1 /* 2 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 /* 7 * lock.c -- IOCTLs for locking -*- linux-c -*- 8 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com 9 */ 10 /* 11 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas. 12 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California. 13 * All Rights Reserved. 14 * 15 * Permission is hereby granted, free of charge, to any person obtaining a 16 * copy of this software and associated documentation files (the "Software"), 17 * to deal in the Software without restriction, including without limitation 18 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 19 * and/or sell copies of the Software, and to permit persons to whom the 20 * Software is furnished to do so, subject to the following conditions: 21 * 22 * The above copyright notice and this permission notice (including the next 23 * paragraph) shall be included in all copies or substantial portions of the 24 * Software. 25 * 26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 29 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 30 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 31 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 32 * OTHER DEALINGS IN THE SOFTWARE. 33 * 34 * Authors: 35 * Rickard E. (Rik) Faith <faith@valinux.com> 36 * Gareth Hughes <gareth@valinux.com> 37 * 38 */ 39 40 #pragma ident "%Z%%M% %I% %E% SMI" 41 42 #include "drmP.h" 43 44 int 45 drm_lock_held(void *info) 46 { 47 __volatile__ unsigned int *lock; 48 49 lock = (__volatile__ unsigned int *)info; 50 return (_DRM_LOCK_IS_HELD(*lock)); 51 } 52 53 int 54 drm_lock_take(__volatile__ unsigned int *lock, unsigned int context) 55 { 56 unsigned int old, new; 57 58 do { 59 old = *lock; 60 if (old & _DRM_LOCK_HELD) new = old | _DRM_LOCK_CONT; 61 else new = context | _DRM_LOCK_HELD; 62 } while (!atomic_cmpset_int(lock, old, new)); 63 64 if (_DRM_LOCKING_CONTEXT(old) == context) { 65 if (old & _DRM_LOCK_HELD) { 66 if (context != DRM_KERNEL_CONTEXT) { 67 DRM_ERROR("%d holds heavyweight lock\n", 68 context); 69 } 70 return (0); 71 } 72 } 73 if (new == (context | _DRM_LOCK_HELD)) { 74 /* Have lock */ 75 return (1); 76 } 77 return (0); 78 } 79 80 /* 81 * This takes a lock forcibly and hands it to context. Should ONLY be used 82 * inside *_unlock to give lock to kernel before calling *_dma_schedule. 83 */ 84 int 85 drm_lock_transfer(drm_device_t *dev, __volatile__ unsigned int *lock, 86 unsigned int context) 87 { 88 unsigned int old, new; 89 90 dev->lock.filp = NULL; 91 do { 92 old = *lock; 93 new = context | _DRM_LOCK_HELD; 94 } while (!atomic_cmpset_int(lock, old, new)); 95 96 return (1); 97 } 98 99 int 100 drm_lock_free(drm_device_t *dev, __volatile__ unsigned int *lock, 101 unsigned int context) 102 { 103 unsigned int old, new; 104 105 mutex_enter(&(dev->lock.lock_mutex)); 106 dev->lock.filp = NULL; 107 do { 108 old = *lock; 109 new = 0; 110 } while (!atomic_cmpset_int(lock, old, new)); 111 112 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { 113 DRM_ERROR("%d freed heavyweight lock held by %d\n", 114 context, _DRM_LOCKING_CONTEXT(old)); 115 return (1); 116 } 117 cv_broadcast(&(dev->lock.lock_cv)); 118 mutex_exit(&(dev->lock.lock_mutex)); 119 return (0); 120 } 121 122 /*ARGSUSED*/ 123 int 124 drm_lock(DRM_IOCTL_ARGS) 125 { 126 DRM_DEVICE; 127 drm_lock_t lock; 128 int ret = 0; 129 130 DRM_COPY_FROM_USER_IOCTL(lock, (drm_lock_t *)data, sizeof (lock)); 131 132 if (lock.context == DRM_KERNEL_CONTEXT) { 133 return (DRM_ERR(EINVAL)); 134 } 135 136 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", 137 lock.context, DRM_CURRENTPID, dev->lock.hw_lock->lock, lock.flags); 138 139 if (dev->use_dma_queue && lock.context < 0) 140 return (DRM_ERR(EINVAL)); 141 142 mutex_enter(&(dev->lock.lock_mutex)); 143 DRM_DEBUG("mutex enter\n"); 144 for (;;) { 145 if (drm_lock_take(&dev->lock.hw_lock->lock, lock.context)) { 146 DRM_DEBUG("drm_lock_take enter\n"); 147 dev->lock.filp = (void *)(uintptr_t)DRM_CURRENTPID; 148 dev->lock.lock_time = jiffies; 149 atomic_inc_32(&dev->counts[_DRM_STAT_LOCKS]); 150 break; /* Got lock */ 151 } 152 DRM_DEBUG("Drm_lock: cv_wait\n"); 153 ret = cv_wait_sig(&(dev->lock.lock_cv), 154 &(dev->lock.lock_mutex)); 155 156 if (ret == 0) { 157 mutex_exit(&(dev->lock.lock_mutex)); 158 return (-1); 159 } 160 } 161 DRM_DEBUG("before mutex_exit\n"); 162 mutex_exit(&(dev->lock.lock_mutex)); 163 DRM_DEBUG("drm_lock: %d %s\n", lock.context, 164 ret ? "interrupted" : "has lock"); 165 166 if (dev->dma_quiescent != NULL && 167 (lock.flags & _DRM_LOCK_QUIESCENT)) 168 dev->dma_quiescent(dev); 169 170 return (0); 171 } 172 173 /*ARGSUSED*/ 174 int 175 drm_unlock(DRM_IOCTL_ARGS) 176 { 177 DRM_DEVICE; 178 drm_lock_t lock; 179 180 DRM_COPY_FROM_USER_IOCTL(lock, (drm_lock_t *)data, sizeof (lock)); 181 182 if (lock.context == DRM_KERNEL_CONTEXT) { 183 DRM_ERROR("Process %d using kernel context %d\n", 184 DRM_CURRENTPID, lock.context); 185 return (DRM_ERR(EINVAL)); 186 } 187 188 atomic_inc_32(&dev->counts[_DRM_STAT_UNLOCKS]); 189 190 DRM_LOCK(); 191 (void) drm_lock_transfer(dev, &dev->lock.hw_lock->lock, 192 DRM_KERNEL_CONTEXT); 193 194 if (drm_lock_free(dev, &dev->lock.hw_lock->lock, DRM_KERNEL_CONTEXT)) { 195 DRM_ERROR("drm_unlock\n"); 196 } 197 DRM_UNLOCK(); 198 199 return (0); 200 } 201