drm: unexport function drm_vblank_no_hw_counter()

The function drm_vblank_no_hw_counter() is now only used in core vblank
wrapper code.  Let's unexport it by making it a static function.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1486458995-31018-4-git-send-email-shawnguo@kernel.org

drivers/gpu/drm/drm_irq.c

@@ -89,6 +89,16 @@ static void store_vblank(struct drm_device *dev, unsigned int pipe,
 	write_sequnlock(&vblank->seqlock);
 }
 
+/*
+ * "No hw counter" fallback implementation of .get_vblank_counter() hook,
+ * if there is no useable hardware frame counter available.
+ */
+static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
+{
+	WARN_ON_ONCE(dev->max_vblank_count != 0);
+	return 0;
+}
+
 static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
 {
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
@@ -1748,21 +1758,3 @@ bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
 	return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
 }
 EXPORT_SYMBOL(drm_crtc_handle_vblank);
-
-/**
- * drm_vblank_no_hw_counter - "No hw counter" implementation of .get_vblank_counter()
- * @dev: DRM device
- * @pipe: CRTC for which to read the counter
- *
- * Drivers can plug this into the .get_vblank_counter() function if
- * there is no useable hardware frame counter available.
- *
- * Returns:
- * 0
- */
-u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
-{
-	WARN_ON_ONCE(dev->max_vblank_count != 0);
-	return 0;
-}
-EXPORT_SYMBOL(drm_vblank_no_hw_counter);

include/drm/drm_drv.h

@@ -120,10 +120,9 @@ struct drm_driver {
 	 *
 	 * Driver callback for fetching a raw hardware vblank counter for the
 	 * CRTC specified with the pipe argument.  If a device doesn't have a
-	 * hardware counter, the driver can simply use
-	 * drm_vblank_no_hw_counter() function. The DRM core will account for
-	 * missed vblank events while interrupts where disabled based on system
-	 * timestamps.
+	 * 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

include/drm/drm_irq.h

@@ -152,7 +152,6 @@ void drm_crtc_vblank_reset(struct drm_crtc *crtc);
 void drm_crtc_vblank_on(struct drm_crtc *crtc);
 void drm_vblank_cleanup(struct drm_device *dev);
 u32 drm_accurate_vblank_count(struct drm_crtc *crtc);
-u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe);
 
 int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
 					  unsigned int pipe, int *max_error,