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/*

 *  arch/s390/mm/ioremap.c

 *

 *  S390 version

 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation

 *    Author(s): Hartmut Penner (hp@de.ibm.com)

 *

 *  Derived from "arch/i386/mm/extable.c"

 *    (C) Copyright 1995 1996 Linus Torvalds

 *

 * 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

 */

#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 | 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(&init_mm, 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 0;

}

/*

 * 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.

 */

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

{

        void * addr;

        struct vm_struct * area;

        if (phys_addr < virt_to_phys(high_memory))

                return phys_to_virt(phys_addr);

        if (phys_addr & ~PAGE_MASK)

                return NULL;

        size = PAGE_ALIGN(size);

        if (!size || size > phys_addr + size)

                return NULL;

        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 addr;

}

void iounmap(void *addr)

{

        if (addr > high_memory)

                return vfree(addr);

}