1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * legacy.c - traditional, old school PCI bus probing
 4 */
 5#include <linux/init.h>
 6#include <linux/export.h>
 7#include <linux/pci.h>
 8#include <asm/jailhouse_para.h>
 9#include <asm/pci_x86.h>
10
11/*
12 * Discover remaining PCI buses in case there are peer host bridges.
13 * We use the number of last PCI bus provided by the PCI BIOS.
14 */
15static void pcibios_fixup_peer_bridges(void)
16{
17	int n;
18
19	if (pcibios_last_bus <= 0 || pcibios_last_bus > 0xff)
20		return;
21	DBG("PCI: Peer bridge fixup\n");
22
23	for (n=0; n <= pcibios_last_bus; n++)
24		pcibios_scan_specific_bus(n);
25}
26
27int __init pci_legacy_init(void)
28{
29	if (!raw_pci_ops)
30		return 1;
 
 
 
 
 
 
 
31
32	pr_info("PCI: Probing PCI hardware\n");
33	pcibios_scan_root(0);
34	return 0;
35}
36
37void pcibios_scan_specific_bus(int busn)
38{
39	int stride = jailhouse_paravirt() ? 1 : 8;
40	int devfn;
 
41	u32 l;
42
43	if (pci_find_bus(0, busn))
44		return;
45
46	for (devfn = 0; devfn < 256; devfn += stride) {
 
47		if (!raw_pci_read(0, busn, devfn, PCI_VENDOR_ID, 2, &l) &&
48		    l != 0x0000 && l != 0xffff) {
49			DBG("Found device at %02x:%02x [%04x]\n", busn, devfn, l);
50			pr_info("PCI: Discovered peer bus %02x\n", busn);
51			pcibios_scan_root(busn);
52			return;
53		}
54	}
55}
56EXPORT_SYMBOL_GPL(pcibios_scan_specific_bus);
57
58static int __init pci_subsys_init(void)
59{
60	/*
61	 * The init function returns an non zero value when
62	 * pci_legacy_init should be invoked.
63	 */
64	if (x86_init.pci.init()) {
65		if (pci_legacy_init()) {
66			pr_info("PCI: System does not support PCI\n");
67			return -ENODEV;
68		}
69	}
70
71	pcibios_fixup_peer_bridges();
72	x86_init.pci.init_irq();
73	pcibios_init();
74
75	return 0;
76}
77subsys_initcall(pci_subsys_init);

 
 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 */
12static 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
24int __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
39void __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}
59EXPORT_SYMBOL_GPL(pcibios_scan_specific_bus);
60
61int __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}
76subsys_initcall(pci_subsys_init);