/* *  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);}