1 /************************************************************************** 2 * 3 * Copyright (c) 2007-2009 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 /* $FreeBSD$ */ 31 32 /** @file ttm_lock.h 33 * This file implements a simple replacement for the buffer manager use 34 * of the DRM heavyweight hardware lock. 35 * The lock is a read-write lock. Taking it in read mode and write mode 36 * is relatively fast, and intended for in-kernel use only. 37 * 38 * The vt mode is used only when there is a need to block all 39 * user-space processes from validating buffers. 40 * It's allowed to leave kernel space with the vt lock held. 41 * If a user-space process dies while having the vt-lock, 42 * it will be released during the file descriptor release. The vt lock 43 * excludes write lock and read lock. 44 * 45 * The suspend mode is used to lock out all TTM users when preparing for 46 * and executing suspend operations. 47 * 48 */ 49 50 #ifndef _TTM_LOCK_H_ 51 #define _TTM_LOCK_H_ 52 53 #include <dev/drm2/drmP.h> 54 #include <dev/drm2/drm.h> 55 #include <dev/drm2/ttm/ttm_object.h> 56 57 /** 58 * struct ttm_lock 59 * 60 * @base: ttm base object used solely to release the lock if the client 61 * holding the lock dies. 62 * @queue: Queue for processes waiting for lock change-of-status. 63 * @lock: Spinlock protecting some lock members. 64 * @rw: Read-write lock counter. Protected by @lock. 65 * @flags: Lock state. Protected by @lock. 66 * @kill_takers: Boolean whether to kill takers of the lock. 67 * @signal: Signal to send when kill_takers is true. 68 */ 69 70 struct ttm_lock { 71 struct ttm_base_object base; 72 struct mtx lock; 73 int32_t rw; 74 uint32_t flags; 75 bool kill_takers; 76 int signal; 77 struct ttm_object_file *vt_holder; 78 }; 79 80 81 /** 82 * ttm_lock_init 83 * 84 * @lock: Pointer to a struct ttm_lock 85 * Initializes the lock. 86 */ 87 extern void ttm_lock_init(struct ttm_lock *lock); 88 89 /** 90 * ttm_read_unlock 91 * 92 * @lock: Pointer to a struct ttm_lock 93 * 94 * Releases a read lock. 95 */ 96 extern void ttm_read_unlock(struct ttm_lock *lock); 97 98 /** 99 * ttm_read_lock 100 * 101 * @lock: Pointer to a struct ttm_lock 102 * @interruptible: Interruptible sleeping while waiting for a lock. 103 * 104 * Takes the lock in read mode. 105 * Returns: 106 * -ERESTARTSYS If interrupted by a signal and interruptible is true. 107 */ 108 extern int ttm_read_lock(struct ttm_lock *lock, bool interruptible); 109 110 /** 111 * ttm_read_trylock 112 * 113 * @lock: Pointer to a struct ttm_lock 114 * @interruptible: Interruptible sleeping while waiting for a lock. 115 * 116 * Tries to take the lock in read mode. If the lock is already held 117 * in write mode, the function will return -EBUSY. If the lock is held 118 * in vt or suspend mode, the function will sleep until these modes 119 * are unlocked. 120 * 121 * Returns: 122 * -EBUSY The lock was already held in write mode. 123 * -ERESTARTSYS If interrupted by a signal and interruptible is true. 124 */ 125 extern int ttm_read_trylock(struct ttm_lock *lock, bool interruptible); 126 127 /** 128 * ttm_lock_downgrade 129 * 130 * @lock: Pointer to a struct ttm_lock 131 * 132 * Downgrades a write lock to a read lock. 133 */ 134 extern void ttm_lock_downgrade(struct ttm_lock *lock); 135 136 /** 137 * ttm_suspend_lock 138 * 139 * @lock: Pointer to a struct ttm_lock 140 * 141 * Takes the lock in suspend mode. Excludes read and write mode. 142 */ 143 extern void ttm_suspend_lock(struct ttm_lock *lock); 144 145 /** 146 * ttm_suspend_unlock 147 * 148 * @lock: Pointer to a struct ttm_lock 149 * 150 * Releases a suspend lock 151 */ 152 extern void ttm_suspend_unlock(struct ttm_lock *lock); 153 154 /** 155 * ttm_vt_lock 156 * 157 * @lock: Pointer to a struct ttm_lock 158 * @interruptible: Interruptible sleeping while waiting for a lock. 159 * @tfile: Pointer to a struct ttm_object_file to register the lock with. 160 * 161 * Takes the lock in vt mode. 162 * Returns: 163 * -ERESTARTSYS If interrupted by a signal and interruptible is true. 164 * -ENOMEM: Out of memory when locking. 165 */ 166 extern int ttm_vt_lock(struct ttm_lock *lock, bool interruptible, 167 struct ttm_object_file *tfile); 168 169 /** 170 * ttm_vt_unlock 171 * 172 * @lock: Pointer to a struct ttm_lock 173 * 174 * Releases a vt lock. 175 * Returns: 176 * -EINVAL If the lock was not held. 177 */ 178 extern int ttm_vt_unlock(struct ttm_lock *lock); 179 180 /** 181 * ttm_write_unlock 182 * 183 * @lock: Pointer to a struct ttm_lock 184 * 185 * Releases a write lock. 186 */ 187 extern void ttm_write_unlock(struct ttm_lock *lock); 188 189 /** 190 * ttm_write_lock 191 * 192 * @lock: Pointer to a struct ttm_lock 193 * @interruptible: Interruptible sleeping while waiting for a lock. 194 * 195 * Takes the lock in write mode. 196 * Returns: 197 * -ERESTARTSYS If interrupted by a signal and interruptible is true. 198 */ 199 extern int ttm_write_lock(struct ttm_lock *lock, bool interruptible); 200 201 void ttm_write_lock_downgrade(struct ttm_lock *lock); 202 203 /** 204 * ttm_lock_set_kill 205 * 206 * @lock: Pointer to a struct ttm_lock 207 * @val: Boolean whether to kill processes taking the lock. 208 * @signal: Signal to send to the process taking the lock. 209 * 210 * The kill-when-taking-lock functionality is used to kill processes that keep 211 * on using the TTM functionality when its resources has been taken down, for 212 * example when the X server exits. A typical sequence would look like this: 213 * - X server takes lock in write mode. 214 * - ttm_lock_set_kill() is called with @val set to true. 215 * - As part of X server exit, TTM resources are taken down. 216 * - X server releases the lock on file release. 217 * - Another dri client wants to render, takes the lock and is killed. 218 * 219 */ 220 static inline void ttm_lock_set_kill(struct ttm_lock *lock, bool val, 221 int signal) 222 { 223 lock->kill_takers = val; 224 if (val) 225 lock->signal = signal; 226 } 227 228 #endif 229