1 /*
2 * Copyright 2016 Intel Corp.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21 * OTHER DEALINGS IN THE SOFTWARE.
22 */
23
24 #ifndef _DRM_VBLANK_H_
25 #define _DRM_VBLANK_H_
26
27 #include <linux/seqlock.h>
28 #include <linux/idr.h>
29 #include <linux/poll.h>
30 #include <linux/kthread.h>
31
32 #include <drm/drm_file.h>
33 #include <drm/drm_modes.h>
34
35 struct drm_device;
36 struct drm_crtc;
37 struct drm_vblank_work;
38
39 /**
40 * struct drm_pending_vblank_event - pending vblank event tracking
41 */
42 struct drm_pending_vblank_event {
43 /**
44 * @base: Base structure for tracking pending DRM events.
45 */
46 struct drm_pending_event base;
47 /**
48 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
49 */
50 unsigned int pipe;
51 /**
52 * @sequence: frame event should be triggered at
53 */
54 u64 sequence;
55 /**
56 * @event: Actual event which will be sent to userspace.
57 */
58 union {
59 /**
60 * @event.base: DRM event base class.
61 */
62 struct drm_event base;
63
64 /**
65 * @event.vbl:
66 *
67 * Event payload for vblank events, requested through
68 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
69 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
70 * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
71 */
72 struct drm_event_vblank vbl;
73
74 /**
75 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
76 */
77 struct drm_event_crtc_sequence seq;
78 } event;
79 };
80
81 /**
82 * struct drm_vblank_crtc - vblank tracking for a CRTC
83 *
84 * This structure tracks the vblank state for one CRTC.
85 *
86 * Note that for historical reasons - the vblank handling code is still shared
87 * with legacy/non-kms drivers - this is a free-standing structure not directly
88 * connected to &struct drm_crtc. But all public interface functions are taking
89 * a &struct drm_crtc to hide this implementation detail.
90 */
91 struct drm_vblank_crtc {
92 /**
93 * @dev: Pointer to the &drm_device.
94 */
95 struct drm_device *dev;
96 /**
97 * @queue: Wait queue for vblank waiters.
98 */
99 wait_queue_head_t queue;
100 /**
101 * @disable_timer: Disable timer for the delayed vblank disabling
102 * hysteresis logic. Vblank disabling is controlled through the
103 * drm_vblank_offdelay module option and the setting of the
104 * &drm_device.max_vblank_count value.
105 */
106 struct timer_list disable_timer;
107
108 /**
109 * @seqlock: Protect vblank count and time.
110 */
111 seqlock_t seqlock;
112
113 /**
114 * @count:
115 *
116 * Current software vblank counter.
117 *
118 * Note that for a given vblank counter value drm_crtc_handle_vblank()
119 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
120 * provide a barrier: Any writes done before calling
121 * drm_crtc_handle_vblank() will be visible to callers of the later
122 * functions, iff the vblank count is the same or a later one.
123 *
124 * IMPORTANT: This guarantee requires barriers, therefor never access
125 * this field directly. Use drm_crtc_vblank_count() instead.
126 */
127 atomic64_t count;
128 /**
129 * @time: Vblank timestamp corresponding to @count.
130 */
131 ktime_t time;
132
133 /**
134 * @refcount: Number of users/waiters of the vblank interrupt. Only when
135 * this refcount reaches 0 can the hardware interrupt be disabled using
136 * @disable_timer.
137 */
138 atomic_t refcount;
139 /**
140 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
141 */
142 u32 last;
143 /**
144 * @max_vblank_count:
145 *
146 * Maximum value of the vblank registers for this crtc. This value +1
147 * will result in a wrap-around of the vblank register. It is used
148 * by the vblank core to handle wrap-arounds.
149 *
150 * If set to zero the vblank core will try to guess the elapsed vblanks
151 * between times when the vblank interrupt is disabled through
152 * high-precision timestamps. That approach is suffering from small
153 * races and imprecision over longer time periods, hence exposing a
154 * hardware vblank counter is always recommended.
