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