1 /* $NetBSD: drm_wait_netbsd.h,v 1.14 2016/05/13 15:25:57 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #ifndef _DRM_DRM_WAIT_NETBSD_H_ 33 #define _DRM_DRM_WAIT_NETBSD_H_ 34 35 #include <sys/param.h> 36 #include <sys/condvar.h> 37 #include <sys/cpu.h> /* cpu_intr_p */ 38 #include <sys/kernel.h> 39 #include <sys/mutex.h> 40 #include <sys/systm.h> 41 42 #include <linux/mutex.h> 43 #include <linux/spinlock.h> 44 45 typedef kcondvar_t drm_waitqueue_t; 46 47 #define DRM_HZ hz /* XXX Hurk... */ 48 49 #define DRM_UDELAY DELAY 50 51 static inline void 52 DRM_INIT_WAITQUEUE(drm_waitqueue_t *q, const char *name) 53 { 54 cv_init(q, name); 55 } 56 57 static inline void 58 DRM_DESTROY_WAITQUEUE(drm_waitqueue_t *q) 59 { 60 cv_destroy(q); 61 } 62 63 static inline bool 64 DRM_WAITERS_P(drm_waitqueue_t *q, struct mutex *interlock) 65 { 66 KASSERT(mutex_is_locked(interlock)); 67 return cv_has_waiters(q); 68 } 69 70 static inline void 71 DRM_WAKEUP_ONE(drm_waitqueue_t *q, struct mutex *interlock) 72 { 73 KASSERT(mutex_is_locked(interlock)); 74 cv_signal(q); 75 } 76 77 static inline void 78 DRM_WAKEUP_ALL(drm_waitqueue_t *q, struct mutex *interlock) 79 { 80 KASSERT(mutex_is_locked(interlock)); 81 cv_broadcast(q); 82 } 83 84 static inline bool 85 DRM_SPIN_WAITERS_P(drm_waitqueue_t *q, spinlock_t *interlock) 86 { 87 KASSERT(spin_is_locked(interlock)); 88 return cv_has_waiters(q); 89 } 90 91 static inline void 92 DRM_SPIN_WAKEUP_ONE(drm_waitqueue_t *q, spinlock_t *interlock) 93 { 94 KASSERT(spin_is_locked(interlock)); 95 cv_signal(q); 96 } 97 98 static inline void 99 DRM_SPIN_WAKEUP_ALL(drm_waitqueue_t *q, spinlock_t *interlock) 100 { 101 KASSERT(spin_is_locked(interlock)); 102 cv_broadcast(q); 103 } 104 105 /* 106 * DRM_SPIN_WAIT_ON is a replacement for the legacy DRM_WAIT_ON 107 * portability macro. It requires a spin interlock, which may require 108 * changes to the surrounding code so that the waits actually are 109 * interlocked by a spin lock. It also polls the condition at every 110 * tick, which masks missing wakeups. Since DRM_WAIT_ON is going away, 111 * in favour of Linux's native wait_event* API, waits in new code 112 * should be written to use the DRM_*WAIT*_UNTIL macros below. 113 * 114 * Like the legacy DRM_WAIT_ON, DRM_SPIN_WAIT_ON returns 115 * 116 * . -EBUSY if timed out (yes, -EBUSY, not -ETIMEDOUT or -EWOULDBLOCK), 117 * . -EINTR/-ERESTART if interrupted by a signal, or 118 * . 0 if the condition was true before or just after the timeout. 119 * 120 * Note that cv_timedwait* return -EWOULDBLOCK, not -EBUSY, on timeout. 