diff options
Diffstat (limited to 'drivers/media/media-entity.c')
| -rw-r--r-- | drivers/media/media-entity.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c new file mode 100644 index 00000000000..5c31df9ed76 --- /dev/null +++ b/drivers/media/media-entity.c @@ -0,0 +1,147 @@ +/* + * Media entity + * + * Copyright (C) 2010 Nokia Corporation + * + * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com> + * Sakari Ailus <sakari.ailus@iki.fi> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <media/media-entity.h> + +/** + * media_entity_init - Initialize a media entity + * + * @num_pads: Total number of sink and source pads. + * @extra_links: Initial estimate of the number of extra links. + * @pads: Array of 'num_pads' pads. + * + * The total number of pads is an intrinsic property of entities known by the + * entity driver, while the total number of links depends on hardware design + * and is an extrinsic property unknown to the entity driver. However, in most + * use cases the entity driver can guess the number of links which can safely + * be assumed to be equal to or larger than the number of pads. + * + * For those reasons the links array can be preallocated based on the entity + * driver guess and will be reallocated later if extra links need to be + * created. + * + * This function allocates a links array with enough space to hold at least + * 'num_pads' + 'extra_links' elements. The media_entity::max_links field will + * be set to the number of allocated elements. + * + * The pads array is managed by the entity driver and passed to + * media_entity_init() where its pointer will be stored in the entity structure. + */ +int +media_entity_init(struct media_entity *entity, u16 num_pads, + struct media_pad *pads, u16 extra_links) +{ + struct media_link *links; + unsigned int max_links = num_pads + extra_links; + unsigned int i; + + links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL); + if (links == NULL) + return -ENOMEM; + + entity->group_id = 0; + entity->max_links = max_links; + entity->num_links = 0; + entity->num_backlinks = 0; + entity->num_pads = num_pads; + entity->pads = pads; + entity->links = links; + + for (i = 0; i < num_pads; i++) { + pads[i].entity = entity; + pads[i].index = i; + } + + return 0; +} +EXPORT_SYMBOL_GPL(media_entity_init); + +void +media_entity_cleanup(struct media_entity *entity) +{ + kfree(entity->links); +} +EXPORT_SYMBOL_GPL(media_entity_cleanup); + +static struct media_link *media_entity_add_link(struct media_entity *entity) +{ + if (entity->num_links >= entity->max_links) { + struct media_link *links = entity->links; + unsigned int max_links = entity->max_links + 2; + unsigned int i; + + links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL); + if (links == NULL) + return NULL; + + for (i = 0; i < entity->num_links; i++) + links[i].reverse->reverse = &links[i]; + + entity->max_links = max_links; + entity->links = links; + } + + return &entity->links[entity->num_links++]; +} + +int +media_entity_create_link(struct media_entity *source, u16 source_pad, + struct media_entity *sink, u16 sink_pad, u32 flags) +{ + struct media_link *link; + struct media_link *backlink; + + BUG_ON(source == NULL || sink == NULL); + BUG_ON(source_pad >= source->num_pads); + BUG_ON(sink_pad >= sink->num_pads); + + link = media_entity_add_link(source); + if (link == NULL) + return -ENOMEM; + + link->source = &source->pads[source_pad]; + link->sink = &sink->pads[sink_pad]; + link->flags = flags; + + /* Create the backlink. Backlinks are used to help graph traversal and + * are not reported to userspace. + */ + backlink = media_entity_add_link(sink); + if (backlink == NULL) { + source->num_links--; + return -ENOMEM; + } + + backlink->source = &source->pads[source_pad]; + backlink->sink = &sink->pads[sink_pad]; + backlink->flags = flags; + + link->reverse = backlink; + backlink->reverse = link; + + sink->num_backlinks++; + + return 0; +} +EXPORT_SYMBOL_GPL(media_entity_create_link); |