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/*

 * arch/x86_64/mm/ioremap.c

 *

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

 * This is needed for high PCI addresses that aren't mapped in the

 * 640k-1MB IO memory area on PC's

 *

 * (C) Copyright 1995 1996 Linus Torvalds

 */

#include <linux/vmalloc.h>

#include <asm/io.h>

#include <asm/pgalloc.h>

static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,

        unsigned long phys_addr, unsigned long flags)

{

        unsigned long end;

        address &= ~PMD_MASK;

        end = address + size;

        if (end > PMD_SIZE)

                end = PMD_SIZE;

        if (address >= end)

                BUG();

        do {

                if (!pte_none(*pte)) {

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

                        BUG();

                }

                set_pte(pte, mk_pte_phys(phys_addr, __pgprot(_PAGE_PRESENT | _PAGE_RW |

                                        _PAGE_GLOBAL | _PAGE_DIRTY | _PAGE_ACCESSED | flags)));

                address += PAGE_SIZE;

                phys_addr += PAGE_SIZE;

                pte++;

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

}

static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,

        unsigned long phys_addr, unsigned long flags)

{

        unsigned long end;

        address &= ~PGDIR_MASK;

        end = address + size;

        if (end > PGDIR_SIZE)

                end = PGDIR_SIZE;

        phys_addr -= address;

        if (address >= end)

                BUG();

        do {

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

                if (!pte)

                        return -ENOMEM;

                remap_area_pte(pte, address, end - address, address + phys_addr, flags);

                address = (address + PMD_SIZE) & PMD_MASK;

                pmd++;

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

        return 0;

}

static int remap_area_pages(unsigned long address, unsigned long phys_addr,

                                 unsigned long size, unsigned long flags)

{

        int error;

        pgd_t * dir;

        unsigned long end = address + size;

        phys_addr -= address;

        dir = pgd_offset_k(address);

        flush_cache_all();

        if (address >= end)

                BUG();

        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,

                                         phys_addr + address, 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;

}

/*

 * 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 * __ioremap(unsigned long phys_addr, unsigned long 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;

        /*

         * Don't remap the low PCI/ISA area, it's always mapped..

         */

        if (phys_addr >= 0xA0000 && last_addr < 0x100000)

                return phys_to_virt(phys_addr);

        /*

         * Don't allow anybody to remap normal RAM that we're using..

         */

        if (phys_addr < virt_to_phys(high_memory)) {

                char *t_addr, *t_end;

                t_addr = __va(phys_addr);

                t_end = t_addr + (size - 1);

#ifndef CONFIG_DISCONTIGMEM

                struct page *page;

                for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)

                        if(!PageReserved(page))

                                return NULL;

#endif

        }

        /*

         * 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 = area->addr;

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

                vfree(addr);

                return NULL;

        }

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

}

void iounmap(void *addr)

{

        if (addr > high_memory)

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

}