include/drm/drm_vblank.h - linux - Git at Google

 /*
  * Copyright 2016 Intel Corp.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  */

 #ifndef _DRM_VBLANK_H_
 #define _DRM_VBLANK_H_

 #include <linux/seqlock.h>
 #include <linux/idr.h>
 #include <linux/poll.h>
 #include <linux/kthread.h>

 #include <drm/drm_file.h>
 #include <drm/drm_modes.h>

 struct drm_device;
 struct drm_crtc;
 struct drm_vblank_work;

 /**
  * struct drm_pending_vblank_event - pending vblank event tracking
  */
 struct drm_pending_vblank_event {
 	/**
 	 * @base: Base structure for tracking pending DRM events.
 	 */
 	struct drm_pending_event base;
 	/**
 	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
 	 */
 	unsigned int pipe;
 	/**
 	 * @sequence: frame event should be triggered at
 	 */
 	u64 sequence;
 	/**
 	 * @event: Actual event which will be sent to userspace.
 	 */
 	union {
 		/**
 		 * @event.base: DRM event base class.
 		 */
 		struct drm_event base;

 		/**
 		 * @event.vbl:
 		 *
 		 * Event payload for vblank events, requested through
 		 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
 		 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
 		 * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
 		 */
 		struct drm_event_vblank vbl;

 		/**
 		 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
 		 */
 		struct drm_event_crtc_sequence seq;
 	} event;
 };

 /**
  * struct drm_vblank_crtc_config - vblank configuration for a CRTC
  */
 struct drm_vblank_crtc_config {
 	/**
 	 * @offdelay_ms: Vblank off delay in ms, used to determine how long
 	 * &drm_vblank_crtc.disable_timer waits before disabling.
 	 *
 	 * Defaults to the value of drm_vblank_offdelay in drm_crtc_vblank_on().
 	 */
 	int offdelay_ms;

 	/**
 	 * @disable_immediate: See &drm_device.vblank_disable_immediate
 	 * for the exact semantics of immediate vblank disabling.
 	 *
 	 * Additionally, this tracks the disable immediate value per crtc, just
 	 * in case it needs to differ from the default value for a given device.
 	 *
 	 * Defaults to the value of &drm_device.vblank_disable_immediate in
 	 * drm_crtc_vblank_on().
 	 */
 	bool disable_immediate;
 };

 /**
  * struct drm_vblank_crtc - vblank tracking for a CRTC
  *
  * This structure tracks the vblank state for one CRTC.
  *
  * Note that for historical reasons - the vblank handling code is still shared
  * with legacy/non-kms drivers - this is a free-standing structure not directly
  * connected to &struct drm_crtc. But all public interface functions are taking
  * a &struct drm_crtc to hide this implementation detail.
  */
 struct drm_vblank_crtc {
 	/**
 	 * @dev: Pointer to the &drm_device.
 	 */
 	struct drm_device *dev;
 	/**
 	 * @queue: Wait queue for vblank waiters.
 	 */
 	wait_queue_head_t queue;
 	/**
 	 * @disable_timer: Disable timer for the delayed vblank disabling
 	 * hysteresis logic. Vblank disabling is controlled through
 	 * &drm_vblank_crtc_config.offdelay_ms and the setting of the
 	 * &drm_device.max_vblank_count value.
 	 */
 	struct timer_list disable_timer;

 	/**
 	 * @seqlock: Protect vblank count and time.
 	 */
 	seqlock_t seqlock;

 	/**
 	 * @count:
 	 *
 	 * Current software vblank counter.
 	 *
 	 * Note that for a given vblank counter value drm_crtc_handle_vblank()
 	 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
 	 * provide a barrier: Any writes done before calling
 	 * drm_crtc_handle_vblank() will be visible to callers of the later
 	 * functions, iff the vblank count is the same or a later one.
 	 *
 	 * IMPORTANT: This guarantee requires barriers, therefor never access
 	 * this field directly. Use drm_crtc_vblank_count() instead.
 	 */
 	atomic64_t count;
 	/**
 	 * @time: Vblank timestamp corresponding to @count.
 	 */
 	ktime_t time;

