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path: root/drivers/media/media-device.c
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2016-01-11[media] media-device: use unsigned ints on some placesMauro Carvalho Chehab
The entity->num_pads are defined as u16. So, better to use an unsigned int, as this prevents additional warnings when W=2 (or W=1 on some architectures). The "i" counter at __media_device_get_topology() is also a monotonic counter that should never be below zero. So, make it unsigned too. Suggested-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] uapi/media.h: Rename entities types to functionsMauro Carvalho Chehab
Rename the userspace types from MEDIA_ENT_T_ to MEDIA_ENT_F_ and add the backward compatibility bits. The changes at the .c files was generated by the following coccinelle script: @@ @@ -MEDIA_ENT_T_UNKNOWN +MEDIA_ENT_F_UNKNOWN @@ @@ -MEDIA_ENT_T_DVB_BASE +MEDIA_ENT_F_DVB_BASE @@ @@ -MEDIA_ENT_T_V4L2_BASE +MEDIA_ENT_F_V4L2_BASE @@ @@ -MEDIA_ENT_T_V4L2_SUBDEV_BASE +MEDIA_ENT_F_V4L2_SUBDEV_BASE @@ @@ -MEDIA_ENT_T_CONNECTOR_BASE +MEDIA_ENT_F_CONNECTOR_BASE @@ @@ -MEDIA_ENT_T_V4L2_VIDEO +MEDIA_ENT_F_IO_V4L @@ @@ -MEDIA_ENT_T_V4L2_VBI +MEDIA_ENT_F_IO_VBI @@ @@ -MEDIA_ENT_T_V4L2_SWRADIO +MEDIA_ENT_F_IO_SWRADIO @@ @@ -MEDIA_ENT_T_V4L2_SUBDEV_UNKNOWN +MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN @@ @@ -MEDIA_ENT_T_CONN_RF +MEDIA_ENT_F_CONN_RF @@ @@ -MEDIA_ENT_T_CONN_SVIDEO +MEDIA_ENT_F_CONN_SVIDEO @@ @@ -MEDIA_ENT_T_CONN_COMPOSITE +MEDIA_ENT_F_CONN_COMPOSITE @@ @@ -MEDIA_ENT_T_CONN_TEST +MEDIA_ENT_F_CONN_TEST @@ @@ -MEDIA_ENT_T_V4L2_SUBDEV_SENSOR +MEDIA_ENT_F_CAM_SENSOR @@ @@ -MEDIA_ENT_T_V4L2_SUBDEV_FLASH +MEDIA_ENT_F_FLASH @@ @@ -MEDIA_ENT_T_V4L2_SUBDEV_LENS +MEDIA_ENT_F_LENS @@ @@ -MEDIA_ENT_T_V4L2_SUBDEV_DECODER +MEDIA_ENT_F_ATV_DECODER @@ @@ -MEDIA_ENT_T_V4L2_SUBDEV_TUNER +MEDIA_ENT_F_TUNER @@ @@ -MEDIA_ENT_T_DVB_DEMOD +MEDIA_ENT_F_DTV_DEMOD @@ @@ -MEDIA_ENT_T_DVB_DEMUX +MEDIA_ENT_F_TS_DEMUX @@ @@ -MEDIA_ENT_T_DVB_TSOUT +MEDIA_ENT_F_IO_DTV @@ @@ -MEDIA_ENT_T_DVB_CA +MEDIA_ENT_F_DTV_CA @@ @@ -MEDIA_ENT_T_DVB_NET_DECAP +MEDIA_ENT_F_DTV_NET_DECAP Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media-device: export the entity function via new ioctlMauro Carvalho Chehab
Now that entities have a main function, expose it via MEDIA_IOC_G_TOPOLOGY ioctl. Please notice that some entities may have secundary functions. Such use case will be addressed later, when we add support for the Media Controller properties. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media-entity.h: rename entity.type to entity.functionMauro Carvalho Chehab
Entities should have one or more functions. Calling it as a type proofed to not be correct, as an entity could eventually have more than one type. So, rename the field as function. Please notice that this patch doesn't extend support for multiple function entities. Such change will happen when we have real case drivers using it. No functional changes. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media-device: supress backlinks at G_TOPOLOGY ioctlMauro Carvalho Chehab
Due to the graph traversal algorithm currently in usage, we need a copy of all data links. Those backlinks should not be send to userspace, as otherwise, all links there will be duplicated. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] dvbdev: returns error if graph object creation failsMauro Carvalho Chehab
Right now, if something gets wrong at dvb_create_media_entity() or at dvb_create_media_graph(), the device will still be registered. Change the logic to properly handle it and free all media graph objects if something goes wrong at dvb_register_device(). Also, change the logic at dvb_create_media_graph() to return an error code if something goes wrong. It is up to the caller to implement the right logic and to call dvb_unregister_device() to unregister the already-created objects. While here, add a missing logic to unregister the created interfaces. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media-device: remove interfaces and interface linksMauro Carvalho Chehab
Just like what's done with entities, when the media controller is unregistered, release any interface and interface links that might still be there. Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] remove interface links at media_entity_unregister()Mauro Carvalho Chehab
Interface links connected to an entity should be removed before the entity itself can be removed. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media-device: add support for MEDIA_IOC_G_TOPOLOGY ioctlMauro Carvalho Chehab
Add support for the new MEDIA_IOC_G_TOPOLOGY ioctl, according with the RFC for the MC next generation. Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media-device: add pads and links to media_deviceMauro Carvalho Chehab
