tjh.dev
Linux kernel mirror (for testing)
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linux
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
31#include <drm/drm_file.h>
32#include <drm/drm_modes.h>
33
34struct drm_device;
35struct drm_crtc;
36
37/**
38 * struct drm_pending_vblank_event - pending vblank event tracking
39 */
40struct drm_pending_vblank_event {
41 /**
42 * @base: Base structure for tracking pending DRM events.
43 */
44 struct drm_pending_event base;
45 /**
46 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
47 */
48 unsigned int pipe;
49 /**
50 * @sequence: frame event should be triggered at
51 */
52 u64 sequence;
53 /**
54 * @event: Actual event which will be sent to userspace.
55 */
56 union {
57 /**
58 * @event.base: DRM event base class.
59 */
60 struct drm_event base;
61
62 /**
63 * @event.vbl:
64 *
65 * Event payload for vblank events, requested through
66 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
67 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
68 * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
69 */
70 struct drm_event_vblank vbl;
71
72 /**
73 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
74 */
75 struct drm_event_crtc_sequence seq;
76 } event;
77};
78
79/**
80 * struct drm_vblank_crtc - vblank tracking for a CRTC
81 *
82 * This structure tracks the vblank state for one CRTC.
83 *
84 * Note that for historical reasons - the vblank handling code is still shared
85 * with legacy/non-kms drivers - this is a free-standing structure not directly
86 * connected to &struct drm_crtc. But all public interface functions are taking
87 * a &struct drm_crtc to hide this implementation detail.
88 */
89struct drm_vblank_crtc {
90 /**
91 * @dev: Pointer to the &drm_device.
92 */
93 struct drm_device *dev;
94 /**
95 * @queue: Wait queue for vblank waiters.
96 */
97 wait_queue_head_t queue;
98 /**
99 * @disable_timer: Disable timer for the delayed vblank disabling
100 * hysteresis logic. Vblank disabling is controlled through the
101 * drm_vblank_offdelay module option and the setting of the
102 * &drm_device.max_vblank_count value.
103 */
104 struct timer_list disable_timer;
105
106 /**
107 * @seqlock: Protect vblank count and time.
108 */
109 seqlock_t seqlock;
110
111 /**
112 * @count:
113 *
114 * Current software vblank counter.
115 *
116 * Note that for a given vblank counter value drm_crtc_handle_vblank()
117 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
118 * provide a barrier: Any writes done before calling
119 * drm_crtc_handle_vblank() will be visible to callers of the later
120 * functions, iff the vblank count is the same or a later one.
121 *
122 * IMPORTANT: This guarantee requires barriers, therefor never access
123 * this field directly. Use drm_crtc_vblank_count() instead.
124 */
125 atomic64_t count;
126 /**
127 * @time: Vblank timestamp corresponding to @count.
128 */
129 ktime_t time;
130
131 /**
132 * @refcount: Number of users/waiters of the vblank interrupt. Only when
133 * this refcount reaches 0 can the hardware interrupt be disabled using
134 * @disable_timer.
135 */
136 atomic_t refcount;
137 /**
138 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
139 */
140 u32 last;
141 /**
142 * @max_vblank_count:
143 *
144 * Maximum value of the vblank registers for this crtc. This value +1
145 * will result in a wrap-around of the vblank register. It is used
146 * by the vblank core to handle wrap-arounds.
147 *
148 * If set to zero the vblank core will try to guess the elapsed vblanks
149 * between times when the vblank interrupt is disabled through
150 * high-precision timestamps. That approach is suffering from small
151 * races and imprecision over longer time periods, hence exposing a
152 * hardware vblank counter is always recommended.
153 *
154 * This is the runtime configurable per-crtc maximum set through
155 * drm_crtc_set_max_vblank_count(). If this is used the driver
156 * must leave the device wide &drm_device.max_vblank_count at zero.
157 *
158 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
159 */
160 u32 max_vblank_count;
161 /**
162 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
163 * For legacy driver bit 2 additionally tracks whether an additional
164 * temporary vblank reference has been acquired to paper over the
165 * hardware counter resetting/jumping. KMS drivers should instead just
166 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
167 * save and restore the vblank count.
168 */
169 unsigned int inmodeset;
170 /**
171 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
172 * structure.
173 */
174 unsigned int pipe;
175 /**
176 * @framedur_ns: Frame/Field duration in ns, used by
177 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
178 * drm_calc_timestamping_constants().
179 */
180 int framedur_ns;
181 /**
182 * @linedur_ns: Line duration in ns, used by
183 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
184 * drm_calc_timestamping_constants().
185 */
186 int linedur_ns;
187
188 /**
189 * @hwmode:
190 *
191 * Cache of the current hardware display mode. Only valid when @enabled
192 * is set. This is used by helpers like
193 * drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access
194 * the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
195 * because that one is really hard to get from interrupt context.
196 */
197 struct drm_display_mode hwmode;
198
199 /**
200 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
201 * avoid double-disabling and hence corrupting saved state. Needed by
202 * drivers not using atomic KMS, since those might go through their CRTC
203 * disabling functions multiple times.
204 */
205 bool enabled;
206};
207
208int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
209bool drm_dev_has_vblank(const struct drm_device *dev);
210u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
211u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
212 ktime_t *vblanktime);
213void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
214 struct drm_pending_vblank_event *e);
215void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
216 struct drm_pending_vblank_event *e);
217void drm_vblank_set_event(struct drm_pending_vblank_event *e,
218 u64 *seq,
219 ktime_t *now);
220bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
221bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
222int drm_crtc_vblank_get(struct drm_crtc *crtc);
223void drm_crtc_vblank_put(struct drm_crtc *crtc);
224void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
225void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
226void drm_crtc_vblank_off(struct drm_crtc *crtc);
227void drm_crtc_vblank_reset(struct drm_crtc *crtc);
228void drm_crtc_vblank_on(struct drm_crtc *crtc);
229u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
230void drm_vblank_restore(struct drm_device *dev, unsigned int pipe);
231void drm_crtc_vblank_restore(struct drm_crtc *crtc);
232
233void drm_calc_timestamping_constants(struct drm_crtc *crtc,
234 const struct drm_display_mode *mode);
235wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
236void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
237 u32 max_vblank_count);
238
239/*
240 * Helpers for struct drm_crtc_funcs
241 */
242
243typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc,
244 bool in_vblank_irq,
245 int *vpos, int *hpos,
246 ktime_t *stime,
247 ktime_t *etime,
248 const struct drm_display_mode *mode);
249
250bool
251drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
252 int *max_error,
253 ktime_t *vblank_time,
254 bool in_vblank_irq,
255 drm_vblank_get_scanout_position_func get_scanout_position);
256bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
257 int *max_error,
258 ktime_t *vblank_time,
259 bool in_vblank_irq);
260
261#endif