[PATCH 11/23] drm: Add get_vblank_timestamp() to struct drm_crtc_funcs

[Thomas Zimmermann <tzimmermann@suse.de>]

The callback get_vblank_timestamp() is currently located in struct
drm_driver, but really belongs into struct drm_crtc_funcs. Add an
equivalent there. Driver will be converted in separate patches.

The default implementation is drm_calc_vbltimestamp_from_scanoutpos().
The patch adds drm_crtc_calc_vbltimestamp_from_scanoutpos(), which is
an implementation for the CRTC callback.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_vblank.c             | 83 +++++++++++++++++++++---
 include/drm/drm_crtc.h                   | 41 ++++++++++++
 include/drm/drm_modeset_helper_vtables.h |  2 +-
 include/drm/drm_vblank.h                 |  4 ++
 4 files changed, 120 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index cbe8f3009df5..7cf436a4b908 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -333,7 +333,9 @@ u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc)
 	u64 vblank;
 	unsigned long flags;
 
-	WARN_ONCE(drm_debug_enabled(DRM_UT_VBL) && !dev->driver->get_vblank_timestamp,
+	WARN_ONCE(drm_debug_enabled(DRM_UT_VBL) &&
+		  !crtc->funcs->get_vblank_timestamp &&
+		  !dev->driver->get_vblank_timestamp,
 		  "This function requires support for accurate vblank timestamps.");
 
 	spin_lock_irqsave(&dev->vblank_time_lock, flags);
@@ -563,6 +565,50 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc,
 }
 EXPORT_SYMBOL(drm_calc_timestamping_constants);
 
+/**
+ * drm_crtc_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
+ * @crtc: CRTC whose vblank timestamp to retrieve
+ * @max_error: Desired maximum allowable error in timestamps (nanosecs)
+ *             On return contains true maximum error of timestamp
+ * @vblank_time: Pointer to time which should receive the timestamp
+ * @in_vblank_irq:
+ *     True when called from drm_crtc_handle_vblank().  Some drivers
+ *     need to apply some workarounds for gpu-specific vblank irq quirks
+ *     if flag is set.
+ *
+ * Implements calculation of exact vblank timestamps from given drm_display_mode
+ * timings and current video scanout position of a CRTC. This can be directly
+ * used as the &drm_crtc_funcs.get_vblank_timestamp implementation of a kms
+ * driver if &drm_crtc_helper_funcs.get_scanout_position is implemented.
+ *
+ * The current implementation only handles standard video modes. For double scan
+ * and interlaced modes the driver is supposed to adjust the hardware mode
+ * (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to
+ * match the scanout position reported.
+ *
+ * Note that atomic drivers must call drm_calc_timestamping_constants() before
+ * enabling a CRTC. The atomic helpers already take care of that in
+ * drm_atomic_helper_update_legacy_modeset_state().
+ *
+ * Returns:
+ *
+ * Returns true on success, and false on failure, i.e. when no accurate
+ * timestamp could be acquired.
+ */
+bool drm_crtc_calc_vbltimestamp_from_scanoutpos(struct drm_crtc *crtc,
+						int *max_error,
+						ktime_t *vblank_time,
+						bool in_vblank_irq)
+{
+	struct drm_device *dev = crtc->dev;
+	unsigned int pipe = crtc->index;
+
+	return drm_calc_vbltimestamp_from_scanoutpos(dev, pipe, max_error,
+						     vblank_time,
+						     in_vblank_irq);
+}
+EXPORT_SYMBOL(drm_crtc_calc_vbltimestamp_from_scanoutpos);
+
 /**
  * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
  * @dev: DRM device
@@ -577,8 +623,8 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants);
  *
  * Implements calculation of exact vblank timestamps from given drm_display_mode
  * timings and current video scanout position of a CRTC. This can be directly
- * used as the &drm_driver.get_vblank_timestamp implementation of a kms driver
- * if &drm_crtc_helper_funcs.get_scanout_position is implemented.
+ * used as the &drm_crtc_funcs.get_vblank_timestamp implementation of a kms
+ * driver if &drm_crtc_helper_funcs.get_scanout_position is implemented.
  *
  * The current implementation only handles standard video modes. For double scan
  * and interlaced modes the driver is supposed to adjust the hardware mode
@@ -733,15 +779,22 @@ static bool
 drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
 			  ktime_t *tvblank, bool in_vblank_irq)
 {
+	struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
 	bool ret = false;
 
 	/* Define requested maximum error on timestamps (nanoseconds). */
 	int max_error = (int) drm_timestamp_precision * 1000;
 
 	/* Query driver if possible and precision timestamping enabled. */
-	if (dev->driver->get_vblank_timestamp && (max_error > 0))
+	if (crtc->funcs->get_vblank_timestamp && (max_error > 0)) {
+		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+
+		ret = crtc->funcs->get_vblank_timestamp(crtc, &max_error,
+							tvblank, in_vblank_irq);
+	} else if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
 		ret = dev->driver->get_vblank_timestamp(dev, pipe, &max_error,
 							tvblank, in_vblank_irq);
+	}
 
