CFG_PAGE_OFFSET
int offset = where + CFG_PAGE_OFFSET;
CFG_PAGE_OFFSET + PCI_VENDOR_ID;
void __iomem *addr = hbus->cfg_addr + CFG_PAGE_OFFSET +
int offset = where + CFG_PAGE_OFFSET;
#define CFG_PAGE_SIZE (PCI_CONFIG_MMIO_LENGTH - CFG_PAGE_OFFSET)