The MC next gen API sends objects to userspace grouped by their types. In the case of pads and links, in order to improve performance and have a simpler code, the best is to store them also on separate linked lists at MC. If we don't do that, we would need this kind of interaction to send data to userspace (code is in structured english): for each entity: for each pad: store pads for each entity: for each link: store link for each interface: for each link: store link With would require one nested loop for pads and two nested loops for links. By using separate linked lists for them, just one loop would be enough. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: move mdev list init to gobjMauro Carvalho Chehab
Let's control the topology changes inside the graph_object. So, move the addition and removal of interfaces/entities from the mdev lists to media_gobj_init() and media_gobj_remove(). The main reason is that mdev should have lists for all object types, as the new MC api will require to store objects in separate places. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] v4l2-subdev: use MEDIA_ENT_T_UNKNOWN for new subdevsMauro Carvalho Chehab
Instead of abusing MEDIA_ENT_T_V4L2_SUBDEV, initialize new subdev entities as MEDIA_ENT_T_UNKNOWN. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: add a linked list to track interfaces by mdevMauro Carvalho Chehab
The media device should list the interface objects, so add a linked list for those interfaces in struct media_device. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: convert links from array to listMauro Carvalho Chehab
The entire logic that represent graph links were developed on a time where there were no needs to dynamic remove links. So, although links are created/removed one by one via some functions, they're stored as an array inside the entity struct. As the array may grow, there's a logic inside the code that checks if the amount of space is not enough to store the needed links. If it isn't the core uses krealloc() to change the size of the link, with is bad, as it leaves the memory fragmented. So, convert links into a list. Also, currently, both source and sink entities need the link at the graph traversal logic inside media_entity. So there's a logic duplicating all links. That makes it to spend twice the memory needed. This is not a big deal for today's usage, where the number of links are not big. Yet, if during the MC workshop discussions, it was said that IIO graphs could have up to 4,000 entities. So, we may want to remove the duplication on some future. The problem is that it would require a separate linked list to store the backlinks inside the entity, or to use a more complex algorithm to do graph backlink traversal, with is something that the current graph traversal inside the core can't cope with. So, let's postpone a such change if/when it is actually needed. It should also be noticed that the media_link structure uses 44 bytes on 32-bit architectures and 84 bytes on 64-bit architecture. It will thus be allocated out of the 64-bytes and 96-bytes pools respectively. That's a 12.5% memory waste on 64-bit architectures and 31.25% on 32-bit architecture. A linked list is less efficient than an array in this case, but this could later be optimized if we can get rid of the reverse links (with would reduce memory allocation by 50%). Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: Don't accept early-created linksMauro Carvalho Chehab
Links are graph objects that represent the links of two already existing objects in the graph. While with the current implementation, it is possible to create the links earlier, It doesn't make any sense to allow linking two objects when they are not both created. So, remove the code that would be handling those early-created links and add a BUG_ON() to ensure that. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: use entity.graph_obj.mdev instead of .parentJavier Martinez Canillas
The struct media_entity has a .parent field that stores a pointer to the parent struct media_device. But recently a media_gobj was embedded into the entities and since struct media_gojb already has a pointer to a struct media_device in the .mdev field, the .parent field becomes redundant and can be removed. This patch replaces all the usage of .parent by .graph_obj.mdev so that field will become unused and can be removed on a later patch. No functional changes. The transformation was made using the following coccinelle spatch: @@ struct media_entity *me; @@ - me->parent + me->graph_obj.mdev @@ struct media_entity *link; @@ - link->source->entity->parent + link->source->entity->graph_obj.mdev @@ struct exynos_video_entity *ve; @@ - ve->vdev.entity.parent + ve->vdev.entity.graph_obj.mdev Suggested-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: add messages when media device gets (un)registeredMauro Carvalho Chehab
