linux/include/drm/drm_vblank.h
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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/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: Current software vblank counter.
 113         */
 114        u64 count;
 115        /**
 116         * @time: Vblank timestamp corresponding to @count.
 117         */
 118        ktime_t time;
 119
 120        /**
 121         * @refcount: Number of users/waiters of the vblank interrupt. Only when
 122         * this refcount reaches 0 can the hardware interrupt be disabled using
 123         * @disable_timer.
 124         */
 125        atomic_t refcount;
 126        /**
 127         * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
 128         */
 129        u32 last;
 130        /**
 131         * @max_vblank_count:
 132         *
 133         * Maximum value of the vblank registers for this crtc. This value +1
 134         * will result in a wrap-around of the vblank register. It is used
 135         * by the vblank core to handle wrap-arounds.
 136         *
 137         * If set to zero the vblank core will try to guess the elapsed vblanks
 138         * between times when the vblank interrupt is disabled through
 139         * high-precision timestamps. That approach is suffering from small
 140         * races and imprecision over longer time periods, hence exposing a
 141         * hardware vblank counter is always recommended.
 142         *
 143         * This is the runtime configurable per-crtc maximum set through
 144         * drm_crtc_set_max_vblank_count(). If this is used the driver
 145         * must leave the device wide &drm_device.max_vblank_count at zero.
 146         *
 147         * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
 148         */
 149        u32 max_vblank_count;
 150        /**
 151         * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
 152         * For legacy driver bit 2 additionally tracks whether an additional
 153         * temporary vblank reference has been acquired to paper over the
 154         * hardware counter resetting/jumping. KMS drivers should instead just
 155         * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
 156         * save and restore the vblank count.
 157         */
 158        unsigned int inmodeset;
 159        /**
 160         * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
 161         * structure.
 162         */
 163        unsigned int pipe;
 164        /**
 165         * @framedur_ns: Frame/Field duration in ns, used by
 166         * drm_calc_vbltimestamp_from_scanoutpos() and computed by
 167         * drm_calc_timestamping_constants().
 168         */
 169        int framedur_ns;
 170        /**
 171         * @linedur_ns: Line duration in ns, used by
 172         * drm_calc_vbltimestamp_from_scanoutpos() and computed by
 173         * drm_calc_timestamping_constants().
 174         */
 175        int linedur_ns;
 176
 177        /**
 178         * @hwmode:
 179         *
 180         * Cache of the current hardware display mode. Only valid when @enabled
 181         * is set. This is used by helpers like
 182         * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
 183         * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
 184         * because that one is really hard to get from interrupt context.
 185         */
 186        struct drm_display_mode hwmode;
 187
 188        /**
 189         * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
 190         * avoid double-disabling and hence corrupting saved state. Needed by
 191         * drivers not using atomic KMS, since those might go through their CRTC
 192         * disabling functions multiple times.
 193         */
 194        bool enabled;
 195};
 196
 197int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
 198u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
 199u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
 200                                   ktime_t *vblanktime);
 201void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
 202                               struct drm_pending_vblank_event *e);
 203void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
 204                              struct drm_pending_vblank_event *e);
 205void drm_vblank_set_event(struct drm_pending_vblank_event *e,
 206                          u64 *seq,
 207                          ktime_t *now);
 208bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
 209bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
 210int drm_crtc_vblank_get(struct drm_crtc *crtc);
 211void drm_crtc_vblank_put(struct drm_crtc *crtc);
 212void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
 213void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
 214void drm_crtc_vblank_off(struct drm_crtc *crtc);
 215void drm_crtc_vblank_reset(struct drm_crtc *crtc);
 216void drm_crtc_vblank_on(struct drm_crtc *crtc);
 217u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
 218void drm_vblank_restore(struct drm_device *dev, unsigned int pipe);
 219void drm_crtc_vblank_restore(struct drm_crtc *crtc);
 220
 221bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
 222                                           unsigned int pipe, int *max_error,
 223                                           ktime_t *vblank_time,
 224                                           bool in_vblank_irq);
 225void drm_calc_timestamping_constants(struct drm_crtc *crtc,
 226                                     const struct drm_display_mode *mode);
 227wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
 228void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
 229                                   u32 max_vblank_count);
 230#endif
 231