videomixer: add EDID manipulation routines

diff --git a/software/videomixer/edid.c b/software/videomixer/edid.c
new file mode 100644 (file)
index 0000000..38cba6d
--- /dev/null
+++ b/software/videomixer/edid.c
@@ -0,0 +1,248 @@
+#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);
+}

diff --git a/software/videomixer/edid.h b/software/videomixer/edid.h
new file mode 100644 (file)
index 0000000..5c6b0a3
--- /dev/null
+++ b/software/videomixer/edid.h
@@ -0,0 +1,27 @@
+#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