1 /* 2 * legacy.c - traditional, old school PCI bus probing 3 */ 4 #include <linux/init.h> 5 #include <linux/pci.h> 6 #include <asm/pci_x86.h> 7 8 /* 9 * Discover remaining PCI buses in case there are peer host bridges. 10 * We use the number of last PCI bus provided by the PCI BIOS. 11 */ 12 static void __devinit pcibios_fixup_peer_bridges(void) 13 { 14 int n; 15 16 if (pcibios_last_bus <= 0 || pcibios_last_bus > 0xff) 17 return; 18 DBG("PCI: Peer bridge fixup\n"); 19 20 for (n=0; n <= pcibios_last_bus; n++) 21 pcibios_scan_specific_bus(n); 22 } 23 24 int __init pci_legacy_init(void) 25 { 26 if (!raw_pci_ops) { 27 printk("PCI: System does not support PCI\n"); 28 return 0; 29 } 30 31 printk("PCI: Probing PCI hardware\n"); 32 pci_root_bus = pcibios_scan_root(0); 33 if (pci_root_bus) 34 pci_bus_add_devices(pci_root_bus); 35 36 return 0; 37 } 38 39 void __devinit pcibios_scan_specific_bus(int busn) 40 { 41 int devfn; 42 long node; 43 u32 l; 44 45 if (pci_find_bus(0, busn)) 46 return; 47 48 node = get_mp_bus_to_node(busn); 49 for (devfn = 0; devfn < 256; devfn += 8) { 50 if (!raw_pci_read(0, busn, devfn, PCI_VENDOR_ID, 2, &l) && 51 l != 0x0000 && l != 0xffff) { 52 DBG("Found device at %02x:%02x [%04x]\n", busn, devfn, l); 53 printk(KERN_INFO "PCI: Discovered peer bus %02x\n", busn); 54 pci_scan_bus_on_node(busn, &pci_root_ops, node); 55 return; 56 } 57 } 58 } 59 EXPORT_SYMBOL_GPL(pcibios_scan_specific_bus); 60 61 int __init pci_subsys_init(void) 62 { 63 /* 64 * The init function returns an non zero value when 65 * pci_legacy_init should be invoked. 66 */ 67 if (x86_init.pci.init()) 68 pci_legacy_init(); 69 70 pcibios_fixup_peer_bridges(); 71 x86_init.pci.init_irq(); 72 pcibios_init(); 73 74 return 0; 75 } 76 subsys_initcall(pci_subsys_init); 77