diff options
| -rw-r--r-- | drivers/media/v4l2-core/v4l2-mc.c | 183 | ||||
| -rw-r--r-- | include/media/v4l2-mc.h | 43 |
2 files changed, 224 insertions, 2 deletions
diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c index 621d2367363c..7291018cf1bf 100644 --- a/drivers/media/v4l2-core/v4l2-mc.c +++ b/drivers/media/v4l2-core/v4l2-mc.c @@ -3,6 +3,8 @@ * * Copyright (c) 2016 Mauro Carvalho Chehab <mchehab@osg.samsung.com> * Copyright (C) 2016 Shuah Khan <shuahkh@osg.samsung.com> + * Copyright (C) 2006-2010 Nokia Corporation + * Copyright (c) 2016 Intel Corporation. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -16,10 +18,15 @@ */ #include <linux/module.h> -#include <media/media-entity.h> +#include <linux/pci.h> +#include <linux/usb.h> #include <media/media-device.h> +#include <media/media-entity.h> #include <media/v4l2-fh.h> #include <media/v4l2-mc.h> +#include <media/v4l2-subdev.h> +#include <media/media-device.h> +#include <media/v4l2-mc.h> #include <media/videobuf2-core.h> int v4l2_mc_create_media_graph(struct media_device *mdev) @@ -236,3 +243,177 @@ int v4l_vb2q_enable_media_source(struct vb2_queue *q) return v4l_enable_media_source(fh->vdev); } EXPORT_SYMBOL_GPL(v4l_vb2q_enable_media_source); + +/* ----------------------------------------------------------------------------- + * Pipeline power management + * + * Entities must be powered up when part of a pipeline that contains at least + * one open video device node. + * + * To achieve this use the entity use_count field to track the number of users. + * For entities corresponding to video device nodes the use_count field stores + * the users count of the node. For entities corresponding to subdevs the + * use_count field stores the total number of users of all video device nodes + * in the pipeline. + * + * The v4l2_pipeline_pm_use() function must be called in the open() and + * close() handlers of video device nodes. It increments or decrements the use + * count of all subdev entities in the pipeline. + * + * To react to link management on powered pipelines, the link setup notification + * callback updates the use count of all entities in the source and sink sides + * of the link. + */ + +/* + * pipeline_pm_use_count - Count the number of users of a pipeline + * @entity: The entity + * + * Return the total number of users of all video device nodes in the pipeline. + */ +static int pipeline_pm_use_count(struct media_entity *entity, + struct media_entity_graph *graph) +{ + int use = 0; + + media_entity_graph_walk_start(graph, entity); + + while ((entity = media_entity_graph_walk_next(graph))) { + if (is_media_entity_v4l2_io(entity)) + use += entity->use_count; + } + + return use; +} + +/* + * pipeline_pm_power_one - Apply power change to an entity + * @entity: The entity + * @change: Use count change + * + * Change the entity use count by @change. If the entity is a subdev update its + * power state by calling the core::s_power operation when the use count goes + * from 0 to != 0 or from != 0 to 0. + * + * Return 0 on success or a negative error code on failure. + */ +static int pipeline_pm_power_one(struct media_entity *entity, int change) +{ + struct v4l2_subdev *subdev; + int ret; + + subdev = is_media_entity_v4l2_subdev(entity) + ? media_entity_to_v4l2_subdev(entity) : NULL; + + if (entity->use_count == 0 && change > 0 && subdev != NULL) { + ret = v4l2_subdev_call(subdev, core, s_power, 1); + if (ret < 0 && ret != -ENOIOCTLCMD) + return ret; + } + + entity->use_count += change; + WARN_ON(entity->use_count < 0); + + if (entity->use_count == 0 && change < 0 && subdev != NULL) + v4l2_subdev_call(subdev, core, s_power, 0); + + return 0; +} + +/* + * pipeline_pm_power - Apply power change to all entities in a pipeline + * @entity: The entity + * @change: Use count change + * + * Walk the pipeline to update the use count and the power state of all non-node + * entities. + * + * Return 0 on success or a negative error code on failure. + */ +static int pipeline_pm_power(struct media_entity *entity, int change, + struct media_entity_graph *graph) +{ + struct media_entity *first = entity; + int ret = 0; + + if (!change) + return 0; + + media_entity_graph_walk_start(graph, entity); + + while (!ret && (entity = media_entity_graph_walk_next(graph))) + if (is_media_entity_v4l2_subdev(entity)) + ret = pipeline_pm_power_one(entity, change); + + if (!ret) + return ret; + + media_entity_graph_walk_start(graph, first); + + while ((first = media_entity_graph_walk_next(graph)) + && first != entity) + if (is_media_entity_v4l2_subdev(first)) + pipeline_pm_power_one(first, -change); + + return ret; +} + +int v4l2_pipeline_pm_use(struct media_entity *entity, int use) +{ + struct media_device *mdev = entity->graph_obj.mdev; + int change = use ? 