[PATCH v3 0/4] Unify MC graph power management code

[PATCH v3 0/4] Unify MC graph power management code

[Sakari Ailus]

Hi folks,

This is the third version of the MC graph power management patches.

v2 can be found here:

<URL:http://www.spinics.net/lists/linux-media/msg96807.html>

since v2:

- Rebase on top of current media-tree.git master branch, including
  dropping the first patch from the set as it was already merged

- Document the added pm_count_walk field in KernelDoc

- Fix a compiler warning in patch "media: Always keep a graph walk large
  enough around" (a GCC bug related to struct value assignment in variable
  declaration)

-- 
Kind regards,
Sakari

[PATCH v3 1/4] media: Always keep a graph walk large enough around

[Sakari Ailus]

From: Sakari Ailus <sakari.ailus@iki.fi>

Re-create the graph walk object as needed in order to have one large enough
available for all entities in the graph.

This enumeration is used for pipeline power management in the future.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/media-device.c | 21 +++++++++++++++++++++
 include/media/media-device.h |  3 +++
 2 files changed, 24 insertions(+)

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 5ebb3cd..c8c1626 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -581,6 +581,26 @@ int __must_check media_device_register_entity(struct media_device *mdev,
 
 	spin_unlock(&mdev->lock);
 
+	mutex_lock(&mdev->graph_mutex);
+	if (mdev->entity_internal_idx_max
+	    >= mdev->pm_count_walk.ent_enum.idx_max) {
+		struct media_entity_graph new = { .top = 0 };
+
+		/*
+		 * Initialise the new graph walk before cleaning up
+		 * the old one in order not to spoil the graph walk
+		 * object of the media device if graph walk init fails.
+		 */
+		ret = media_entity_graph_walk_init(&new, mdev);
+		if (ret) {
+			mutex_unlock(&mdev->graph_mutex);
+			return ret;
+		}
+		media_entity_graph_walk_cleanup(&mdev->pm_count_walk);
+		mdev->pm_count_walk = new;
+	}
+	mutex_unlock(&mdev->graph_mutex);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(media_device_register_entity);
@@ -656,6 +676,7 @@ void media_device_cleanup(struct media_device *mdev)
 {
 	ida_destroy(&mdev->entity_internal_idx);
 	mdev->entity_internal_idx_max = 0;
+	media_entity_graph_walk_cleanup(&mdev->pm_count_walk);
 	mutex_destroy(&mdev->graph_mutex);
 }
 EXPORT_SYMBOL_GPL(media_device_cleanup);
diff --git a/include/media/media-device.h b/include/media/media-device.h
index 165451b..168ccb3 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -289,6 +289,8 @@ struct device;
  * @links:	List of registered links
  * @lock:	Entities list lock
  * @graph_mutex: Entities graph operation lock
+ * @pm_count_walk: Graph walk for power state walk. Access serialised using
+		   graph_mutex.
  * @link_notify: Link state change notification callback
  *
  * This structure represents an abstract high-level media device. It allows easy
@@ -328,6 +330,7 @@ struct media_device {
 	spinlock_t lock;
 	/* Serializes graph operations. */
 	struct mutex graph_mutex;
+	struct media_entity_graph pm_count_walk;
 
 	int (*link_notify)(struct media_link *link, u32 flags,
 			   unsigned int notification);
-- 
2.1.4

[PATCH v3 2/4] v4l: Add generic pipeline power management code

[Sakari Ailus]

From: Sakari Ailus <sakari.ailus@iki.fi>

When the Media controller framework was merged, it was decided not to add
pipeline power management code for it was not seen generic. As a result, a
number of drivers have copied the same piece of code, with same bugfixes
done to them at different points of time (or not at all).

Add these functions to V4L2. Their use is optional for drivers.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/v4l2-core/v4l2-mc.c | 179 +++++++++++++++++++++++++++++++++++++-
 include/media/v4l2-mc.h           |  42 +++++++++
 2 files changed, 220 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-mc.c b/drivers/media/v4l2-core/v4l2-mc.c
index a7f41b3..1a6fda8 100644
--- a/drivers/media/v4l2-core/v4l2-mc.c
+++ b/drivers/media/v4l2-core/v4l2-mc.c
@@ -2,6 +2,8 @@
  * Media Controller ancillary functions
  *
  * (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
@@ -17,9 +19,10 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/usb.h>
+#include <media/media-device.h>
 #include <media/media-entity.h>
 #include <media/v4l2-mc.h>
-
+#include <media/v4l2-subdev.h>
 
 struct media_device *v4l2_mc_pci_media_device_init(struct pci_dev *pci_dev,
 						   const char *name)
@@ -256,3 +259,177 @@ int v4l2_mc_create_media_graph(struct media_device *mdev)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_mc_create_media_graph);
+
+/* -----------------------------------------------------------------------------
+ * 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 79d84bb..3f71b8d 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
@@ -18,6 +20,7 @@
 #define _V4L2_MC_H
 
