/*
* arch/x86_64/mm/ioremap.c
*
* 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
*
* (C) Copyright 1995 1996 Linus Torvalds
*/
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <asm/io.h>
#include <asm/pgalloc.h>
#include <asm/fixmap.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/proto.h>
#define ISA_START_ADDRESS 0xa0000
#define ISA_END_ADDRESS 0x100000
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;
address &= ~PMD_MASK;
end = address + size;
if (end > PMD_SIZE)
end = PMD_SIZE;
if (address >= end)
BUG();
pfn = phys_addr >> PAGE_SHIFT;
do {
if (!pte_none(*pte)) {
printk("remap_area_pte: page already exists\n");
BUG();
}
set_pte(pte, pfn_pte(pfn, __pgprot(_PAGE_PRESENT | _PAGE_RW |
_PAGE_GLOBAL | _PAGE_DIRTY | _PAGE_ACCESSED | flags)));
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 &= ~PUD_MASK;
end = address + size;
if (end > PUD_SIZE)
end = PUD_SIZE;
phys_addr -= address;
if (address >= end)
BUG();
do {
pte_t * pte = pte_alloc_kernel(&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 inline int remap_area_pud(pud_t * pud, 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 {
pmd_t * pmd = pmd_alloc(&init_mm, pud, address);
if (!pmd)
return -ENOMEM;
remap_area_pmd(pmd, address, end - address, address + phys_addr, flags);
address = (address + PUD_SIZE) & PUD_MASK;
pud++;
} 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 *pgd;
unsigned long end = address + size;
phys_addr -= address;
pgd = pgd_offset_k(address);
flush_cache_all();
if (address >= end)
BUG();
spin_lock(&init_mm.page_table_lock);
do {
pud_t *pud;
pud = pud_alloc(&init_mm, pgd, address);
error = -ENOMEM;
if (!pud)
break;
if (remap_area_pud(pud, address, end - address,
phys_addr + address, flags))
break;
error = 0;
address = (address + PGDIR_SIZE) & PGDIR_MASK;
pgd++;
} while (address && (address < end));
spin_unlock(&init_mm.page_table_lock);
flush_tlb_all();
return error;
}
/*
* Fix up the linear direct mapping of the kernel to avoid cache attribute
* conflicts.
*/
static int
ioremap_change_attr(unsigned long phys_addr, unsigned long size,
unsigned long flags)
{
int err = 0;
if (flags && phys_addr + size - 1 < (end_pfn_map << PAGE_SHIFT)) {
unsigned long npages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long vaddr = (unsigned long) __va(phys_addr);
/*
* Must use a address here and not struct page because the phys addr
* can be a in hole between nodes and not have an memmap entry.
*/
err = change_page_attr_addr(vaddr,npages,__pgprot(__PAGE_KERNEL|flags));
if (!err)
global_flush_tlb();
}
return err;
}
/*
* Generic mapping function
*/
/*
* Remap an arbitrary physical address space into the kernel virtual
* address space. Needed when the kernel wants to access high addresses
* directly.
*
* NOTE! We need to allow non-page-aligned mappings too: we will obviously
* have to convert them into an offset in a page-aligned mapping, but the
* caller shouldn't need to know that small detail.
*/
void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
{
void * addr;
struct vm_struct * area;
unsigned long offset, last_addr;
/* Don't allow wraparound or zero size */
last_addr = phys_addr + size - 1;
if (!size || last_addr < phys_addr)
return NULL;
/*
* Don't remap the low PCI/ISA area, it's always mapped..
*/
if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
return (__force void __iomem *)phys_to_virt(phys_addr);
#ifndef CONFIG_DISCONTIGMEM
/*
* Don't allow anybody to remap normal RAM that we're using..
*/
if (last_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;
}
#endif
/*
* 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 | (flags << 20));
if (!area)
return NULL;
area->phys_addr = phys_addr;
addr = area->addr;
if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
return NULL;
}
if (ioremap_change_attr(phys_addr, size, flags) < 0) {
area->flags &= 0xffffff;
vunmap(addr);
return NULL;
}
return (__force void __iomem *) (offset + (char *)addr);
}
/**
* ioremap_nocache - map bus memory into CPU space
* @offset: bus address of the memory
* @size: size of the resource to map
*
* ioremap_nocache performs a platform specific sequence of operations to
* make bus memory CPU accessible via the readb/readw/readl/writeb/
* writew/writel functions and the other mmio helpers. The returned
* address is not guaranteed to be usable directly as a virtual
* address.
*
* This version of ioremap ensures that the memory is marked uncachable
* on the CPU as well as honouring existing caching rules from things like
* the PCI bus. Note that there are other caches and buffers on many
* busses. In particular driver authors should read up on PCI writes
*
* It's useful if some control registers are in such an area and
* write combining or read caching is not desirable:
*
* Must be freed with iounmap.
*/
void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
{
return __ioremap(phys_addr, size, _PAGE_PCD);
}
void iounmap(volatile void __iomem *addr)
{
struct vm_struct *p, **pprev;
if (addr <= high_memory)
return;
if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
addr < phys_to_virt(ISA_END_ADDRESS))
return;
write_lock(&vmlist_lock);
for (p = vmlist, pprev = &vmlist; p != NULL; pprev = &p->next, p = *pprev)
if (p->addr == (void *)(PAGE_MASK & (unsigned long)addr))
break;
if (!p) {
printk("__iounmap: bad address %p\n", addr);
goto out_unlock;
}
*pprev = p->next;
unmap_vm_area(p);
if ((p->flags >> 20) &&
p->phys_addr + p->size - 1 < virt_to_phys(high_memory)) {
/* p->size includes the guard page, but cpa doesn't like that */
change_page_attr(virt_to_page(__va(p->phys_addr)),
p->size >> PAGE_SHIFT,
PAGE_KERNEL);
global_flush_tlb();
}
out_unlock:
write_unlock(&vmlist_lock);
kfree(p);
}
