x86: Reduce PIRQ routing table size

There is no need to populate multiple irq info entries with the same
bus number and device number, but with different interrupt pin. We
can use the same entry to store all the 4 interrupt pin (INT A/B/C/D)
routing information to reduce the whole PIRQ routing table size.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/irq.c b/arch/x86/cpu/irq.c
index df4300c..97dd000 100644
--- a/arch/x86/cpu/irq.c
+++ b/arch/x86/cpu/irq.c
@@ -58,17 +58,28 @@
 		writeb(irq, irq_router.ibase + LINK_N2V(link, base));
 }
 
-static inline void fill_irq_info(struct irq_info **slotp, int *entries, u8 bus,
-				 u8 device, u8 pin, u8 pirq)
+static struct irq_info *check_dup_entry(struct irq_info *slot_base,
+					int entry_num, int bus, int device)
 {
-	struct irq_info *slot = *slotp;
+	struct irq_info *slot = slot_base;
+	int i;
 
+	for (i = 0; i < entry_num; i++) {
+		if (slot->bus == bus && slot->devfn == (device << 3))
+			break;
+		slot++;
+	}
+
+	return (i == entry_num) ? NULL : slot;
+}
+
+static inline void fill_irq_info(struct irq_info *slot, int bus, int device,
+				 int pin, int pirq)
+{
 	slot->bus = bus;
 	slot->devfn = (device << 3) | 0;
 	slot->irq[pin - 1].link = LINK_N2V(pirq, irq_router.link_base);
 	slot->irq[pin - 1].bitmap = irq_router.irq_mask;
-	(*entries)++;
-	(*slotp)++;
 }
 
 __weak void cpu_irq_init(void)
@@ -84,7 +95,7 @@
 	int len, count;
 	const u32 *cell;
 	struct irq_routing_table *rt;
-	struct irq_info *slot;
+	struct irq_info *slot, *slot_base;
 	int irq_entries = 0;
 	int i;
 	int ret;
@@ -167,7 +178,7 @@
 	rt->rtr_vendor = PCI_VENDOR_ID_INTEL;
 	rt->rtr_device = PCI_DEVICE_ID_INTEL_ICH7_31;
 
-	slot = rt->slots;
+	slot_base = rt->slots;
 
 	/* Now fill in the irq_info entries in the PIRQ table */
 	for (i = 0; i < count; i++) {
@@ -181,8 +192,44 @@
 		      i, PCI_BUS(pr.bdf), PCI_DEV(pr.bdf),
 		      PCI_FUNC(pr.bdf), 'A' + pr.pin - 1,
 		      'A' + pr.pirq);
-		fill_irq_info(&slot, &irq_entries, PCI_BUS(pr.bdf),
-			      PCI_DEV(pr.bdf), pr.pin, pr.pirq);
+
+		slot = check_dup_entry(slot_base, irq_entries,
+				       PCI_BUS(pr.bdf), PCI_DEV(pr.bdf));
+		if (slot) {
+			debug("found entry for bus %d device %d, ",
+			      PCI_BUS(pr.bdf), PCI_DEV(pr.bdf));
+
+			if (slot->irq[pr.pin - 1].link) {
+				debug("skipping\n");
+
+				/*
+				 * Sanity test on the routed PIRQ pin
+				 *
+				 * If they don't match, show a warning to tell
+				 * there might be something wrong with the PIRQ
+				 * routing information in the device tree.
+				 */
+				if (slot->irq[pr.pin - 1].link !=
+					LINK_N2V(pr.pirq, irq_router.link_base))
+					debug("WARNING: Inconsistent PIRQ routing information\n");
+
+				cell += sizeof(struct pirq_routing) /
+					sizeof(u32);
+				continue;
+			} else {
+				debug("writing INT%c\n", 'A' + pr.pin - 1);
+				fill_irq_info(slot, PCI_BUS(pr.bdf),
+					      PCI_DEV(pr.bdf), pr.pin, pr.pirq);
+				cell += sizeof(struct pirq_routing) /
+					sizeof(u32);
+				continue;
+			}
+		}
+
+		slot = slot_base + irq_entries;
+		fill_irq_info(slot, PCI_BUS(pr.bdf), PCI_DEV(pr.bdf),
+			      pr.pin, pr.pirq);
+		irq_entries++;
 		cell += sizeof(struct pirq_routing) / sizeof(u32);
 	}