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77 lines
1.6 KiB
77 lines
1.6 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* legacy.c - traditional, old school PCI bus probing |
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*/ |
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#include <linux/init.h> |
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#include <linux/export.h> |
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#include <linux/pci.h> |
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#include <asm/jailhouse_para.h> |
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#include <asm/pci_x86.h> |
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/* |
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* Discover remaining PCI buses in case there are peer host bridges. |
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* We use the number of last PCI bus provided by the PCI BIOS. |
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*/ |
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static void pcibios_fixup_peer_bridges(void) |
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{ |
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int n; |
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if (pcibios_last_bus <= 0 || pcibios_last_bus > 0xff) |
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return; |
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DBG("PCI: Peer bridge fixup\n"); |
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for (n=0; n <= pcibios_last_bus; n++) |
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pcibios_scan_specific_bus(n); |
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} |
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int __init pci_legacy_init(void) |
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{ |
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if (!raw_pci_ops) |
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return 1; |
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pr_info("PCI: Probing PCI hardware\n"); |
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pcibios_scan_root(0); |
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return 0; |
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} |
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void pcibios_scan_specific_bus(int busn) |
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{ |
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int stride = jailhouse_paravirt() ? 1 : 8; |
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int devfn; |
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u32 l; |
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if (pci_find_bus(0, busn)) |
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return; |
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for (devfn = 0; devfn < 256; devfn += stride) { |
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if (!raw_pci_read(0, busn, devfn, PCI_VENDOR_ID, 2, &l) && |
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l != 0x0000 && l != 0xffff) { |
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DBG("Found device at %02x:%02x [%04x]\n", busn, devfn, l); |
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pr_info("PCI: Discovered peer bus %02x\n", busn); |
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pcibios_scan_root(busn); |
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return; |
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} |
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} |
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} |
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EXPORT_SYMBOL_GPL(pcibios_scan_specific_bus); |
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static int __init pci_subsys_init(void) |
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{ |
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/* |
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* The init function returns an non zero value when |
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* pci_legacy_init should be invoked. |
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*/ |
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if (x86_init.pci.init()) { |
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if (pci_legacy_init()) { |
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pr_info("PCI: System does not support PCI\n"); |
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return -ENODEV; |
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} |
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} |
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pcibios_fixup_peer_bridges(); |
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x86_init.pci.init_irq(); |
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pcibios_init(); |
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return 0; |
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} |
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subsys_initcall(pci_subsys_init);
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