videomixer: add EDID manipulation routines

This commit is contained in:
Sebastien Bourdeauducq 2013-11-10 23:50:18 +01:00
parent 75d25af3aa
commit f5211aff30
2 changed files with 275 additions and 0 deletions

248
software/videomixer/edid.c Normal file
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#include <stdint.h>
#include <string.h>
#include "edid.h"
struct edid {
uint8_t header[8];
uint8_t manufacturer[2];
uint8_t product_code[2];
uint8_t serial_number[4];
uint8_t manufacture_week;
uint8_t manufacture_year;
uint8_t edid_version;
uint8_t edid_revision;
uint8_t video_input;
uint8_t h_image_size;
uint8_t v_image_size;
uint8_t gamma;
uint8_t feature_support;
uint8_t cc_rg_l;
uint8_t cc_bw_l;
uint8_t cc_rx_h;
uint8_t cc_ry_h;
uint8_t cc_gx_h;
uint8_t cc_gy_h;
uint8_t cc_bx_h;
uint8_t cc_by_h;
uint8_t cc_wx_h;
uint8_t cc_wy_h;
uint8_t est_timings_1;
uint8_t est_timings_2;
uint8_t rsv_timings;
uint8_t timings_std[16];
uint8_t data_blocks[4][18];
uint8_t ext_block_count;
uint8_t checksum;
} __attribute__((packed));
struct edid_timing {
uint8_t pixel_clock[2];
uint8_t h_active_l;
uint8_t h_blanking_l;
uint8_t h_active_blanking_h;
uint8_t v_active_l;
uint8_t v_blanking_l;
uint8_t v_active_blanking_h;
uint8_t h_sync_offset_l;
uint8_t h_sync_width_l;
uint8_t v_sync_offset_width_l;
uint8_t hv_sync_offset_width_h;
uint8_t h_image_size_l;
uint8_t v_image_size_l;
uint8_t hv_image_size_h;
uint8_t h_border;
uint8_t v_border;
uint8_t flags;
} __attribute__((packed));
struct edid_descriptor {
uint8_t flag0;
uint8_t flag1;
uint8_t flag2;
uint8_t data_type;
uint8_t flag3;
uint8_t data[13];
} __attribute__((packed));
static const char correct_header[8] = {0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00};
static uint8_t compute_checksum(struct edid *e)
{
uint8_t *p = (uint8_t *)e;
uint8_t sum;
int i;
sum = 0;
for(i=0;i<127;i++)
sum += p[i];
return -sum;
}
int validate_edid(const void *buf)
{
struct edid *e = (struct edid *)buf;
if(memcmp(e->header, correct_header, 8) != 0)
return 0;
if(compute_checksum(e) != e->checksum)
return 0;
return 1;
}
void get_monitor_name(const void *buf, char *name)
{
struct edid *e = (struct edid *)buf;
int i;
uint8_t *data_block;
char *c;
name[0] = 0;
data_block = NULL;
for(i=0;i<4;i++)
if((e->data_blocks[i][0] == 0x00)
&& (e->data_blocks[i][1] == 0x00)
&& (e->data_blocks[i][2] == 0x00)
&& (e->data_blocks[i][3] == 0xfc)) {
data_block = e->data_blocks[i];
break;
}
if(!data_block)
return;
name[MAX_MONITOR_NAME_LEN] = 0;
memcpy(name, &data_block[5], MAX_MONITOR_NAME_LEN);
c = strchr(name, '\n');
if(c)
*c = 0;
}
static void generate_edid_timing(uint8_t *data_block, const struct video_timing *timing)
{
struct edid_timing *t = (struct edid_timing *)data_block;
unsigned int h_image_size, v_image_size;
t->pixel_clock[0] = timing->pixel_clock & 0xff;
t->pixel_clock[1] = timing->pixel_clock >> 8;
t->h_active_l = timing->h_active & 0xff;
t->h_blanking_l = timing->h_blanking & 0xff;
t->h_active_blanking_h = ((timing->h_active >> 8) << 4) | (timing->h_blanking >> 8);
t->v_active_l = timing->v_active & 0xff;
t->v_blanking_l = timing->v_blanking & 0xff;
