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/*
* Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2009 Wind River Systems Inc
* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
* Copyright (C) 2004 Microtronix Datacom Ltd.
*
* 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.
*/
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/io.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.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;
unsigned long pfn;
pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_READ
| _PAGE_WRITE | flags);
address &= ~PMD_MASK;
end = address + size;
if (end > PMD_SIZE)
end = PMD_SIZE;
if (address >= end)
BUG();
pfn = PFN_DOWN(phys_addr);
do {
if (!pte_none(*pte)) {
pr_err("remap_area_pte: page already exists\n");
BUG();
}
set_pte(pte, pfn_pte(pfn, pgprot));
address += PAGE_SIZE;
pfn++;
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_kernel(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();
do {
pud_t *pud;
pmd_t *pmd;
error = -ENOMEM;
pud = pud_alloc(&init_mm, dir, address);
if (!pud)
break;
pmd = pmd_alloc(&init_mm, pud, address);
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));
flush_tlb_all();
return error;
}
#define IS_MAPPABLE_UNCACHEABLE(addr) (addr < 0x20000000UL)
/*
* Map some physical address range into the kernel address space.
*/
void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
{
struct vm_struct *area;
unsigned long offset;
unsigned long last_addr;
void *addr;
/* Don't allow wraparound or zero size */
last_addr = phys_addr + size - 1;
if (!size || last_addr < phys_addr)
return NULL;
/* Don't allow anybody to remap normal RAM that we're using */
if (phys_addr > PHYS_OFFSET && phys_addr < virt_to_phys(high_memory)) {
char *t_addr, *t_end;
struct page *page;
t_addr = __va(phys_addr);
t_end = t_addr + (size - 1);
for (page = virt_to_page(t_addr);
page <= virt_to_page(t_end); page++)
if (!PageReserved(page))
return NULL;
}
/*
* Map uncached objects in the low part of address space to
* CONFIG_NIOS2_IO_REGION_BASE
*/
if (IS_MAPPABLE_UNCACHEABLE(phys_addr) &&
IS_MAPPABLE_UNCACHEABLE(last_addr))
return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr);
/* 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((unsigned long) addr, phys_addr, size, 0)) {
vunmap(addr);
return NULL;
}
return (void __iomem *) (offset + (char *)addr);
}
EXPORT_SYMBOL(ioremap);
/*
* iounmap unmaps nearly everything, so be careful
* it doesn't free currently pointer/page tables anymore but it
* wasn't used anyway and might be added later.
*/
void iounmap(void __iomem *addr)
{
struct vm_struct *p;
if ((unsigned long) addr > CONFIG_NIOS2_IO_REGION_BASE)
return;
p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
if (!p)
pr_err("iounmap: bad address %p\n", addr);
kfree(p);
}
EXPORT_SYMBOL(iounmap);
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