xref: /netbsd-src/sys/external/bsd/drm2/dist/include/drm/drm_vblank.h (revision 20b3eca72a814c21590ad0dff56efb261ebd9323)
1 /*	$NetBSD: drm_vblank.h,v 1.12 2021/12/20 12:56:07 riastradh Exp $	*/
2 
3 /*
4  * Copyright 2016 Intel Corp.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the next
14  * paragraph) shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23  * OTHER DEALINGS IN THE SOFTWARE.
24  */
25 
26 #ifndef _DRM_VBLANK_H_
27 #define _DRM_VBLANK_H_
28 
29 #ifdef __NetBSD__
30 #include <sys/types.h>
31 #include <sys/file.h>
32 #define	pipe	pipe_drmhack	/* see intel_display.h */
33 #endif
34 
35 #include <linux/seqlock.h>
36 #include <linux/idr.h>
37 #include <linux/poll.h>
38 #include <linux/timer.h>
39 #include <linux/ktime.h>
40 
41 #include <drm/drm_file.h>
42 #include <drm/drm_modes.h>
43 
44 #ifdef __NetBSD__		/* XXX */
45 #include <drm/drm_wait_netbsd.h>
46 #endif
47 
48 struct drm_device;
49 struct drm_crtc;
50 
51 /**
52  * struct drm_pending_vblank_event - pending vblank event tracking
53  */
54 struct drm_pending_vblank_event {
55 	/**
56 	 * @base: Base structure for tracking pending DRM events.
57 	 */
58 	struct drm_pending_event base;
59 	/**
60 	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
61 	 */
62 	unsigned int pipe;
63 	/**
64 	 * @sequence: frame event should be triggered at
65 	 */
66 	u64 sequence;
67 	/**
68 	 * @event: Actual event which will be sent to userspace.
69 	 */
70 	union {
71 		/**
72 		 * @event.base: DRM event base class.
73 		 */
74 		struct drm_event base;
75 
76 		/**
77 		 * @event.vbl:
78 		 *
79 		 * Event payload for vblank events, requested through
80 		 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
81 		 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
82 		 * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
83 		 */
84 		struct drm_event_vblank vbl;
85 
86 		/**
87 		 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
88 		 */
89 		struct drm_event_crtc_sequence seq;
90 	} event;
91 };
92 
93 /**
94  * struct drm_vblank_crtc - vblank tracking for a CRTC
95  *
96  * This structure tracks the vblank state for one CRTC.
97  *
98  * Note that for historical reasons - the vblank handling code is still shared
99  * with legacy/non-kms drivers - this is a free-standing structure not directly
100  * connected to &struct drm_crtc. But all public interface functions are taking
101  * a &struct drm_crtc to hide this implementation detail.
102  */
103 struct drm_vblank_crtc {
104 	/**
105 	 * @dev: Pointer to the &drm_device.
106 	 */
107 	struct drm_device *dev;
108 	/**
109 	 * @queue: Wait queue for vblank waiters.
110 	 */
111 	drm_waitqueue_t queue;
112 	/**
113 	 * @disable_timer: Disable timer for the delayed vblank disabling
114 	 * hysteresis logic. Vblank disabling is controlled through the
115 	 * drm_vblank_offdelay module option and the setting of the
116 	 * &drm_device.max_vblank_count value.
117 	 */
118 	struct timer_list disable_timer;
119 
120 	/**
121 	 * @seqlock: Protect vblank count and time.
122 	 */
123 	seqlock_t seqlock;
124 
125 	/**
126 	 * @count:
127 	 *
128 	 * Current software vblank counter.
129 	 *
130 	 * Note that for a given vblank counter value drm_crtc_handle_vblank()
131 	 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
132 	 * provide a barrier: Any writes done before calling
133 	 * drm_crtc_handle_vblank() will be visible to callers of the later
134 	 * functions, iff the vblank count is the same or a later one.
135 	 *
136 	 * IMPORTANT: This guarantee requires barriers, therefor never access
137 	 * this field directly. Use drm_crtc_vblank_count() instead.