 	/**
 	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
 	 * this refcount reaches 0 can the hardware interrupt be disabled using
 	 * @disable_timer.
 	 */
 	atomic_t refcount;
 	/**
 	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
 	 */
 	u32 last;
 	/**
 	 * @max_vblank_count:
 	 *
 	 * Maximum value of the vblank registers for this crtc. This value +1
 	 * will result in a wrap-around of the vblank register. It is used
 	 * by the vblank core to handle wrap-arounds.
 	 *
 	 * If set to zero the vblank core will try to guess the elapsed vblanks
 	 * between times when the vblank interrupt is disabled through
 	 * high-precision timestamps. That approach is suffering from small
 	 * races and imprecision over longer time periods, hence exposing a
 	 * hardware vblank counter is always recommended.
 	 *
 	 * This is the runtime configurable per-crtc maximum set through
 	 * drm_crtc_set_max_vblank_count(). If this is used the driver
 	 * must leave the device wide &drm_device.max_vblank_count at zero.
 	 *
 	 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
 	 */
 	u32 max_vblank_count;
 	/**
 	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
 	 * For legacy driver bit 2 additionally tracks whether an additional
 	 * temporary vblank reference has been acquired to paper over the
 	 * hardware counter resetting/jumping. KMS drivers should instead just
 	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
 	 * save and restore the vblank count.
 	 */
 	unsigned int inmodeset;
 	/**
 	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
 	 * structure.
 	 */
 	unsigned int pipe;
 	/**
 	 * @framedur_ns: Frame/Field duration in ns, used by
 	 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
 	 * drm_calc_timestamping_constants().
 	 */
 	int framedur_ns;
 	/**
 	 * @linedur_ns: Line duration in ns, used by
 	 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
 	 * drm_calc_timestamping_constants().
 	 */
 	int linedur_ns;

 	/**
 	 * @hwmode:
 	 *
 	 * Cache of the current hardware display mode. Only valid when @enabled
 	 * is set. This is used by helpers like
 	 * drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access
 	 * the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
 	 * because that one is really hard to get from interrupt context.
 	 */
 	struct drm_display_mode hwmode;

 	/**
 	 * @config: Stores vblank configuration values for a given CRTC.
 	 * Also, see drm_crtc_vblank_on_config().
 	 */
 	struct drm_vblank_crtc_config config;

 	/**
 	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
 	 * avoid double-disabling and hence corrupting saved state. Needed by
 	 * drivers not using atomic KMS, since those might go through their CRTC
 	 * disabling functions multiple times.
 	 */
 	bool enabled;

 	/**
 	 * @worker: The &kthread_worker used for executing vblank works.
 	 */
 	struct kthread_worker *worker;

 	/**
 	 * @pending_work: A list of scheduled &drm_vblank_work items that are
 	 * waiting for a future vblank.
 	 */
 	struct list_head pending_work;

 	/**
 	 * @work_wait_queue: The wait queue used for signaling that a
 	 * &drm_vblank_work item has either finished executing, or was
 	 * cancelled.
 	 */
 	wait_queue_head_t work_wait_queue;
 };

 struct drm_vblank_crtc *drm_crtc_vblank_crtc(struct drm_crtc *crtc);
 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
 bool drm_dev_has_vblank(const struct drm_device *dev);
 u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
 				   ktime_t *vblanktime);
 int drm_crtc_next_vblank_start(struct drm_crtc *crtc, ktime_t *vblanktime);
 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
 			       struct drm_pending_vblank_event *e);
 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
 			      struct drm_pending_vblank_event *e);
 void drm_vblank_set_event(struct drm_pending_vblank_event *e,
 			  u64 *seq,
 			  ktime_t *now);
 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
 bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
 int drm_crtc_vblank_get(struct drm_crtc *crtc);
 void drm_crtc_vblank_put(struct drm_crtc *crtc);
 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
 void drm_crtc_vblank_off(struct drm_crtc *crtc);
 void drm_crtc_vblank_reset(struct drm_crtc *crtc);
 void drm_crtc_vblank_on_config(struct drm_crtc *crtc,
 			       const struct drm_vblank_crtc_config *config);
 void drm_crtc_vblank_on(struct drm_crtc *crtc);
 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
 void drm_crtc_vblank_restore(struct drm_crtc *crtc);

 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
 				     const struct drm_display_mode *mode);
 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
 void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
 				   u32 max_vblank_count);

 /*
  * Helpers for struct drm_crtc_funcs
  */

 typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc,
 						     bool in_vblank_irq,
 						     int *vpos, int *hpos,
 						     ktime_t *stime,
 						     ktime_t *etime,
 						     const struct drm_display_mode *mode);

 bool
 drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
 						     int *max_error,
 						     ktime_t *vblank_time,
 						     bool in_vblank_irq,
 						     drm_vblank_get_scanout_position_func get_scanout_position);
 bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
 						 int *max_error,
 						 ktime_t *vblank_time,
 						 bool in_vblank_irq);