121 */ 122 123 #define DRM_SPIN_WAIT_ON(RET, Q, INTERLOCK, TICKS, CONDITION) do \ 124 { \ 125 unsigned _dswo_ticks = (TICKS); \ 126 unsigned _dswo_start, _dswo_end; \ 127 \ 128 KASSERT(spin_is_locked((INTERLOCK))); \ 129 KASSERT(!cpu_intr_p()); \ 130 KASSERT(!cpu_softintr_p()); \ 131 KASSERT(!cold); \ 132 \ 133 for (;;) { \ 134 if (CONDITION) { \ 135 (RET) = 0; \ 136 break; \ 137 } \ 138 if (_dswo_ticks == 0) { \ 139 (RET) = -EBUSY; /* Match Linux... */ \ 140 break; \ 141 } \ 142 _dswo_start = hardclock_ticks; \ 143 /* XXX errno NetBSD->Linux */ \ 144 (RET) = -cv_timedwait_sig((Q), &(INTERLOCK)->sl_lock, 1); \ 145 _dswo_end = hardclock_ticks; \ 146 if (_dswo_end - _dswo_start < _dswo_ticks) \ 147 _dswo_ticks -= _dswo_end - _dswo_start; \ 148 else \ 149 _dswo_ticks = 0; \ 150 if (RET) { \ 151 if ((RET) == -EWOULDBLOCK) \ 152 /* Waited only one tick. */ \ 153 continue; \ 154 break; \ 155 } \ 156 } \ 157 } while (0) 158 159 /* 160 * The DRM_*WAIT*_UNTIL macros are replacements for the Linux 161 * wait_event* macros. Like DRM_SPIN_WAIT_ON, they add an interlock, 162 * and so may require some changes to the surrounding code. They have 163 * a different return value convention from DRM_SPIN_WAIT_ON and a 164 * different return value convention from cv_*wait*. 165 * 166 * The untimed DRM_*WAIT*_UNTIL macros return 167 * 168 * . -EINTR/-ERESTART if interrupted by a signal, or 169 * . zero if the condition evaluated 170 * 171 * The timed DRM_*TIMED_WAIT*_UNTIL macros return 172 * 173 * . -EINTR/-ERESTART if interrupted by a signal, 174 * . 0 if the condition was false after the timeout, 175 * . 1 if the condition was true just after the timeout, or 176 * . the number of ticks remaining if the condition was true before the 177 * timeout. 178 * 179 * Contrast DRM_SPIN_WAIT_ON which returns -EINTR/-ERESTART on signal, 180 * -EBUSY on timeout, and zero on success; and cv_*wait*, which return 181 * -EINTR/-ERESTART on signal, -EWOULDBLOCK on timeout, and zero on 182 * success. 183 * 184 * XXX In retrospect, giving the timed and untimed macros a different 185 * return convention from one another to match Linux may have been a 186 * bad idea. All of this inconsistent timeout return convention logic 187 * has been a consistent source of bugs. 188 */ 189 190 #define _DRM_WAIT_UNTIL(RET, WAIT, Q, INTERLOCK, CONDITION) do \ 191 { \ 192 KASSERT(mutex_is_locked((INTERLOCK))); \ 193 ASSERT_SLEEPABLE(); \ 194 KASSERT(!cold); \ 195 for (;;) { \ 196 if (CONDITION) { \ 197 (RET) = 0; \ 198 break; \ 199 } \ 200 /* XXX errno NetBSD->Linux */ \ 201 (RET) = -WAIT((Q), &(INTERLOCK)->mtx_lock); \ 202 if (RET) \ 203 break; \ 204 } \ 205 } while (0) 206 207 #define cv_wait_nointr(Q, I) (cv_wait((Q), (I)), 0) 208 209 #define DRM_WAIT_NOINTR_UNTIL(RET, Q, I, C) \ 210 _DRM_WAIT_UNTIL(RET, cv_wait_nointr, Q, I, C) 211 212 #define DRM_WAIT_UNTIL(RET, Q, I, C) \ 213 _DRM_WAIT_UNTIL(RET, cv_wait_sig, Q, I, C) 214 215 #define _DRM_TIMED_WAIT_UNTIL(RET, WAIT, Q, INTERLOCK, TICKS, CONDITION) do \ 216 { \ 217 unsigned _dtwu_ticks = (TICKS); \ 218 unsigned _dtwu_start, _dtwu_end; \ 219 \ 220 KASSERT(mutex_is_locked((INTERLOCK))); \ 221 ASSERT_SLEEPABLE(); \ 222 KASSERT(!cold); \ 223 \ 224 for (;;) { \ 225 if (CONDITION) { \ 226 (RET) = MAX(_dtwu_ticks, 1); \ 227 break; \ 228 } \ 