138 	 */
139 	atomic64_t count;
140 	/**
141 	 * @time: Vblank timestamp corresponding to @count.
142 	 */
143 	ktime_t time;
144 
145 	/**
146 	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
147 	 * this refcount reaches 0 can the hardware interrupt be disabled using
148 	 * @disable_timer.
149 	 */
150 	atomic_t refcount;
151 	/**
152 	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
153 	 */
154 	u32 last;
155 	/**
156 	 * @max_vblank_count:
157 	 *
158 	 * Maximum value of the vblank registers for this crtc. This value +1
159 	 * will result in a wrap-around of the vblank register. It is used
160 	 * by the vblank core to handle wrap-arounds.
161 	 *
162 	 * If set to zero the vblank core will try to guess the elapsed vblanks
163 	 * between times when the vblank interrupt is disabled through
164 	 * high-precision timestamps. That approach is suffering from small
165 	 * races and imprecision over longer time periods, hence exposing a
166 	 * hardware vblank counter is always recommended.
167 	 *
168 	 * This is the runtime configurable per-crtc maximum set through
169 	 * drm_crtc_set_max_vblank_count(). If this is used the driver
170 	 * must leave the device wide &drm_device.max_vblank_count at zero.
171 	 *
172 	 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
173 	 */
174 	u32 max_vblank_count;
175 	/**
176 	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
177 	 * For legacy driver bit 2 additionally tracks whether an additional
178 	 * temporary vblank reference has been acquired to paper over the
179 	 * hardware counter resetting/jumping. KMS drivers should instead just
180 	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
181 	 * save and restore the vblank count.
182 	 */
183 	unsigned int inmodeset;
184 	/**
185 	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
186 	 * structure.
187 	 */
188 	unsigned int pipe;
189 	/**
190 	 * @framedur_ns: Frame/Field duration in ns, used by
191 	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
192 	 * drm_calc_timestamping_constants().
193 	 */
194 	int framedur_ns;
195 	/**
196 	 * @linedur_ns: Line duration in ns, used by
197 	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
198 	 * drm_calc_timestamping_constants().
199 	 */
200 	int linedur_ns;
201 
202 	/**
203 	 * @hwmode:
204 	 *
205 	 * Cache of the current hardware display mode. Only valid when @enabled
206 	 * is set. This is used by helpers like
207 	 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
208 	 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
209 	 * because that one is really hard to get from interrupt context.
210 	 */
211 	struct drm_display_mode hwmode;
212 
213 	/**
214 	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
215 	 * avoid double-disabling and hence corrupting saved state. Needed by
216 	 * drivers not using atomic KMS, since those might go through their CRTC
217 	 * disabling functions multiple times.
218 	 */
219 	bool enabled;
220 };
221 
222 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
223 u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
224 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
225 				   ktime_t *vblanktime);
226 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
227 			       struct drm_pending_vblank_event *e);
228 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
229 			      struct drm_pending_vblank_event *e);
230 void drm_vblank_set_event(struct drm_pending_vblank_event *e,
231 			  u64 *seq,
232 			  ktime_t *now);
233 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
234 bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
235 int drm_crtc_vblank_get(struct drm_crtc *crtc);
236 int drm_crtc_vblank_get_locked(struct drm_crtc *crtc);
237 void drm_crtc_vblank_put(struct drm_crtc *crtc);
238 void drm_crtc_vblank_put_locked(struct drm_crtc *crtc);
239 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
240 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
241 void drm_crtc_vblank_off(struct drm_crtc *crtc);
242 void drm_crtc_vblank_reset(struct drm_crtc *crtc);
243 void drm_crtc_vblank_on(struct drm_crtc *crtc);
244 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
245 void drm_vblank_restore(struct drm_device *dev, unsigned int pipe);
246 void drm_crtc_vblank_restore(struct drm_crtc *crtc);
247 
248 bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
249 					   unsigned int pipe, int *max_error,
250 					   ktime_t *vblank_time,
251 					   bool in_vblank_irq);
252 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
253 				     const struct drm_display_mode *mode);
254 drm_waitqueue_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
255 void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
256 				   u32 max_vblank_count);
257 #endif
258