parisc: fix serial ports on C8000 workstation

The C8000 workstation (64 bit kernel only) has a somewhat different
serial port configuration than other models.
Thomas Bogendoerfer sent a patch to fix this in September 2010, which
was now minimally modified by me.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/parisc/iosapic.c

@@ -811,6 +811,70 @@ int iosapic_fixup_irq(void *isi_obj, struct pci_dev *pcidev)
 	return pcidev->irq;
 }
 
+static struct iosapic_info *first_isi = NULL;
+
+#ifdef CONFIG_64BIT
+int iosapic_serial_irq(int num)
+{
+	struct iosapic_info *isi = first_isi;
+	struct irt_entry *irte = NULL;  /* only used if PAT PDC */
+	struct vector_info *vi;
+	int isi_line;	/* line used by device */
+
+	/* lookup IRT entry for isi/slot/pin set */
+	irte = &irt_cell[num];
+
+	DBG_IRT("iosapic_serial_irq(): irte %p %x %x %x %x %x %x %x %x\n",
+		irte,
+		irte->entry_type,
+		irte->entry_length,
+		irte->polarity_trigger,
+		irte->src_bus_irq_devno,
+		irte->src_bus_id,
+		irte->src_seg_id,
+		irte->dest_iosapic_intin,
+		(u32) irte->dest_iosapic_addr);
+	isi_line = irte->dest_iosapic_intin;
+
+	/* get vector info for this input line */
+	vi = isi->isi_vector + isi_line;
+	DBG_IRT("iosapic_serial_irq:  line %d vi 0x%p\n", isi_line, vi);
+
+	/* If this IRQ line has already been setup, skip it */
+	if (vi->irte)
+		goto out;
+
+	vi->irte = irte;
+
+	/*
+	 * Allocate processor IRQ
+	 *
+	 * XXX/FIXME The txn_alloc_irq() code and related code should be
+	 * moved to enable_irq(). That way we only allocate processor IRQ
+	 * bits for devices that actually have drivers claiming them.
+	 * Right now we assign an IRQ to every PCI device present,
+	 * regardless of whether it's used or not.
+	 */
+	vi->txn_irq = txn_alloc_irq(8);
+
+	if (vi->txn_irq < 0)
+		panic("I/O sapic: couldn't get TXN IRQ\n");
+
+	/* enable_irq() will use txn_* to program IRdT */
+	vi->txn_addr = txn_alloc_addr(vi->txn_irq);
+	vi->txn_data = txn_alloc_data(vi->txn_irq);
+
+	vi->eoi_addr = isi->addr + IOSAPIC_REG_EOI;
+	vi->eoi_data = cpu_to_le32(vi->txn_data);
+
+	cpu_claim_irq(vi->txn_irq, &iosapic_interrupt_type, vi);
+
+ out:
+
+	return vi->txn_irq;
+}
+#endif
+
 
 /*
 ** squirrel away the I/O Sapic Version
@@ -877,6 +941,8 @@ void *iosapic_register(unsigned long hpa)
 		vip->irqline = (unsigned char) cnt;
 		vip->iosapic = isi;
 	}
+	if (!first_isi)
+		first_isi = isi;
 	return isi;
 }