 #endif
	/*
	* Copyright 2016 Intel Corp.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	*/

	#ifndef _DRM_VBLANK_H_
	#define _DRM_VBLANK_H_

	#include <linux/seqlock.h>
	#include <linux/idr.h>
	#include <linux/poll.h>
	#include <linux/kthread.h>

	#include <drm/drm_file.h>
	#include <drm/drm_modes.h>

	struct drm_device;
	struct drm_crtc;
	struct drm_vblank_work;

	/**
	* struct drm_pending_vblank_event - pending vblank event tracking
	*/
	struct drm_pending_vblank_event {
	/**
	* @base: Base structure for tracking pending DRM events.
	*/
	struct drm_pending_event base;
	/**
	* @pipe: drm_crtc_index() of the &drm_crtc this event is for.
	*/
	unsigned int pipe;
	/**
	* @sequence: frame event should be triggered at
	*/
	u64 sequence;
	/**
	* @event: Actual event which will be sent to userspace.
	*/
	union {
	/**
	* @event.base: DRM event base class.
	*/
	struct drm_event base;

	/**
	* @event.vbl:
	*
	* Event payload for vblank events, requested through
	* either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
	* generated by the legacy WAIT_VBLANK IOCTL, but new userspace
	* should use MODE_QUEUE_SEQUENCE and &event.seq instead.
	*/
	struct drm_event_vblank vbl;

	/**
	* @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
	*/
	struct drm_event_crtc_sequence seq;
	} event;
	};

	/**
	* struct drm_vblank_crtc_config - vblank configuration for a CRTC
	*/
	struct drm_vblank_crtc_config {
	/**
	* @offdelay_ms: Vblank off delay in ms, used to determine how long
	* &drm_vblank_crtc.disable_timer waits before disabling.
	*
	* Defaults to the value of drm_vblank_offdelay in drm_crtc_vblank_on().
	*/
	int offdelay_ms;

	/**
	* @disable_immediate: See &drm_device.vblank_disable_immediate
	* for the exact semantics of immediate vblank disabling.
	*
	* Additionally, this tracks the disable immediate value per crtc, just
	* in case it needs to differ from the default value for a given device.
	*
	* Defaults to the value of &drm_device.vblank_disable_immediate in
	* drm_crtc_vblank_on().
	*/
	bool disable_immediate;
	};

	/**
	* struct drm_vblank_crtc - vblank tracking for a CRTC
	*
	* This structure tracks the vblank state for one CRTC.
	*
	* Note that for historical reasons - the vblank handling code is still shared
	* with legacy/non-kms drivers - this is a free-standing structure not directly
	* connected to &struct drm_crtc. But all public interface functions are taking
	* a &struct drm_crtc to hide this implementation detail.
	*/
	struct drm_vblank_crtc {
	/**
	* @dev: Pointer to the &drm_device.
	*/
	struct drm_device *dev;
	/**
	* @queue: Wait queue for vblank waiters.
	*/
	wait_queue_head_t queue;
	/**
	* @disable_timer: Disable timer for the delayed vblank disabling
	* hysteresis logic. Vblank disabling is controlled through
	* &drm_vblank_crtc_config.offdelay_ms and the setting of the
	* &drm_device.max_vblank_count value.
	*/
	struct timer_list disable_timer;

	/**
	* @seqlock: Protect vblank count and time.
	*/
	seqlock_t seqlock;

	/**
	* @count:
	*
	* Current software vblank counter.
	*
	* Note that for a given vblank counter value drm_crtc_handle_vblank()
	* and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
	* provide a barrier: Any writes done before calling
	* drm_crtc_handle_vblank() will be visible to callers of the later
	* functions, iff the vblank count is the same or a later one.
	*
	* IMPORTANT: This guarantee requires barriers, therefor never access
	* this field directly. Use drm_crtc_vblank_count() instead.
	*/
	atomic64_t count;
	/**
	* @time: Vblank timestamp corresponding to @count.
	*/
	ktime_t time;