 #include <media/media-device.h>
+#include <linux/types.h>
 
 /**
  * enum tuner_pad_index - tuner pad index for MEDIA_ENT_F_TUNER
@@ -169,4 +172,43 @@ struct media_device *__v4l2_mc_usb_media_device_init(struct usb_device *udev,
 #define v4l2_mc_usb_media_device_init(udev, name) \
 	__v4l2_mc_usb_media_device_init(udev, name, KBUILD_MODNAME)
 
+/**
+ * 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);
+
+
 #endif
-- 
2.1.4

[PATCH v3 3/4] v4l: omap3isp: Use V4L2 graph PM operations

[Sakari Ailus]

From: Sakari Ailus <sakari.ailus@iki.fi>

Power on devices represented by entities in the graph through the pipeline
state using V4L2 graph PM operations instead of what was in the omap3isp
driver.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/platform/omap3isp/isp.c      | 213 +----------------------------
 drivers/media/platform/omap3isp/isp.h      |   4 -
 drivers/media/platform/omap3isp/ispvideo.c |  13 +-
 drivers/media/platform/omap3isp/ispvideo.h |   1 -
 4 files changed, 6 insertions(+), 225 deletions(-)

diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
index f9e5245..5d54e2c 100644
--- a/drivers/media/platform/omap3isp/isp.c
+++ b/drivers/media/platform/omap3isp/isp.c
@@ -64,6 +64,7 @@
 
 #include <media/v4l2-common.h>
 #include <media/v4l2-device.h>
+#include <media/v4l2-mc.h>
 #include <media/v4l2-of.h>
 
 #include "isp.h"
@@ -657,216 +658,6 @@ static irqreturn_t isp_isr(int irq, void *_isp)
 }
 
 /* -----------------------------------------------------------------------------
- * 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 omap3isp_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.
- */
-
-/*
- * isp_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 isp_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;
-}
-
-/*
- * isp_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 isp_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;
-}
-
-/*
- * isp_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 isp_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 = isp_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))
-			isp_pipeline_pm_power_one(first, -change);
-
-	return ret;
-}
-
-/*
- * omap3isp_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.
- *
- * 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 omap3isp_pipeline_pm_use(struct media_entity *entity, int use,
-			     struct media_entity_graph *graph)
-{
-	int change = use ? 1 : -1;
-	int ret;
-
-	mutex_lock(&entity->graph_obj.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 = isp_pipeline_pm_power(entity, change, graph);
-	if (ret < 0)
-		entity->use_count -= change;
-
-	mutex_unlock(&entity->graph_obj.mdev->graph_mutex);
-
-	return ret;
-}
-
-/*
- * isp_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.
- *
- * 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.
- */
-static int isp_pipeline_link_notify(struct media_link *link, u32 flags,
-				    unsigned int notification)
-{
-	struct media_entity_graph *graph =
-		&container_of(link->graph_obj.mdev, struct isp_device,
-			      media_dev)->pm_count_graph;
-	struct media_entity *source = link->source->entity;
-	struct media_entity *sink = link->sink->entity;
-	int source_use;
-	int sink_use;
-	int ret = 0;
-
-	if (notification == MEDIA_DEV_NOTIFY_PRE_LINK_CH) {
-		ret = media_entity_graph_walk_init(graph,
-						   link->graph_obj.mdev);
-		if (ret)
-			return ret;
-	}
-
-	source_use = isp_pipeline_pm_use_count(source, graph);
-	sink_use = isp_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. */
-		isp_pipeline_pm_power(source, -sink_use, graph);
-		isp_pipeline_pm_power(sink, -source_use, graph);
-		return 0;
-	}
-
-	if (notification == MEDIA_DEV_NOTIFY_PRE_LINK_CH &&
-		(flags & MEDIA_LNK_FL_ENABLED)) {
-
-		ret = isp_pipeline_pm_power(source, sink_use, graph);
-		if (ret < 0)
-			return ret;
-
-		ret = isp_pipeline_pm_power(sink, source_use, graph);
-		if (ret < 0)
-			isp_pipeline_pm_power(source, -sink_use, graph);
-	}
-
-	if (notification == MEDIA_DEV_NOTIFY_POST_LINK_CH)
-		media_entity_graph_walk_cleanup(graph);
-
-	return ret;
-}
-
-/* -----------------------------------------------------------------------------
  * Pipeline stream management
  */
 
