fbdev/hyperv_fb: Use fb_ops helpers for deferred I/O

Generate callback functions for struct fb_ops with the fbdev macro
FB_GEN_DEFAULT_DEFERRED_IOMEM_OPS(). Initialize struct fb_ops to
the generated functions with fbdev initializer macros.

The hyperv_fb driver is incomplete in its handling of deferred I/O
and damage framebuffers. Write operations do no trigger damage handling.
Fixing this is beyond the scope of this patch.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230828132131.29295-5-tzimmermann@suse.de

drivers/video/fbdev/Kconfig

@@ -1905,11 +1905,8 @@ config FB_BROADSHEET
 config FB_HYPERV
 	tristate "Microsoft Hyper-V Synthetic Video support"
 	depends on FB && HYPERV
-	select FB_CFB_FILLRECT
-	select FB_CFB_COPYAREA
-	select FB_CFB_IMAGEBLIT
-	select FB_DEFERRED_IO
 	select DMA_CMA if HAVE_DMA_CONTIGUOUS && CMA
+	select FB_IOMEM_HELPERS_DEFERRED
 	select VIDEO_NOMODESET
 	help
 	  This framebuffer driver supports Microsoft Hyper-V Synthetic Video.

drivers/video/fbdev/hyperv_fb.c

@@ -848,58 +848,38 @@ static int hvfb_blank(int blank, struct fb_info *info)
 	return 1;	/* get fb_blank to set the colormap to all black */
 }
 
-static void hvfb_cfb_fillrect(struct fb_info *p,
-			      const struct fb_fillrect *rect)
+static void hvfb_ops_damage_range(struct fb_info *info, off_t off, size_t len)
 {
-	struct hvfb_par *par = p->par;
-
-	cfb_fillrect(p, rect);
-	if (par->synchronous_fb)
-		synthvid_update(p, 0, 0, INT_MAX, INT_MAX);
-	else
-		hvfb_ondemand_refresh_throttle(par, rect->dx, rect->dy,
-					       rect->width, rect->height);
+	/* TODO: implement damage handling */
 }
 
-static void hvfb_cfb_copyarea(struct fb_info *p,
-			      const struct fb_copyarea *area)
+static void hvfb_ops_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
 {
-	struct hvfb_par *par = p->par;
+	struct hvfb_par *par = info->par;
 
-	cfb_copyarea(p, area);
 	if (par->synchronous_fb)
-		synthvid_update(p, 0, 0, INT_MAX, INT_MAX);
+		synthvid_update(info, 0, 0, INT_MAX, INT_MAX);
 	else
-		hvfb_ondemand_refresh_throttle(par, area->dx, area->dy,
-					       area->width, area->height);
+		hvfb_ondemand_refresh_throttle(par, x, y, width, height);
 }
 
-static void hvfb_cfb_imageblit(struct fb_info *p,
-			       const struct fb_image *image)
-{
-	struct hvfb_par *par = p->par;
-
-	cfb_imageblit(p, image);
-	if (par->synchronous_fb)
-		synthvid_update(p, 0, 0, INT_MAX, INT_MAX);
-	else
-		hvfb_ondemand_refresh_throttle(par, image->dx, image->dy,
-					       image->width, image->height);
-}
+/*
+ * TODO: GEN1 codepaths allocate from system or DMA-able memory. Fix the
+ *       driver to use the _SYSMEM_ or _DMAMEM_ helpers in these cases.
+ */
+FB_GEN_DEFAULT_DEFERRED_IOMEM_OPS(hvfb_ops,
+				  hvfb_ops_damage_range,
+				  hvfb_ops_damage_area)
 
 static const struct fb_ops hvfb_ops = {
 	.owner = THIS_MODULE,
+	FB_DEFAULT_DEFERRED_OPS(hvfb_ops),
 	.fb_check_var = hvfb_check_var,
 	.fb_set_par = hvfb_set_par,
 	.fb_setcolreg = hvfb_setcolreg,
-	.fb_fillrect = hvfb_cfb_fillrect,
-	.fb_copyarea = hvfb_cfb_copyarea,
-	.fb_imageblit = hvfb_cfb_imageblit,
 	.fb_blank = hvfb_blank,
-	.fb_mmap = fb_deferred_io_mmap,
 };
 
-
 /* Get options from kernel paramenter "video=" */
 static void hvfb_get_option(struct fb_info *info)
 {