pcibios_read_config_byte
pcibios_read_config_byte(first_bus, first_devfn & ~0x7,
pcibios_read_config_byte(bus, devfn, PCI_HEADER_TYPE, &hdr_type);
pcibios_read_config_byte(bus, devfn, i, &byte);
pcibios_read_config_byte(p->bus, p->devfn, PCI_LATENCY_TIMER, &pci_latency);
extern int pcibios_read_config_byte(unsigned int bus, unsigned int device_fn, unsigned int where, uint8_t *value);
return pcibios_read_config_byte(dev->bus, dev->devfn, where, value);
pcibios_read_config_byte(p->bus,p->devfn, 0x48, ®);
pcibios_read_config_byte(pci->bus,pci->devfn, PCI_REVISION, &revision);
pcibios_read_config_byte(pci->bus, pci->devfn, PCI_REVISION, &chip_rev);