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/*
* 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/bootmem.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <asm/cacheflush.h>
#include <asm/e820.h>
#include <asm/fixmap.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
#include <asm/pat.h>
#ifdef CONFIG_X86_64
unsigned long __phys_addr(unsigned long x)
{
if (x >= __START_KERNEL_map)
return x - __START_KERNEL_map + phys_base;
return x - PAGE_OFFSET;
}
EXPORT_SYMBOL(__phys_addr);
static inline int phys_addr_valid(unsigned long addr)
{
return addr < (1UL << boot_cpu_data.x86_phys_bits);
}
#else
static inline int phys_addr_valid(unsigned long addr)
{
return 1;
}
#endif
int page_is_ram(unsigned long pagenr)
{
resource_size_t addr, end;
int i;
/*
* A special case is the first 4Kb of memory;
* This is a BIOS owned area, not kernel ram, but generally
* not listed as such in the E820 table.
*/
if (pagenr == 0)
return 0;
/*
* Second special case: Some BIOSen report the PC BIOS
* area (640->1Mb) as ram even though it is not.
*/
if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
pagenr < (BIOS_END >> PAGE_SHIFT))
return 0;
for (i = 0; i < e820.nr_map; i++) {
/*
* Not usable memory:
*/
if (e820.map[i].type != E820_RAM)
continue;
addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
if ((pagenr >= addr) && (pagenr < end))
return 1;
}
return 0;
}
/*
* Fix up the linear direct mapping of the kernel to avoid cache attribute
* conflicts.
*/
int ioremap_change_attr(unsigned long vaddr, unsigned long size,
unsigned long prot_val)
{
unsigned long nrpages = size >> PAGE_SHIFT;
int err;
switch (prot_val) {
case _PAGE_CACHE_UC:
default:
err = _set_memory_uc(vaddr, nrpages);
break;
case _PAGE_CACHE_WC:
err = _set_memory_wc(vaddr, nrpages);
break;
case _PAGE_CACHE_WB:
err = _set_memory_wb(vaddr, nrpages);
break;
}
return err;
}
/*
* 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.
*/
static void __iomem *__ioremap_caller(resource_size_t phys_addr,
unsigned long size, unsigned long prot_val, void *caller)
{
unsigned long pfn, offset, vaddr;
resource_size_t last_addr;
struct vm_struct *area;
unsigned long new_prot_val;
pgprot_t prot;
int retval;
/* Don't allow wraparound or zero size */
last_addr = phys_addr + size - 1;
if (!size || last_addr < phys_addr)
return NULL;
if (!phys_addr_valid(phys_addr)) {
printk(KERN_WARNING "ioremap: invalid physical address %llx\n",
(unsigned long long)phys_addr);
WARN_ON_ONCE(1);
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);
/*
* Don't allow anybody to remap normal RAM that we're using..
*/
for (pfn = phys_addr >> PAGE_SHIFT;
(pfn << PAGE_SHIFT) < (last_addr & PAGE_MASK);
pfn++) {
int is_ram = page_is_ram(pfn);
if (is_ram && pfn_valid(pfn) && !PageReserved(pfn_to_page(pfn)))
return NULL;
WARN_ON_ONCE(is_ram);
}
/*
* Mappings have to be page-aligned
*/
offset = phys_addr & ~PAGE_MASK;
phys_addr &= PAGE_MASK;
size = PAGE_ALIGN(last_addr+1) - phys_addr;
retval = reserve_memtype(phys_addr, phys_addr + size,
prot_val, &new_prot_val);
if (retval) {
pr_debug("Warning: reserve_memtype returned %d\n", retval);
return NULL;
}
if (prot_val != new_prot_val) {
/*
* Do not fallback to certain memory types with certain
* requested type:
* - request is uc-, return cannot be write-back
* - request is uc-, return cannot be write-combine
* - request is write-combine, return cannot be write-back
*/
if ((prot_val == _PAGE_CACHE_UC_MINUS &&
(new_prot_val == _PAGE_CACHE_WB ||
new_prot_val == _PAGE_CACHE_WC)) ||
(prot_val == _PAGE_CACHE_WC &&
new_prot_val == _PAGE_CACHE_WB)) {
pr_debug(
"ioremap error for 0x%llx-0x%llx, requested 0x%lx, got 0x%lx\n",
(unsigned long long)phys_addr,
(unsigned long long)(phys_addr + size),
prot_val, new_prot_val);
free_memtype(phys_addr, phys_addr + size);
return NULL;
}
prot_val = new_prot_val;
}
switch (prot_val) {
case _PAGE_CACHE_UC:
default:
prot = PAGE_KERNEL_NOCACHE;
break;
case _PAGE_CACHE_UC_MINUS:
prot = PAGE_KERNEL_UC_MINUS;
break;
case _PAGE_CACHE_WC:
prot = PAGE_KERNEL_WC;
break;
case _PAGE_CACHE_WB:
prot = PAGE_KERNEL;
break;
}
/*
* Ok, go for it..
*/
area = get_vm_area_caller(size, VM_IOREMAP, caller);
if (!area)
return NULL;
area->phys_addr = phys_addr;
vaddr = (unsigned long) area->addr;
if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
free_memtype(phys_addr, phys_addr + size);
free_vm_area(area);
return NULL;
}
if (ioremap_change_attr(vaddr, size, prot_val) < 0) {
free_memtype(phys_addr, phys_addr + size);
vunmap(area->addr);
return NULL;
}
return (void __iomem *) (vaddr + offset);
}
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