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Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * legacy.c - traditional, old school PCI bus probing | |
4 | */ | |
5 | #include <linux/init.h> | |
69c60c88 | 6 | #include <linux/export.h> |
1da177e4 | 7 | #include <linux/pci.h> |
690f4304 | 8 | #include <asm/jailhouse_para.h> |
82487711 | 9 | #include <asm/pci_x86.h> |
1da177e4 LT |
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 | */ | |
a18e3690 | 15 | static void pcibios_fixup_peer_bridges(void) |
1da177e4 | 16 | { |
5707b24a | 17 | int n; |
1da177e4 | 18 | |
9dd1e9eb | 19 | if (pcibios_last_bus <= 0 || pcibios_last_bus > 0xff) |
1da177e4 LT |
20 | return; |
21 | DBG("PCI: Peer bridge fixup\n"); | |
22 | ||
5707b24a AR |
23 | for (n=0; n <= pcibios_last_bus; n++) |
24 | pcibios_scan_specific_bus(n); | |
1da177e4 LT |
25 | } |
26 | ||
b72d0db9 | 27 | int __init pci_legacy_init(void) |
1da177e4 | 28 | { |
aae3e318 TG |
29 | if (!raw_pci_ops) |
30 | return 1; | |
1da177e4 | 31 | |
aae3e318 | 32 | pr_info("PCI: Probing PCI hardware\n"); |
b7869ba1 | 33 | pcibios_scan_root(0); |
1da177e4 LT |
34 | return 0; |
35 | } | |
5707b24a | 36 | |
a18e3690 | 37 | void pcibios_scan_specific_bus(int busn) |
5707b24a | 38 | { |
690f4304 | 39 | int stride = jailhouse_paravirt() ? 1 : 8; |
5707b24a | 40 | int devfn; |
5707b24a AR |
41 | u32 l; |
42 | ||
43 | if (pci_find_bus(0, busn)) | |
44 | return; | |
45 | ||
690f4304 | 46 | for (devfn = 0; devfn < 256; devfn += stride) { |
5707b24a AR |
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); | |
aae3e318 | 50 | pr_info("PCI: Discovered peer bus %02x\n", busn); |
3d2a3661 | 51 | pcibios_scan_root(busn); |
5707b24a AR |
52 | return; |
53 | } | |
54 | } | |
55 | } | |
d1fd4fb6 | 56 | EXPORT_SYMBOL_GPL(pcibios_scan_specific_bus); |
1da177e4 | 57 | |
68d0d979 | 58 | static int __init pci_subsys_init(void) |
8dd779b1 | 59 | { |
b72d0db9 TG |
60 | /* |
61 | * The init function returns an non zero value when | |
62 | * pci_legacy_init should be invoked. | |
63 | */ | |
aae3e318 TG |
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 | } | |
b72d0db9 | 70 | |
e42d1fe8 | 71 | pcibios_fixup_peer_bridges(); |
ab3b3793 | 72 | x86_init.pci.init_irq(); |
8dd779b1 | 73 | pcibios_init(); |
3a62ed73 RR |
74 | |
75 | return 0; | |
8dd779b1 RR |
76 | } |
77 | subsys_initcall(pci_subsys_init); |