cbgfx: coreboot graphics library

This change introduces cbgfx, a graphics library, which provides APIs for
drawing basic shapes, texts, graphic data, etc. on a screen.

BUG=chrome-os-partner:43444
BRANCH=tot
TEST=Drew boxes by draw command of depthcharge cli on Samus

Change-Id: I6019e5998e65dca3ab4785a90669b5db02463d2e
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Original-Commit-Id: 5b3ebce8eae91be742e4f977d3407d24e1537580
Original-Reviewed-on: https://chromium-review.googlesource.com/290301
Original-Reviewed-by: Stefan Reinauer <reinauer@google.com>
Original-Change-Id: I10db27715cb907bdc451a33ed99d257e3af241b7
Original-Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/291065
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11408
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

payloads/libpayload/drivers/Makefile.inc

@@ -68,6 +68,9 @@ libc-$(CONFIG_LP_GEODELX_VIDEO_CONSOLE) += video/font8x16.c
 libc-$(CONFIG_LP_COREBOOT_VIDEO_CONSOLE) += video/corebootfb.c
 libc-$(CONFIG_LP_COREBOOT_VIDEO_CONSOLE) += video/font8x16.c
 
+# cbgfx: coreboot graphics library
+libc-y += video/graphics.c
+
 # AHCI/ATAPI driver
 libc-$(CONFIG_LP_STORAGE) += storage/storage.c
 libc-$(CONFIG_LP_STORAGE_AHCI) += storage/ahci.c

payloads/libpayload/drivers/video/graphics.c

@@ -0,0 +1,148 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2015 Google, Inc.
+ */
+
+#include <libpayload.h>
+#include <sysinfo.h>
+
+/*
+ * 'canvas' is the drawing area located in the center of the screen. It's a
+ * square area, stretching vertically to the edges of the screen, leaving
+ * non-drawing areas on the left and right. The screen is assumed to be
+ * landscape.
+ */
+static struct vector canvas;
+static uint32_t canvas_offset;		/* horizontal position of canvas */
+
+/*
+ * Framebuffer is assumed to assign a higher coordinate (larger x, y) to
+ * a higher address
+ */
+static struct cb_framebuffer *fbinfo;
+static uint8_t *fbaddr;
+
+static char initialized = 0;
+#define LOG(x...)	printf("CBGFX: " x)
+
+static void add_vectors(struct vector *out,
+			const struct vector *v1, const struct vector *v2)
+{
+	out->x = v1->x + v2->x;
+	out->y = v1->y + v2->y;
+}
+
+static void to_canvas(const struct vector *relative, struct vector *absolute)
+{
+	absolute->x = canvas.width * relative->x / CANVAS_SCALE;
+	absolute->y = canvas.height * relative->y / CANVAS_SCALE;
+}
+
+static int within_canvas(const struct vector *v)
+{
+	return v->x < canvas.width && v->y < canvas.height;
+}
+
+static inline uint32_t calculate_color(const struct rgb_color *rgb)
+{
+	uint32_t color = 0;
+	color |= (rgb->red >> (8 - fbinfo->red_mask_size))
+		<< fbinfo->red_mask_pos;
+	color |= (rgb->green >> (8 - fbinfo->green_mask_size))
+		<< fbinfo->green_mask_pos;
+	color |= (rgb->blue >> (8 - fbinfo->blue_mask_size))
+		<< fbinfo->blue_mask_pos;
+	return color;
+}
+
+/*
+ * Plot a pixel in a framebuffer. This is called from tight loops. Keep it slim
+ * and do the validation at callers' site.
+ */
+static inline void set_pixel(struct vector *coord, uint32_t color)
+{
+	const int bpp = fbinfo->bits_per_pixel;
+	int i;
+	uint8_t * const pixel = fbaddr + (coord->x + canvas_offset +
+			coord->y * fbinfo->x_resolution) * bpp / 8;
+	for (i = 0; i < bpp / 8; i++)
+		pixel[i] = (color >> (i * 8));
+}
+
+/*
+ * Initializes the library. Automatically called by APIs. It sets up
+ * the canvas and the framebuffer.
+ */
+static int cbgfx_init(void)
+{
+	if (initialized)
+		return 0;
+
+	fbinfo = lib_sysinfo.framebuffer;
+	if (!fbinfo)
+		return -1;
+
+	fbaddr = phys_to_virt((uint8_t *)(uintptr_t)(fbinfo->physical_address));
+	if (!fbaddr)
+		return -1;
+
+	/* calculate canvas size, assuming the screen is landscape */
+	canvas.height = fbinfo->y_resolution;
+	canvas.width = canvas.height;
+	canvas_offset = (fbinfo->x_resolution - canvas.width) / 2;
+	if (canvas_offset < 0) {
+		LOG("Portrait screens are not supported\n");
+		return -1;
+	}
+
+	initialized = 1;
+	LOG("cbgfx initialized: canvas width=%d, height=%d, offset=%d\n",
+	    canvas.width, canvas.height, canvas_offset);
+
+	return 0;
+}
+
+int draw_box(const struct vector *top_left_rel,
+	     const struct vector *size_rel,
+	     const struct rgb_color *rgb)
+{
+	struct vector top_left;
+	struct vector size;
+	struct vector p, t;
+	const uint32_t color = calculate_color(rgb);
+
+	if (cbgfx_init())
+		return CBGFX_ERROR_INIT;
+
+	to_canvas(top_left_rel, &top_left);
+	to_canvas(size_rel, &size);
+	add_vectors(&t, &top_left, &size);
+	if (!within_canvas(&t)) {
+		LOG("Box exceeds canvas boundary\n");
+		return CBGFX_ERROR_BOUNDARY;
+	}
+
+	for (p.y = top_left.y; p.y < t.y; p.y++)
+		for (p.x = top_left.x; p.x < t.x; p.x++)
+			set_pixel(&p, color);
+
+	return CBGFX_SUCCESS;
+}
+
+int clear_canvas(struct rgb_color *rgb)
+{
+	const struct vector coord = {
+		.x = 0,
+		.y = 0,
+	};
+	const struct vector size = {
+		.width = CANVAS_SCALE,
+		.height = CANVAS_SCALE,
+	};
+
+	if (cbgfx_init())
+		return CBGFX_ERROR_INIT;
+
+	return draw_box(&coord, &size, rgb);
+}

