1 /* 2 * Copyright 2009 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 #include "drmP.h" 41 42 int 43 drm_lock_take(drm_lock_data_t *lock_data, unsigned int context) 44 { 45 unsigned int old, new; 46 volatile unsigned int *lock = &lock_data->hw_lock->lock; 47 48 do { 49 old = *lock; 50 if (old & _DRM_LOCK_HELD) 51 new = old | _DRM_LOCK_CONT; 52 else 53 new = context | _DRM_LOCK_HELD; 54 } while (!atomic_cmpset_int(lock, old, new)); 55 56 if (_DRM_LOCKING_CONTEXT(old) == context) { 57 if (old & _DRM_LOCK_HELD) { 58 if (context != DRM_KERNEL_CONTEXT) { 59 DRM_ERROR("%d holds heavyweight lock\n", 60 context); 61 } 62 return (0); 63 } 64 } 65 if (new == (context | _DRM_LOCK_HELD)) { 66 /* Have lock */ 67 return (1); 68 } 69 return (0); 70 } 71 72 /* 73 * This takes a lock forcibly and hands it to context. Should ONLY be used 74 * inside *_unlock to give lock to kernel before calling *_dma_schedule. 75 */ 76 int 77 drm_lock_transfer(drm_device_t *dev, drm_lock_data_t *lock_data, 78 unsigned int context) 79 { 80 unsigned int old, new; 81 volatile unsigned int *lock = &lock_data->hw_lock->lock; 82 83 dev->lock.filp = NULL; 84 do { 85 old = *lock; 86 new = context | _DRM_LOCK_HELD; 87 } while (!atomic_cmpset_int(lock, old, new)); 88 89 return (1); 90 } 91 92 int 93 drm_lock_free(drm_device_t *dev, volatile unsigned int *lock, 94 unsigned int context) 95 { 96 unsigned int old, new; 97 98 mutex_enter(&(dev->lock.lock_mutex)); 99 dev->lock.filp = NULL; 100 do { 101 old = *lock; 102 new = 0; 103 } while (!atomic_cmpset_int(lock, old, new)); 104 105 if (_DRM_LOCK_IS_HELD(old) && 106 (_DRM_LOCKING_CONTEXT(old) != context)) { 107 DRM_ERROR("%d freed heavyweight lock held by %d\n", 108 context, _DRM_LOCKING_CONTEXT(old)); 109 mutex_exit(&(dev->lock.lock_mutex)); 110 return (1); 111 } 112 cv_broadcast(&(dev->lock.lock_cv)); 113 mutex_exit(&(dev->lock.lock_mutex)); 114 return (0); 115 } 116 117 /*ARGSUSED*/ 118 int 119 drm_lock(DRM_IOCTL_ARGS) 120 { 121 DRM_DEVICE; 122 drm_lock_t lock; 123 int ret = 0; 124 125 DRM_COPYFROM_WITH_RETURN(&lock, (void *)data, sizeof (lock)); 126 127 if (lock.context == DRM_KERNEL_CONTEXT) { 128 DRM_ERROR("Process %d using kernel context %d\n", 129 DRM_CURRENTPID, lock.context); 130 return (EINVAL); 131 } 132 133 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", 134 lock.context, DRM_CURRENTPID, dev->lock.hw_lock->lock, 135 lock.flags); 136 if (dev->driver->use_dma_queue && lock.context < 0) 137 return (EINVAL); 138 139 mutex_enter(&(dev->lock.lock_mutex)); 140 for (;;) { 141 if (drm_lock_take(&dev->lock, lock.context)) { 142 dev->lock.filp = fpriv; 143 dev->lock.lock_time = jiffies; 144 break; /* Got lock */ 145 } 146 ret = cv_wait_sig(&(dev->lock.lock_cv), 147 &(dev->lock.lock_mutex)); 148 149 if (ret == 0) { 150 mutex_exit(&(dev->lock.lock_mutex)); 151 return (EINTR); 152 } 153 } 154 mutex_exit(&(dev->lock.lock_mutex)); 155 DRM_DEBUG("%d %s\n", lock.context, ret ? "interrupted" : "has lock"); 156 157 if (dev->driver->dma_quiescent != NULL && 158 (lock.flags & _DRM_LOCK_QUIESCENT)) 159 dev->driver->dma_quiescent(dev); 160 161 return (0); 162 } 163 164 /*ARGSUSED*/ 165 int 166 drm_unlock(DRM_IOCTL_ARGS) 167 { 168 DRM_DEVICE; 169 drm_lock_t lock; 170 171 DRM_COPYFROM_WITH_RETURN(&lock, (void *)data, sizeof (lock)); 172 173 DRM_DEBUG("%d (pid %d) requests unlock (0x%08x), flags = 0x%08x\n", 174 lock.context, DRM_CURRENTPID, dev->lock.hw_lock->lock, 175 lock.flags); 176 177 if (lock.context == DRM_KERNEL_CONTEXT) { 178 DRM_ERROR("Process %d using kernel context %d\n", 179 DRM_CURRENTPID, lock.context); 180 return (EINVAL); 181 } 182 atomic_inc_32(&dev->counts[_DRM_STAT_UNLOCKS]); 183 184 DRM_LOCK(); 185 if (drm_lock_free(dev, &dev->lock.hw_lock->lock, lock.context)) { 186 DRM_ERROR("drm_unlock\n"); 187 } 188 DRM_UNLOCK(); 189 return (0); 190 } 191