reservation: add support for fences to enable cross-device synchronisation

 * Copyright (C) 2012 Texas Instruments

 *

 * Authors:

 * Rob Clark <rob.clark@linaro.org>

 * Rob Clark <robdclark@gmail.com>

 * Maarten Lankhorst <maarten.lankhorst@canonical.com>

 * Thomas Hellstrom <thellstrom-at-vmware-dot-com>

 *

#define _LINUX_RESERVATION_H

#include <linux/ww_mutex.h>

#include <linux/fence.h>

#include <linux/slab.h>

extern struct ww_class reservation_ww_class;

struct reservation_object {

	struct ww_mutex lock;

	struct fence *fence_excl;

	struct fence **fence_shared;

	u32 fence_shared_count, fence_shared_max;

};

static inline void

reservation_object_init(struct reservation_object *obj)

{

	ww_mutex_init(&obj->lock, &reservation_ww_class);

	obj->fence_shared_count = obj->fence_shared_max = 0;

	obj->fence_shared = NULL;

	obj->fence_excl = NULL;

}

static inline void

reservation_object_fini(struct reservation_object *obj)

{

	int i;

	if (obj->fence_excl)

		fence_put(obj->fence_excl);

	for (i = 0; i < obj->fence_shared_count; ++i)

		fence_put(obj->fence_shared[i]);

	kfree(obj->fence_shared);

	ww_mutex_destroy(&obj->lock);

}