ast_plane_vaddr
u8 __iomem *dst = ast_plane_vaddr(ast_plane); /* TODO: Use mapping abstraction properly */
u8 __iomem *dst = ast_plane_vaddr(&ast->cursor_plane.base);
void __iomem *ast_plane_vaddr(struct ast_plane *ast);
struct iosys_map dst = IOSYS_MAP_INIT_VADDR_IOMEM(ast_plane_vaddr(ast_plane));
iosys_map_set_vaddr_iomem(&sb->map[0], ast_plane_vaddr(ast_plane));