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 */
pcibios_fixup_peer_bridges(void)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
pci_legacy_init(void)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
pcibios_scan_specific_bus(int busn)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
pci_subsys_init(void)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