endif /* used to keep track of the registered subdevs */ struct list_head subdevs; /* lock this struct; can be used by the driver as well if this

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

When registering/unregistering the subdevice, 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@maxwell.research.nokia.com --- Documentation/video4linux/v4l2-framework.txt | 23 ++++++++++++++ drivers/media/video/v4l2-device.c | 39 ++++++++++++++++++++---- drivers/media/video/v4l2-subdev.c | 41 ++++++++++++++++++++++++- include/media/v4l2-subdev.h | 10 ++++++ 4 files changed, 104 insertions(+), 9 deletions(-)

diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index f231bc20..d0fb880 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -268,6 +268,26 @@ A sub-device driver initializes the v4l2_subdev struct using: Afterwards you need to initialize subdev->name with a unique name and set the module owner. This is done for you if you use the i2c helper functions.

+If integration with the media framework is needed, you must initialize the +media_entity struct embedded in the v4l2_subdev struct (entity field) by +calling media_entity_init(): + + struct media_pad *pads = &my_sd->pads; + int err; + + err = media_entity_init(&sd->entity, npads, pads, 0); + +The pads array must have been previously initialized. There is no need to +manually set the struct media_entity type and name fields, but the revision +field must be initialized if needed. + +A reference to the entity will be automatically acquired/released when the +subdev device node (if any) is opened/closed. + +Don't forget to cleanup the media entity before the sub-device is destroyed: + + media_entity_cleanup(&sd->entity); + A device (bridge) driver needs to register the v4l2_subdev with the v4l2_device:

@@ -277,6 +297,9 @@ This can fail if the subdev module disappeared before it could be registered. After this function was called successfully the subdev->dev field points to the v4l2_device.

+If the v4l2_device parent device has a non-NULL mdev field, the sub-device +entity will be automatically registered with the media device. + You can unregister a sub-device using:

v4l2_device_unregister_subdev(sd); diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c index 5c16a12..69cb429 100644 --- a/drivers/media/video/v4l2-device.c +++ b/drivers/media/video/v4l2-device.c @@ -116,8 +116,11 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev) EXPORT_SYMBOL_GPL(v4l2_device_unregister);

int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev, - struct v4l2_subdev *sd) + struct v4l2_subdev *sd) { +#if defined(CONFIG_MEDIA_CONTROLLER) + struct media_entity *entity = &sd->entity; +#endif struct video_device *vdev; int err;

@@ -135,7 +138,16 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev, err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler); if (err) return err; - +#if defined(CONFIG_MEDIA_CONTROLLER) + /* Register the entity. */ + if (v4l2_dev->mdev) { + err = media_device_register_entity(v4l2_dev->mdev, entity); + if (err < 0) { + module_put(sd->owner); + return err; + } + } +#endif sd->v4l2_dev = v4l2_dev; spin_lock(&v4l2_dev->lock); list_add_tail(&sd->list, &v4l2_dev->subdevs); @@ -150,26 +162,39 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev, if (sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE) { err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1, sd->owner); - if (err < 0) + if (err < 0) { v4l2_device_unregister_subdev(sd); + return err; + } } - - return err; +#if defined(CONFIG_MEDIA_CONTROLLER) + entity->v4l.major = VIDEO_MAJOR; + entity->v4l.minor = vdev->minor; +#endif + return 0; } EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);

void v4l2_device_unregister_subdev(struct v4l2_subdev *sd) { + struct v4l2_device *v4l2_dev; + /* return if it isn't registered */ if (sd == NULL || sd->v4l2_dev == NULL) return;

