cbgfx: add clear_screen

clear_screen clears the screen with the specified color.

BUG=none
BRANCH=tot
TEST=Tested on Samus

Change-Id: I45e61c67485dbdbe15e2b602718232bc6382ad00
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Original-Commit-Id: 1ab04e2cc8d3c3e36e4eb41d9e7b0fdc25595200
Original-Change-Id: I1b3890b9e8ca52e796f417b5f41d4fa02a97a255
Original-Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/301451
Original-Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: http://review.coreboot.org/11924
Tested-by: build bot (Jenkins)

payloads/libpayload/drivers/video/graphics.c

@@ -194,6 +194,22 @@ int clear_canvas(struct rgb_color *rgb)
 	return draw_box(&box, rgb);
 }
 
+int clear_screen(struct rgb_color *rgb)
+{
+	uint32_t color;
+	struct vector p;
+
+	if (cbgfx_init())
+		return CBGFX_ERROR_INIT;
+
+	color = calculate_color(rgb);
+	for (p.y = 0; p.y < screen.size.height; p.y++)
+		for (p.x = 0; p.x < screen.size.width; p.x++)
+			set_pixel(&p, color);
+
+	return CBGFX_SUCCESS;
+}
+
 /*
  * This check guarantees we will not try to read outside pixel data.
  */

payloads/libpayload/include/cbgfx.h

@@ -90,6 +90,11 @@ int draw_box(const struct rect *box, const struct rgb_color *rgb);
  */
 int clear_canvas(struct rgb_color *rgb);
 
+/*
+ * Clear the screen
+ */
+int clear_screen(struct rgb_color *rgb);
+
 /*
  * Draw a bitmap image on screen.
  *