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/hrtimer.h>
 29#include <linux/idr.h>
 30#include <linux/poll.h>
 31#include <linux/kthread.h>
 32
 33#include <drm/drm_file.h>
 34#include <drm/drm_modes.h>
 35
 36struct drm_device;
 37struct drm_crtc;
 38struct drm_vblank_work;
 39
 40/**
 41 * struct drm_pending_vblank_event - pending vblank event tracking
 42 */
 43struct drm_pending_vblank_event {
 44	/**
 45	 * @base: Base structure for tracking pending DRM events.
 46	 */
 47	struct drm_pending_event base;
 48	/**
 49	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
 50	 */
 51	unsigned int pipe;
 52	/**
 53	 * @sequence: frame event should be triggered at
 54	 */
 55	u64 sequence;
 56	/**
 57	 * @event: Actual event which will be sent to userspace.
 58	 */
 59	union {
 60		/**
 61		 * @event.base: DRM event base class.
 62		 */
 63		struct drm_event base;
 64
 65		/**
 66		 * @event.vbl:
 67		 *
 68		 * Event payload for vblank events, requested through
 69		 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
 70		 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
 71		 * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
 72		 */
 73		struct drm_event_vblank vbl;
 74
 75		/**
 76		 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
 77		 */
 78		struct drm_event_crtc_sequence seq;
 79	} event;
 80};
 81
 82/**
 83 * struct drm_vblank_crtc_config - vblank configuration for a CRTC
 84 */
 85struct drm_vblank_crtc_config {
 86	/**
 87	 * @offdelay_ms: Vblank off delay in ms, used to determine how long
 88	 * &drm_vblank_crtc.disable_timer waits before disabling.
 89	 *
 90	 * Defaults to the value of drm_vblank_offdelay in drm_crtc_vblank_on().
 91	 */
 92	int offdelay_ms;
 93
 94	/**
 95	 * @disable_immediate: See &drm_device.vblank_disable_immediate
 96	 * for the exact semantics of immediate vblank disabling.
 97	 *
 98	 * Additionally, this tracks the disable immediate value per crtc, just
 99	 * in case it needs to differ from the default value for a given device.
100	 *
101	 * Defaults to the value of &drm_device.vblank_disable_immediate in
102	 * drm_crtc_vblank_on().
103	 */
104	bool disable_immediate;
105};
106
107/**
108 * struct drm_vblank_crtc_timer - vblank timer for a CRTC
109 */
110struct drm_vblank_crtc_timer {
111	/**
112	 * @timer: The vblank's high-resolution timer
113	 */
114	struct hrtimer timer;
115	/**
116	 * @interval_lock: Protects @interval
117	 */
118	spinlock_t interval_lock;
119	/**
120	 * @interval: Duration between two vblanks
121	 */
122	ktime_t interval;
123	/**
124	 * @crtc: The timer's CRTC
125	 */
126	struct drm_crtc *crtc;
127};
128
129/**
130 * struct drm_vblank_crtc - vblank tracking for a CRTC
131 *
132 * This structure tracks the vblank state for one CRTC.
133 *
134 * Note that for historical reasons - the vblank handling code is still shared
135 * with legacy/non-kms drivers - this is a free-standing structure not directly
136 * connected to &struct drm_crtc. But all public interface functions are taking
137 * a &struct drm_crtc to hide this implementation detail.
138 */
139struct drm_vblank_crtc {
140	/**
141	 * @dev: Pointer to the &drm_device.
142	 */
143	struct drm_device *dev;
144	/**
145	 * @queue: Wait queue for vblank waiters.
146	 */
147	wait_queue_head_t queue;
148	/**
149	 * @disable_timer: Disable timer for the delayed vblank disabling
150	 * hysteresis logic. Vblank disabling is controlled through
151	 * &drm_vblank_crtc_config.offdelay_ms and the setting of the
152	 * &drm_device.max_vblank_count value.
153	 */
154	struct timer_list disable_timer;
155
156	/**
157	 * @seqlock: Protect vblank count and time.
158	 */
159	seqlock_t seqlock;
160
161	/**
162	 * @count:
163	 *
164	 * Current software vblank counter.
165	 *
166	 * Note that for a given vblank counter value drm_crtc_handle_vblank()
167	 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
168	 * provide a barrier: Any writes done before calling
169	 * drm_crtc_handle_vblank() will be visible to callers of the later
170	 * functions, iff the vblank count is the same or a later one.
171	 *
172	 * IMPORTANT: This guarantee requires barriers, therefor never access
173	 * this field directly. Use drm_crtc_vblank_count() instead.
174	 */
175	atomic64_t count;
176	/**
177	 * @time: Vblank timestamp corresponding to @count.
178	 */
179	ktime_t time;
180
181	/**
182	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
183	 * this refcount reaches 0 can the hardware interrupt be disabled using
184	 * @disable_timer.
185	 */
186	atomic_t refcount;
187	/**
188	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
189	 */
190	u32 last;
191	/**
192	 * @max_vblank_count:
193	 *
194	 * Maximum value of the vblank registers for this crtc. This value +1
195	 * will result in a wrap-around of the vblank register. It is used
196	 * by the vblank core to handle wrap-arounds.
