edid: add function to manually specify mode

This patch will let you to choose a favourite mode to
display, while not just taking the edid detail timing.
But not all modes are able to set, only modes that
are in established or standard timing, and we only
support a few common common resolutions for now.

BUG=chrome-os-partner:42946
BRANCH=firmware-veyron
TEST=tested dev mode on Mickey at 640x480@60Hz

Change-Id: I8a9dedfe08057d42d85b8ca129935a258cb26762
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Original-Commit-Id: 090583f90ff720d88e5cfe69fcb2d541c716f0e6
Original-Change-Id: Iaa8c9a6fad106ee792f7cd1a0ac77e3dcbadf481
Original-Signed-off-by: Yakir Yang <ykk@rock-chips.com>
Original-Signed-off-by: David Hendricks <dhendrix@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/289671
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/11390
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/include/edid.h

@@ -21,8 +21,13 @@
 #define EDID_H
 
 enum edid_modes {
-	EDID_MODE_AUTO = 0,
 	EDID_MODE_640x480_60Hz,
+	EDID_MODE_720x480_60Hz,
+	EDID_MODE_1280x720_60Hz,
+	EDID_MODE_1920x1080_60Hz,
+	NUM_KNOWN_MODES,
+
+	EDID_MODE_AUTO
 };
 
 struct edid_mode {
@@ -75,6 +80,7 @@ struct edid {
 	unsigned int panel_bits_per_pixel;
 	/* used to compute timing for graphics chips. */
 	struct edid_mode mode;
+	u8 mode_is_supported[NUM_KNOWN_MODES];
 	unsigned int link_clock;
 	/* 3 variables needed for coreboot framebuffer.
 	 * In most cases, they are the same as the ha
@@ -89,5 +95,6 @@ struct edid {
 /* Defined in src/lib/edid.c */
 int decode_edid(unsigned char *edid, int size, struct edid *out);
 void set_vbe_mode_info_valid(struct edid *edid, uintptr_t fb_addr);
+int set_display_mode(struct edid *edid, enum edid_modes mode);
 
 #endif /* EDID_H */

src/lib/edid.c

@@ -976,6 +976,52 @@ static void dump_breakdown(unsigned char *edid)
 	printk(BIOS_SPEW, "\n");
 }
 
+/*
+ * Lookup table of some well-known modes that can be useful in case the
+ * auto-detected mode is unsuitable.
+ * ha = hdisplay;			va = vdisplay;
+ * hbl = htotal - hdisplay;		vbl = vtotal - vdisplay;
+ * hso = hsync_start - hdsiplay;	vso = vsync_start - vdisplay;
+ * hspw = hsync_end - hsync_start;	vspw = vsync_end - vsync_start;
+ */
+static struct edid_mode known_modes[NUM_KNOWN_MODES] = {
+	[EDID_MODE_640x480_60Hz] = {
+		.name = "640x480@60Hz", .pixel_clock = 25175, .refresh = 60,
+		.ha = 640, .hbl = 160, .hso = 16, .hborder = 96,
+		.va = 480, .vbl = 45, .vso = 10, .vspw = 2,
+		.phsync = '-', .pvsync = '-' },
+	[EDID_MODE_720x480_60Hz] = {
+		.name = "720x480@60Hz", .pixel_clock = 27000, .refresh = 60,
+		.ha = 720, .hbl = 78, .hso = 16, .hborder = 62,
+		.va = 480, .vbl = 45, .vso = 9, .vspw = 6,
+		.phsync = '-', .pvsync = '-' },
+	[EDID_MODE_1280x720_60Hz] = {
+		.name = "1280x720@60Hz", .pixel_clock = 74250, .refresh = 60,
+		.ha = 1280, .hbl = 370, .hso = 110, .hborder = 40,
+		.va = 720, .vbl = 30, .vso = 5, .vspw = 20,
+		.phsync = '+', .pvsync = '+' },
+	[EDID_MODE_1920x1080_60Hz] = {
+		.name = "1920x1080@60Hz", .pixel_clock = 148500, .refresh = 60,
+		.ha = 1920, .hbl = 280, .hso = 88, .hborder = 44,
+		.va = 1080, .vbl = 45, .vso = 4, .vspw = 5,
+		.phsync = '+', .pvsync = '+' },
+};
+
+int set_display_mode(struct edid *edid, enum edid_modes mode)
+{
+	if (mode == EDID_MODE_AUTO)
+		return 0;
+
+	if (edid->mode_is_supported[mode]) {
+		printk(BIOS_DEBUG, "Forcing mode %s\n", known_modes[mode].name);
+		edid->mode = known_modes[mode];
+		return 0;
+	}
+
+	printk(BIOS_ERR, "Requested display mode not supported.\n");
+	return -1;
+}
+
 /*
  * Given a raw edid bloc, decode it into a form
  * that other parts of coreboot can use -- mainly
@@ -986,7 +1032,7 @@ static void dump_breakdown(unsigned char *edid)
  */
 int decode_edid(unsigned char *edid, int size, struct edid *out)
 {
-	int analog, i;
+	int analog, i, j;
 	struct edid_context c = {
 	    .has_valid_cvt = 1,
 	    .has_valid_dummy_block = 1,
@@ -1210,6 +1256,14 @@ int decode_edid(unsigned char *edid, int size, struct edid *out)
 			printk(BIOS_SPEW, "  %dx%d@%dHz\n", established_timings[i].x,
 			       established_timings[i].y, established_timings[i].refresh);
 		}
+
+		for (j = 0; j < NUM_KNOWN_MODES; j++) {
+			if (known_modes[j].ha == established_timings[i].x &&
+				known_modes[j].va == established_timings[i].y &&
+				known_modes[j].refresh ==  established_timings[i].refresh)
+					out->mode_is_supported[j] = 1;
+		}
+
 	}
 
 	printk(BIOS_SPEW, "Standard timings supported:\n");
@@ -1245,6 +1299,11 @@ int decode_edid(unsigned char *edid, int size, struct edid *out)
 		refresh = 60 + (b2 & 0x3f);
 
 		printk(BIOS_SPEW, "  %dx%d@%dHz\n", x, y, refresh);
+		for (j = 0; j < NUM_KNOWN_MODES; j++) {
+			if (known_modes[j].ha == x && known_modes[j].va == y &&
+					known_modes[j].refresh == refresh)
+				out->mode_is_supported[j] = 1;
+		}
 	}
 
 	/* detailed timings */