t->v_active_blanking_h = ((timing->v_active >> 8) << 4) | (timing->v_blanking >> 8);
t->h_sync_offset_l = timing->h_sync_offset & 0xff;
t->h_sync_width_l = timing->h_sync_width & 0xff;
t->v_sync_offset_width_l = timing->v_sync_offset & 0xff;
t->hv_sync_offset_width_h = ((timing->h_sync_offset >> 8) << 6) | ((timing->h_sync_width >> 8) << 4)
| ((timing->v_sync_offset >> 8) << 2) | (timing->v_sync_width >> 8);
h_image_size = 10*timing->h_active/64;
v_image_size = 10*timing->v_active/64;
t->h_image_size_l = h_image_size & 0xff;
t->v_image_size_l = v_image_size & 0xff;
t->hv_image_size_h = ((h_image_size >> 8) << 4) | (v_image_size >> 8);
t->h_border = 0;
t->v_border = 0;
t->flags = 0x1e;
}
static void generate_monitor_name(uint8_t *data_block, const char *name)
{
struct edid_descriptor *d = (struct edid_descriptor *)data_block;
int i;
d->flag0 = d->flag1 = d->flag2 = d->flag3 = 0;
d->data_type = 0xfc;
for(i=0;i<12;i++) {
if(!name[i])
break;
d->data[i] = name[i];
}
d->data[i++] = 0x0a;
for(;i<13;i++)
d->data[i] = 0x20;
}
static void generate_unused(uint8_t *data_block)
{
struct edid_descriptor *d = (struct edid_descriptor *)data_block;
memset(d, 0, sizeof(struct edid_descriptor));
d->data_type = 0x10;
}
void generate_edid(void *out,
const char mfg_name[3], uint8_t product_code[2], int year,
const char *name,
const struct video_timing *timing)
{
struct edid *e = (struct edid *)out;
int i, j, k;
memcpy(e->header, correct_header, 8);
i = mfg_name[0] - 'A' + 1;
j = mfg_name[1] - 'A' + 1;
k = mfg_name[2] - 'A' + 1;
e->manufacturer[0] = (i << 2) | (j >> 3);
e->manufacturer[1] = ((j & 0x07) << 5) | k;
e->product_code[0] = product_code[0]; e->product_code[1] = product_code[1];
e->serial_number[0] = e->serial_number[1] = e->serial_number[2] = e->serial_number[3] = 0;
e->manufacture_week = 0;
e->manufacture_year = year - 1990;
e->edid_version = 1;
e->edid_revision = 3;
e->video_input = 0x80; /* digital */
e->h_image_size = timing->h_active/64;
e->v_image_size = timing->v_active/64;
e->gamma = 0xff;
e->feature_support = 0x06;
e->cc_rg_l = 0;
e->cc_bw_l = 0;
e->cc_rx_h = 0;
e->cc_ry_h = 0;
e->cc_gx_h = 0;
e->cc_gy_h = 0;
e->cc_bx_h = 0;
e->cc_by_h = 0;
e->cc_wx_h = 0;
e->cc_wy_h = 0;
e->est_timings_1 = 0;
e->est_timings_2 = 0;
e->rsv_timings = 0;
memset(e->timings_std, 0x01, 16);
generate_edid_timing(e->data_blocks[0], timing);
generate_monitor_name(e->data_blocks[1], name);
generate_unused(e->data_blocks[2]);
generate_unused(e->data_blocks[3]);
e->ext_block_count = 0;
e->checksum = compute_checksum(e);
}

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#ifndef __EDID_H
#define __EDID_H
#define MAX_MONITOR_NAME_LEN 13
struct video_timing {
unsigned int pixel_clock; /* in tens of kHz */
unsigned int h_active;
unsigned int h_blanking;
unsigned int h_sync_offset;
unsigned int h_sync_width;
unsigned int v_active;
unsigned int v_blanking;
unsigned int v_sync_offset;
unsigned int v_sync_width;
};
int validate_edid(const void *buf);
void get_monitor_name(const void *buf, char *name);
void generate_edid(void *out,
const char mfg_name[3], uint8_t product_code[2], int year,
const char *name,
const struct video_timing *timing);
#endif