drivers/staging/android/sync.h

/*
 * include/linux/sync.h
 *
 * Copyright (C) 2012 Google, Inc.
 *
 * 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.
 *
 */

#ifndef _LINUX_SYNC_H
#define _LINUX_SYNC_H

#include <linux/types.h>
#include <linux/kref.h>
#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/fence.h>

#include <linux/sync_file.h>
#include <uapi/linux/sync_file.h>

struct sync_timeline;

/**
 * struct sync_timeline_ops - sync object implementation ops
 * @driver_name:	name of the implementation
 * @has_signaled:	returns:
 *			  1 if pt has signaled
 *			  0 if pt has not signaled
 *			 <0 on error
 * @timeline_value_str: fill str with the value of the sync_timeline's counter
 * @fence_value_str:	fill str with the value of the fence
 */
struct sync_timeline_ops {
	const char *driver_name;

	/* required */
	int (*has_signaled)(struct fence *fence);

	/* optional */
	void (*timeline_value_str)(struct sync_timeline *timeline, char *str,
				   int size);

	/* optional */
	void (*fence_value_str)(struct fence *fence, char *str, int size);
};

/**
 * struct sync_timeline - sync object
 * @kref:		reference count on fence.
 * @ops:		ops that define the implementation of the sync_timeline
 * @name:		name of the sync_timeline. Useful for debugging
 * @destroyed:		set when sync_timeline is destroyed
 * @child_list_head:	list of children sync_pts for this sync_timeline
 * @child_list_lock:	lock protecting @child_list_head, destroyed, and
 *			fence.status
 * @active_list_head:	list of active (unsignaled/errored) sync_pts
 * @sync_timeline_list:	membership in global sync_timeline_list
 */
struct sync_timeline {
	struct kref		kref;
	const struct sync_timeline_ops	*ops;
	char			name[32];

	/* protected by child_list_lock */
	bool			destroyed;
	int			context, value;

	struct list_head	child_list_head;
	spinlock_t		child_list_lock;

	struct list_head	active_list_head;

#ifdef CONFIG_DEBUG_FS
	struct list_head	sync_timeline_list;
#endif
};

static inline struct sync_timeline *fence_parent(struct fence *fence)
{
	return container_of(fence->lock, struct sync_timeline,
			    child_list_lock);
}

/*
 * API for sync_timeline implementers
 */

/**
 * sync_timeline_create() - creates a sync object
 * @ops:	specifies the implementation ops for the object
 * @size:	size to allocate for this obj
 * @name:	sync_timeline name
 *
 * Creates a new sync_timeline which will use the implementation specified by
 * @ops.  @size bytes will be allocated allowing for implementation specific
 * data to be kept after the generic sync_timeline struct. Returns the
 * sync_timeline object or NULL in case of error.
 */
struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
					   int size, const char *name);

/**
 * sync_timeline_destroy() - destroys a sync object
 * @obj:	sync_timeline to destroy
 *
 * A sync implementation should call this when the @obj is going away
 * (i.e. module unload.)  @obj won't actually be freed until all its children
 * fences are freed.
 */
void sync_timeline_destroy(struct sync_timeline *obj);

/**
 * sync_timeline_signal() - signal a status change on a sync_timeline
 * @obj:	sync_timeline to signal
 *
 * A sync implementation should call this any time one of it's fences
 * has signaled or has an error condition.
 */
void sync_timeline_signal(struct sync_timeline *obj);

/**
 * sync_pt_create() - creates a sync pt
 * @parent:	fence's parent sync_timeline
 * @size:	size to allocate for this pt
 *
 * Creates a new fence as a child of @parent.  @size bytes will be
 * allocated allowing for implementation specific data to be kept after
 * the generic sync_timeline struct. Returns the fence object or
 * NULL in case of error.
 */
struct fence *sync_pt_create(struct sync_timeline *parent, int size);

#ifdef CONFIG_DEBUG_FS

void sync_timeline_debug_add(struct sync_timeline *obj);
void sync_timeline_debug_remove(struct sync_timeline *obj);
void sync_file_debug_add(struct sync_file *fence);
void sync_file_debug_remove(struct sync_file *fence);
void sync_dump(void);

#else
# define sync_timeline_debug_add(obj)
# define sync_timeline_debug_remove(obj)
# define sync_file_debug_add(fence)
# define sync_file_debug_remove(fence)
# define sync_dump()
#endif

#endif /* _LINUX_SYNC_H */