drm: add vblank hooks to struct drm_crtc_funcs

The vblank is mostly CRTC specific and implemented as part of CRTC
driver.  Let's keep the vblank hooks struct drm_driver for legacy
drivers, and add corresponding hooks in struct drm_crtc_funcs.  These
hooks take struct drm_crtc pointer as argument, and will be called by
core vblank handling code for DRIVER_MODESET drivers.

The new hooks get plugged into core by adding wrapper functions for
vblank handling code.  The .get_vblank_counter hook is effectively
optional, as we provide drm_vblank_no_hw_counter() as the default
fallback in the wrapper function.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1486458995-31018-2-git-send-email-shawnguo@kernel.org

drivers/gpu/drm/drm_irq.c

@@ -89,6 +89,21 @@ static void store_vblank(struct drm_device *dev, unsigned int pipe,
 	write_sequnlock(&vblank->seqlock);
 }
 
+static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
+{
+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+
+		if (crtc->funcs->get_vblank_counter)
+			return crtc->funcs->get_vblank_counter(crtc);
+	}
+
+	if (dev->driver->get_vblank_counter)
+		return dev->driver->get_vblank_counter(dev, pipe);
+
+	return drm_vblank_no_hw_counter(dev, pipe);
+}
+
 /*
  * Reset the stored timestamp for the current vblank count to correspond
  * to the last vblank occurred.
@@ -112,9 +127,9 @@ static void drm_reset_vblank_timestamp(struct drm_device *dev, unsigned int pipe
 	 * when drm_vblank_enable() applies the diff
 	 */
 	do {
-		cur_vblank = dev->driver->get_vblank_counter(dev, pipe);
+		cur_vblank = __get_vblank_counter(dev, pipe);
 		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, 0);
-	} while (cur_vblank != dev->driver->get_vblank_counter(dev, pipe) && --count > 0);
+	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
 
 	/*
 	 * Only reinitialize corresponding vblank timestamp if high-precision query
@@ -168,9 +183,9 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
 	 * corresponding vblank timestamp.
 	 */
 	do {
-		cur_vblank = dev->driver->get_vblank_counter(dev, pipe);
+		cur_vblank = __get_vblank_counter(dev, pipe);
 		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, flags);
-	} while (cur_vblank != dev->driver->get_vblank_counter(dev, pipe) && --count > 0);
+	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
 
 	if (dev->max_vblank_count != 0) {
 		/* trust the hw counter when it's around */
@@ -275,6 +290,20 @@ u32 drm_accurate_vblank_count(struct drm_crtc *crtc)
 }
 EXPORT_SYMBOL(drm_accurate_vblank_count);
 
+static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
+{
+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+
+		if (crtc->funcs->disable_vblank) {
+			crtc->funcs->disable_vblank(crtc);
+			return;
+		}
+	}
+
+	dev->driver->disable_vblank(dev, pipe);
+}
+
 /*
  * Disable vblank irq's on crtc, make sure that last vblank count
  * of hardware and corresponding consistent software vblank counter
@@ -298,7 +327,7 @@ static void vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
 	 * hardware potentially runtime suspended.
 	 */
 	if (vblank->enabled) {
-		dev->driver->disable_vblank(dev, pipe);
+		__disable_vblank(dev, pipe);
 		vblank->enabled = false;
 	}
 
@@ -1027,6 +1056,18 @@ void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
 }
 EXPORT_SYMBOL(drm_crtc_send_vblank_event);
 
+static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
+{
+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
+		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+
+		if (crtc->funcs->enable_vblank)
+			return crtc->funcs->enable_vblank(crtc);
+	}
+
+	return dev->driver->enable_vblank(dev, pipe);
+}
+
 /**
  * drm_vblank_enable - enable the vblank interrupt on a CRTC
  * @dev: DRM device
@@ -1052,7 +1093,7 @@ static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
 		 * timestamps. Filtercode in drm_handle_vblank() will
 		 * prevent double-accounting of same vblank interval.
 		 */
-		ret = dev->driver->enable_vblank(dev, pipe);
+		ret = __enable_vblank(dev, pipe);
 		DRM_DEBUG("enabling vblank on crtc %u, ret: %d\n", pipe, ret);
 		if (ret)
 			atomic_dec(&vblank->refcount);

include/drm/drm_crtc.h

@@ -608,6 +608,50 @@ struct drm_crtc_funcs {
 	 */
 	void (*atomic_print_state)(struct drm_printer *p,
 				   const struct drm_crtc_state *state);
+
+	/**
+	 * @get_vblank_counter:
+	 *
+	 * Driver callback for fetching a raw hardware vblank counter for the
+	 * CRTC. It's meant to be used by new drivers as the replacement of
+	 * &drm_driver.get_vblank_counter hook.
+	 *
+	 * This callback is optional. If a device doesn't have a hardware
+	 * counter, the driver can simply leave the hook as NULL. The DRM core
+	 * will account for missed vblank events while interrupts where disabled
+	 * based on system timestamps.
+	 *
+	 * Wraparound handling and loss of events due to modesetting is dealt
+	 * with in the DRM core code, as long as drivers call
+	 * drm_crtc_vblank_off() and drm_crtc_vblank_on() when disabling or
+	 * enabling a CRTC.
+	 *
+	 * Returns:
+	 *
+	 * Raw vblank counter value.
+	 */
+	u32 (*get_vblank_counter)(struct drm_crtc *crtc);
+
+	/**
+	 * @enable_vblank:
+	 *
+	 * Enable vblank interrupts for the CRTC. It's meant to be used by
+	 * new drivers as the replacement of &drm_driver.enable_vblank hook.
+	 *
+	 * Returns:
+	 *
+	 * Zero on success, appropriate errno if the vblank interrupt cannot
+	 * be enabled.
+	 */
+	int (*enable_vblank)(struct drm_crtc *crtc);
+
+	/**
+	 * @disable_vblank:
+	 *
+	 * Disable vblank interrupts for the CRTC. It's meant to be used by
+	 * new drivers as the replacement of &drm_driver.disable_vblank hook.
+	 */
+	void (*disable_vblank)(struct drm_crtc *crtc);
 };
 
 /**

include/drm/drm_drv.h

@@ -130,6 +130,9 @@ struct drm_driver {
 	 * drm_crtc_vblank_off() and drm_crtc_vblank_on() when disabling or
 	 * enabling a CRTC.
 	 *
+	 * This is deprecated and should not be used by new drivers.
+	 * Use &drm_crtc_funcs.get_vblank_counter instead.
+	 *
 	 * Returns:
 	 *
 	 * Raw vblank counter value.
@@ -142,6 +145,9 @@ struct drm_driver {
 	 * Enable vblank interrupts for the CRTC specified with the pipe
 	 * argument.
 	 *
+	 * This is deprecated and should not be used by new drivers.
+	 * Use &drm_crtc_funcs.enable_vblank instead.
+	 *
 	 * Returns:
 	 *
 	 * Zero on success, appropriate errno if the given @crtc's vblank
@@ -154,6 +160,9 @@ struct drm_driver {
 	 *
 	 * Disable vblank interrupts for the CRTC specified with the pipe
 	 * argument.
+	 *
+	 * This is deprecated and should not be used by new drivers.
+	 * Use &drm_crtc_funcs.disable_vblank instead.
 	 */
 	void (*disable_vblank) (struct drm_device *dev, unsigned int pipe);