155 *
156 * This is the runtime configurable per-crtc maximum set through
157 * drm_crtc_set_max_vblank_count(). If this is used the driver
158 * must leave the device wide &drm_device.max_vblank_count at zero.
159 *
160 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
161 */
162 u32 max_vblank_count;
163 /**
164 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
165 * For legacy driver bit 2 additionally tracks whether an additional
166 * temporary vblank reference has been acquired to paper over the
167 * hardware counter resetting/jumping. KMS drivers should instead just
168 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
169 * save and restore the vblank count.
170 */
171 unsigned int inmodeset;
172 /**
173 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
174 * structure.
175 */
176 unsigned int pipe;
177 /**
178 * @framedur_ns: Frame/Field duration in ns, used by
179 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
180 * drm_calc_timestamping_constants().
181 */
182 int framedur_ns;
183 /**
184 * @linedur_ns: Line duration in ns, used by
185 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
186 * drm_calc_timestamping_constants().
187 */
188 int linedur_ns;
189
190 /**
191 * @hwmode:
192 *
193 * Cache of the current hardware display mode. Only valid when @enabled
194 * is set. This is used by helpers like
195 * drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access
196 * the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
197 * because that one is really hard to get from interrupt context.
198 */
199 struct drm_display_mode hwmode;
200
201 /**
202 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
203 * avoid double-disabling and hence corrupting saved state. Needed by
204 * drivers not using atomic KMS, since those might go through their CRTC
205 * disabling functions multiple times.
206 */
207 bool enabled;
208
209 /**
210 * @worker: The &kthread_worker used for executing vblank works.
211 */
212 struct kthread_worker *worker;
213
214 /**
215 * @pending_work: A list of scheduled &drm_vblank_work items that are
216 * waiting for a future vblank.
217 */
218 struct list_head pending_work;
219
220 /**
221 * @work_wait_queue: The wait queue used for signaling that a
222 * &drm_vblank_work item has either finished executing, or was
223 * cancelled.
224 */
225 wait_queue_head_t work_wait_queue;
226 };
227
228 struct drm_vblank_crtc *drm_crtc_vblank_crtc(struct drm_crtc *crtc);
229 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
230 bool drm_dev_has_vblank(const struct drm_device *dev);
231 u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
232 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
233 ktime_t *vblanktime);
234 int drm_crtc_next_vblank_start(struct drm_crtc *crtc, ktime_t *vblanktime);
235 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
236 struct drm_pending_vblank_event *e);
237 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
238 struct drm_pending_vblank_event *e);
239 void drm_vblank_set_event(struct drm_pending_vblank_event *e,
240 u64 *seq,
241 ktime_t *now);
242 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
243 bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
244 int drm_crtc_vblank_get(struct drm_crtc *crtc);
245 void drm_crtc_vblank_put(struct drm_crtc *crtc);
246 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
247 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
248 void drm_crtc_vblank_off(struct drm_crtc *crtc);
249 void drm_crtc_vblank_reset(struct drm_crtc *crtc);
250 void drm_crtc_vblank_on(struct drm_crtc *crtc);
251 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
252 void drm_crtc_vblank_restore(struct drm_crtc *crtc);
253
254 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
255 const struct drm_display_mode *mode);
256 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
257 void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
258 u32 max_vblank_count);
259
260 /*
261 * Helpers for struct drm_crtc_funcs
262 */
263
264 typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc,
265 bool in_vblank_irq,
266 int *vpos, int *hpos,
267 ktime_t *stime,
268 ktime_t *etime,
269 const struct drm_display_mode *mode);
270
271 bool
272 drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
273 int *max_error,
274 ktime_t *vblank_time,
275 bool in_vblank_irq,
276 drm_vblank_get_scanout_position_func get_scanout_position);
277 bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
278 int *max_error,
279 ktime_t *vblank_time,
280 bool in_vblank_irq);
281
282 #endif
283
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.