drm/tegra: Implement page-flipping support

All the necessary support bits like .mode_set_base() and VBLANK are now
available, so page-flipping case easily be implemented on top.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index 01f0aee..6dd75a2 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -84,6 +84,9 @@
 	struct drm_info_list *debugfs_files;
 	struct drm_minor *minor;
 	struct dentry *debugfs;
+
+	/* page-flip handling */
+	struct drm_pending_vblank_event *event;
 };
 
 static inline struct tegra_dc *host1x_client_to_dc(struct host1x_client *client)
@@ -133,6 +136,8 @@
 				 const struct tegra_dc_window *window);
 extern void tegra_dc_enable_vblank(struct tegra_dc *dc);
 extern void tegra_dc_disable_vblank(struct tegra_dc *dc);
+extern void tegra_dc_cancel_page_flip(struct drm_crtc *crtc,
+				      struct drm_file *file);
 
 struct tegra_output_ops {
 	int (*enable)(struct tegra_output *output);