1 files changed, 77 insertions, 0 deletions
diff --git a/src/southbridge/via/vt8235/early_serial.c b/src/southbridge/via/vt8235/early_serial.c
new file mode 100644
index 0000000000..11f98fae39
--- /dev/null
+++ b/src/southbridge/via/vt8235/early_serial.c
@@ -0,0 +1,77 @@
+/*
+ * Enable the serial evices on the VIA
+ */
+
+
+/* The base address is 0x15c, 0x2e, depending on config bytes */
+
+#define SIO_BASE 0x3f0
+#define SIO_DATA  SIO_BASE+1
+
+static void vt8235_writepnpaddr(uint8_t val)
+{
+	outb(val, 0x2e);
+	outb(val, 0xeb);
+}
+
+static void vt8235_writepnpdata(uint8_t val)
+{
+	outb(val, 0x2f);
+	outb(val, 0xeb);
+}
+
+
+static void vt8235_writesiobyte(uint16_t reg, uint8_t val)
+{
+	outb(val, reg);
+}
+
+static void vt8235_writesioword(uint16_t reg, uint16_t val)
+{
+	outw(val, reg);
+}
+
+
+/* regs we use: 85, and the southbridge devfn is defined by the
+   mainboard
+ */
+
+static void enable_vt8235_serial(void)
+{
+	// turn on pnp
+	vt8235_writepnpaddr(0x87);
+	vt8235_writepnpaddr(0x87);
+	// now go ahead and set up com1.
+	// set address
+	vt8235_writepnpaddr(0x7);
+	vt8235_writepnpdata(0x2);
+	// enable serial out
+	vt8235_writepnpaddr(0x30);
+	vt8235_writepnpdata(0x1);
+	// serial port 1 base address (FEh)
+	vt8235_writepnpaddr(0x60);
+	vt8235_writepnpdata(0xfe);
+	// serial port 1 IRQ (04h)
+	vt8235_writepnpaddr(0x70);
+	vt8235_writepnpdata(0x4);
+	// serial port 1 control
+	vt8235_writepnpaddr(0xf0);
+	vt8235_writepnpdata(0x2);
+	// turn of pnp
+	vt8235_writepnpaddr(0xaa);
+
+	// set up reg to set baud rate.
+	vt8235_writesiobyte(0x3fb, 0x80);
+	// Set 115 kb
+	vt8235_writesioword(0x3f8, 1);
+	// Set 9.6 kb
+	//	WRITESIOWORD(0x3f8, 12)
+	// now set no parity, one stop, 8 bits
+	vt8235_writesiobyte(0x3fb, 3);
+	// now turn on RTS, DRT
+	vt8235_writesiobyte(0x3fc, 3);
+	// Enable interrupts
+	vt8235_writesiobyte(0x3f9, 0xf);
+	// should be done. Dump a char for fun.
+	vt8235_writesiobyte(0x3f8, 48);
+}