text: #ifndef __GENERIC_IO_H
  #define __GENERIC_IO_H
  
  #include <linux/linkage.h>
  #include <asm/byteorder.h>
  
  /*
   * These are the "generic" interfaces for doing new-style
   * memory-mapped or PIO accesses. Architectures may do
   * their own arch-optimized versions, these just act as
   * wrappers around the old-style IO register access functions:
   * read[bwl]/write[bwl]/in[bwl]/out[bwl]
   *
   * Don't include this directly, include it from <asm/io.h>.
   */
  
  /*
   * Read/write from/to an (offsettable) iomem cookie. It might be a PIO
   * access or a MMIO access, these functions don't care. The info is
   * encoded in the hardware mapping set up by the mapping functions
   * (or the cookie itself, depending on implementation and hw).
   *
   * The generic routines just encode the PIO/MMIO as part of the
   * cookie, and coldly assume that the MMIO IO mappings are not
   * in the low address range. Architectures for which this is not
   * true can't use this generic implementation.
   */
  extern unsigned int fastcall ioread8(void __iomem *);
  extern unsigned int fastcall ioread16(void __iomem *);
  extern unsigned int fastcall ioread16be(void __iomem *);
  extern unsigned int fastcall ioread32(void __iomem *);
  extern unsigned int fastcall ioread32be(void __iomem *);
  
  extern void fastcall iowrite8(u8, void __iomem *);
  extern void fastcall iowrite16(u16, void __iomem *);
  extern void fastcall iowrite16be(u16, void __iomem *);
  extern void fastcall iowrite32(u32, void __iomem *);
  extern void fastcall iowrite32be(u32, void __iomem *);
  
  /*
   * "string" versions of the above. Note that they
   * use native byte ordering for the accesses (on
   * the assumption that IO and memory agree on a
   * byte order, and CPU byteorder is irrelevant).
   *
   * They do _not_ update the port address. If you
   * want MMIO that copies stuff laid out in MMIO
   * memory across multiple ports, use "memcpy_toio()"
   * and friends.
   */
  extern void fastcall ioread8_rep(void __iomem *port, void *buf, unsigned long count);
  extern void fastcall ioread16_rep(void __iomem *port, void *buf, unsigned long count);
  extern void fastcall ioread32_rep(void __iomem *port, void *buf, unsigned long count);
  
  extern void fastcall iowrite8_rep(void __iomem *port, const void *buf, unsigned long count);
  extern void fastcall iowrite16_rep(void __iomem *port, const void *buf, unsigned long count);
  extern void fastcall iowrite32_rep(void __iomem *port, const void *buf, unsigned long count);
  
  /* Create a virtual mapping cookie for an IO port range */
  extern void __iomem *ioport_map(unsigned long port, unsigned int nr);
  extern void ioport_unmap(void __iomem *);
  
  /* Create a virtual mapping cookie for a PCI BAR (memory or IO) */
  struct pci_dev;
  extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
  extern void pci_iounmap(struct pci_dev *dev, void __iomem *);
  
  #endif
  