@@ -1889,7 +1680,7 @@ static int isp_register_entities(struct isp_device *isp)
 	strlcpy(isp->media_dev.model, "TI OMAP3 ISP",
 		sizeof(isp->media_dev.model));
 	isp->media_dev.hw_revision = isp->revision;
-	isp->media_dev.link_notify = isp_pipeline_link_notify;
+	isp->media_dev.link_notify = v4l2_pipeline_link_notify;
 	media_device_init(&isp->media_dev);
 
 	isp->v4l2_dev.mdev = &isp->media_dev;
diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
index 49b7f71..7e6f663 100644
--- a/drivers/media/platform/omap3isp/isp.h
+++ b/drivers/media/platform/omap3isp/isp.h
@@ -177,7 +177,6 @@ struct isp_device {
 	struct v4l2_device v4l2_dev;
 	struct v4l2_async_notifier notifier;
 	struct media_device media_dev;
-	struct media_entity_graph pm_count_graph;
 	struct device *dev;
 	u32 revision;
 
@@ -267,9 +266,6 @@ void omap3isp_subclk_enable(struct isp_device *isp,
 void omap3isp_subclk_disable(struct isp_device *isp,
 			     enum isp_subclk_resource res);
 
-int omap3isp_pipeline_pm_use(struct media_entity *entity, int use,
-			     struct media_entity_graph *graph);
-
 int omap3isp_register_entities(struct platform_device *pdev,
 			       struct v4l2_device *v4l2_dev);
 void omap3isp_unregister_entities(struct platform_device *pdev);
diff --git a/drivers/media/platform/omap3isp/ispvideo.c b/drivers/media/platform/omap3isp/ispvideo.c
index 2aff755..ac76d29 100644
--- a/drivers/media/platform/omap3isp/ispvideo.c
+++ b/drivers/media/platform/omap3isp/ispvideo.c
@@ -22,8 +22,10 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
+
 #include <media/v4l2-dev.h>
 #include <media/v4l2-ioctl.h>
+#include <media/v4l2-mc.h>
 #include <media/videobuf2-dma-contig.h>
 
 #include "ispvideo.h"
@@ -1292,12 +1294,7 @@ static int isp_video_open(struct file *file)
 		goto done;
 	}
 
-	ret = media_entity_graph_walk_init(&handle->graph,
-					   &video->isp->media_dev);
-	if (ret)
-		goto done;
-
-	ret = omap3isp_pipeline_pm_use(&video->video.entity, 1, &handle->graph);
+	ret = v4l2_pipeline_pm_use(&video->video.entity, 1);
 	if (ret < 0) {
 		omap3isp_put(video->isp);
 		goto done;
@@ -1328,7 +1325,6 @@ static int isp_video_open(struct file *file)
 done:
 	if (ret < 0) {
 		v4l2_fh_del(&handle->vfh);
-		media_entity_graph_walk_cleanup(&handle->graph);
 		kfree(handle);
 	}
 
@@ -1348,8 +1344,7 @@ static int isp_video_release(struct file *file)
 	vb2_queue_release(&handle->queue);
 	mutex_unlock(&video->queue_lock);
 
-	omap3isp_pipeline_pm_use(&video->video.entity, 0, &handle->graph);
-	media_entity_graph_walk_cleanup(&handle->graph);
+	v4l2_pipeline_pm_use(&video->video.entity, 0);
 
 	/* Release the file handle. */
 	v4l2_fh_del(vfh);
diff --git a/drivers/media/platform/omap3isp/ispvideo.h b/drivers/media/platform/omap3isp/ispvideo.h
index 1564298..6a48d58 100644
--- a/drivers/media/platform/omap3isp/ispvideo.h
+++ b/drivers/media/platform/omap3isp/ispvideo.h
@@ -189,7 +189,6 @@ struct isp_video_fh {
 	struct vb2_queue queue;
 	struct v4l2_format format;
 	struct v4l2_fract timeperframe;
-	struct media_entity_graph graph;
 };
 
 #define to_isp_video_fh(fh)	container_of(fh, struct isp_video_fh, vfh)
-- 
2.1.4

[PATCH v3 4/4] staging: v4l: omap4iss: Use V4L2 graph PM operations

[Sakari Ailus]

