1 files changed, 54 insertions, 0 deletions
diff --git a/arch/i386/pci/legacy.c b/arch/i386/pci/legacy.c
new file mode 100644
index 00000000000..1492e375386
--- /dev/null
+++ b/arch/i386/pci/legacy.c
@@ -0,0 +1,54 @@
+/*
+ * legacy.c - traditional, old school PCI bus probing
+ */
+#include <linux/init.h>
+#include <linux/pci.h>
+#include "pci.h"
+
+/*
+ * Discover remaining PCI buses in case there are peer host bridges.
+ * We use the number of last PCI bus provided by the PCI BIOS.
+ */
+static void __devinit pcibios_fixup_peer_bridges(void)
+{
+	int n, devfn;
+
+	if (pcibios_last_bus <= 0 || pcibios_last_bus >= 0xff)
+		return;
+	DBG("PCI: Peer bridge fixup\n");
+
+	for (n=0; n <= pcibios_last_bus; n++) {
+		u32 l;
+		if (pci_find_bus(0, n))
+			continue;
+		for (devfn = 0; devfn < 256; devfn += 8) {
+			if (!raw_pci_ops->read(0, n, devfn, PCI_VENDOR_ID, 2, &l) &&
+			    l != 0x0000 && l != 0xffff) {
+				DBG("Found device at %02x:%02x [%04x]\n", n, devfn, l);
+				printk(KERN_INFO "PCI: Discovered peer bus %02x\n", n);
+				pci_scan_bus(n, &pci_root_ops, NULL);
+				break;
+			}
+		}
+	}
+}
+
+static int __init pci_legacy_init(void)
+{
+	if (!raw_pci_ops) {
+		printk("PCI: System does not support PCI\n");
+		return 0;
+	}
+
+	if (pcibios_scanned++)
+		return 0;
+
+	printk("PCI: Probing PCI hardware\n");
+	pci_root_bus = pcibios_scan_root(0);
+
+	pcibios_fixup_peer_bridges();
+
+	return 0;
+}
+
+subsys_initcall(pci_legacy_init);