1/**************************************************************************
2 *
3 * Copyright 2008-2009 VMware, Inc., Palo Alto, CA., USA
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27/*
28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29 */
30
31#include <linux/mutex.h>
32#include <linux/slab.h>
33#include <linux/module.h>
34#include <drm/drm_global.h>
35
36struct drm_global_item {
37	struct mutex mutex;
38	void *object;
39	int refcount;
40};
41
42static struct drm_global_item glob[DRM_GLOBAL_NUM];
43
44void drm_global_init(void)
45{
46	int i;
47
48	for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
49		struct drm_global_item *item = &glob[i];
50		mutex_init(&item->mutex);
51		item->object = NULL;
52		item->refcount = 0;
53	}
54}
55
56void drm_global_release(void)
57{
58	int i;
59	for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
60		struct drm_global_item *item = &glob[i];
61		BUG_ON(item->object != NULL);
62		BUG_ON(item->refcount != 0);
63	}
64}
65
66int drm_global_item_ref(struct drm_global_reference *ref)
67{
68	int ret;
69	struct drm_global_item *item = &glob[ref->global_type];
70
71	mutex_lock(&item->mutex);
72	if (item->refcount == 0) {
73		item->object = kzalloc(ref->size, GFP_KERNEL);
74		if (unlikely(item->object == NULL)) {
75			ret = -ENOMEM;
76			goto out_err;
77		}
78
79		ref->object = item->object;
80		ret = ref->init(ref);
81		if (unlikely(ret != 0))
82			goto out_err;
83
84	}
85	++item->refcount;
86	ref->object = item->object;
87	mutex_unlock(&item->mutex);
88	return 0;
89out_err:
90	mutex_unlock(&item->mutex);
91	item->object = NULL;
92	return ret;
93}
94EXPORT_SYMBOL(drm_global_item_ref);
95
96void drm_global_item_unref(struct drm_global_reference *ref)
97{
98	struct drm_global_item *item = &glob[ref->global_type];
99
100	mutex_lock(&item->mutex);
101	BUG_ON(item->refcount == 0);
102	BUG_ON(ref->object != item->object);
103	if (--item->refcount == 0) {
104		ref->release(ref);
105		item->object = NULL;
106	}
107	mutex_unlock(&item->mutex);
108}
109EXPORT_SYMBOL(drm_global_item_unref);
110
111