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
  34 struct drm_device;
  35 struct drm_crtc;
  36
  37 /**
  38  * struct drm_pending_vblank_event - pending vblank event tracking
  39  */
  40 struct 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  */
  89 struct 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_calc_vbltimestamp_from_scanoutpos() 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_calc_vbltimestamp_from_scanoutpos() 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_calc_vbltimestamp_from_scanoutpos(). We can't just access the
 194          * 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
 208 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
 209 u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
 210 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
 211                                    ktime_t *vblanktime);
 212 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
 213                                struct drm_pending_vblank_event *e);
 214 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
 215                               struct drm_pending_vblank_event *e);
 216 void drm_vblank_set_event(struct drm_pending_vblank_event *e,
 217                           u64 *seq,
 218                           ktime_t *now);
 219 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
 220 bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
 221 int drm_crtc_vblank_get(struct drm_crtc *crtc);
 222 void drm_crtc_vblank_put(struct drm_crtc *crtc);
 223 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
 224 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
 225 void drm_crtc_vblank_off(struct drm_crtc *crtc);
 226 void drm_crtc_vblank_reset(struct drm_crtc *crtc);
 227 void drm_crtc_vblank_on(struct drm_crtc *crtc);
 228 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
 229 void drm_vblank_restore(struct drm_device *dev, unsigned int pipe);
 230 void drm_crtc_vblank_restore(struct drm_crtc *crtc);
 231
 232 bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
 233                                            unsigned int pipe, int *max_error,
 234                                            ktime_t *vblank_time,
 235                                            bool in_vblank_irq);
 236 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
 237                                      const struct drm_display_mode *mode);
 238 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
 239 void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
 240                                    u32 max_vblank_count);
 241 #endif