drm: Make drm_crtc_check_viewport non-static

This function will be used by the universal plane helpers and may also
be useful for individual drivers.
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/drm_crtc.c

@@ -2186,11 +2186,16 @@ int drm_mode_set_config_internal(struct drm_mode_set *set)
 }
 EXPORT_SYMBOL(drm_mode_set_config_internal);
 
-/*
- * Checks that the framebuffer is big enough for the CRTC viewport
- * (x, y, hdisplay, vdisplay)
+/**
+ * drm_crtc_check_viewport - Checks that a framebuffer is big enough for the
+ *     CRTC viewport
+ * @crtc: CRTC that framebuffer will be displayed on
+ * @x: x panning
+ * @y: y panning
+ * @mode: mode that framebuffer will be displayed under
+ * @fb: framebuffer to check size of
  */
-static int drm_crtc_check_viewport(const struct drm_crtc *crtc,
+int drm_crtc_check_viewport(const struct drm_crtc *crtc,
 			    int x, int y,
 			    const struct drm_display_mode *mode,
 			    const struct drm_framebuffer *fb)
@@ -2224,6 +2229,7 @@ static int drm_crtc_check_viewport(const struct drm_crtc *crtc,
 
 	return 0;
 }
+EXPORT_SYMBOL(drm_crtc_check_viewport);
 
 /**
  * drm_mode_setcrtc - set CRTC configuration

include/drm/drm_crtc.h

@@ -882,6 +882,10 @@ extern int drm_plane_init(struct drm_device *dev,
 			  bool priv);
 extern void drm_plane_cleanup(struct drm_plane *plane);
 extern void drm_plane_force_disable(struct drm_plane *plane);
+extern int drm_crtc_check_viewport(const struct drm_crtc *crtc,
+				   int x, int y,
+				   const struct drm_display_mode *mode,
+				   const struct drm_framebuffer *fb);
 
 extern void drm_encoder_cleanup(struct drm_encoder *encoder);