drm/fbdev-dma: Use regular fbdev I/O helpers

Use the regular fbdev helpers for framebuffer I/O instead of DRM's
helpers. Fbdev-dma does not use damage handling, so DRM's fbdev helpers
are mere wrappers around the fbdev code.

By using fbdev helpers directly within each DRM fbdev emulation,
we can eventually remove DRM's wrapper functions entirely.

v4:
	* use initializer macros for struct fb_ops
v2:
	* use FB_SYS_HELPERS option

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230530151228.22979-8-tzimmermann@suse.de

Author: tdz

drivers/gpu/drm/Kconfig

@@ -223,6 +223,7 @@ config DRM_TTM_HELPER
 config DRM_GEM_DMA_HELPER
 	tristate
 	depends on DRM
+	select FB_SYS_HELPERS if DRM_FBDEV_EMULATION
 	help
 	  Choose this if you need the GEM DMA helper functions
 

drivers/gpu/drm/drm_fbdev_dma.c

@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: MIT
 
+#include <linux/fb.h>
+
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fb_helper.h>
@@ -64,14 +66,11 @@ static const struct fb_ops drm_fbdev_dma_fb_ops = {
 	.owner = THIS_MODULE,
 	.fb_open = drm_fbdev_dma_fb_open,
 	.fb_release = drm_fbdev_dma_fb_release,
-	.fb_read = drm_fb_helper_sys_read,
-	.fb_write = drm_fb_helper_sys_write,
+	__FB_DEFAULT_SYS_OPS_RDWR,
 	DRM_FB_HELPER_DEFAULT_OPS,
-	.fb_fillrect = drm_fb_helper_sys_fillrect,
-	.fb_copyarea = drm_fb_helper_sys_copyarea,
-	.fb_imageblit = drm_fb_helper_sys_imageblit,
-	.fb_destroy = drm_fbdev_dma_fb_destroy,
+	__FB_DEFAULT_SYS_OPS_DRAW,
 	.fb_mmap = drm_fbdev_dma_fb_mmap,
+	.fb_destroy = drm_fbdev_dma_fb_destroy,
 };
 
 /*