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