ioremap.c
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* (C) Copyright 1995 1996 Linus Torvalds
* (C) Copyright 2001, 2002 Ralf Baechle
*/
#include <linux/export.h>
#include <asm/addrspace.h>
#include <asm/byteorder.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mm_types.h>
#include <linux/io.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <ioremap.h>
#define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL))
#define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
void *arg)
{
unsigned long i;
for (i = 0; i < nr_pages; i++) {
if (pfn_valid(start_pfn + i) &&
!PageReserved(pfn_to_page(start_pfn + i)))
return 1;
}
return 0;
}
/*
* ioremap_prot - map bus memory into CPU space
* @phys_addr: bus address of the memory
* @size: size of the resource to map
*
* ioremap_prot gives the caller control over cache coherency attributes (CCA)
*/
void __iomem *ioremap_prot(phys_addr_t phys_addr, unsigned long size,
unsigned long prot_val)
{
unsigned long flags = prot_val & _CACHE_MASK;
unsigned long offset, pfn, last_pfn;
struct vm_struct *area;
phys_addr_t last_addr;
unsigned long vaddr;
void __iomem *cpu_addr;
cpu_addr = plat_ioremap(phys_addr, size, flags);
if (cpu_addr)
return cpu_addr;
phys_addr = fixup_bigphys_addr(phys_addr, size);
/* Don't allow wraparound or zero size */
last_addr = phys_addr + size - 1;
if (!size || last_addr < phys_addr)
return NULL;
/*
* Map uncached objects in the low 512mb of address space using KSEG1,
* otherwise map using page tables.
*/
if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
flags == _CACHE_UNCACHED)
return (void __iomem *) CKSEG1ADDR(phys_addr);
/*
* Don't allow anybody to remap RAM that may be allocated by the page
* allocator, since that could lead to races & data clobbering.
*/
pfn = PFN_DOWN(phys_addr);
last_pfn = PFN_DOWN(last_addr);
if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
__ioremap_check_ram) == 1) {
WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
&phys_addr, &last_addr);
return NULL;
}
/*
* 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;
vaddr = (unsigned long)area->addr;
flags |= _PAGE_GLOBAL | _PAGE_PRESENT | __READABLE | __WRITEABLE;
if (ioremap_page_range(vaddr, vaddr + size, phys_addr,
__pgprot(flags))) {
free_vm_area(area);
return NULL;
}
return (void __iomem *)(vaddr + offset);
}
EXPORT_SYMBOL(ioremap_prot);
void iounmap(const volatile void __iomem *addr)
{
if (!plat_iounmap(addr) && !IS_KSEG1(addr))
vunmap((void *)((unsigned long)addr & PAGE_MASK));
}
EXPORT_SYMBOL(iounmap);