Add DDC/plug and play monitor support to S3 ViRGE.

src/vid_ddc.c

@@ -251,6 +251,12 @@ void ddc_i2c_change(int new_clock, int new_data)
                 case I2C_TRANSMIT_START:
                 if (!i2c.clock && new_clock)
                         i2c.state = I2C_TRANSMIT;
+                if (i2c.clock && new_clock && !i2c.last_data && new_data) /*Stop bit*/
+                {
+//                        pclog("Stop bit received\n");
+                        i2c.state = I2C_IDLE;
+                        prom_stop();
+                }
                 case I2C_TRANSMIT:
                 if (!i2c.clock && new_clock)
                 {

src/vid_s3_virge.c

@@ -8,6 +8,7 @@
 #include "rom.h"
 #include "thread.h"
 #include "video.h"
+#include "vid_ddc.h"
 #include "vid_s3_virge.h"
 #include "vid_svga.h"
 #include "vid_svga_render.h"
@@ -235,6 +236,8 @@ typedef struct virge_t
         int virge_busy;
         
         uint8_t subsys_stat, subsys_cntl;
+
+        uint8_t serialport;
 } virge_t;
 
 static inline void wake_fifo_thread(virge_t *virge)
@@ -306,6 +309,11 @@ enum
 #define INT_3DF_EMP  (1 << 6)
 #define INT_MASK 0xff
 
+#define SERIAL_PORT_SCW (1 << 0)
+#define SERIAL_PORT_SDW (1 << 1)
+#define SERIAL_PORT_SCR (1 << 2)
+#define SERIAL_PORT_SDR (1 << 3)
+
 static void s3_virge_update_irqs(virge_t *virge)
 {
         if ((virge->svga.crtc[0x32] & 0x10) && (virge->subsys_stat & virge->subsys_cntl & INT_MASK))
@@ -786,6 +794,14 @@ static uint8_t s3_virge_mmio_read(uint32_t addr, void *p)
                 case 0x83d8: case 0x83d9: case 0x83da: case 0x83db:
                 case 0x83dc: case 0x83dd: case 0x83de: case 0x83df:
                 return s3_virge_in(addr & 0x3ff, p);
+
+                case 0xff20: case 0xff21:
+                ret = virge->serialport & ~(SERIAL_PORT_SCR | SERIAL_PORT_SDR);
+                if ((virge->serialport & SERIAL_PORT_SCW) && ddc_read_clock())
+                        ret |= SERIAL_PORT_SCR;
+                if ((virge->serialport & SERIAL_PORT_SDW) && ddc_read_data())
+                        ret |= SERIAL_PORT_SDR;
+                return ret;
         }
         return 0xff;
 }
@@ -1355,9 +1371,12 @@ static void s3_virge_mmio_write(uint32_t addr, uint8_t val, void *p)
                 case 0x83dc: case 0x83dd: case 0x83de: case 0x83df:
                 s3_virge_out(addr & 0x3ff, val, p);
                 break;
-        }
-
                 
+                case 0xff20:
+                virge->serialport = val;
+                ddc_i2c_change((val & SERIAL_PORT_SCW) ? 1 : 0, (val & SERIAL_PORT_SDW) ? 1 : 0);
+                break;
+        }
 }
 static void s3_virge_mmio_write_w(uint32_t addr, uint16_t val, void *p)
 {
@@ -1374,6 +1393,10 @@ static void s3_virge_mmio_write_w(uint32_t addr, uint16_t val, void *p)
                 s3_virge_mmio_write(addr, val, p);
                 s3_virge_mmio_write(addr + 1, val >> 8, p);
                 break;
+
+                case 0xff20:
+                s3_virge_mmio_write(addr, val, p);
+                break;
         }
 }
 static void s3_virge_mmio_write_l(uint32_t addr, uint32_t val, void *p)
@@ -1817,6 +1840,10 @@ static void s3_virge_mmio_write_l(uint32_t addr, uint32_t val, void *p)
 
 //                        s3_virge_triangle(virge);
                 break;
+
+                case 0xff20:
+                s3_virge_mmio_write(addr, val, p);
+                break;
         }
 }
 
@@ -3916,6 +3943,8 @@ static void *s3_virge_init()
         virge->fifo_not_full_event = thread_create_event();
         virge->fifo_thread = thread_create(fifo_thread, virge);
  
+        ddc_init();
+
         return virge;
 }
 
@@ -4012,7 +4041,9 @@ static void *s3_virge_375_init()
         virge->wake_fifo_thread = thread_create_event();
         virge->fifo_not_full_event = thread_create_event();
         virge->fifo_thread = thread_create(fifo_thread, virge);
- 
+
+        ddc_init();
+
         return virge;
 }