#ifndef _LINUX_PFN_H_
  #define _LINUX_PFN_H_

  #ifndef __ASSEMBLY__
  #include <linux/types.h>

  
  /*
   * pfn_t: encapsulates a page-frame number that is optionally backed
   * by memmap (struct page).  Whether a pfn_t has a 'struct page'
   * backing is indicated by flags in the high bits of the value.
   */
  typedef struct {

  	u64 val;

  } pfn_t;

  #endif

  #define PFN_ALIGN(x)	(((unsigned long)(x) + (PAGE_SIZE - 1)) & PAGE_MASK)
  #define PFN_UP(x)	(((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
  #define PFN_DOWN(x)	((x) >> PAGE_SHIFT)

  #define PFN_PHYS(x)	((phys_addr_t)(x) << PAGE_SHIFT)

  #define PHYS_PFN(x)	((unsigned long)((x) >> PAGE_SHIFT))

  
  #endif