From: Sakari Ailus <sakari.ailus@iki.fi>

Power on devices represented by entities in the graph through the pipeline
state using V4L2 graph PM operations instead of what was in the omap3isp
driver.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/staging/media/omap4iss/iss.c       | 211 +----------------------------
 drivers/staging/media/omap4iss/iss.h       |   6 +-
 drivers/staging/media/omap4iss/iss_video.c |  15 +-
 drivers/staging/media/omap4iss/iss_video.h |   1 -
 4 files changed, 7 insertions(+), 226 deletions(-)

diff --git a/drivers/staging/media/omap4iss/iss.c b/drivers/staging/media/omap4iss/iss.c
index 30b473c..fb80d2b 100644
--- a/drivers/staging/media/omap4iss/iss.c
+++ b/drivers/staging/media/omap4iss/iss.c
@@ -363,215 +363,6 @@ static irqreturn_t iss_isr(int irq, void *_iss)
 }
 
 /* -----------------------------------------------------------------------------
- * 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 omap4iss_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.
- */
-
-/*
- * iss_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 iss_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;
-}
-
-/*
- * iss_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 iss_pipeline_pm_power_one(struct media_entity *entity, int change)
-{
-	struct v4l2_subdev *subdev;
-
-	subdev = is_media_entity_v4l2_subdev(entity)
-	       ? media_entity_to_v4l2_subdev(entity) : NULL;
-
-	if (entity->use_count == 0 && change > 0 && subdev) {
-		int ret;
-
-		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)
-		v4l2_subdev_call(subdev, core, s_power, 0);
-
-	return 0;
-}
-
-/*
- * iss_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 iss_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 = iss_pipeline_pm_power_one(entity, change);
-
-	if (!ret)
-		return 0;
-
-	media_entity_graph_walk_start(graph, first);
-
-	while ((first = media_entity_graph_walk_next(graph)) &&
-	       first != entity)
-		if (is_media_entity_v4l2_subdev(first))
-			iss_pipeline_pm_power_one(first, -change);
-
-	return ret;
-}
-
-/*
- * omap4iss_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.
- *
- * 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 omap4iss_pipeline_pm_use(struct media_entity *entity, int use,
-			     struct media_entity_graph *graph)
-{
-	int change = use ? 1 : -1;
-	int ret;
-
-	mutex_lock(&entity->graph_obj.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 = iss_pipeline_pm_power(entity, change, graph);
-	if (ret < 0)
-		entity->use_count -= change;
-
-	mutex_unlock(&entity->graph_obj.mdev->graph_mutex);
-
-	return ret;
-}
-
-/*
- * iss_pipeline_link_notify - Link management notification callback
- * @link: The link
- * @flags: New link flags that will be applied
- *
- * 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.
- *
- * 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.
- */
-static int iss_pipeline_link_notify(struct media_link *link, u32 flags,
-				    unsigned int notification)
-{
-	struct media_entity_graph *graph =
-		&container_of(link->graph_obj.mdev, struct iss_device,
-			      media_dev)->pm_count_graph;
-	struct media_entity *source = link->source->entity;
-	struct media_entity *sink = link->sink->entity;
-	int source_use;
-	int sink_use;
-	int ret;
-
-	if (notification == MEDIA_DEV_NOTIFY_PRE_LINK_CH) {
-		ret = media_entity_graph_walk_init(graph,
-						   link->graph_obj.mdev);
-		if (ret)
-			return ret;
-	}
-
-	source_use = iss_pipeline_pm_use_count(source, graph);
-	sink_use = iss_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. */
-		iss_pipeline_pm_power(source, -sink_use, graph);
-		iss_pipeline_pm_power(sink, -source_use, graph);
-		return 0;
-	}
-
-	if (notification == MEDIA_DEV_NOTIFY_PRE_LINK_CH &&
-	    (flags & MEDIA_LNK_FL_ENABLED)) {
-		ret = iss_pipeline_pm_power(source, sink_use, graph);
-		if (ret < 0)
-			return ret;
-
-		ret = iss_pipeline_pm_power(sink, source_use, graph);
-		if (ret < 0)
-			iss_pipeline_pm_power(source, -sink_use, graph);
-	}
-
-	if (notification == MEDIA_DEV_NOTIFY_POST_LINK_CH)
-		media_entity_graph_walk_cleanup(graph);
-
-	return ret;
-}
-
-/* -----------------------------------------------------------------------------
  * Pipeline stream management
  */
 
