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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/hrtimer.h>
29#include <linux/idr.h>
30#include <linux/poll.h>
31#include <linux/kthread.h>
32
33#include <drm/drm_file.h>
34#include <drm/drm_modes.h>
35
36struct drm_device;
37struct drm_crtc;
38struct drm_vblank_work;
39
40/**
41 * struct drm_pending_vblank_event - pending vblank event tracking
42 */
43struct drm_pending_vblank_event {
44 /**
45 * @base: Base structure for tracking pending DRM events.
46 */
47 struct drm_pending_event base;
48 /**
49 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
50 */
51 unsigned int pipe;
52 /**
53 * @sequence: frame event should be triggered at
54 */
55 u64 sequence;
56 /**
57 * @event: Actual event which will be sent to userspace.
58 */
59 union {
60 /**
61 * @event.base: DRM event base class.
62 */
63 struct drm_event base;
64
65 /**
66 * @event.vbl:
67 *
68 * Event payload for vblank events, requested through
69 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
70 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
71 * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
72 */
73 struct drm_event_vblank vbl;
74
75 /**
76 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
77 */
78 struct drm_event_crtc_sequence seq;
79 } event;
80};
81
82/**
83 * struct drm_vblank_crtc_config - vblank configuration for a CRTC
84 */
85struct drm_vblank_crtc_config {
86 /**
87 * @offdelay_ms: Vblank off delay in ms, used to determine how long
88 * &drm_vblank_crtc.disable_timer waits before disabling.
89 *
90 * Defaults to the value of drm_vblank_offdelay in drm_crtc_vblank_on().
91 */
92 int offdelay_ms;
93
94 /**
95 * @disable_immediate: See &drm_device.vblank_disable_immediate
96 * for the exact semantics of immediate vblank disabling.
97 *
98 * Additionally, this tracks the disable immediate value per crtc, just
99 * in case it needs to differ from the default value for a given device.
100 *
101 * Defaults to the value of &drm_device.vblank_disable_immediate in
102 * drm_crtc_vblank_on().
103 */
104 bool disable_immediate;
105};
106
107/**
108 * struct drm_vblank_crtc_timer - vblank timer for a CRTC
109 */
110struct drm_vblank_crtc_timer {
111 /**
112 * @timer: The vblank's high-resolution timer
113 */
114 struct hrtimer timer;
115 /**
116 * @interval_lock: Protects @interval
117 */
118 spinlock_t interval_lock;
119 /**
120 * @interval: Duration between two vblanks
121 */
122 ktime_t interval;
123 /**
124 * @crtc: The timer's CRTC
125 */
126 struct drm_crtc *crtc;
127};
128
129/**
130 * struct drm_vblank_crtc - vblank tracking for a CRTC
131 *
132 * This structure tracks the vblank state for one CRTC.
133 *
134 * Note that for historical reasons - the vblank handling code is still shared
135 * with legacy/non-kms drivers - this is a free-standing structure not directly
136 * connected to &struct drm_crtc. But all public interface functions are taking
137 * a &struct drm_crtc to hide this implementation detail.
138 */
139struct drm_vblank_crtc {
140 /**
141 * @dev: Pointer to the &drm_device.
142 */
143 struct drm_device *dev;
144 /**
145 * @queue: Wait queue for vblank waiters.
146 */
147 wait_queue_head_t queue;
148 /**
149 * @disable_timer: Disable timer for the delayed vblank disabling
150 * hysteresis logic. Vblank disabling is controlled through
151 * &drm_vblank_crtc_config.offdelay_ms and the setting of the
152 * &drm_device.max_vblank_count value.
153 */
154 struct timer_list disable_timer;
155
156 /**
157 * @seqlock: Protect vblank count and time.
158 */
159 seqlock_t seqlock;
160
161 /**
162 * @count:
163 *
164 * Current software vblank counter.
165 *
166 * Note that for a given vblank counter value drm_crtc_handle_vblank()
167 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
168 * provide a barrier: Any writes done before calling
169 * drm_crtc_handle_vblank() will be visible to callers of the later
170 * functions, iff the vblank count is the same or a later one.
171 *
172 * IMPORTANT: This guarantee requires barriers, therefor never access
173 * this field directly. Use drm_crtc_vblank_count() instead.
174 */
175 atomic64_t count;
176 /**
177 * @time: Vblank timestamp corresponding to @count.
178 */
179 ktime_t time;
180
181 /**
182 * @refcount: Number of users/waiters of the vblank interrupt. Only when
183 * this refcount reaches 0 can the hardware interrupt be disabled using
184 * @disable_timer.
185 */
186 atomic_t refcount;
187 /**
188 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
189 */
190 u32 last;
191 /**
192 * @max_vblank_count:
193 *
194 * Maximum value of the vblank registers for this crtc. This value +1
195 * will result in a wrap-around of the vblank register. It is used
196 * by the vblank core to handle wrap-arounds.
