ioremap.c

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/*
 * Based on arch/arm/mm/ioremap.c
 *
 * (C) Copyright 1995 1996 Linus Torvalds
 * Hacked for ARM by Phil Blundell <[email protected]>
 * Hacked to allow all architectures to build, and various cleanups
 * by Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * 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.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/export.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/io.h>

static void __iomem *__ioremap_caller(phys_addr_t phys_addr, size_t size,
                      pgprot_t prot, void *caller)
{
    unsigned long last_addr;
    unsigned long offset = phys_addr & ~PAGE_MASK;
    int err;
    unsigned long addr;
    struct vm_struct *area;

    /*
     * Page align the mapping address and size, taking account of any
     * offset.
     */
    phys_addr &= PAGE_MASK;
    size = PAGE_ALIGN(size + offset);

    /*
     * Don't allow wraparound, zero size or outside PHYS_MASK.
     */
    last_addr = phys_addr + size - 1;
    if (!size || last_addr < phys_addr || (last_addr & ~PHYS_MASK))
        return NULL;

    /*
     * Don't allow RAM to be mapped.
     */
    if (WARN_ON(pfn_valid(__phys_to_pfn(phys_addr))))
        return NULL;

    area = get_vm_area_caller(size, VM_IOREMAP, caller);
    if (!area)
        return NULL;
    addr = (unsigned long)area->addr;

    err = ioremap_page_range(addr, addr + size, phys_addr, prot);
    if (err) {
        vunmap((void *)addr);
        return NULL;
    }

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

void __iomem *__ioremap(phys_addr_t phys_addr, size_t size, pgprot_t prot)
{
    return __ioremap_caller(phys_addr, size, prot,
                __builtin_return_address(0));
}
EXPORT_SYMBOL(__ioremap);

void __iounmap(volatile void __iomem *io_addr)
{
    void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);

    vunmap(addr);
}
EXPORT_SYMBOL(__iounmap);