drm/ast: Update cursor image and checksum from same function

Cursor image and checksum go hand in hand. Update both in the same
place. The helper cannot fail, so remove the return type.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200702115029.5281-5-tzimmermann@suse.de

drivers/gpu/drm/ast/ast_cursor.c

@@ -84,7 +84,7 @@ void ast_cursor_fini(struct ast_private *ast)
 	}
 }
 
-static u32 copy_cursor_image(u8 *src, u8 *dst, int width, int height)
+static void update_cursor_image(u8 __iomem *dst, const u8 *src, int width, int height)
 {
 	union {
 		u32 ul;
@@ -96,7 +96,8 @@ static u32 copy_cursor_image(u8 *src, u8 *dst, int width, int height)
 	} data16;
 	u32 csum = 0;
 	s32 alpha_dst_delta, last_alpha_dst_delta;
-	u8 *srcxor, *dstxor;
+	u8 __iomem *dstxor;
+	const u8 *srcxor;
 	int i, j;
 	u32 per_pixel_copy, two_pixel_copy;
 
@@ -137,16 +138,6 @@ static u32 copy_cursor_image(u8 *src, u8 *dst, int width, int height)
 		}
 		dstxor += last_alpha_dst_delta;
 	}
-	return csum;
-}
-
-static int ast_cursor_update(void *dst, void *src, unsigned int width,
-			     unsigned int height)
-{
-	u32 csum;
-
-	/* do data transfer to cursor cache */
-	csum = copy_cursor_image(src, dst, width, height);
 
 	/* write checksum + signature */
 	dst += AST_HWC_SIZE;
@@ -155,8 +146,6 @@ static int ast_cursor_update(void *dst, void *src, unsigned int width,
 	writel(height, dst + AST_HWC_SIGNATURE_SizeY);
 	writel(0, dst + AST_HWC_SIGNATURE_HOTSPOTX);
 	writel(0, dst + AST_HWC_SIGNATURE_HOTSPOTY);
-
-	return 0;
 }
 
 int ast_cursor_blit(struct ast_private *ast, struct drm_framebuffer *fb)
@@ -188,9 +177,8 @@ int ast_cursor_blit(struct ast_private *ast, struct drm_framebuffer *fb)
 		goto err_drm_gem_vram_vunmap_src;
 	}
 
-	ret = ast_cursor_update(dst, src, fb->width, fb->height);
-	if (ret)
-		goto err_drm_gem_vram_vunmap_dst;
+	/* do data transfer to cursor BO */
+	update_cursor_image(dst, src, fb->width, fb->height);
 
 	/*
 	 * Always unmap buffers here. Destination buffers are
@@ -203,8 +191,6 @@ int ast_cursor_blit(struct ast_private *ast, struct drm_framebuffer *fb)
 
 	return 0;
 
-err_drm_gem_vram_vunmap_dst:
-	drm_gem_vram_vunmap(ast->cursor.gbo[ast->cursor.next_index], dst);
 err_drm_gem_vram_vunmap_src:
 	drm_gem_vram_vunmap(gbo, src);
 err_drm_gem_vram_unpin: