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/*
* (C) Copyright 1995 1996 Linus Torvalds
* (C) Copyright 2012 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/io.h>
#include <asm/pgtable.h>
/*
* 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.
*/
static void __iomem *__ioremap_caller(phys_addr_t addr, size_t size,
pgprot_t prot, void *caller)
{
phys_addr_t last_addr;
unsigned long offset, vaddr;
struct vm_struct *area;
/* Disallow wrap-around or zero size */
last_addr = addr + size - 1;
if (!size || last_addr < addr)
return NULL;
/* Page-align mappings */
offset = addr & (~PAGE_MASK);
addr &= PAGE_MASK;
size = PAGE_ALIGN(size + offset);
area = get_vm_area_caller(size, VM_IOREMAP, caller);
if (!area)
return NULL;
vaddr = (unsigned long)area->addr;
if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) {
free_vm_area(area);
return NULL;
}
return (void __iomem *)(vaddr + offset);
}
/*
* ioremap - map bus memory into CPU space
* @offset: bus address of the memory
* @size: size of the resource to map
*
* ioremap performs a platform specific sequence of operations to
* make bus memory CPU accessible via the readb/readw/readl/writeb/
* writew/writel functions and the other mmio helpers. The returned
* address is not guaranteed to be usable directly as a virtual
* address.
*
* Must be freed with iounmap.
*/
void __iomem *ioremap(phys_addr_t offset, unsigned long size)
{
return __ioremap_caller(offset, size, PAGE_KERNEL,
__builtin_return_address(0));
}
EXPORT_SYMBOL(ioremap);
/**
* iounmap - Free a IO remapping
* @addr: virtual address from ioremap_*
*
* Caller must ensure there is only one unmapping for the same pointer.
*/
void iounmap(volatile void __iomem *addr)
{
vunmap((void *)((unsigned long)addr & PAGE_MASK));
}
EXPORT_SYMBOL(iounmap);
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