1/* lock.c -- IOCTLs for locking -*- linux-c -*-
2 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
3 */
4/*-
5 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
6 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
7 * All Rights Reserved.
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice (including the next
17 * paragraph) shall be included in all copies or substantial portions of the
18 * Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
24 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
25 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
26 * OTHER DEALINGS IN THE SOFTWARE.
27 *
28 * Authors:
29 * Rickard E. (Rik) Faith <faith@valinux.com>
30 * Gareth Hughes <gareth@valinux.com>
31 *
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32 * $FreeBSD: head/sys/dev/drm/drm_lock.c 145132 2005-04-16 03:44:47Z anholt $
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32 */
33
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34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: head/sys/dev/drm/drm_lock.c 152909 2005-11-28 23:13:57Z anholt $");
36 |
37#include "dev/drm/drmP.h"
38
39int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context)
40{
41 unsigned int old, new;
42
43 do {
44 old = *lock;
45 if (old & _DRM_LOCK_HELD) new = old | _DRM_LOCK_CONT;
46 else new = context | _DRM_LOCK_HELD;
47 } while (!atomic_cmpset_int(lock, old, new));
48
49 if (_DRM_LOCKING_CONTEXT(old) == context) {
50 if (old & _DRM_LOCK_HELD) {
51 if (context != DRM_KERNEL_CONTEXT) {
52 DRM_ERROR("%d holds heavyweight lock\n",
53 context);
54 }
55 return 0;
56 }
57 }
58 if (new == (context | _DRM_LOCK_HELD)) {
59 /* Have lock */
60 return 1;
61 }
62 return 0;
63}
64
65/* This takes a lock forcibly and hands it to context. Should ONLY be used
66 inside *_unlock to give lock to kernel before calling *_dma_schedule. */
67int drm_lock_transfer(drm_device_t *dev,
68 __volatile__ unsigned int *lock, unsigned int context)
69{
70 unsigned int old, new;
71
72 dev->lock.filp = NULL;
73 do {
74 old = *lock;
75 new = context | _DRM_LOCK_HELD;
76 } while (!atomic_cmpset_int(lock, old, new));
77
78 return 1;
79}
80
81int drm_lock_free(drm_device_t *dev,
82 __volatile__ unsigned int *lock, unsigned int context)
83{
84 unsigned int old, new;
85
86 dev->lock.filp = NULL;
87 do {
88 old = *lock;
89 new = 0;
90 } while (!atomic_cmpset_int(lock, old, new));
91
92 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
93 DRM_ERROR("%d freed heavyweight lock held by %d\n",
94 context, _DRM_LOCKING_CONTEXT(old));
95 return 1;
96 }
97 DRM_WAKEUP_INT((void *)&dev->lock.lock_queue);
98 return 0;
99}
100
101int drm_lock(DRM_IOCTL_ARGS)
102{
103 DRM_DEVICE;
104 drm_lock_t lock;
105 int ret = 0;
106
107 DRM_COPY_FROM_USER_IOCTL(lock, (drm_lock_t *)data, sizeof(lock));
108
109 if (lock.context == DRM_KERNEL_CONTEXT) {
110 DRM_ERROR("Process %d using kernel context %d\n",
111 DRM_CURRENTPID, lock.context);
112 return EINVAL;
113 }
114
115 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
116 lock.context, DRM_CURRENTPID, dev->lock.hw_lock->lock, lock.flags);
117
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116 if (dev->use_dma_queue && lock.context < 0)
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| 118 if (dev->driver.use_dma_queue && lock.context < 0) |
119 return EINVAL;
120
121 DRM_LOCK();
122 for (;;) {
123 if (drm_lock_take(&dev->lock.hw_lock->lock, lock.context)) {
124 dev->lock.filp = (void *)(uintptr_t)DRM_CURRENTPID;
125 dev->lock.lock_time = jiffies;
126 atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
127 break; /* Got lock */
128 }
129
130 /* Contention */
131#if defined(__FreeBSD__) && __FreeBSD_version > 500000
132 ret = msleep((void *)&dev->lock.lock_queue, &dev->dev_lock,
133 PZERO | PCATCH, "drmlk2", 0);
134#else
135 ret = tsleep((void *)&dev->lock.lock_queue, PZERO | PCATCH,
136 "drmlk2", 0);
137#endif
138 if (ret != 0)
139 break;
140 }
141 DRM_UNLOCK();
142 DRM_DEBUG("%d %s\n", lock.context, ret ? "interrupted" : "has lock");
143
144 if (ret != 0)
145 return ret;
146
147 /* XXX: Add signal blocking here */
148
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147 if (dev->dma_quiescent != NULL && (lock.flags & _DRM_LOCK_QUIESCENT))
148 dev->dma_quiescent(dev);
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149 if (dev->driver.dma_quiescent != NULL &&
150 (lock.flags & _DRM_LOCK_QUIESCENT))
151 dev->driver.dma_quiescent(dev); |
152
153 return 0;
154}
155
156int drm_unlock(DRM_IOCTL_ARGS)
157{
158 DRM_DEVICE;
159 drm_lock_t lock;
160
161 DRM_COPY_FROM_USER_IOCTL(lock, (drm_lock_t *)data, sizeof(lock));
162
163 if (lock.context == DRM_KERNEL_CONTEXT) {
164 DRM_ERROR("Process %d using kernel context %d\n",
165 DRM_CURRENTPID, lock.context);
166 return EINVAL;
167 }
168
169 atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
170
171 DRM_LOCK();
172 drm_lock_transfer(dev, &dev->lock.hw_lock->lock, DRM_KERNEL_CONTEXT);
173
174 if (drm_lock_free(dev, &dev->lock.hw_lock->lock, DRM_KERNEL_CONTEXT)) {
175 DRM_ERROR("\n");
176 }
177 DRM_UNLOCK();
178
179 return 0;
180}
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