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The PCI initialization in pci_subsys_init() is a mess. pci_numaq_init, pci_acpi_init, pci_visws_init and pci_legacy_init are called and each implementation checks and eventually modifies the global variable pcibios_scanned. x86_init functions allow us to do this more elegant. The pci.init function pointer is preset to pci_legacy_init. numaq, acpi and visws can modify the pointer in their early setup functions. The functions return 0 when they did the full initialization including bus scan. A non zero return value indicates that pci_legacy_init needs to be called either because the selected function failed or wants the generic bus scan in pci_legacy_init to happen (e.g. visws). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <43F901BD926A4E43B106BF17856F07559FB80CFE@orsmsx508.amr.corp.intel.com> Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
69 lines
1.5 KiB
C
69 lines
1.5 KiB
C
/*
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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/pci.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 __devinit pcibios_fixup_peer_bridges(void)
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{
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int n, devfn;
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long node;
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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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u32 l;
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if (pci_find_bus(0, n))
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continue;
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node = get_mp_bus_to_node(n);
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for (devfn = 0; devfn < 256; devfn += 8) {
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if (!raw_pci_read(0, n, 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", n, devfn, l);
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printk(KERN_INFO "PCI: Discovered peer bus %02x\n", n);
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pci_scan_bus_on_node(n, &pci_root_ops, node);
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break;
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}
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}
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}
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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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printk("PCI: System does not support PCI\n");
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return 0;
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}
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printk("PCI: Probing PCI hardware\n");
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pci_root_bus = pcibios_scan_root(0);
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if (pci_root_bus)
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pci_bus_add_devices(pci_root_bus);
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return 0;
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}
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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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pci_legacy_init();
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pcibios_fixup_peer_bridges();
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pcibios_irq_init();
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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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