- spin_lock(&sd->v4l2_dev->lock); + v4l2_dev = sd->v4l2_dev; + + spin_lock(&v4l2_dev->lock); list_del(&sd->list); - spin_unlock(&sd->v4l2_dev->lock); + spin_unlock(&v4l2_dev->lock); sd->v4l2_dev = NULL;

module_put(sd->owner); +#if defined(CONFIG_MEDIA_CONTROLLER) + if (v4l2_dev->mdev) + media_device_unregister_entity(&sd->entity); +#endif video_unregister_device(&sd->devnode); } EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev); diff --git a/drivers/media/video/v4l2-subdev.c b/drivers/media/video/v4l2-subdev.c index fbccefd..a49856a 100644 --- a/drivers/media/video/v4l2-subdev.c +++ b/drivers/media/video/v4l2-subdev.c @@ -35,7 +35,10 @@ static int subdev_open(struct file *file) { struct video_device *vdev = video_devdata(file); struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev); - struct v4l2_fh *vfh; +#if defined(CONFIG_MEDIA_CONTROLLER) + struct media_entity *entity; +#endif + struct v4l2_fh *vfh = NULL; int ret;

if (!sd->initialized) @@ -61,11 +64,20 @@ static int subdev_open(struct file *file) v4l2_fh_add(vfh); file->private_data = vfh; } - +#if defined(CONFIG_MEDIA_CONTROLLER) + if (sd->v4l2_dev->mdev) { + entity = media_entity_get(&sd->entity); + if (!entity) { + ret = -EBUSY; + goto err; + } + } +#endif return 0;

err: if (vfh != NULL) { + v4l2_fh_del(vfh); v4l2_fh_exit(vfh); kfree(vfh); } @@ -75,8 +87,16 @@ err:

static int subdev_close(struct file *file) { +#if defined(CONFIG_MEDIA_CONTROLLER) + struct video_device *vdev = video_devdata(file); + struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev); +#endif struct v4l2_fh *vfh = file->private_data;

+#if defined(CONFIG_MEDIA_CONTROLLER) + if (sd->v4l2_dev->mdev) + media_entity_put(&sd->entity); +#endif if (vfh != NULL) { v4l2_fh_del(vfh); v4l2_fh_exit(vfh); @@ -176,5 +196,22 @@ void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops) sd->dev_priv = NULL; sd->host_priv = NULL; sd->initialized = 1; +#if defined(CONFIG_MEDIA_CONTROLLER) + sd->entity.name = sd->name; + sd->entity.type = MEDIA_ENT_T_V4L2_SUBDEV; +#endif } EXPORT_SYMBOL(v4l2_subdev_init); + +#if defined(CONFIG_MEDIA_CONTROLLER) +int v4l2_subdev_set_power(struct media_entity *entity, int power) +{ + struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity); + + dev_dbg(entity->parent->dev, + "%s power%s\n", entity->name, power ? "on" : "off"); + + return v4l2_subdev_call(sd, core, s_power, power); +} +EXPORT_SYMBOL_GPL(v4l2_subdev_set_power); +#endif diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index 68cbe48..7d55b0c 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -21,6 +21,7 @@ #ifndef _V4L2_SUBDEV_H #define _V4L2_SUBDEV_H

+#include <media/media-entity.h> #include <media/v4l2-common.h> #include <media/v4l2-dev.h> #include <media/v4l2-mediabus.h> @@ -437,6 +438,9 @@ struct v4l2_subdev_ops { stand-alone or embedded in a larger struct. */ struct v4l2_subdev { +#if defined(CONFIG_MEDIA_CONTROLLER) + struct media_entity entity; +#endif struct list_head list; struct module *owner; u32 flags; @@ -458,6 +462,8 @@ struct v4l2_subdev { unsigned int nevents; };

+#define media_entity_to_v4l2_subdev(ent) \ + container_of(ent, struct v4l2_subdev, entity) #define vdev_to_v4l2_subdev(vdev) \ container_of(vdev, struct v4l2_subdev, devnode)

@@ -486,6 +492,10 @@ static inline void *v4l2_get_subdev_hostdata(const struct v4l2_subdev *sd) void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops);

+#if defined(CONFIG_MEDIA_CONTROLLER) +int v4l2_subdev_set_power(struct media_entity *entity, int power); +#endif + /* Call an ops of a v4l2_subdev, doing the right checks against NULL pointers.