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
45typedef kcondvar_t drm_waitqueue_t;
46
47#define DRM_HZ hz /* XXX Hurk... */
48
49#define DRM_UDELAY DELAY
50
51static inline void
52DRM_INIT_WAITQUEUE(drm_waitqueue_t *q, const char *name)
53{
54 cv_init(q, name);
55}
56
57static inline void
58DRM_DESTROY_WAITQUEUE(drm_waitqueue_t *q)
59{
60 cv_destroy(q);
61}
62
63static inline bool
64DRM_WAITERS_P(drm_waitqueue_t *q, struct mutex *interlock)
65{
66 KASSERT(mutex_is_locked(interlock));
67 return cv_has_waiters(q);
68}
69
70static inline void
71DRM_WAKEUP_ONE(drm_waitqueue_t *q, struct mutex *interlock)
72{
73 KASSERT(mutex_is_locked(interlock));
74 cv_signal(q);
75}
76
77static inline void
78DRM_WAKEUP_ALL(drm_waitqueue_t *q, struct mutex *interlock)
79{
80 KASSERT(mutex_is_locked(interlock));
81 cv_broadcast(q);
82}
83
84static inline bool
85DRM_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
91static inline void
92DRM_SPIN_WAKEUP_ONE(drm_waitqueue_t *q, spinlock_t *interlock)
93{
94 KASSERT(spin_is_locked(interlock));
95 cv_signal(q);
96}
97
98static inline void
99DRM_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