xref: /openbmc/linux/include/drm/drm_vblank.h (revision 6aa7de05)
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 	 * @event: Actual event which will be sent to userspace.
52 	 */
53 	struct drm_event_vblank event;
54 };
55 
56 /**
57  * struct drm_vblank_crtc - vblank tracking for a CRTC
58  *
59  * This structure tracks the vblank state for one CRTC.
60  *
61  * Note that for historical reasons - the vblank handling code is still shared
62  * with legacy/non-kms drivers - this is a free-standing structure not directly
63  * connected to &struct drm_crtc. But all public interface functions are taking
64  * a &struct drm_crtc to hide this implementation detail.
65  */
66 struct drm_vblank_crtc {
67 	/**
68 	 * @dev: Pointer to the &drm_device.
69 	 */
70 	struct drm_device *dev;
71 	/**
72 	 * @queue: Wait queue for vblank waiters.
73 	 */
74 	wait_queue_head_t queue;	/**< VBLANK wait queue */
75 	/**
76 	 * @disable_timer: Disable timer for the delayed vblank disabling
77 	 * hysteresis logic. Vblank disabling is controlled through the
78 	 * drm_vblank_offdelay module option and the setting of the
79 	 * &drm_device.max_vblank_count value.
80 	 */
81 	struct timer_list disable_timer;
82 
83 	/**
84 	 * @seqlock: Protect vblank count and time.
85 	 */
86 	seqlock_t seqlock;		/* protects vblank count and time */
87 
88 	/**
89 	 * @count: Current software vblank counter.
90 	 */
91 	u32 count;
92 	/**
93 	 * @time: Vblank timestamp corresponding to @count.
94 	 */
95 	struct timeval time;
96 
97 	/**
98 	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
99 	 * this refcount reaches 0 can the hardware interrupt be disabled using
100 	 * @disable_timer.
101 	 */
102 	atomic_t refcount;		/* number of users of vblank interruptsper crtc */
103 	/**
104 	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
105 	 */
106 	u32 last;
107 	/**
108 	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
109 	 * For legacy driver bit 2 additionally tracks whether an additional
110 	 * temporary vblank reference has been acquired to paper over the
111 	 * hardware counter resetting/jumping. KMS drivers should instead just
112 	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
113 	 * save and restore the vblank count.
114 	 */
115 	unsigned int inmodeset;		/* Display driver is setting mode */
116 	/**
117 	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
118 	 * structure.
119 	 */
120 	unsigned int pipe;
121 	/**
122 	 * @framedur_ns: Frame/Field duration in ns, used by
123 	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
124 	 * drm_calc_timestamping_constants().
125 	 */
126 	int framedur_ns;
127 	/**
128 	 * @linedur_ns: Line duration in ns, used by
129 	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
130 	 * drm_calc_timestamping_constants().
131 	 */
132 	int linedur_ns;
133 
134 	/**
135 	 * @hwmode:
136 	 *
137 	 * Cache of the current hardware display mode. Only valid when @enabled
138 	 * is set. This is used by helpers like
139 	 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
140 	 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
141 	 * because that one is really hard to get from interrupt context.
142 	 */
143 	struct drm_display_mode hwmode;
144 
145 	/**
146 	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
147 	 * avoid double-disabling and hence corrupting saved state. Needed by
148 	 * drivers not using atomic KMS, since those might go through their CRTC
149 	 * disabling functions multiple times.
150 	 */
151 	bool enabled;
152 };
153 
154 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
155 u32 drm_crtc_vblank_count(struct drm_crtc *crtc);
156 u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
157 				   struct timeval *vblanktime);
158 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
159 			       struct drm_pending_vblank_event *e);
160 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
161 			      struct drm_pending_vblank_event *e);
162 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
163 bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
164 int drm_crtc_vblank_get(struct drm_crtc *crtc);
165 void drm_crtc_vblank_put(struct drm_crtc *crtc);
166 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
167 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
168 void drm_crtc_vblank_off(struct drm_crtc *crtc);
169 void drm_crtc_vblank_reset(struct drm_crtc *crtc);
170 void drm_crtc_vblank_on(struct drm_crtc *crtc);
171 u32 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
172 
173 bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
174 					   unsigned int pipe, int *max_error,
175 					   struct timeval *vblank_time,
176 					   bool in_vblank_irq);
177 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
178 				     const struct drm_display_mode *mode);
179 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
180 #endif
181