We can only free the media device after being sure that no graph object is used. In order to help tracking it, let's add debug messages that will print when the media controller gets registered or unregistered. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: use media_gobj inside linksMauro Carvalho Chehab
Just like entities and pads, links also need to have unique Object IDs along a given media controller. So, let's add a media_gobj inside it and initialize the object then a new link is created. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Tested-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: use media_gobj inside padsMauro Carvalho Chehab
PADs also need unique object IDs that won't conflict with the entity object IDs. The pad objects are currently created via media_entity_init() and, once created, never change. While this will likely change in the future in order to support dynamic changes, for now we'll keep PADs as arrays and initialize the media_gobj embedded structs when registering the entity. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Tested-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: use media_gobj inside entitiesMauro Carvalho Chehab
As entities are graph objects, let's embed media_gobj on it. That ensures an unique ID for entities that can be global along the entire media controller. For now, we'll keep the already existing entity ID. Such field need to be dropped at some point, but for now, let's not do this, to avoid needing to review all drivers and the userspace apps. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Tested-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: create a macro to get entity IDMauro Carvalho Chehab
Instead of accessing directly entity.id, let's create a macro, as this field will be moved into a common struct later on. Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: define Media Controller API when CONFIG_MEDIA_CONTROLLER enabledShuah Khan
Change to define Media Controller API when CONFIG_MEDIA_CONTROLLER is enabled. Define stubs for CONFIG_MEDIA_CONTROLLER disabled case. This will help avoid drivers needing to enclose Media Controller code within ifdef CONFIG_MEDIA_CONTROLLER block. Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2016-01-11[media] media: new media controller API for device resource supportShuah Khan
Add new media controller API to allocate media device as a device resource. When a media device is created on the main struct device which is the parent device for the interface device, it will be available to all drivers associated with that interface. For example, if a usb media device driver creates the media device on the main struct device which is common for all the drivers that control the media device, including the non-media ALSA driver, media controller API can be used to share access to the resources on the media device. This new interface provides the above described feature. A second interface that finds and returns the media device is added to allow drivers to find the media device created by any of the drivers associated with the device. Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2014-09-21[media] media: Use strlcpy instead of custom codeLaurent Pinchart
Replace strncpy + manually setting the terminating '\0' with an strlcpy call. Reported-by: Joe Perches <joe@perches.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2014-07-22[media] media-device: Remove duplicated memset() in media_enum_entities()Salva Peiró
After the zeroing the whole struct struct media_entity_desc u_ent, it is no longer necessary to memset(0) its u_ent.name field. CC: stable@vger.kernel.org Signed-off-by: Salva Peiró <speiro@ai2.upv.es> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-05-21Merge tag 'v3.15-rc6' into patchworkMauro Carvalho Chehab
Linux 3.15-rc6 * tag 'v3.15-rc6': (1314 commits) Linux 3.15-rc6 Btrfs: send, fix incorrect ref access when using extrefs Btrfs: fix EIO on reading file after ioctl clone works on it scripts/checksyscalls.sh: Make renameat optional asm-generic: Add renameat2 syscall ia64: add renameat2 syscall parisc: add renameat2 syscall m68k: add renameat2 syscall sysfs: make sure read buffer is zeroed ahci: imx: PLL clock needs 100us to settle down PCI: Wrong register used to check pending traffic target: fix memory leak on XCOPY random: fix BUG_ON caused by accounting simplification clk: tegra: Fix wrong value written to PLLE_AUX staging: rtl8723au: Do not reset wdev->iftype in netdev_close() ACPI / video: Revert native brightness quirk for ThinkPad T530 staging: rtl8723au: Use correct pipe type for USB interrupts crush: decode and initialize chooseleaf_vary_r libceph: fix corruption when using page_count 0 page in rbd arm64: fix pud_huge() for 2-level pagetables ...
