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/*

 *  linux/arch/arm/mm/ioremap.c

 *

 * Re-map IO memory to kernel address space so that we can access it.

 *

 * (C) Copyright 1995 1996 Linus Torvalds

 *

 * Hacked for ARM by Phil Blundell <philb@gnu.org>

 * Hacked to allow all architectures to build, and various cleanups

 * by Russell King

 *

 * This allows a driver to remap an arbitrary region of bus memory into

 * virtual space.  One should *only* use readl, writel, memcpy_toio and

 * so on with such remapped areas.

 *

 * ioremap support tweaked to allow support for large page mappings.  We

 * have several issues that needs to be resolved first however:

 *

 *  1. We need set_pte, or something like set_pte to understand large

 *     page mappings.

 *

 *  2. we need the unmap_* functions to likewise understand large page

 *     mappings.

 */

#include <linux/errno.h>

#include <linux/mm.h>

#include <linux/vmalloc.h>

#include <asm/page.h>

#include <asm/pgalloc.h>

#include <asm/io.h>

static inline void

remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,

               unsigned long pfn, pgprot_t pgprot)

{

        unsigned long end;

        address &= ~PMD_MASK;

        end = address + size;

        if (end > PMD_SIZE)

                end = PMD_SIZE;

        BUG_ON(address >= end);

        do {

                if (!pte_none(*pte))

                        goto bad;

                set_pte(pte, pfn_pte(pfn, pgprot));

                address += PAGE_SIZE;

                pfn++;

                pte++;

        } while (address && (address < end));

        return;

 bad:

        printk("remap_area_pte: page already exists\n");

        BUG();

}

static inline int

remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,

               unsigned long pfn, unsigned long flags)

{

        unsigned long end;

        pgprot_t pgprot;

        address &= ~PGDIR_MASK;

        end = address + size;

        if (end > PGDIR_SIZE)

                end = PGDIR_SIZE;

        pfn -= address >> PAGE_SHIFT;

        BUG_ON(address >= end);

        pgprot = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | L_PTE_WRITE | flags);

        do {

                pte_t * pte = pte_alloc(&init_mm, pmd, address);

                if (!pte)

                        return -ENOMEM;

                remap_area_pte(pte, address, end - address, pfn + (address >> PAGE_SHIFT), pgprot);

                address = (address + PMD_SIZE) & PMD_MASK;

                pmd++;

        } while (address && (address < end));

        return 0;

}

static int

remap_area_pages(unsigned long address, unsigned long pfn,

                 unsigned long size, unsigned long flags)

{

        int error;

        pgd_t * dir;

        unsigned long end = address + size;

        pfn -= address >> PAGE_SHIFT;

        dir = pgd_offset(&init_mm, address);

        flush_cache_all();

        BUG_ON(address >= end);

        spin_lock(&init_mm.page_table_lock);

        do {

                pmd_t *pmd;

                pmd = pmd_alloc(&init_mm, dir, address);

                error = -ENOMEM;

                if (!pmd)

                        break;

                if (remap_area_pmd(pmd, address, end - address,

                                         pfn + (address >> PAGE_SHIFT), flags))

                        break;

                error = 0;

                address = (address + PGDIR_SIZE) & PGDIR_MASK;

                dir++;

        } while (address && (address < end));

        spin_unlock(&init_mm.page_table_lock);

        flush_tlb_all();

        return error;

}

/*

 * 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.

 *

 * 'flags' are the extra L_PTE_ flags that you want to specify for this

 * mapping.  See include/asm-arm/proc-armv/pgtable.h for more information.

 */

void * __ioremap(unsigned long phys_addr, size_t size, unsigned long flags)

{

        void * 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) - phys_addr;

        /*

         * Ok, go for it..

         */

        area = get_vm_area(size, VM_IOREMAP);

        if (!area)

                return NULL;

        addr = area->addr;

        if (remap_area_pages(VMALLOC_VMADDR(addr), phys_addr >> PAGE_SHIFT, size, flags)) {

                vfree(addr);

                return NULL;

        }

        return (void *) (offset + (char *)addr);

}

void __iounmap(void *addr)

{

        vfree((void *) (PAGE_MASK & (unsigned long) addr));

}