197 *
198 * If set to zero the vblank core will try to guess the elapsed vblanks
199 * between times when the vblank interrupt is disabled through
200 * high-precision timestamps. That approach is suffering from small
201 * races and imprecision over longer time periods, hence exposing a
202 * hardware vblank counter is always recommended.
203 *
204 * This is the runtime configurable per-crtc maximum set through
205 * drm_crtc_set_max_vblank_count(). If this is used the driver
206 * must leave the device wide &drm_device.max_vblank_count at zero.
207 *
208 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
209 */
210 u32 max_vblank_count;
211 /**
212 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
213 * For legacy driver bit 2 additionally tracks whether an additional
214 * temporary vblank reference has been acquired to paper over the
215 * hardware counter resetting/jumping. KMS drivers should instead just
216 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
217 * save and restore the vblank count.
218 */
219 unsigned int inmodeset;
220 /**
221 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
222 * structure.
223 */
224 unsigned int pipe;
225 /**
226 * @framedur_ns: Frame/Field duration in ns, used by
227 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
228 * drm_calc_timestamping_constants().
229 */
230 int framedur_ns;
231 /**
232 * @linedur_ns: Line duration in ns, used by
233 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
234 * drm_calc_timestamping_constants().
235 */
236 int linedur_ns;
237
238 /**
239 * @hwmode:
240 *
241 * Cache of the current hardware display mode. Only valid when @enabled
242 * is set. This is used by helpers like
243 * drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access
244 * the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
245 * because that one is really hard to get from interrupt context.
246 */
247 struct drm_display_mode hwmode;
248
249 /**
250 * @config: Stores vblank configuration values for a given CRTC.
251 * Also, see drm_crtc_vblank_on_config().
252 */
253 struct drm_vblank_crtc_config config;
254
255 /**
256 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
257 * avoid double-disabling and hence corrupting saved state. Needed by
258 * drivers not using atomic KMS, since those might go through their CRTC
259 * disabling functions multiple times.
260 */
261 bool enabled;
262
263 /**
264 * @worker: The &kthread_worker used for executing vblank works.
265 */
266 struct kthread_worker *worker;
267
268 /**
269 * @pending_work: A list of scheduled &drm_vblank_work items that are
270 * waiting for a future vblank.
271 */
272 struct list_head pending_work;
273
274 /**
275 * @work_wait_queue: The wait queue used for signaling that a
276 * &drm_vblank_work item has either finished executing, or was
277 * cancelled.
278 */
279 wait_queue_head_t work_wait_queue;
280
281 /**
282 * @vblank_timer: Holds the state of the vblank timer
283 */
284 struct drm_vblank_crtc_timer vblank_timer;
285};
286
287struct drm_vblank_crtc *drm_crtc_vblank_crtc(struct drm_crtc *crtc);
288int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
289bool drm_dev_has_vblank(const struct drm_device *dev);
290u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
291u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
292 ktime_t *vblanktime);
293int drm_crtc_next_vblank_start(struct drm_crtc *crtc, ktime_t *vblanktime);
294void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
295 struct drm_pending_vblank_event *e);
296void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
297 struct drm_pending_vblank_event *e);
298void drm_vblank_set_event(struct drm_pending_vblank_event *e,
299 u64 *seq,
300 ktime_t *now);
301bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
302bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
303int drm_crtc_vblank_get(struct drm_crtc *crtc);
304void drm_crtc_vblank_put(struct drm_crtc *crtc);
305int drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
306void drm_crtc_vblank_off(struct drm_crtc *crtc);
307void drm_crtc_vblank_reset(struct drm_crtc *crtc);
308void drm_crtc_vblank_on_config(struct drm_crtc *crtc,
309 const struct drm_vblank_crtc_config *config);
310void drm_crtc_vblank_on(struct drm_crtc *crtc);
311u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
312void drm_crtc_vblank_restore(struct drm_crtc *crtc);
313
314void drm_calc_timestamping_constants(struct drm_crtc *crtc,
315 const struct drm_display_mode *mode);
316wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
317void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
318 u32 max_vblank_count);
319
320int drm_crtc_vblank_start_timer(struct drm_crtc *crtc);
321void drm_crtc_vblank_cancel_timer(struct drm_crtc *crtc);
322void drm_crtc_vblank_get_vblank_timeout(struct drm_crtc *crtc, ktime_t *vblank_time);
323
324/*
325 * Helpers for struct drm_crtc_funcs
326 */
327
328typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc,
329 bool in_vblank_irq,
330 int *vpos, int *hpos,
331 ktime_t *stime,
332 ktime_t *etime,
333 const struct drm_display_mode *mode);
334
335bool
336drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
337 int *max_error,
338 ktime_t *vblank_time,
339 bool in_vblank_irq,
340 drm_vblank_get_scanout_position_func get_scanout_position);
341bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
342 int *max_error,
343 ktime_t *vblank_time,
344 bool in_vblank_irq);
345
346#endif