229 if (_dtwu_ticks == 0) { \ 230 (RET) = 0; \ 231 break; \ 232 } \ 233 _dtwu_start = hardclock_ticks; \ 234 /* XXX errno NetBSD->Linux */ \ 235 (RET) = -WAIT((Q), &(INTERLOCK)->mtx_lock, \ 236 MIN(_dtwu_ticks, INT_MAX/2)); \ 237 _dtwu_end = hardclock_ticks; \ 238 if ((_dtwu_end - _dtwu_start) < _dtwu_ticks) \ 239 _dtwu_ticks -= _dtwu_end - _dtwu_start; \ 240 else \ 241 _dtwu_ticks = 0; \ 242 if (RET) { \ 243 if ((RET) == -EWOULDBLOCK) \ 244 (RET) = (CONDITION) ? 1 : 0; \ 245 break; \ 246 } \ 247 } \ 248 } while (0) 249 250 #define DRM_TIMED_WAIT_NOINTR_UNTIL(RET, Q, I, T, C) \ 251 _DRM_TIMED_WAIT_UNTIL(RET, cv_timedwait, Q, I, T, C) 252 253 #define DRM_TIMED_WAIT_UNTIL(RET, Q, I, T, C) \ 254 _DRM_TIMED_WAIT_UNTIL(RET, cv_timedwait_sig, Q, I, T, C) 255 256 /* 257 * XXX Can't assert sleepable here because we hold a spin lock. At 258 * least we can assert that we're not in (soft) interrupt context, and 259 * hope that nobody tries to use these with a sometimes quickly 260 * satisfied condition while holding a different spin lock. 261 */ 262 263 #define _DRM_SPIN_WAIT_UNTIL(RET, WAIT, Q, INTERLOCK, CONDITION) do \ 264 { \ 265 KASSERT(spin_is_locked((INTERLOCK))); \ 266 KASSERT(!cpu_intr_p()); \ 267 KASSERT(!cpu_softintr_p()); \ 268 KASSERT(!cold); \ 269 (RET) = 0; \ 270 while (!(CONDITION)) { \ 271 /* XXX errno NetBSD->Linux */ \ 272 (RET) = -WAIT((Q), &(INTERLOCK)->sl_lock); \ 273 if (RET) \ 274 break; \ 275 } \ 276 } while (0) 277 278 #define DRM_SPIN_WAIT_NOINTR_UNTIL(RET, Q, I, C) \ 279 _DRM_SPIN_WAIT_UNTIL(RET, cv_wait_nointr, Q, I, C) 280 281 #define DRM_SPIN_WAIT_UNTIL(RET, Q, I, C) \ 282 _DRM_SPIN_WAIT_UNTIL(RET, cv_wait_sig, Q, I, C) 283 284 #define _DRM_SPIN_TIMED_WAIT_UNTIL(RET, WAIT, Q, INTERLOCK, TICKS, CONDITION) \ 285 do \ 286 { \ 287 unsigned _dstwu_ticks = (TICKS); \ 288 unsigned _dstwu_start, _dstwu_end; \ 289 \ 290 KASSERT(spin_is_locked((INTERLOCK))); \ 291 KASSERT(!cpu_intr_p()); \ 292 KASSERT(!cpu_softintr_p()); \ 293 KASSERT(!cold); \ 294 \ 295 for (;;) { \ 296 if (CONDITION) { \ 297 (RET) = MAX(_dstwu_ticks, 1); \ 298 break; \ 299 } \ 300 if (_dstwu_ticks == 0) { \ 301 (RET) = 0; \ 302 break; \ 303 } \ 304 _dstwu_start = hardclock_ticks; \ 305 /* XXX errno NetBSD->Linux */ \ 306 (RET) = -WAIT((Q), &(INTERLOCK)->sl_lock, \ 307 MIN(_dstwu_ticks, INT_MAX/2)); \ 308 _dstwu_end = hardclock_ticks; \ 309 if ((_dstwu_end - _dstwu_start) < _dstwu_ticks) \ 310 _dstwu_ticks -= _dstwu_end - _dstwu_start; \ 311 else \ 312 _dstwu_ticks = 0; \ 313 if (RET) { \ 314 if ((RET) == -EWOULDBLOCK) \ 315 (RET) = (CONDITION) ? 1 : 0; \ 316 break; \ 317 } \ 318 } \ 319 } while (0) 320 321 #define DRM_SPIN_TIMED_WAIT_NOINTR_UNTIL(RET, Q, I, T, C) \ 322 _DRM_SPIN_TIMED_WAIT_UNTIL(RET, cv_timedwait, Q, I, T, C) 323 324 #define DRM_SPIN_TIMED_WAIT_UNTIL(RET, Q, I, T, C) \ 325 _DRM_SPIN_TIMED_WAIT_UNTIL(RET, cv_timedwait_sig, Q, I, T, C) 326 327 #endif /* _DRM_DRM_WAIT_NETBSD_H_ */ 328