	/**
	* @refcount: Number of users/waiters of the vblank interrupt. Only when
	* this refcount reaches 0 can the hardware interrupt be disabled using
	* @disable_timer.
	*/
	atomic_t refcount;
	/**
	* @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
	*/
	u32 last;
	/**
	* @max_vblank_count:
	*
	* Maximum value of the vblank registers for this crtc. This value +1
	* will result in a wrap-around of the vblank register. It is used
	* by the vblank core to handle wrap-arounds.
	*
	* If set to zero the vblank core will try to guess the elapsed vblanks
	* between times when the vblank interrupt is disabled through
	* high-precision timestamps. That approach is suffering from small
	* races and imprecision over longer time periods, hence exposing a
	* hardware vblank counter is always recommended.
	*
	* This is the runtime configurable per-crtc maximum set through
	* drm_crtc_set_max_vblank_count(). If this is used the driver
	* must leave the device wide &drm_device.max_vblank_count at zero.
	*
	* If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
	*/
	u32 max_vblank_count;
	/**
	* @inmodeset: Tracks whether the vblank is disabled due to a modeset.
	* For legacy driver bit 2 additionally tracks whether an additional
	* temporary vblank reference has been acquired to paper over the
	* hardware counter resetting/jumping. KMS drivers should instead just
	* call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
	* save and restore the vblank count.
	*/
	unsigned int inmodeset;
	/**
	* @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
	* structure.
	*/
	unsigned int pipe;
	/**
	* @framedur_ns: Frame/Field duration in ns, used by
	* drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
	* drm_calc_timestamping_constants().
	*/
	int framedur_ns;
	/**
	* @linedur_ns: Line duration in ns, used by
	* drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
	* drm_calc_timestamping_constants().
	*/
	int linedur_ns;

	/**
	* @hwmode:
	*
	* Cache of the current hardware display mode. Only valid when @enabled
	* is set. This is used by helpers like
	* drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access
	* the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
	* because that one is really hard to get from interrupt context.
	*/
	struct drm_display_mode hwmode;

	/**
	* @config: Stores vblank configuration values for a given CRTC.
	* Also, see drm_crtc_vblank_on_config().
	*/
	struct drm_vblank_crtc_config config;

	/**
	* @enabled: Tracks the enabling state of the corresponding &drm_crtc to
	* avoid double-disabling and hence corrupting saved state. Needed by
	* drivers not using atomic KMS, since those might go through their CRTC
	* disabling functions multiple times.
	*/
	bool enabled;

	/**
	* @worker: The &kthread_worker used for executing vblank works.
	*/
	struct kthread_worker *worker;

	/**
	* @pending_work: A list of scheduled &drm_vblank_work items that are
	* waiting for a future vblank.
	*/
	struct list_head pending_work;

	/**
	* @work_wait_queue: The wait queue used for signaling that a
	* &drm_vblank_work item has either finished executing, or was
	* cancelled.
	*/
	wait_queue_head_t work_wait_queue;
	};

	struct drm_vblank_crtc drm_crtc_vblank_crtc(struct drm_crtc crtc);
	int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
	bool drm_dev_has_vblank(const struct drm_device *dev);
	u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
	u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
	ktime_t *vblanktime);
	int drm_crtc_next_vblank_start(struct drm_crtc crtc, ktime_t vblanktime);
	void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
	struct drm_pending_vblank_event *e);
	void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
	struct drm_pending_vblank_event *e);
	void drm_vblank_set_event(struct drm_pending_vblank_event *e,
	u64 *seq,
	ktime_t *now);
	bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
	bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
	int drm_crtc_vblank_get(struct drm_crtc *crtc);
	void drm_crtc_vblank_put(struct drm_crtc *crtc);
	void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
	void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
	void drm_crtc_vblank_off(struct drm_crtc *crtc);
	void drm_crtc_vblank_reset(struct drm_crtc *crtc);
	void drm_crtc_vblank_on_config(struct drm_crtc *crtc,
	const struct drm_vblank_crtc_config *config);
	void drm_crtc_vblank_on(struct drm_crtc *crtc);
	u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
	void drm_crtc_vblank_restore(struct drm_crtc *crtc);

	void drm_calc_timestamping_constants(struct drm_crtc *crtc,
	const struct drm_display_mode *mode);
	wait_queue_head_t drm_crtc_vblank_waitqueue(struct drm_crtc crtc);
	void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
	u32 max_vblank_count);

	/*
	* Helpers for struct drm_crtc_funcs
	*/

	typedef bool (drm_vblank_get_scanout_position_func)(struct drm_crtc crtc,
	bool in_vblank_irq,
	int vpos, int hpos,
	ktime_t *stime,
	ktime_t *etime,
	const struct drm_display_mode *mode);

	bool
	drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
	int *max_error,
	ktime_t *vblank_time,
	bool in_vblank_irq,
	drm_vblank_get_scanout_position_func get_scanout_position);
	bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
	int *max_error,
	ktime_t *vblank_time,
	bool in_vblank_irq);

	#endif