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kernel/linux-rt-4.4.41/arch/cris/mm/ioremap.c 2.34 KB
5113f6f70   김현기   kernel add
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  /*
   * arch/cris/mm/ioremap.c
   *
   * Re-map IO memory to kernel address space so that we can access it.
   * Needed for memory-mapped I/O devices mapped outside our normal DRAM
   * window (that is, all memory-mapped I/O devices).
   *
   * (C) Copyright 1995 1996 Linus Torvalds
   * CRIS-port by Axis Communications AB
   */
  
  #include <linux/vmalloc.h>
  #include <linux/io.h>
  #include <asm/pgalloc.h>
  #include <arch/memmap.h>
  
  /*
   * Generic mapping function (not visible outside):
   */
  
  /*
   * Remap an arbitrary physical address space into the kernel virtual
   * address space. Needed when the kernel wants to access high addresses
   * directly.
   *
   * NOTE! We need to allow non-page-aligned mappings too: we will obviously
   * have to convert them into an offset in a page-aligned mapping, but the
   * caller shouldn't need to know that small detail.
   */
  void __iomem * __ioremap_prot(unsigned long phys_addr, unsigned long size, pgprot_t prot)
  {
  	void __iomem * addr;
  	struct vm_struct * area;
  	unsigned long offset, last_addr;
  
  	/* Don't allow wraparound or zero size */
  	last_addr = phys_addr + size - 1;
  	if (!size || last_addr < phys_addr)
  		return NULL;
  
  	/*
  	 * Mappings have to be page-aligned
  	 */
  	offset = phys_addr & ~PAGE_MASK;
  	phys_addr &= PAGE_MASK;
  	size = PAGE_ALIGN(last_addr+1) - phys_addr;
  
  	/*
  	 * Ok, go for it..
  	 */
  	area = get_vm_area(size, VM_IOREMAP);
  	if (!area)
  		return NULL;
  	addr = (void __iomem *)area->addr;
  	if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
  			       phys_addr, prot)) {
  		vfree((void __force *)addr);
  		return NULL;
  	}
  	return (void __iomem *) (offset + (char __iomem *)addr);
  }
  
  void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
  {
  	return __ioremap_prot(phys_addr, size,
  		              __pgprot(_PAGE_PRESENT | __READABLE |
  				       __WRITEABLE | _PAGE_GLOBAL |
  				       _PAGE_KERNEL | flags));
  }
  
  /**
   * ioremap_nocache     -   map bus memory into CPU space
   * @offset:    bus address of the memory
   * @size:      size of the resource to map
   *
   * Must be freed with iounmap.
   */
  
  void __iomem *ioremap_nocache(unsigned long phys_addr, unsigned long size)
  {
          return __ioremap(phys_addr | MEM_NON_CACHEABLE, size, 0);
  }
  EXPORT_SYMBOL(ioremap_nocache);
  
  void iounmap(volatile void __iomem *addr)
  {
  	if (addr > high_memory)
  		return vfree((void *) (PAGE_MASK & (unsigned long) addr));
  }