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![Sakari Ailus](/assets/img/avatar_default.png)
The purpose of the link_validate() op is to allow an entity driver to ensure that the properties of the pads at the both ends of the link are suitable for starting the pipeline. link_validate is called on sink pads on active links which belong to the active part of the graph. Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
593 lines
16 KiB
C
593 lines
16 KiB
C
/*
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* Media entity
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*
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* Copyright (C) 2010 Nokia Corporation
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*
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* Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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* Sakari Ailus <sakari.ailus@iki.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <media/media-entity.h>
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#include <media/media-device.h>
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/**
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* media_entity_init - Initialize a media entity
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*
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* @num_pads: Total number of sink and source pads.
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* @extra_links: Initial estimate of the number of extra links.
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* @pads: Array of 'num_pads' pads.
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*
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* The total number of pads is an intrinsic property of entities known by the
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* entity driver, while the total number of links depends on hardware design
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* and is an extrinsic property unknown to the entity driver. However, in most
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* use cases the entity driver can guess the number of links which can safely
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* be assumed to be equal to or larger than the number of pads.
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*
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* For those reasons the links array can be preallocated based on the entity
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* driver guess and will be reallocated later if extra links need to be
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* created.
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*
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* This function allocates a links array with enough space to hold at least
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* 'num_pads' + 'extra_links' elements. The media_entity::max_links field will
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* be set to the number of allocated elements.
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*
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* The pads array is managed by the entity driver and passed to
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* media_entity_init() where its pointer will be stored in the entity structure.
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*/
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int
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media_entity_init(struct media_entity *entity, u16 num_pads,
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struct media_pad *pads, u16 extra_links)
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{
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struct media_link *links;
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unsigned int max_links = num_pads + extra_links;
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unsigned int i;
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links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL);
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if (links == NULL)
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return -ENOMEM;
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entity->group_id = 0;
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entity->max_links = max_links;
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entity->num_links = 0;
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entity->num_backlinks = 0;
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entity->num_pads = num_pads;
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entity->pads = pads;
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entity->links = links;
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for (i = 0; i < num_pads; i++) {
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pads[i].entity = entity;
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pads[i].index = i;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(media_entity_init);
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void
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media_entity_cleanup(struct media_entity *entity)
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{
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kfree(entity->links);
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}
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EXPORT_SYMBOL_GPL(media_entity_cleanup);
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/* -----------------------------------------------------------------------------
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* Graph traversal
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*/
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static struct media_entity *
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media_entity_other(struct media_entity *entity, struct media_link *link)
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{
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if (link->source->entity == entity)
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return link->sink->entity;
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else
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return link->source->entity;
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}
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/* push an entity to traversal stack */
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static void stack_push(struct media_entity_graph *graph,
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struct media_entity *entity)
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{
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if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
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WARN_ON(1);
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return;
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}
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graph->top++;
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graph->stack[graph->top].link = 0;
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graph->stack[graph->top].entity = entity;
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}
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static struct media_entity *stack_pop(struct media_entity_graph *graph)
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{
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struct media_entity *entity;
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entity = graph->stack[graph->top].entity;
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graph->top--;
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return entity;
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}
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#define stack_peek(en) ((en)->stack[(en)->top - 1].entity)
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#define link_top(en) ((en)->stack[(en)->top].link)
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#define stack_top(en) ((en)->stack[(en)->top].entity)
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/**
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* media_entity_graph_walk_start - Start walking the media graph at a given entity
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* @graph: Media graph structure that will be used to walk the graph
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* @entity: Starting entity
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*
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* This function initializes the graph traversal structure to walk the entities
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* graph starting at the given entity. The traversal structure must not be
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* modified by the caller during graph traversal. When done the structure can
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* safely be freed.
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*/
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void media_entity_graph_walk_start(struct media_entity_graph *graph,
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struct media_entity *entity)
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{
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graph->top = 0;
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graph->stack[graph->top].entity = NULL;
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stack_push(graph, entity);
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}
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EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
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/**
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* media_entity_graph_walk_next - Get the next entity in the graph
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* @graph: Media graph structure
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*
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* Perform a depth-first traversal of the given media entities graph.
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*
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* The graph structure must have been previously initialized with a call to
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* media_entity_graph_walk_start().
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*
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* Return the next entity in the graph or NULL if the whole graph have been
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* traversed.
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*/
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struct media_entity *
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media_entity_graph_walk_next(struct media_entity_graph *graph)
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{
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if (stack_top(graph) == NULL)
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return NULL;
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/*
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* Depth first search. Push entity to stack and continue from
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* top of the stack until no more entities on the level can be
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* found.