@@ -1197,7 +988,7 @@ static int iss_register_entities(struct iss_device *iss)
 	strlcpy(iss->media_dev.model, "TI OMAP4 ISS",
 		sizeof(iss->media_dev.model));
 	iss->media_dev.hw_revision = iss->revision;
-	iss->media_dev.link_notify = iss_pipeline_link_notify;
+	iss->media_dev.link_notify = v4l2_pipeline_link_notify;
 	ret = media_device_register(&iss->media_dev);
 	if (ret < 0) {
 		dev_err(iss->dev, "Media device registration failed (%d)\n",
diff --git a/drivers/staging/media/omap4iss/iss.h b/drivers/staging/media/omap4iss/iss.h
index 05f08a3..760ee27 100644
--- a/drivers/staging/media/omap4iss/iss.h
+++ b/drivers/staging/media/omap4iss/iss.h
@@ -15,6 +15,8 @@
 #define _OMAP4_ISS_H_
 
 #include <media/v4l2-device.h>
+#include <media/v4l2-mc.h>
+
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
@@ -87,7 +89,6 @@ struct iss_reg {
 struct iss_device {
 	struct v4l2_device v4l2_dev;
 	struct media_device media_dev;
-	struct media_entity_graph pm_count_graph;
 	struct device *dev;
 	u32 revision;
 
@@ -152,9 +153,6 @@ void omap4iss_isp_subclk_enable(struct iss_device *iss,
 void omap4iss_isp_subclk_disable(struct iss_device *iss,
 				 enum iss_isp_subclk_resource res);
 
-int omap4iss_pipeline_pm_use(struct media_entity *entity, int use,
-			     struct media_entity_graph *graph);
-
 int omap4iss_register_entities(struct platform_device *pdev,
 			       struct v4l2_device *v4l2_dev);
 void omap4iss_unregister_entities(struct platform_device *pdev);
diff --git a/drivers/staging/media/omap4iss/iss_video.c b/drivers/staging/media/omap4iss/iss_video.c
index 058233a..f54349b 100644
--- a/drivers/staging/media/omap4iss/iss_video.c
+++ b/drivers/staging/media/omap4iss/iss_video.c
@@ -19,8 +19,10 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/module.h>
+
 #include <media/v4l2-dev.h>
 #include <media/v4l2-ioctl.h>
+#include <media/v4l2-mc.h>
 
 #include "iss_video.h"
 #include "iss.h"
@@ -1009,13 +1011,7 @@ static int iss_video_open(struct file *file)
 		goto done;
 	}
 
-	ret = media_entity_graph_walk_init(&handle->graph,
-					   &video->iss->media_dev);
-	if (ret)
-		goto done;
-
-	ret = omap4iss_pipeline_pm_use(&video->video.entity, 1,
-				       &handle->graph);
+	ret = v4l2_pipeline_pm_use(&video->video.entity, 1);
 	if (ret < 0) {
 		omap4iss_put(video->iss);
 		goto done;
@@ -1054,7 +1050,6 @@ static int iss_video_open(struct file *file)
 done:
 	if (ret < 0) {
 		v4l2_fh_del(&handle->vfh);
-		media_entity_graph_walk_cleanup(&handle->graph);
 		kfree(handle);
 	}
 
@@ -1070,13 +1065,11 @@ static int iss_video_release(struct file *file)
 	/* Disable streaming and free the buffers queue resources. */
 	iss_video_streamoff(file, vfh, video->type);
 
-	omap4iss_pipeline_pm_use(&video->video.entity, 0, &handle->graph);
+	v4l2_pipeline_pm_use(&video->video.entity, 0);
 
 	/* Release the videobuf2 queue */
 	vb2_queue_release(&handle->queue);
 
-	/* Release the file handle. */
-	media_entity_graph_walk_cleanup(&handle->graph);
 	v4l2_fh_del(vfh);
 	kfree(handle);
 	file->private_data = NULL;
diff --git a/drivers/staging/media/omap4iss/iss_video.h b/drivers/staging/media/omap4iss/iss_video.h
index 34588b7..c8bd295 100644
--- a/drivers/staging/media/omap4iss/iss_video.h
+++ b/drivers/staging/media/omap4iss/iss_video.h
@@ -183,7 +183,6 @@ struct iss_video_fh {
 	struct vb2_queue queue;
 	struct v4l2_format format;
 	struct v4l2_fract timeperframe;
-	struct media_entity_graph graph;
 };
 
 #define to_iss_video_fh(fh)	container_of(fh, struct iss_video_fh, vfh)
-- 
2.1.4