/*
   * Re-map IO memory to kernel address space so that we can access it.
   *
   * These functions should only be used when it is necessary to map a
   * physical address space into the kernel address space before ioremap()
   * can be used, e.g. early in boot before paging_init().
   *
   * Copyright (C) 2009  Matt Fleming
   */
  
  #include <linux/vmalloc.h>
  #include <linux/ioport.h>
  #include <linux/module.h>
  #include <linux/mm.h>
  #include <linux/io.h>
  #include <linux/bootmem.h>
  #include <linux/proc_fs.h>

  #include <asm/fixmap.h>
  #include <asm/page.h>
  #include <asm/pgalloc.h>
  #include <asm/addrspace.h>
  #include <asm/cacheflush.h>
  #include <asm/tlbflush.h>
  #include <asm/mmu.h>
  #include <asm/mmu_context.h>
  
  struct ioremap_map {
  	void __iomem *addr;
  	unsigned long size;
  	unsigned long fixmap_addr;
  };
  
  static struct ioremap_map ioremap_maps[FIX_N_IOREMAPS];
  
  void __init ioremap_fixed_init(void)
  {
  	struct ioremap_map *map;
  	int i;
  
  	for (i = 0; i < FIX_N_IOREMAPS; i++) {
  		map = &ioremap_maps[i];
  		map->fixmap_addr = __fix_to_virt(FIX_IOREMAP_BEGIN + i);
  	}
  }
  
  void __init __iomem *

  ioremap_fixed(phys_addr_t phys_addr, unsigned long size, pgprot_t prot)

  {
  	enum fixed_addresses idx0, idx;

  	struct ioremap_map *map;

  	unsigned int nrpages;

  	unsigned long offset;

  	int i, slot;

  	/*
  	 * Mappings have to be page-aligned
  	 */
  	offset = phys_addr & ~PAGE_MASK;
  	phys_addr &= PAGE_MASK;
  	size = PAGE_ALIGN(phys_addr + size) - phys_addr;

  	slot = -1;
  	for (i = 0; i < FIX_N_IOREMAPS; i++) {
  		map = &ioremap_maps[i];
  		if (!map->addr) {
  			map->size = size;
  			slot = i;
  			break;
  		}
  	}
  
  	if (slot < 0)
  		return NULL;

  	/*
  	 * Mappings have to fit in the FIX_IOREMAP area.
  	 */
  	nrpages = size >> PAGE_SHIFT;
  	if (nrpages > FIX_N_IOREMAPS)
  		return NULL;
  
  	/*
  	 * Ok, go for it..
  	 */
  	idx0 = FIX_IOREMAP_BEGIN + slot;
  	idx = idx0;
  	while (nrpages > 0) {
  		pgprot_val(prot) |= _PAGE_WIRED;
  		__set_fixmap(idx, phys_addr, prot);
  		phys_addr += PAGE_SIZE;
  		idx++;
  		--nrpages;
  	}
  
  	map->addr = (void __iomem *)(offset + map->fixmap_addr);
  	return map->addr;
  }

  int iounmap_fixed(void __iomem *addr)

  {
  	enum fixed_addresses idx;

  	struct ioremap_map *map;

  	unsigned int nrpages;
  	int i, slot;

  
  	slot = -1;
  	for (i = 0; i < FIX_N_IOREMAPS; i++) {
  		map = &ioremap_maps[i];
  		if (map->addr == addr) {
  			slot = i;
  			break;
  		}
  	}

  	/*
  	 * If we don't match, it's not for us.
  	 */

  	if (slot < 0)

  		return -EINVAL;

  	nrpages = map->size >> PAGE_SHIFT;

  	idx = FIX_IOREMAP_BEGIN + slot + nrpages - 1;

  	while (nrpages > 0) {

  		__clear_fixmap(idx, __pgprot(_PAGE_WIRED));

  		--idx;
  		--nrpages;
  	}
  
  	map->size = 0;
  	map->addr = NULL;

  
  	return 0;

  }