payloads/libpayload/include/cbgfx.h

@@ -0,0 +1,66 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2015 Google, Inc.
+ */
+
+#include <stdint.h>
+
+/*
+ * API error codes
+ */
+#define CBGFX_SUCCESS		0
+/* unknown error */
+#define CBGFX_ERROR_UNKNOWN	1
+/* failed to initialize cbgfx library */
+#define CBGFX_ERROR_INIT	2
+/* drawing beyond canvas boundary */
+#define CBGFX_ERROR_BOUNDARY	3
+
+struct vector {
+	union {
+		uint32_t x;
+		uint32_t width;
+	};
+	union {
+		uint32_t y;
+		uint32_t height;
+	};
+};
+
+struct rgb_color {
+	uint8_t red;
+	uint8_t green;
+	uint8_t blue;
+};
+
+/*
+ * Resolution of scale parameters used to describe height, width, coordinate,
+ * etc. relative to the canvas. For example, if it's 100, scales range from 0 to
+ * 100%.
+ */
+#define CANVAS_SCALE		100
+
+/*
+ * The coordinate system is expected to have (0, 0) at top left corner with
+ * y values increasing towards bottom of screen.
+ */
+
+/*
+ * draw a box filled with a color on screen
+ *
+ * top_left_rel: coordinate of top left corner of the box, relative to canvas.
+ * (0 - CANVAS_SCALE).
+ * size_rel: width and height of the box, relative to canvas. (0 - CANVAS_SCALE)
+ * rgb: RGB color of the box.
+ *
+ * return: CBGFX_* error codes
+ */
+int draw_box(const struct vector *top_left_rel,
+	     const struct vector *size_rel,
+	     const struct rgb_color *rgb);
+
+/*
+ * Clear the canvas
+ */
+int clear_canvas(struct rgb_color *rgb);

payloads/libpayload/include/libpayload.h

@@ -44,6 +44,7 @@
 #define _LIBPAYLOAD_H
 
 #include <libpayload-config.h>
+#include <cbgfx.h>
 #include <ctype.h>
 #include <die.h>
 #include <endian.h>