edid.h

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#ifndef EDID_H
#define EDID_H
 
#include <stdint.h>
#include <framebuffer_info.h>
#include "commonlib/coreboot_tables.h"
 
enum edid_modes {
        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 {
        const char *name;
        unsigned int pixel_clock;
        int lvds_dual_channel;
        unsigned int refresh;
        unsigned int ha;
        unsigned int hbl;
        unsigned int hso;
        unsigned int hspw;
        unsigned int hborder;
        unsigned int va;
        unsigned int vbl;
        unsigned int vso;
        unsigned int vspw;
        unsigned int vborder;
        unsigned char phsync;
        unsigned char pvsync;
        unsigned int x_mm;
        unsigned int y_mm;
};
 
/* structure for communicating EDID information from a raw EDID block to
 * higher level functions.
 * The size of the data types is not critical, so we leave them as
 * unsigned int. We can move more into this struct as needed.
 */
 
#define EDID_ASCII_STRING_LENGTH 13
 
struct edid {
        /* These next three things used to all be called bpp.
         * Merriment ensued. The identifier
         * 'bpp' is herewith banished from our
         * Kingdom.
         */
        /* How many bits in the framebuffer per pixel.
         * Under all reasonable circumstances, it's 32.
         */
        unsigned int framebuffer_bits_per_pixel;
        /* On the panel, how many bits per color?
         * In almost all cases, it's 6 or 8.
         * The standard allows for much more!
         */
        unsigned int panel_bits_per_color;
        /* On the panel, how many bits per pixel.
         * On Planet Earth, there are three colors
         * per pixel, but this is convenient to have here
         * instead of having 3*panel_bits_per_color
         * all over the place.
         */
        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
         * and va variables, but not always, as in the
         * case of a 1366 wide display.
         */
        u32 x_resolution;
        u32 y_resolution;
        u32 bytes_per_line;
 
        int hdmi_monitor_detected;
        char ascii_string[EDID_ASCII_STRING_LENGTH + 1];
        char manufacturer_name[3 + 1];
};
 
enum edid_status {
        EDID_CONFORMANT,
        EDID_NOT_CONFORMANT,
        EDID_ABSENT,
};
 
/* Defined in src/lib/edid.c */
int decode_edid(unsigned char *edid, int size, struct edid *out);
void edid_set_framebuffer_bits_per_pixel(struct edid *edid, int fb_bpp,
                                         int row_byte_alignment);
int set_display_mode(struct edid *edid, enum edid_modes mode);
 
#endif /* EDID_H */