197	 *
198	 * If set to zero the vblank core will try to guess the elapsed vblanks
199	 * between times when the vblank interrupt is disabled through
200	 * high-precision timestamps. That approach is suffering from small
201	 * races and imprecision over longer time periods, hence exposing a
202	 * hardware vblank counter is always recommended.
203	 *
204	 * This is the runtime configurable per-crtc maximum set through
205	 * drm_crtc_set_max_vblank_count(). If this is used the driver
206	 * must leave the device wide &drm_device.max_vblank_count at zero.
207	 *
208	 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
209	 */
210	u32 max_vblank_count;
211	/**
212	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
213	 * For legacy driver bit 2 additionally tracks whether an additional
214	 * temporary vblank reference has been acquired to paper over the
215	 * hardware counter resetting/jumping. KMS drivers should instead just
216	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
217	 * save and restore the vblank count.
218	 */
219	unsigned int inmodeset;
220	/**
221	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
222	 * structure.
223	 */
224	unsigned int pipe;
225	/**
226	 * @framedur_ns: Frame/Field duration in ns, used by
227	 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
228	 * drm_calc_timestamping_constants().
229	 */
230	int framedur_ns;
231	/**
232	 * @linedur_ns: Line duration in ns, used by
233	 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
234	 * drm_calc_timestamping_constants().
235	 */
236	int linedur_ns;
237
238	/**
239	 * @hwmode:
240	 *
241	 * Cache of the current hardware display mode. Only valid when @enabled
242	 * is set. This is used by helpers like
243	 * drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access
244	 * the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
245	 * because that one is really hard to get from interrupt context.
246	 */
247	struct drm_display_mode hwmode;
248
249	/**
250	 * @config: Stores vblank configuration values for a given CRTC.
251	 * Also, see drm_crtc_vblank_on_config().
252	 */
253	struct drm_vblank_crtc_config config;
254
255	/**
256	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
257	 * avoid double-disabling and hence corrupting saved state. Needed by
258	 * drivers not using atomic KMS, since those might go through their CRTC
259	 * disabling functions multiple times.
260	 */
261	bool enabled;
262
263	/**
264	 * @worker: The &kthread_worker used for executing vblank works.
265	 */
266	struct kthread_worker *worker;
267
268	/**
269	 * @pending_work: A list of scheduled &drm_vblank_work items that are
270	 * waiting for a future vblank.
271	 */
272	struct list_head pending_work;
273
274	/**
275	 * @work_wait_queue: The wait queue used for signaling that a
276	 * &drm_vblank_work item has either finished executing, or was
277	 * cancelled.
278	 */
279	wait_queue_head_t work_wait_queue;
280
281	/**
282	 * @vblank_timer: Holds the state of the vblank timer
283	 */
284	struct drm_vblank_crtc_timer vblank_timer;
285};
286
287struct drm_vblank_crtc *drm_crtc_vblank_crtc(struct drm_crtc *crtc);
288int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
289bool drm_dev_has_vblank(const struct drm_device *dev);
290u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
291u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
292				   ktime_t *vblanktime);
293int drm_crtc_next_vblank_start(struct drm_crtc *crtc, ktime_t *vblanktime);
294void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
295			       struct drm_pending_vblank_event *e);
296void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
297			      struct drm_pending_vblank_event *e);
298void drm_vblank_set_event(struct drm_pending_vblank_event *e,
299			  u64 *seq,
300			  ktime_t *now);
301bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
302bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
303int drm_crtc_vblank_get(struct drm_crtc *crtc);
304void drm_crtc_vblank_put(struct drm_crtc *crtc);
305void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
306void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
307void drm_crtc_vblank_off(struct drm_crtc *crtc);
308void drm_crtc_vblank_reset(struct drm_crtc *crtc);
309void drm_crtc_vblank_on_config(struct drm_crtc *crtc,
310			       const struct drm_vblank_crtc_config *config);
311void drm_crtc_vblank_on(struct drm_crtc *crtc);
312u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
313void drm_crtc_vblank_restore(struct drm_crtc *crtc);
314
315void drm_calc_timestamping_constants(struct drm_crtc *crtc,
316				     const struct drm_display_mode *mode);
317wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
318void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
319				   u32 max_vblank_count);
320
321int drm_crtc_vblank_start_timer(struct drm_crtc *crtc);
322void drm_crtc_vblank_cancel_timer(struct drm_crtc *crtc);
323void drm_crtc_vblank_get_vblank_timeout(struct drm_crtc *crtc, ktime_t *vblank_time);
324
325/*
326 * Helpers for struct drm_crtc_funcs
327 */
328
329typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc,
330						     bool in_vblank_irq,
331						     int *vpos, int *hpos,
332						     ktime_t *stime,
333						     ktime_t *etime,
334						     const struct drm_display_mode *mode);
335
336bool
337drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
338						     int *max_error,
339						     ktime_t *vblank_time,
340						     bool in_vblank_irq,
341						     drm_vblank_get_scanout_position_func get_scanout_position);
342bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
343						 int *max_error,
344						 ktime_t *vblank_time,
345						 bool in_vblank_irq);
346
347#endif