ioremap.c

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/*
 * (c) Copyright 2006, 2007 Hewlett-Packard Development Company, L.P.
 *  Bjorn Helgaas <[email protected]>
 *
 * 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 *
early_ioremap (unsigned long phys_addr, unsigned long size)
{
    return __ioremap(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
early_iounmap (volatile void __iomem *addr, unsigned long size)
{
}

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