1 : -1; + int ret; + + mutex_lock(&mdev->graph_mutex); + + /* Apply use count to node. */ + entity->use_count += change; + WARN_ON(entity->use_count < 0); + + /* Apply power change to connected non-nodes. */ + ret = pipeline_pm_power(entity, change, &mdev->pm_count_walk); + if (ret < 0) + entity->use_count -= change; + + mutex_unlock(&mdev->graph_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(v4l2_pipeline_pm_use); + +int v4l2_pipeline_link_notify(struct media_link *link, u32 flags, + unsigned int notification) +{ + struct media_entity_graph *graph = &link->graph_obj.mdev->pm_count_walk; + struct media_entity *source = link->source->entity; + struct media_entity *sink = link->sink->entity; + int source_use; + int sink_use; + int ret = 0; + + source_use = pipeline_pm_use_count(source, graph); + sink_use = pipeline_pm_use_count(sink, graph); + + if (notification == MEDIA_DEV_NOTIFY_POST_LINK_CH && + !(flags & MEDIA_LNK_FL_ENABLED)) { + /* Powering off entities is assumed to never fail. */ + pipeline_pm_power(source, -sink_use, graph); + pipeline_pm_power(sink, -source_use, graph); + return 0; + } + + if (notification == MEDIA_DEV_NOTIFY_PRE_LINK_CH && + (flags & MEDIA_LNK_FL_ENABLED)) { + + ret = pipeline_pm_power(source, sink_use, graph); + if (ret < 0) + return ret; + + ret = pipeline_pm_power(sink, source_use, graph); + if (ret < 0) + pipeline_pm_power(source, -sink_use, graph); + } + + return ret; +} +EXPORT_SYMBOL_GPL(v4l2_pipeline_link_notify); diff --git a/include/media/v4l2-mc.h b/include/media/v4l2-mc.h index f9477b88014d..406f845034b9 100644 --- a/include/media/v4l2-mc.h +++ b/include/media/v4l2-mc.h @@ -2,6 +2,8 @@ * v4l2-mc.h - Media Controller V4L2 types and prototypes * * Copyright (C) 2016 Mauro Carvalho Chehab <mchehab@osg.samsung.com> + * Copyright (C) 2006-2010 Nokia Corporation + * Copyright (c) 2016 Intel Corporation. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -19,6 +21,7 @@ #include <media/media-device.h> #include <media/v4l2-dev.h> +#include <linux/types.h> /** * enum tuner_pad_index - tuner pad index for MEDIA_ENT_F_TUNER @@ -165,6 +168,45 @@ void v4l_disable_media_source(struct video_device *vdev); */ int v4l_vb2q_enable_media_source(struct vb2_queue *q); + +/** + * v4l2_pipeline_pm_use - Update the use count of an entity + * @entity: The entity + * @use: Use (1) or stop using (0) the entity + * + * Update the use count of all entities in the pipeline and power entities on or + * off accordingly. + * + * This function is intended to be called in video node open (use == + * 1) and release (use == 0). It uses struct media_entity.use_count to + * track the power status. The use of this function should be paired + * with v4l2_pipeline_link_notify(). + * + * Return 0 on success or a negative error code on failure. Powering entities + * off is assumed to never fail. No failure can occur when the use parameter is + * set to 0. + */ +int v4l2_pipeline_pm_use(struct media_entity *entity, int use); + + +/** + * v4l2_pipeline_link_notify - Link management notification callback + * @link: The link + * @flags: New link flags that will be applied + * @notification: The link's state change notification type (MEDIA_DEV_NOTIFY_*) + * + * React to link management on powered pipelines by updating the use count of + * all entities in the source and sink sides of the link. Entities are powered + * on or off accordingly. The use of this function should be paired + * with v4l2_pipeline_pm_use(). + * + * Return 0 on success or a negative error code on failure. Powering entities + * off is assumed to never fail. This function will not fail for disconnection + * events. + */ +int v4l2_pipeline_link_notify(struct media_link *link, u32 flags, + unsigned int notification); + #else static inline int v4l2_mc_create_media_graph(struct media_device *mdev) @@ -186,6 +228,5 @@ static int v4l_vb2q_enable_media_source(struct vb2_queue *q) { return 0; } - #endif #endif /* _V4L2_MC_H */ |