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/*
* Media entity
*
* Copyright (C) 2010 Nokia Corporation
*
* Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
* Sakari Ailus <sakari.ailus@iki.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/bitmap.h>
#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
*
* @num_pads: Total number of sink and source pads.
* @extra_links: Initial estimate of the number of extra links.
* @pads: Array of 'num_pads' pads.
*
* The total number of pads is an intrinsic property of entities known by the
* entity driver, while the total number of links depends on hardware design
* and is an extrinsic property unknown to the entity driver. However, in most
* use cases the entity driver can guess the number of links which can safely
* be assumed to be equal to or larger than the number of pads.
*
* For those reasons the links array can be preallocated based on the entity
* driver guess and will be reallocated later if extra links need to be
* created.
*
* This function allocates a links array with enough space to hold at least
* 'num_pads' + 'extra_links' elements. The media_entity::max_links field will
* be set to the number of allocated elements.
*
* The pads array is managed by the entity driver and passed to
* media_entity_init() where its pointer will be stored in the entity structure.
*/
int
media_entity_init(struct media_entity *entity, u16 num_pads,
struct media_pad *pads, u16 extra_links)
{
struct media_link *links;
unsigned int max_links = num_pads + extra_links;
unsigned int i;
links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL);
if (links == NULL)
return -ENOMEM;
entity->group_id = 0;
entity->max_links = max_links;
entity->num_links = 0;
entity->num_backlinks = 0;
entity->num_pads = num_pads;
entity->pads = pads;
entity->links = links;
for (i = 0; i < num_pads; i++) {
pads[i].entity = entity;
pads[i].index = i;
}
return 0;
}
EXPORT_SYMBOL_GPL(media_entity_init);
void
media_entity_cleanup(struct media_entity *entity)
{
kfree(entity->links);
}
EXPORT_SYMBOL_GPL(media_entity_cleanup);
/* -----------------------------------------------------------------------------
* Graph traversal
*/
static struct media_entity *
media_entity_other(struct media_entity *entity, struct media_link *link)
{
if (link->source->entity == entity)
return link->sink->entity;
else
return link->source->entity;
}
/* push an entity to traversal stack */
static void stack_push(struct media_entity_graph *graph,
struct media_entity *entity)
{
if (graph->top == MEDIA_ENTITY_ENUM_MAX_DEPTH - 1) {
WARN_ON(1);
return;
}
graph->top++;
graph->stack[graph->top].link = 0;
graph->stack[graph->top].entity = entity;
}
static struct media_entity *stack_pop(struct media_entity_graph *graph)
{
struct media_entity *entity;
entity = graph->stack[graph->top].entity;
graph->top--;
return entity;
}
#define link_top(en) ((en)->stack[(en)->top].link)
#define stack_top(en) ((en)->stack[(en)->top].entity)
/**
* media_entity_graph_walk_start - Start walking the media graph at a given entity
* @graph: Media graph structure that will be used to walk the graph
* @entity: Starting entity
*
* This function initializes the graph traversal structure to walk the entities
* graph starting at the given entity. The traversal structure must not be
* modified by the caller during graph traversal. When done the structure can
* safely be freed.
*/
void media_entity_graph_walk_start(struct media_entity_graph *graph,
struct media_entity *entity)
{
graph->top = 0;
graph->stack[graph->top].entity = NULL;
bitmap_zero(graph->entities, MEDIA_ENTITY_ENUM_MAX_ID);
if (WARN_ON(entity->id >= MEDIA_ENTITY_ENUM_MAX_ID))
return;
__set_bit(entity->id, graph->entities);
stack_push(graph, entity);
}
EXPORT_SYMBOL_GPL(media_entity_graph_walk_start);
/**
* media_entity_graph_walk_next - Get the next entity in the graph
* @graph: Media graph structure
*
* Perform a depth-first traversal of the given media entities graph.
*
* The graph structure must have been previously initialized with a call to
* media_entity_graph_walk_start().
*
* Return the next entity in the graph or NULL if the whole graph have been
* traversed.
*/
struct media_entity *
media_entity_graph_walk_next(struct media_entity_graph *graph)
{
if (stack_top(graph) == NULL)
return NULL;
/*
* Depth first search. Push entity to stack and continue from
* top of the stack until no more entities on the level can be
* found.
*/
while (link_top(graph) < stack_top(graph)->num_links) {
struct media_entity *entity = stack_top(graph);
struct media_link *link = &entity->links[link_top(graph)];
struct media_entity *next;
/* The link is not enabled so we do not follow. */
if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
link_top(graph)++;
continue;
}
/* Get the entity in the other end of the link . */
next = media_entity_other(entity, link);
if (WARN_ON(next->id >= MEDIA_ENTITY_ENUM_MAX_ID))
return NULL;
/* Has the entity already been visited? */
if (__test_and_set_bit(next->id, graph->entities)) {
link_top(graph)++;
continue;
}
/* Push the new entity to stack and start over. */
link_top(graph)++;
stack_push(graph, next);
}
return stack_pop(graph);
}
EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
/* -----------------------------------------------------------------------------
* Pipeline management
*/
/**
* media_entity_pipeline_start - Mark a pipeline as streaming
* @entity: Starting entity
* @pipe: Media pipeline to be assigned to all entities in the pipeline.
*
* Mark all entities connected to a given entity through enabled links, either
* directly or indirectly, as streaming. The given pipeline object is assigned to
* every entity in the pipeline and stored in the media_entity pipe field.
*
* Calls to this function can be nested, in which case the same number of
* media_entity_pipeline_stop() calls will be required to stop streaming. The
* pipeline pointer must be identical for all nested calls to
* media_entity_pipeline_start().
*/
__must_check int media_entity_pipeline_start(struct media_entity *entity,
struct media_pipeline *pipe)
{
struct media_device *mdev = entity->parent;
struct media_entity_graph graph;
struct media_entity *entity_err = entity;
int ret;
mutex_lock(&mdev->graph_mutex);
media_entity_graph_walk_start(&graph, entity);
while ((entity = media_entity_graph_walk_next(&graph))) {
DECLARE_BITMAP(active, entity->num_pads);
DECLARE_BITMAP(has_no_links, entity->num_pads);
unsigned int i;
entity->stream_count++;
WARN_ON(entity->pipe && entity->pipe != pipe);
entity->pipe = pipe;
/* Already streaming --- no need to check. */
if (entity->stream_count > 1)
continue;
if (!entity->ops || !entity->ops->link_validate)
continue;
bitmap_zero(active, entity->num_pads);
bitmap_fill(has_no_links, entity->num_pads);
for (i = 0; i < entity->num_links; i++) {
struct media_link *link = &entity->links[i];
struct media_pad *pad = link->sink
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