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*/
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while (link_top(graph) < stack_top(graph)->num_links) {
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struct media_entity *entity = stack_top(graph);
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struct media_link *link = &entity->links[link_top(graph)];
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struct media_entity *next;
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/* The link is not enabled so we do not follow. */
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if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
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link_top(graph)++;
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continue;
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}
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/* Get the entity in the other end of the link . */
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next = media_entity_other(entity, link);
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/* Was it the entity we came here from? */
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if (next == stack_peek(graph)) {
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link_top(graph)++;
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continue;
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}
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/* Push the new entity to stack and start over. */
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link_top(graph)++;
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stack_push(graph, next);
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}
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return stack_pop(graph);
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}
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EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
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/* -----------------------------------------------------------------------------
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* Pipeline management
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*/
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/**
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* media_entity_pipeline_start - Mark a pipeline as streaming
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* @entity: Starting entity
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* @pipe: Media pipeline to be assigned to all entities in the pipeline.
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*
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* Mark all entities connected to a given entity through enabled links, either
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* directly or indirectly, as streaming. The given pipeline object is assigned to
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* every entity in the pipeline and stored in the media_entity pipe field.
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*
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* Calls to this function can be nested, in which case the same number of
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* media_entity_pipeline_stop() calls will be required to stop streaming. The
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* pipeline pointer must be identical for all nested calls to
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* media_entity_pipeline_start().
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*/
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__must_check int media_entity_pipeline_start(struct media_entity *entity,
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struct media_pipeline *pipe)
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{
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struct media_device *mdev = entity->parent;
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struct media_entity_graph graph;
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struct media_entity *entity_err = entity;
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int ret;
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mutex_lock(&mdev->graph_mutex);
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media_entity_graph_walk_start(&graph, entity);
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while ((entity = media_entity_graph_walk_next(&graph))) {
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unsigned int i;
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entity->stream_count++;
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WARN_ON(entity->pipe && entity->pipe != pipe);
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entity->pipe = pipe;
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/* Already streaming --- no need to check. */
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if (entity->stream_count > 1)
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continue;
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if (!entity->ops || !entity->ops->link_validate)
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continue;
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for (i = 0; i < entity->num_links; i++) {
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struct media_link *link = &entity->links[i];
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/* Is this pad part of an enabled link? */
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if (!(link->flags & MEDIA_LNK_FL_ENABLED))
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continue;
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/* Are we the sink or not? */
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if (link->sink->entity != entity)
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continue;
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ret = entity->ops->link_validate(link);
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if (ret < 0 && ret != -ENOIOCTLCMD)
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goto error;
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}
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}
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mutex_unlock(&mdev->graph_mutex);
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return 0;
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error:
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/*
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* Link validation on graph failed. We revert what we did and
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* return the error.
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*/
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media_entity_graph_walk_start(&graph, entity_err);
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while ((entity_err = media_entity_graph_walk_next(&graph))) {
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entity_err->stream_count--;
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if (entity_err->stream_count == 0)
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entity_err->pipe = NULL;
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/*
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* We haven't increased stream_count further than this
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* so we quit here.
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*/
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if (entity_err == entity)
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break;
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}
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mutex_unlock(&mdev->graph_mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
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/**
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* media_entity_pipeline_stop - Mark a pipeline as not streaming
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* @entity: Starting entity
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*
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* Mark all entities connected to a given entity through enabled links, either
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* directly or indirectly, as not streaming. The media_entity pipe field is
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* reset to NULL.
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*
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* If multiple calls to media_entity_pipeline_start() have been made, the same
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* number of calls to this function are required to mark the pipeline as not
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* streaming.
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*/
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void media_entity_pipeline_stop(struct media_entity *entity)
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{
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struct media_device *mdev = entity->parent;
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struct media_entity_graph graph;
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mutex_lock(&mdev->graph_mutex);
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media_entity_graph_walk_start(&graph, entity);
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while ((entity = media_entity_graph_walk_next(&graph))) {
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entity->stream_count--;
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if (entity->stream_count == 0)
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entity->pipe = NULL;
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}
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mutex_unlock(&mdev->graph_mutex);
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}
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EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);
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/* -----------------------------------------------------------------------------
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* Module use count
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*/
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/*
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* media_entity_get - Get a reference to the parent module
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* @entity: The entity
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*
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* Get a reference to the parent media device module.
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*
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* The function will return immediately if @entity is NULL.
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*
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* Return a pointer to the entity on success or NULL on failure.
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*/
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struct media_entity *media_entity_get(struct media_entity *entity)
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{
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if (entity == NULL)
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return NULL;
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if (entity->parent->dev &&
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!try_module_get(entity->parent->dev->driver->owner))
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return NULL;
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return entity;
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}
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EXPORT_SYMBOL_GPL(media_entity_get);
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/*
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* media_entity_put - Release the reference to the parent module
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* @entity: The entity
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*
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* Release the reference count acquired by media_entity_get().
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*
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* The function will return immediately if @entity is NULL.
