Logo Search packages:      
Sourcecode: linux version File versions  Download package

ioremap.c

/*
 * (c) Copyright 2006, 2007 Hewlett-Packard Development Company, L.P.
 *    Bjorn Helgaas <bjorn.helgaas@hp.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/efi.h>
#include <linux/io.h>
#include <linux/vmalloc.h>
#include <asm/io.h>
#include <asm/meminit.h>

static inline void __iomem *
__ioremap (unsigned long phys_addr)
{
      return (void __iomem *) (__IA64_UNCACHED_OFFSET | phys_addr);
}

void __iomem *
ioremap (unsigned long phys_addr, unsigned long size)
{
      void __iomem *addr;
      struct vm_struct *area;
      unsigned long offset;
      pgprot_t prot;
      u64 attr;
      unsigned long gran_base, gran_size;
      unsigned long page_base;

      /*
       * For things in kern_memmap, we must use the same attribute
       * as the rest of the kernel.  For more details, see
       * Documentation/ia64/aliasing.txt.
       */
      attr = kern_mem_attribute(phys_addr, size);
      if (attr & EFI_MEMORY_WB)
            return (void __iomem *) phys_to_virt(phys_addr);
      else if (attr & EFI_MEMORY_UC)
            return __ioremap(phys_addr);

      /*
       * Some chipsets don't support UC access to memory.  If
       * WB is supported for the whole granule, we prefer that.
       */
      gran_base = GRANULEROUNDDOWN(phys_addr);
      gran_size = GRANULEROUNDUP(phys_addr + size) - gran_base;
      if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)
            return (void __iomem *) phys_to_virt(phys_addr);

      /*
       * WB is not supported for the whole granule, so we can't use
       * the region 7 identity mapping.  If we can safely cover the
       * area with kernel page table mappings, we can use those
       * instead.
       */
      page_base = phys_addr & PAGE_MASK;
      size = PAGE_ALIGN(phys_addr + size) - page_base;
      if (efi_mem_attribute(page_base, size) & EFI_MEMORY_WB) {
            prot = PAGE_KERNEL;

            /*
             * Mappings have to be page-aligned
             */
            offset = phys_addr & ~PAGE_MASK;
            phys_addr &= PAGE_MASK;

            /*
             * Ok, go for it..
             */
            area = get_vm_area(size, VM_IOREMAP);
            if (!area)
                  return NULL;

            area->phys_addr = phys_addr;
            addr = (void __iomem *) area->addr;
            if (ioremap_page_range((unsigned long) addr,
                        (unsigned long) addr + size, phys_addr, prot)) {
                  vunmap((void __force *) addr);
                  return NULL;
            }

            return (void __iomem *) (offset + (char __iomem *)addr);
      }

      return __ioremap(phys_addr);
}
EXPORT_SYMBOL(ioremap);

void __iomem *
ioremap_nocache (unsigned long phys_addr, unsigned long size)
{
      if (kern_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)
            return NULL;

      return __ioremap(phys_addr);
}
EXPORT_SYMBOL(ioremap_nocache);

void
iounmap (volatile void __iomem *addr)
{
      if (REGION_NUMBER(addr) == RGN_GATE)
            vunmap((void *) ((unsigned long) addr & PAGE_MASK));
}
EXPORT_SYMBOL(iounmap);

Generated by  Doxygen 1.6.0   Back to index