 	/* GPU high precision timestamp query unsupported or failed.
 	 * Return current monotonic/gettimeofday timestamp as best estimate.
@@ -1050,11 +1103,19 @@ EXPORT_SYMBOL(drm_crtc_vblank_get);
 
 static bool __vblank_disable_immediate(struct drm_device *dev, unsigned int pipe)
 {
+	struct drm_crtc *crtc;
+
 	if (!dev->vblank_disable_immediate)
 		return false;
-	if (!dev->driver->get_vblank_timestamp)
-		return false;
-	return true;
+
+	crtc = drm_crtc_from_index(dev, pipe);
+	if (crtc && crtc->funcs->get_vblank_timestamp)
+		return true;
+
+	if (dev->driver->get_vblank_timestamp)
+		return true;
+
+	return false;
 }
 
 static void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
@@ -1733,9 +1794,11 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data,
 
 static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
 {
+	struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
 	struct drm_pending_vblank_event *e, *t;
 	ktime_t now;
 	u64 seq;
+	bool high_prec;
 
 	assert_spin_locked(&dev->event_lock);
 
@@ -1755,8 +1818,10 @@ static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
 		send_vblank_event(dev, e, seq, now);
 	}
 
-	trace_drm_vblank_event(pipe, seq, now,
-			dev->driver->get_vblank_timestamp != NULL);
+	high_prec = crtc->funcs->get_vblank_timestamp ||
+		    dev->driver->get_vblank_timestamp;
+
+	trace_drm_vblank_event(pipe, seq, now, high_prec);
 }
 
 /**
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 5e9b15a0e8c5..2caad975f415 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -867,6 +867,47 @@ struct drm_crtc_funcs {
 	 * new drivers as the replacement of &drm_driver.disable_vblank hook.
 	 */
 	void (*disable_vblank)(struct drm_crtc *crtc);
+
+	/**
+	 * @get_vblank_timestamp:
+	 *
+	 * Called by drm_get_last_vbltimestamp(). Should return a precise
+	 * timestamp when the most recent vblank interval ended or will end.
+	 *
+	 * Specifically, the timestamp in @vblank_time should correspond as
+	 * closely as possible to the time when the first video scanline of
+	 * the video frame after the end of vblank will start scanning out,
+	 * the time immediately after end of the vblank interval. If the
+	 * @crtc is currently inside vblank, this will be a time in the future.
+	 * If the @crtc is currently scanning out a frame, this will be the
+	 * past start time of the current scanout. This is meant to adhere
+	 * to the OpenML OML_sync_control extension specification.
+	 *
+	 * Parameters:
+	 *
+	 * crtc:
+	 *     CRTC for which timestamp should be returned.
+	 * max_error:
+	 *     Maximum allowable timestamp error in nanoseconds.
+	 *     Implementation should strive to provide timestamp
+	 *     with an error of at most max_error nanoseconds.
+	 *     Returns true upper bound on error for timestamp.
+	 * vblank_time:
+	 *     Target location for returned vblank timestamp.
+	 * in_vblank_irq:
+	 *     True when called from drm_crtc_handle_vblank().  Some drivers
+	 *     need to apply some workarounds for gpu-specific vblank irq quirks
+	 *     if flag is set.
+	 *
+	 * Returns:
+	 *
+	 * True on success, false on failure, which means the core should
+	 * fallback to a simple timestamp taken in drm_crtc_handle_vblank().
+	 */
+	bool (*get_vblank_timestamp)(struct drm_crtc *crtc,
+				     int *max_error,
+				     ktime_t *vblank_time,
+				     bool in_vblank_irq);
 };
 
 /**
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index e398512bfd5f..d735f7088a10 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -460,7 +460,7 @@ struct drm_crtc_helper_funcs {
 	 * optional accurate ktime_get() timestamp of when the position was
 	 * measured. Note that this is a helper callback which is only used
 	 * if a driver uses drm_calc_vbltimestamp_from_scanoutpos() for the
-	 * @drm_driver.get_vblank_timestamp callback.
+	 * @drm_crtc_funcs.get_vblank_timestamp callback.
 	 *
 	 * Parameters:
 	 *
diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h
index c16c44052b3d..cdc567c83805 100644
--- a/include/drm/drm_vblank.h
+++ b/include/drm/drm_vblank.h
@@ -233,6 +233,10 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
 					   unsigned int pipe, int *max_error,
 					   ktime_t *vblank_time,
 					   bool in_vblank_irq);
+bool drm_crtc_calc_vbltimestamp_from_scanoutpos(struct drm_crtc *crtc,
+						int *max_error,
+						ktime_t *vblank_time,
+						bool in_vblank_irq);
 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);
-- 
2.24.1