OPTI Viper-M/N+ chipset support (by Michael Mueller)]

@@ -241,18 +241,56 @@
 }
 
 static int pirq_opti_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
 {
 	write_config_nybble(router, 0xb8, pirq >> 4, irq);
 	return 1;
 }
 
 /*
+ * OPTI Viper-M/N+: Bit field with 3 bits per entry.
+ * Due to the lack of a specification the information about this chipset
+ * was taken from the NetBSD source code.
+ */
+static int pirq_viper_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
+{
+	static const int viper_irq_decode[] = { 0, 5, 9, 10, 11, 12, 14, 15 };
+	u32 irq;
+
+	pci_read_config_dword(router, 0x40, &irq);
+	irq >>= (pirq-1)*3;
+	irq &= 7;
+
+	return viper_irq_decode[irq];
+}
+
+static int pirq_viper_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
+{
+	static const int viper_irq_map[] = { -1, -1, -1, -1, -1, 1, -1, -1, -1, 2, 3, 4, 5, -1, 6, 7 };
+	int newval = viper_irq_map[irq];
+	u32 val;
+	u32 mask = 7 << (3*(pirq-1));
+#if 0
+	mask |= 0x10000UL << (pirq-1);	/* edge triggered */
+#endif
+
+	if ( newval == -1 )
+		return 0;
+	
+	pci_read_config_dword(router, 0x40, &val);
+	val &= ~mask;
+	val |= newval << (3*(pirq-1));
+	pci_write_config_dword(router, 0x40, val);
+
+	return 1;
+}
+
+/*
  * Cyrix: nibble offset 0x5C
  */
 static int pirq_cyrix_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
 {
 	return read_config_nybble(router, 0x5C, (pirq-1)^1);
 }
 
 static int pirq_cyrix_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
 {

@@ -707,21 +745,28 @@
 
 static __init int opti_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
 {
 	switch(device)
 	{
 		case PCI_DEVICE_ID_OPTI_82C700:
 			r->name = "OPTI";
 			r->get = pirq_opti_get;
 			r->set = pirq_opti_set;
-			return 1;
+			break;
+		case PCI_DEVICE_ID_OPTI_82C558:
+			r->name = "OPTI VIPER";
+			r->get = pirq_viper_get;
+			r->set = pirq_viper_set;
+			break;
+		default:
+			return 0;
 	}
-	return 0;
+	return 1;
 }
 
 static __init int ite_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
 {
 	switch(device)
 	{
 		case PCI_DEVICE_ID_ITE_IT8330G_0:
 			r->name = "ITE";
 			r->get = pirq_ite_get;