1 /* 2 * Copyright 2008 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_take(drm_lock_data_t *lock_data, unsigned int context) 46 { 47 unsigned int old, new, prev; 48 volatile unsigned int *lock = &lock_data->hw_lock->lock; 49 50 do { 51 old = *lock; 52 if (old & _DRM_LOCK_HELD) 53 new = old | _DRM_LOCK_CONT; 54 else 55 new = context | _DRM_LOCK_HELD; 56 prev = atomic_cas_uint(lock, old, new); 57 } while (prev != old); 58 59 if (_DRM_LOCKING_CONTEXT(old) == context) { 60 if (old & _DRM_LOCK_HELD) { 61 if (context != DRM_KERNEL_CONTEXT) { 62 DRM_ERROR("%d holds heavyweight lock\n", 63 context); 64 } 65 return (0); 66 } 67 } 68 if ((_DRM_LOCKING_CONTEXT(new)) == context && 69 _DRM_LOCK_IS_HELD(new)) { 70 /* Have lock */ 71 return (1); 72 } 73 return (0); 74 } 75 76 /* 77 * This takes a lock forcibly and hands it to context. Should ONLY be used 78 * inside *_unlock to give lock to kernel before calling *_dma_schedule. 79 */ 80 int 81 drm_lock_transfer(drm_device_t *dev, volatile unsigned int *lock, 82 unsigned int context) 83 { 84 unsigned int old, new, prev; 85 86 dev->lock.filp = NULL; 87 do { 88 old = *lock; 89 new = context | _DRM_LOCK_HELD; 90 prev = atomic_cas_uint(lock, old, new); 91 } while (prev != old); 92 93 return (1); 94 } 95 96 int 97 drm_lock_free(drm_device_t *dev, volatile unsigned int *lock, 98 unsigned int context) 99 { 100 unsigned int old, new, prev; 101 102 mutex_enter(&(dev->lock.lock_mutex)); 103 dev->lock.filp = NULL; 104 do { 105 old = *lock; 106 new = 0; 107 prev = atomic_cas_uint(lock, old, new); 108 } while (prev != old); 109 110 if (_DRM_LOCK_IS_HELD(old) && 111 (_DRM_LOCKING_CONTEXT(old) != context)) { 112 DRM_ERROR("%d freed heavyweight lock held by %d\n", 113 context, _DRM_LOCKING_CONTEXT(old)); 114 mutex_exit(&(dev->lock.lock_mutex)); 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_COPYFROM_WITH_RETURN(&lock, (void *)data, sizeof (lock)); 131 132 if (lock.context == DRM_KERNEL_CONTEXT) { 133 return (EINVAL); 134 } 135 136 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)); 155 156 if (dev->driver->dma_quiescent != NULL && 157 (lock.flags & _DRM_LOCK_QUIESCENT)) 158 dev->driver->dma_quiescent(dev); 159 160 return (0); 161 } 162 163 /*ARGSUSED*/ 164 int 165 drm_unlock(DRM_IOCTL_ARGS) 166 { 167 DRM_DEVICE; 168 drm_lock_t lock; 169 170 DRM_COPYFROM_WITH_RETURN(&lock, (void *)data, sizeof (lock)); 171 172 if (lock.context == DRM_KERNEL_CONTEXT) { 173 DRM_ERROR("Process %d using kernel context %d\n", 174 DRM_CURRENTPID, lock.context); 175 return (EINVAL); 176 } 177 atomic_inc_32(&dev->counts[_DRM_STAT_UNLOCKS]); 178 179 DRM_LOCK(); 180 if (drm_lock_free(dev, &dev->lock.hw_lock->lock, lock.context)) { 181 DRM_ERROR("drm_unlock\n"); 182 } 183 DRM_UNLOCK(); 184 return (0); 185 } 186