ioremap.c

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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));
}

void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
{
        return __ioremap(phys_addr | MEM_NON_CACHEABLE, size, 0);
}

void iounmap(volatile void __iomem *addr)
{
    if (addr > high_memory)
        return vfree((void *) (PAGE_MASK & (unsigned long) addr));
}