2014-05-13[media] media: Use a better owner for the media deviceSakari Ailus
mdev->fops->owner is actually the owner of the very same module which implements media_device_register(), so it can't be unloaded anyway. Instead, use THIS_MODULE through a macro as does video_register_device(). Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-05-01[media] media-device: fix infoleak in ioctl media_enum_entities()Salva Peiró
This fixes CVE-2014-1739. Signed-off-by: Salva Peiró <speiro@ai2.upv.es> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: stable@vger.kernel.org Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2013-06-12[media] media: info leak in __media_device_enum_links()Dan Carpenter
These structs have holes and reserved struct members which aren't cleared. I've added a memset() so we don't leak stack information. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2013-04-23[media] media: info leak in media_device_enum_entities()Dan Carpenter
The last part of the "u_ent.name" buffer isn't cleared so it still has uninitialized stack memory. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2013-03-18[media] media: implement 32-on-64 bit compat IOCTL handlingSakari Ailus
Use the same handlers where the structs are the same. Implement a new handler for link enumeration since struct media_links_enum is different on 32-bit and 64-bit systems. Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-08-12[media] media: fix MEDIA_IOC_DEVICE_INFO return codeNicolas THERY
The MEDIA_IOC_DEVICE_INFO ioctl was returning a positive value rather than a negative error code when failing to copy output parameter to user-space. Tested by compilation only. Signed-off-by: Nicolas Thery <nicolas.thery@st.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-12-20[media] media: fix truncated entity specificationClemens Ladisch
When enumerating an entity, assign the entire entity specification instead of only the first two words. (This requires giving the specification union a name.) So far, no driver actually uses more than two words, but this will be needed for ALSA entities. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> [laurent.pinchart@ideasonboard.com: Rename specification to info] Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-10-31drivers/media: Add export.h for EXPORT_SYMBOL/THIS_MODULE as requiredPaul Gortmaker
These two macros were in module.h but now module.h is no longer sprayed across every source file imaginable, so the users need to expicitly call out their use of them. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-03-22[media] media: Links setupLaurent Pinchart
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@iki.fi> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-03-22[media] media: Entities, pads and links enumerationLaurent Pinchart
Create the following two ioctls and implement them at the media device level to enumerate entities, pads and links. - MEDIA_IOC_ENUM_ENTITIES: Enumerate entities and their properties - MEDIA_IOC_ENUM_LINKS: Enumerate all pads and links for a given entity Entity IDs can be non-contiguous. Userspace applications should enumerate entities using the MEDIA_ENT_ID_FLAG_NEXT flag. When the flag is set in the entity ID, the MEDIA_IOC_ENUM_ENTITIES will return the next entity with an ID bigger than the requested one. Only forward links that originate at one of the entity's source pads are returned during the enumeration process. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-03-22[media] media: Media device information queryLaurent Pinchart
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> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-03-22[media] media: Entity use countLaurent Pinchart
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> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-03-22[media] media: Entities, pads and linksLaurent Pinchart
As video hardware pipelines become increasingly complex and configurable, the current hardware description through v4l2 subdevices reaches its limits. In addition to enumerating and configuring subdevices, video camera drivers need a way to discover and modify at runtime how those subdevices are connected. This is done through new elements called entities, pads and links. An entity is a basic media hardware building block. It can correspond to a large variety of logical blocks such as physical hardware devices (CMOS sensor for instance), logical hardware devices (a building block in a System-on-Chip image processing pipeline), DMA channels or physical connectors. A pad is a connection endpoint through which an entity can interact with other entities. Data (not restricted to video) produced by an entity flows from the entity's output to one or more entity inputs. Pads should not be confused with physical pins at chip boundaries. A link is a point-to-point oriented connection between two pads, either on the same entity or on different entities. Data flows from a source pad to a sink pad. Links are stored in the source entity. To make backwards graph walk faster, a copy of all links is also stored in the sink entity. The copy is known as a backlink and is only used to help graph traversal. The entity API is made of three functions: - media_entity_init() initializes an entity. The caller must provide an array of pads as well as an estimated number of links. The links array is allocated dynamically and will be reallocated if it grows beyond the initial estimate. - media_entity_cleanup() frees resources allocated for an entity. It must be called during the cleanup phase after unregistering the entity and before freeing it. - media_entity_create_link() creates a link between two entities. An entry in the link array of each entity is allocated and stores pointers to source and sink pads. When a media device is unregistered, all its entities are unregistered automatically. The code is based on Hans Verkuil <hverkuil@xs4all.nl> initial work. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-03-22[media] media: Media deviceLaurent Pinchart
The media_device structure abstracts functions common to all kind of media devices (v4l2, dvb, alsa, ...). It manages media entities and offers a userspace API to discover and configure the media device internal topology. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>