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 <linux/kernel.h>
35#include <linux/export.h>
36#include <asm/bug.h>
37#include <drm/drm_global.h>
38
39struct drm_global_item {
40 struct mutex mutex;
41 void *object;
42 int refcount;
43};
44
45static struct drm_global_item glob[DRM_GLOBAL_NUM];
46
47void drm_global_init(void)
48{
49 int i;
50
51 for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
52 struct drm_global_item *item = &glob[i];
53#ifdef __NetBSD__
54 linux_mutex_init(&item->mutex);
55#else
56 mutex_init(&item->mutex);
57#endif
58 item->object = NULL;
59 item->refcount = 0;
60 }
61}
62
63void drm_global_release(void)
64{
65 int i;
66 for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
67 struct drm_global_item *item = &glob[i];
68 (void)item; /* ignore */
69 BUG_ON(item->object != NULL);
70 BUG_ON(item->refcount != 0);
71 }
72}
73
74int drm_global_item_ref(struct drm_global_reference *ref)
75{
76 int ret;
77 struct drm_global_item *item = &glob[ref->global_type];
78
79 mutex_lock(&item->mutex);
80 if (item->refcount == 0) {
81 item->object = kzalloc(ref->size, GFP_KERNEL);
82 if (unlikely(item->object == NULL)) {
83 ret = -ENOMEM;
84 goto out_err;
85 }
86
87 ref->object = item->object;
88 ret = ref->init(ref);
89 if (unlikely(ret != 0))
90 goto out_err;
91
92 }
93 ++item->refcount;
94 ref->object = item->object;
95 mutex_unlock(&item->mutex);
96 return 0;
97out_err:
98 mutex_unlock(&item->mutex);
99 item->object = NULL;
100 return ret;
101}
102EXPORT_SYMBOL(drm_global_item_ref);
103
104void drm_global_item_unref(struct drm_global_reference *ref)
105{
106 struct drm_global_item *item = &glob[ref->global_type];
107
108 mutex_lock(&item->mutex);
109 BUG_ON(item->refcount == 0);
110 BUG_ON(ref->object != item->object);
111 if (--item->refcount == 0) {
112 ref->release(ref);
113 item->object = NULL;
114 }
115 mutex_unlock(&item->mutex);
116}
117EXPORT_SYMBOL(drm_global_item_unref);
118
119