1/*
  2 *  linux/arch/m32r/mm/ioremap.c
  3 *
  4 *  Copyright (c) 2001, 2002  Hiroyuki Kondo
  5 *
  6 *  Taken from mips version.
  7 *    (C) Copyright 1995 1996 Linus Torvalds
  8 *    (C) Copyright 2001 Ralf Baechle
  9 */
 10
 11/*
 12 * This file is subject to the terms and conditions of the GNU General Public
 13 * License.  See the file "COPYING" in the main directory of this archive
 14 * for more details.
 15 *
 16 */
 17
 18#include <linux/module.h>
 19#include <asm/addrspace.h>
 20#include <asm/byteorder.h>
 21
 22#include <linux/vmalloc.h>
 23#include <linux/io.h>
 24#include <asm/pgalloc.h>
 25
 26/*
 27 * Generic mapping function (not visible outside):
 28 */
 29
 30/*
 31 * Remap an arbitrary physical address space into the kernel virtual
 32 * address space. Needed when the kernel wants to access high addresses
 33 * directly.
 34 *
 35 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 36 * have to convert them into an offset in a page-aligned mapping, but the
 37 * caller shouldn't need to know that small detail.
 38 */
 39
 40#define IS_LOW512(addr) (!((unsigned long)(addr) & ~0x1fffffffUL))
 41
 42void __iomem *
 43__ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 44{
 45	void __iomem * addr;
 46	struct vm_struct * area;
 47	unsigned long offset, last_addr;
 48	pgprot_t pgprot;
 49
 50	/* Don't allow wraparound or zero size */
 51	last_addr = phys_addr + size - 1;
 52	if (!size || last_addr < phys_addr)
 53		return NULL;
 54
 55	/*
 56	 * Map objects in the low 512mb of address space using KSEG1, otherwise
 57	 * map using page tables.
 58	 */
 59	if (IS_LOW512(phys_addr) && IS_LOW512(phys_addr + size - 1))
 60		return (void *) KSEG1ADDR(phys_addr);
 61
 62	/*
 63	 * Don't allow anybody to remap normal RAM that we're using..
 64	 */
 65	if (phys_addr < virt_to_phys(high_memory)) {
 66		char *t_addr, *t_end;
 67		struct page *page;
 68
 69		t_addr = __va(phys_addr);
 70		t_end = t_addr + (size - 1);
 71
 72		for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
 73			if(!PageReserved(page))
 74				return NULL;
 75	}
 76
 77	pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_READ
 78			  | _PAGE_WRITE | flags);
 79
 80	/*
 81	 * Mappings have to be page-aligned
 82	 */
 83	offset = phys_addr & ~PAGE_MASK;
 84	phys_addr &= PAGE_MASK;
 85	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 86
 87	/*
 88	 * Ok, go for it..
 89	 */
 90	area = get_vm_area(size, VM_IOREMAP);
 91	if (!area)
 92		return NULL;
 93	area->phys_addr = phys_addr;
 94	addr = (void __iomem *) area->addr;
 95	if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
 96			       phys_addr, pgprot)) {
 97		vunmap((void __force *) addr);
 98		return NULL;
 99	}
100
101	return (void __iomem *) (offset + (char __iomem *)addr);
102}
103
104#define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == KSEG1)
105
106void iounmap(volatile void __iomem *addr)
107{
108	if (!IS_KSEG1(addr))
109		vfree((void *) (PAGE_MASK & (unsigned long) addr));
110}
111