include/drm/drm_vblank.h

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