3 files changed, 43 insertions, 15 deletions

diff --git a/arch/i386/pci/common.c b/arch/i386/pci/common.c
index 720975e1af50..2a2e79fbfef8 100644
--- a/arch/i386/pci/common.c
+++ b/arch/i386/pci/common.c
@@ -25,7 +25,8 @@ unsigned int pci_probe = PCI_PROBE_BIOS | PCI_PROBE_CONF1 | PCI_PROBE_CONF2 |
 
 int pci_routeirq;
 int pcibios_last_bus = -1;
-struct pci_bus *pci_root_bus = NULL;
+unsigned long pirq_table_addr;
+struct pci_bus *pci_root_bus;
 struct pci_raw_ops *raw_pci_ops;
 
 static int pci_read(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *value)
@@ -188,6 +189,9 @@ char * __devinit  pcibios_setup(char *str)
         } else if (!strcmp(str, "biosirq")) {
                 pci_probe |= PCI_BIOS_IRQ_SCAN;
                 return NULL;
+        } else if (!strncmp(str, "pirqaddr=", 9)) {
+                pirq_table_addr = simple_strtoul(str+9, NULL, 0);
+                return NULL;
         }
 #endif
 #ifdef CONFIG_PCI_DIRECT
diff --git a/arch/i386/pci/irq.c b/arch/i386/pci/irq.c
index 83458f81e661..78ca1ecbb907 100644
--- a/arch/i386/pci/irq.c
+++ b/arch/i386/pci/irq.c
@@ -58,6 +58,35 @@ struct irq_router_handler {
 int (*pcibios_enable_irq)(struct pci_dev *dev) = NULL;
 
 /*
+ *  Check passed address for the PCI IRQ Routing Table signature
+ *  and perform checksum verification.
+ */
+
+static inline struct irq_routing_table * pirq_check_routing_table(u8 *addr)
+{
+        struct irq_routing_table *rt;
+        int i;
+        u8 sum;
+
+        rt = (struct irq_routing_table *) addr;
+        if (rt->signature != PIRQ_SIGNATURE ||
+            rt->version != PIRQ_VERSION ||
+            rt->size % 16 ||
+            rt->size < sizeof(struct irq_routing_table))
+                return NULL;
+        sum = 0;
+        for (i=0; i < rt->size; i++)
+                sum += addr[i];
+        if (!sum) {
+                DBG("PCI: Interrupt Routing Table found at 0x%p\n", rt);
+                return rt;
+        }
+        return NULL;
+}
+
+
+
+/*
  *  Search 0xf0000 -- 0xfffff for the PCI IRQ Routing Table.
  */
 
@@ -65,23 +94,17 @@ static struct irq_routing_table * __init pirq_find_routing_table(void)
 {
         u8 *addr;
         struct irq_routing_table *rt;
-        int i;
-        u8 sum;
 
+        if (pirq_table_addr) {
+                rt = pirq_check_routing_table((u8 *) __va(pirq_table_addr));
+                if (rt)
+                        return rt;
+                printk(KERN_WARNING "PCI: PIRQ table NOT found at pirqaddr\n");
+        }
         for(addr = (u8 *) __va(0xf0000); addr < (u8 *) __va(0x100000); addr += 16) {
-                rt = (struct irq_routing_table *) addr;
-                if (rt->signature != PIRQ_SIGNATURE ||
-                    rt->version != PIRQ_VERSION ||
-                    rt->size % 16 ||
-                    rt->size < sizeof(struct irq_routing_table))
-                        continue;
-                sum = 0;
-                for(i=0; i<rt->size; i++)
-                        sum += addr[i];
-                if (!sum) {
-                        DBG("PCI: Interrupt Routing Table found at 0x%p\n", rt);
+                rt = pirq_check_routing_table(addr);
+                if (rt)
                         return rt;
-                }
         }
         return NULL;
 }
diff --git a/arch/i386/pci/pci.h b/arch/i386/pci/pci.h
index a8fc80ca69f3..a80f0f55ff51 100644
--- a/arch/i386/pci/pci.h
+++ b/arch/i386/pci/pci.h
@@ -27,6 +27,7 @@
 #define PCI_ASSIGN_ALL_BUSSES   0x4000
 
 extern unsigned int pci_probe;
+extern unsigned long pirq_table_addr;
 
 /* pci-i386.c */