xref: /aosp_15_r20/external/coreboot/src/include/edid.h (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 
3 #ifndef EDID_H
4 #define EDID_H
5 
6 #include <stdint.h>
7 #include <framebuffer_info.h>
8 #include "commonlib/coreboot_tables.h"
9 
10 enum edid_modes {
11 	EDID_MODE_640x480_60Hz,
12 	EDID_MODE_720x480_60Hz,
13 	EDID_MODE_1280x720_60Hz,
14 	EDID_MODE_1920x1080_60Hz,
15 	NUM_KNOWN_MODES,
16 
17 	EDID_MODE_AUTO
18 };
19 
20 struct edid_mode {
21 	const char *name;
22 	unsigned int pixel_clock;
23 	int lvds_dual_channel;
24 	unsigned int refresh;
25 	unsigned int ha;
26 	unsigned int hbl;
27 	unsigned int hso;
28 	unsigned int hspw;
29 	unsigned int hborder;
30 	unsigned int va;
31 	unsigned int vbl;
32 	unsigned int vso;
33 	unsigned int vspw;
34 	unsigned int vborder;
35 	unsigned char phsync;
36 	unsigned char pvsync;
37 	unsigned int x_mm;
38 	unsigned int y_mm;
39 };
40 
41 /* structure for communicating EDID information from a raw EDID block to
42  * higher level functions.
43  * The size of the data types is not critical, so we leave them as
44  * unsigned int. We can move more into this struct as needed.
45  */
46 
47 #define EDID_ASCII_STRING_LENGTH 13
48 
49 struct edid {
50 	/* These next three things used to all be called bpp.
51 	 * Merriment ensued. The identifier
52 	 * 'bpp' is herewith banished from our
53 	 * Kingdom.
54 	 */
55 	/* How many bits in the framebuffer per pixel.
56 	 * Under all reasonable circumstances, it's 32.
57 	 */
58 	unsigned int framebuffer_bits_per_pixel;
59 	/* On the panel, how many bits per color?
60 	 * In almost all cases, it's 6 or 8.
61 	 * The standard allows for much more!
62 	 */
63 	unsigned int panel_bits_per_color;
64 	/* On the panel, how many bits per pixel.
65 	 * On Planet Earth, there are three colors
66 	 * per pixel, but this is convenient to have here
67 	 * instead of having 3*panel_bits_per_color
68 	 * all over the place.
69 	 */
70 	unsigned int panel_bits_per_pixel;
71 	/* used to compute timing for graphics chips. */
72 	struct edid_mode mode;
73 	u8 mode_is_supported[NUM_KNOWN_MODES];
74 	unsigned int link_clock;
75 	/* 3 variables needed for coreboot framebuffer.
76 	 * In most cases, they are the same as the ha
77 	 * and va variables, but not always, as in the
78 	 * case of a 1366 wide display.
79 	 */
80 	u32 x_resolution;
81 	u32 y_resolution;
82 	u32 bytes_per_line;
83 
84 	int hdmi_monitor_detected;
85 	char ascii_string[EDID_ASCII_STRING_LENGTH + 1];
86 	char manufacturer_name[3 + 1];
87 };
88 
89 enum edid_status {
90 	EDID_CONFORMANT,
91 	EDID_NOT_CONFORMANT,
92 	EDID_ABSENT,
93 };
94 
95 /* Defined in src/lib/edid.c */
96 int decode_edid(unsigned char *edid, int size, struct edid *out);
97 void edid_set_framebuffer_bits_per_pixel(struct edid *edid, int fb_bpp,
98 					 int row_byte_alignment);
99 int set_display_mode(struct edid *edid, enum edid_modes mode);
100 
101 #endif /* EDID_H */
102