[media] media: Add an API to manage entity enumerations

[deliverable/linux.git] / drivers / media / media-entity.c

diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index 13c8ca11f169ef0a96346bb61a7b83f8fe4359ef..5e3f32f631876f832e2dbb625ba36067489d39e8 100644 (file)
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -70,6 +70,46 @@ static inline const char *intf_type(struct media_interface *intf)
        }
 };
 
+/**
+ * __media_entity_enum_init - Initialise an entity enumeration
+ *
+ * @ent_enum: Entity enumeration to be initialised
+ * @idx_max: Maximum number of entities in the enumeration
+ *
+ * Returns zero on success or a negative error code.
+ */
+__must_check int __media_entity_enum_init(struct media_entity_enum *ent_enum,
+                                         int idx_max)
+{
+       if (idx_max > MEDIA_ENTITY_ENUM_MAX_ID) {
+               ent_enum->bmap = kcalloc(DIV_ROUND_UP(idx_max, BITS_PER_LONG),
+                                        sizeof(long), GFP_KERNEL);
+               if (!ent_enum->bmap)
+                       return -ENOMEM;
+       } else {
+               ent_enum->bmap = ent_enum->prealloc_bmap;
+       }
+
+       bitmap_zero(ent_enum->bmap, idx_max);
+       ent_enum->idx_max = idx_max;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(__media_entity_enum_init);
+
+/**
+ * media_entity_enum_cleanup - Release resources of an entity enumeration
+ *
+ * @e: Entity enumeration to be released
+ */
+void media_entity_enum_cleanup(struct media_entity_enum *ent_enum)
+{
+       if (ent_enum->bmap != ent_enum->prealloc_bmap)
+               kfree(ent_enum->bmap);
+       ent_enum->bmap = NULL;
+}
+EXPORT_SYMBOL_GPL(media_entity_enum_cleanup);
+
 /**
  *  dev_dbg_obj - Prints in debug mode a change on some object
  *