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kernel/linux-imx6_3.14.28/arch/x86/pci/legacy.c 1.53 KB
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  /*
   * legacy.c - traditional, old school PCI bus probing
   */
  #include <linux/init.h>
  #include <linux/export.h>
  #include <linux/pci.h>
  #include <asm/pci_x86.h>
  
  /*
   * Discover remaining PCI buses in case there are peer host bridges.
   * We use the number of last PCI bus provided by the PCI BIOS.
   */
  static void pcibios_fixup_peer_bridges(void)
  {
  	int n;
  
  	if (pcibios_last_bus <= 0 || pcibios_last_bus > 0xff)
  		return;
  	DBG("PCI: Peer bridge fixup
  ");
  
  	for (n=0; n <= pcibios_last_bus; n++)
  		pcibios_scan_specific_bus(n);
  }
  
  int __init pci_legacy_init(void)
  {
  	if (!raw_pci_ops) {
  		printk("PCI: System does not support PCI
  ");
  		return 0;
  	}
  
  	printk("PCI: Probing PCI hardware
  ");
  	pcibios_scan_root(0);
  	return 0;
  }
  
  void pcibios_scan_specific_bus(int busn)
  {
  	int devfn;
  	long node;
  	u32 l;
  
  	if (pci_find_bus(0, busn))
  		return;
  
  	node = get_mp_bus_to_node(busn);
  	for (devfn = 0; devfn < 256; devfn += 8) {
  		if (!raw_pci_read(0, busn, devfn, PCI_VENDOR_ID, 2, &l) &&
  		    l != 0x0000 && l != 0xffff) {
  			DBG("Found device at %02x:%02x [%04x]
  ", busn, devfn, l);
  			printk(KERN_INFO "PCI: Discovered peer bus %02x
  ", busn);
  			pci_scan_bus_on_node(busn, &pci_root_ops, node);
  			return;
  		}
  	}
  }
  EXPORT_SYMBOL_GPL(pcibios_scan_specific_bus);
  
  int __init pci_subsys_init(void)
  {
  	/*
  	 * The init function returns an non zero value when
  	 * pci_legacy_init should be invoked.
  	 */
  	if (x86_init.pci.init())
  		pci_legacy_init();
  
  	pcibios_fixup_peer_bridges();
  	x86_init.pci.init_irq();
  	pcibios_init();
  
  	return 0;
  }
  subsys_initcall(pci_subsys_init);