Laurent Pinchart | 53e269c | 2009-12-09 08:40:00 -0300 | [diff] [blame^] | 1 | /* |
| 2 | * Media entity |
| 3 | * |
| 4 | * Copyright (C) 2010 Nokia Corporation |
| 5 | * |
| 6 | * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com> |
| 7 | * Sakari Ailus <sakari.ailus@iki.fi> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 as |
| 11 | * published by the Free Software Foundation. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU General Public License |
| 19 | * along with this program; if not, write to the Free Software |
| 20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 21 | */ |
| 22 | |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/slab.h> |
| 25 | #include <media/media-entity.h> |
| 26 | |
| 27 | /** |
| 28 | * media_entity_init - Initialize a media entity |
| 29 | * |
| 30 | * @num_pads: Total number of sink and source pads. |
| 31 | * @extra_links: Initial estimate of the number of extra links. |
| 32 | * @pads: Array of 'num_pads' pads. |
| 33 | * |
| 34 | * The total number of pads is an intrinsic property of entities known by the |
| 35 | * entity driver, while the total number of links depends on hardware design |
| 36 | * and is an extrinsic property unknown to the entity driver. However, in most |
| 37 | * use cases the entity driver can guess the number of links which can safely |
| 38 | * be assumed to be equal to or larger than the number of pads. |
| 39 | * |
| 40 | * For those reasons the links array can be preallocated based on the entity |
| 41 | * driver guess and will be reallocated later if extra links need to be |
| 42 | * created. |
| 43 | * |
| 44 | * This function allocates a links array with enough space to hold at least |
| 45 | * 'num_pads' + 'extra_links' elements. The media_entity::max_links field will |
| 46 | * be set to the number of allocated elements. |
| 47 | * |
| 48 | * The pads array is managed by the entity driver and passed to |
| 49 | * media_entity_init() where its pointer will be stored in the entity structure. |
| 50 | */ |
| 51 | int |
| 52 | media_entity_init(struct media_entity *entity, u16 num_pads, |
| 53 | struct media_pad *pads, u16 extra_links) |
| 54 | { |
| 55 | struct media_link *links; |
| 56 | unsigned int max_links = num_pads + extra_links; |
| 57 | unsigned int i; |
| 58 | |
| 59 | links = kzalloc(max_links * sizeof(links[0]), GFP_KERNEL); |
| 60 | if (links == NULL) |
| 61 | return -ENOMEM; |
| 62 | |
| 63 | entity->group_id = 0; |
| 64 | entity->max_links = max_links; |
| 65 | entity->num_links = 0; |
| 66 | entity->num_backlinks = 0; |
| 67 | entity->num_pads = num_pads; |
| 68 | entity->pads = pads; |
| 69 | entity->links = links; |
| 70 | |
| 71 | for (i = 0; i < num_pads; i++) { |
| 72 | pads[i].entity = entity; |
| 73 | pads[i].index = i; |
| 74 | } |
| 75 | |
| 76 | return 0; |
| 77 | } |
| 78 | EXPORT_SYMBOL_GPL(media_entity_init); |
| 79 | |
| 80 | void |
| 81 | media_entity_cleanup(struct media_entity *entity) |
| 82 | { |
| 83 | kfree(entity->links); |
| 84 | } |
| 85 | EXPORT_SYMBOL_GPL(media_entity_cleanup); |
| 86 | |
| 87 | static struct media_link *media_entity_add_link(struct media_entity *entity) |
| 88 | { |
| 89 | if (entity->num_links >= entity->max_links) { |
| 90 | struct media_link *links = entity->links; |
| 91 | unsigned int max_links = entity->max_links + 2; |
| 92 | unsigned int i; |
| 93 | |
| 94 | links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL); |
| 95 | if (links == NULL) |
| 96 | return NULL; |
| 97 | |
| 98 | for (i = 0; i < entity->num_links; i++) |
| 99 | links[i].reverse->reverse = &links[i]; |
| 100 | |
| 101 | entity->max_links = max_links; |
| 102 | entity->links = links; |
| 103 | } |
| 104 | |
| 105 | return &entity->links[entity->num_links++]; |
| 106 | } |
| 107 | |
| 108 | int |
| 109 | media_entity_create_link(struct media_entity *source, u16 source_pad, |
| 110 | struct media_entity *sink, u16 sink_pad, u32 flags) |
| 111 | { |
| 112 | struct media_link *link; |
| 113 | struct media_link *backlink; |
| 114 | |
| 115 | BUG_ON(source == NULL || sink == NULL); |
| 116 | BUG_ON(source_pad >= source->num_pads); |
| 117 | BUG_ON(sink_pad >= sink->num_pads); |
| 118 | |
| 119 | link = media_entity_add_link(source); |
| 120 | if (link == NULL) |
| 121 | return -ENOMEM; |
| 122 | |
| 123 | link->source = &source->pads[source_pad]; |
| 124 | link->sink = &sink->pads[sink_pad]; |
| 125 | link->flags = flags; |
| 126 | |
| 127 | /* Create the backlink. Backlinks are used to help graph traversal and |
| 128 | * are not reported to userspace. |
| 129 | */ |
| 130 | backlink = media_entity_add_link(sink); |
| 131 | if (backlink == NULL) { |
| 132 | source->num_links--; |
| 133 | return -ENOMEM; |
| 134 | } |
| 135 | |
| 136 | backlink->source = &source->pads[source_pad]; |
| 137 | backlink->sink = &sink->pads[sink_pad]; |
| 138 | backlink->flags = flags; |
| 139 | |
| 140 | link->reverse = backlink; |
| 141 | backlink->reverse = link; |
| 142 | |
| 143 | sink->num_backlinks++; |
| 144 | |
| 145 | return 0; |
| 146 | } |
| 147 | EXPORT_SYMBOL_GPL(media_entity_create_link); |