xref: /openbmc/linux/include/drm/drm_vblank.h (revision 82e6fdd6)
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 #include <uapi/drm/drm.h>
34 
35 struct drm_device;
36 struct drm_crtc;
37 
38 /**
39  * struct drm_pending_vblank_event - pending vblank event tracking
40  */
41 struct drm_pending_vblank_event {
42 	/**
43 	 * @base: Base structure for tracking pending DRM events.
44 	 */
45 	struct drm_pending_event base;
46 	/**
47 	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
48 	 */
49 	unsigned int pipe;
50 	/**
51 	 * @sequence: frame event should be triggered at
52 	 */
53 	u64 sequence;
54 	/**
55 	 * @event: Actual event which will be sent to userspace.
56 	 */
57 	union {
58 		struct drm_event base;
59 		struct drm_event_vblank vbl;
60 		struct drm_event_crtc_sequence seq;
61 	} event;
62 };
63 
64 /**
65  * struct drm_vblank_crtc - vblank tracking for a CRTC
66  *
67  * This structure tracks the vblank state for one CRTC.
68  *
69  * Note that for historical reasons - the vblank handling code is still shared
70  * with legacy/non-kms drivers - this is a free-standing structure not directly
71  * connected to &struct drm_crtc. But all public interface functions are taking
72  * a &struct drm_crtc to hide this implementation detail.
73  */
74 struct drm_vblank_crtc {
75 	/**
76 	 * @dev: Pointer to the &drm_device.
77 	 */
78 	struct drm_device *dev;
79 	/**
80 	 * @queue: Wait queue for vblank waiters.
81 	 */
82 	wait_queue_head_t queue;	/**< VBLANK wait queue */
83 	/**
84 	 * @disable_timer: Disable timer for the delayed vblank disabling
85 	 * hysteresis logic. Vblank disabling is controlled through the
86 	 * drm_vblank_offdelay module option and the setting of the
87 	 * &drm_device.max_vblank_count value.
88 	 */
89 	struct timer_list disable_timer;
90 
91 	/**
92 	 * @seqlock: Protect vblank count and time.
93 	 */
94 	seqlock_t seqlock;		/* protects vblank count and time */
95 
96 	/**
97 	 * @count: Current software vblank counter.
98 	 */
99 	u64 count;
100 	/**
101 	 * @time: Vblank timestamp corresponding to @count.
102 	 */
103 	ktime_t time;
104 
105 	/**
106 	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
107 	 * this refcount reaches 0 can the hardware interrupt be disabled using
108 	 * @disable_timer.
109 	 */
110 	atomic_t refcount;		/* number of users of vblank interruptsper crtc */
111 	/**
112 	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
113 	 */
114 	u32 last;
115 	/**
116 	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
117 	 * For legacy driver bit 2 additionally tracks whether an additional
118 	 * temporary vblank reference has been acquired to paper over the
119 	 * hardware counter resetting/jumping. KMS drivers should instead just
120 	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
121 	 * save and restore the vblank count.
122 	 */
123 	unsigned int inmodeset;		/* Display driver is setting mode */
124 	/**
125 	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
126 	 * structure.
127 	 */
128 	unsigned int pipe;
129 	/**
130 	 * @framedur_ns: Frame/Field duration in ns, used by
131 	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
132 	 * drm_calc_timestamping_constants().
133 	 */
134 	int framedur_ns;
135 	/**
136 	 * @linedur_ns: Line duration in ns, used by
137 	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
138 	 * drm_calc_timestamping_constants().
139 	 */
140 	int linedur_ns;
141 
142 	/**
143 	 * @hwmode:
144 	 *
145 	 * Cache of the current hardware display mode. Only valid when @enabled
146 	 * is set. This is used by helpers like
147 	 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
148 	 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
149 	 * because that one is really hard to get from interrupt context.
150 	 */
151 	struct drm_display_mode hwmode;
152 
153 	/**
154 	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
155 	 * avoid double-disabling and hence corrupting saved state. Needed by
156 	 * drivers not using atomic KMS, since those might go through their CRTC
157 	 * disabling functions multiple times.
158 	 */
159 	bool enabled;
160 };
161 
162 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
163 u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
164 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
165 				   ktime_t *vblanktime);
166 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
167 			       struct drm_pending_vblank_event *e);
168 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
169 			      struct drm_pending_vblank_event *e);
170 void drm_vblank_set_event(struct drm_pending_vblank_event *e,
171 			  u64 *seq,
172 			  ktime_t *now);
173 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
174 bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
175 int drm_crtc_vblank_get(struct drm_crtc *crtc);
176 void drm_crtc_vblank_put(struct drm_crtc *crtc);
177 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
178 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
179 void drm_crtc_vblank_off(struct drm_crtc *crtc);
180 void drm_crtc_vblank_reset(struct drm_crtc *crtc);
181 void drm_crtc_vblank_on(struct drm_crtc *crtc);
182 u32 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
183 
184 bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
185 					   unsigned int pipe, int *max_error,
186 					   ktime_t *vblank_time,
187 					   bool in_vblank_irq);
188 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
189 				     const struct drm_display_mode *mode);
190 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
191 #endif
192