src/include/edid.h

   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 */