cuda.c: implement dummy IIC access commands

These are used by MacOS 9 on boot. Here we return an error except for 4-byte
commands which write to the IIC bus in a similar manner to MOL.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

hw/misc/macio/cuda.c

@@ -529,6 +529,24 @@ static void cuda_receive_packet(CUDAState *s,
         cuda_send_packet_to_host(s, obuf, 3);
         qemu_system_reset_request();
         break;
+    case CUDA_COMBINED_FORMAT_IIC:
+        obuf[0] = ERROR_PACKET;
+        obuf[1] = 0x5;
+        obuf[2] = CUDA_PACKET;
+        obuf[3] = data[0];
+        cuda_send_packet_to_host(s, obuf, 4);
+        break;
+    case CUDA_GET_SET_IIC:
+        if (len == 4) {
+            cuda_send_packet_to_host(s, obuf, 3);
+        } else {
+            obuf[0] = ERROR_PACKET;
+            obuf[1] = 0x2;
+            obuf[2] = CUDA_PACKET;
+            obuf[3] = data[0];
+            cuda_send_packet_to_host(s, obuf, 4);
+        }
+        break;
     default:
         break;
     }