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*/
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void media_entity_put(struct media_entity *entity)
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{
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if (entity == NULL)
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return;
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if (entity->parent->dev)
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module_put(entity->parent->dev->driver->owner);
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}
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EXPORT_SYMBOL_GPL(media_entity_put);
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/* -----------------------------------------------------------------------------
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* Links management
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*/
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static struct media_link *media_entity_add_link(struct media_entity *entity)
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{
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if (entity->num_links >= entity->max_links) {
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struct media_link *links = entity->links;
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unsigned int max_links = entity->max_links + 2;
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unsigned int i;
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links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL);
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if (links == NULL)
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return NULL;
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for (i = 0; i < entity->num_links; i++)
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links[i].reverse->reverse = &links[i];
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entity->max_links = max_links;
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entity->links = links;
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}
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return &entity->links[entity->num_links++];
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}
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int
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media_entity_create_link(struct media_entity *source, u16 source_pad,
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struct media_entity *sink, u16 sink_pad, u32 flags)
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{
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struct media_link *link;
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struct media_link *backlink;
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BUG_ON(source == NULL || sink == NULL);
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BUG_ON(source_pad >= source->num_pads);
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BUG_ON(sink_pad >= sink->num_pads);
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link = media_entity_add_link(source);
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if (link == NULL)
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return -ENOMEM;
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link->source = &source->pads[source_pad];
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link->sink = &sink->pads[sink_pad];
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link->flags = flags;
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/* Create the backlink. Backlinks are used to help graph traversal and
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* are not reported to userspace.
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*/
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backlink = media_entity_add_link(sink);
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if (backlink == NULL) {
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source->num_links--;
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return -ENOMEM;
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}
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backlink->source = &source->pads[source_pad];
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backlink->sink = &sink->pads[sink_pad];
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backlink->flags = flags;
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link->reverse = backlink;
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backlink->reverse = link;
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sink->num_backlinks++;
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return 0;
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}
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EXPORT_SYMBOL_GPL(media_entity_create_link);
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static int __media_entity_setup_link_notify(struct media_link *link, u32 flags)
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{
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int ret;
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/* Notify both entities. */
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ret = media_entity_call(link->source->entity, link_setup,
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link->source, link->sink, flags);
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if (ret < 0 && ret != -ENOIOCTLCMD)
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return ret;
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ret = media_entity_call(link->sink->entity, link_setup,
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link->sink, link->source, flags);
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if (ret < 0 && ret != -ENOIOCTLCMD) {
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media_entity_call(link->source->entity, link_setup,
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link->source, link->sink, link->flags);
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return ret;
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}
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link->flags = flags;
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link->reverse->flags = link->flags;
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return 0;
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}
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/**
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* __media_entity_setup_link - Configure a media link
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* @link: The link being configured
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* @flags: Link configuration flags
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*
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* The bulk of link setup is handled by the two entities connected through the
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* link. This function notifies both entities of the link configuration change.
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*
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* If the link is immutable or if the current and new configuration are
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* identical, return immediately.
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*
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* The user is expected to hold link->source->parent->mutex. If not,
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* media_entity_setup_link() should be used instead.
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*/
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int __media_entity_setup_link(struct media_link *link, u32 flags)
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{
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const u32 mask = MEDIA_LNK_FL_ENABLED;
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struct media_device *mdev;
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struct media_entity *source, *sink;
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int ret = -EBUSY;
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if (link == NULL)
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return -EINVAL;
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/* The non-modifiable link flags must not be modified. */
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if ((link->flags & ~mask) != (flags & ~mask))
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return -EINVAL;
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if (link->flags & MEDIA_LNK_FL_IMMUTABLE)
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return link->flags == flags ? 0 : -EINVAL;
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if (link->flags == flags)
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return 0;
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source = link->source->entity;
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sink = link->sink->entity;
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if (!(link->flags & MEDIA_LNK_FL_DYNAMIC) &&
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(source->stream_count || sink->stream_count))
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return -EBUSY;
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mdev = source->parent;
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if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify) {
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ret = mdev->link_notify(link->source, link->sink,
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MEDIA_LNK_FL_ENABLED);
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if (ret < 0)
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return ret;
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}
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ret = __media_entity_setup_link_notify(link, flags);
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if (ret < 0)
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goto err;
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if (!(flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify)
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mdev->link_notify(link->source, link->sink, 0);
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return 0;
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err:
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if ((flags & MEDIA_LNK_FL_ENABLED) && mdev->link_notify)
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mdev->link_notify(link->source, link->sink, 0);
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return ret;
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}
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int media_entity_setup_link(struct media_link *link, u32 flags)
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{
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int ret;
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mutex_lock(&link->source->entity->parent->graph_mutex);
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ret = __media_entity_setup_link(link, flags);
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mutex_unlock(&link->source->entity->parent->graph_mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(media_entity_setup_link);
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/**
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* media_entity_find_link - Find a link between two pads
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* @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);
|