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x86: PAT add ioremap_wc() interface 

Introduce ioremap_wc for wc remap.

(generic wrapper is in a later patch)

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
venkatesh.pallipadi@intel.com 2008-03-18 17:00:24 -07:00 committed by Ingo Molnar
parent ef354af462
commit b310f381d2
3 changed files with 35 additions and 0 deletions
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30
arch/x86/mm/ioremap.c
View File

@ -97,6 +97,9 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size,
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;
@ -166,8 +169,13 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size,
* Do not fallback to certain memory types with certain
* requested type:
* - request is uncached, return cannot be write-back
* - request is uncached, return cannot be write-combine
* - request is write-combine, return cannot be write-back
*/
if ((prot_val == _PAGE_CACHE_UC &&
(new_prot_val == _PAGE_CACHE_WB ||
new_prot_val == _PAGE_CACHE_WC)) ||
(prot_val == _PAGE_CACHE_WC &&
new_prot_val == _PAGE_CACHE_WB)) {
free_memtype(phys_addr, phys_addr + size);
return NULL;
@ -180,6 +188,9 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size,
default:
prot = PAGE_KERNEL_NOCACHE;
break;
case _PAGE_CACHE_WC:
prot = PAGE_KERNEL_WC;
break;
case _PAGE_CACHE_WB:
prot = PAGE_KERNEL;
break;
@ -235,6 +246,25 @@ void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
}
EXPORT_SYMBOL(ioremap_nocache);
/**
* ioremap_wc - map memory into CPU space write combined
* @offset: bus address of the memory
* @size: size of the resource to map
*
* This version of ioremap ensures that the memory is marked write combining.
* Write combining allows faster writes to some hardware devices.
*
* Must be freed with iounmap.
*/
void __iomem *ioremap_wc(unsigned long phys_addr, unsigned long size)
{
if (pat_wc_enabled)
return __ioremap(phys_addr, size, _PAGE_CACHE_WC);
else
return ioremap_nocache(phys_addr, size);
}
EXPORT_SYMBOL(ioremap_wc);
void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size)
{
return __ioremap(phys_addr, size, _PAGE_CACHE_WB);

3
include/asm-x86/io.h
View File

@ -1,3 +1,5 @@
#define ARCH_HAS_IOREMAP_WC
#ifdef CONFIG_X86_32
# include "io_32.h"
#else
@ -5,4 +7,5 @@
#endif
extern int ioremap_change_attr(unsigned long vaddr, unsigned long size,
unsigned long prot_val);
extern void __iomem * ioremap_wc(unsigned long offset, unsigned long size);

2
include/asm-x86/pgtable.h
View File

@ -90,6 +90,7 @@ extern pteval_t __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
#define __PAGE_KERNEL_RO (__PAGE_KERNEL & ~_PAGE_RW)
#define __PAGE_KERNEL_RX (__PAGE_KERNEL_EXEC & ~_PAGE_RW)
#define __PAGE_KERNEL_EXEC_NOCACHE (__PAGE_KERNEL_EXEC | _PAGE_PCD | _PAGE_PWT)
#define __PAGE_KERNEL_WC (__PAGE_KERNEL | _PAGE_CACHE_WC)
#define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL | _PAGE_PCD | _PAGE_PWT)
#define __PAGE_KERNEL_UC_MINUS (__PAGE_KERNEL | _PAGE_PCD)
#define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RX | _PAGE_USER)
@ -107,6 +108,7 @@ extern pteval_t __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
#define PAGE_KERNEL_RO MAKE_GLOBAL(__PAGE_KERNEL_RO)
#define PAGE_KERNEL_EXEC MAKE_GLOBAL(__PAGE_KERNEL_EXEC)
#define PAGE_KERNEL_RX MAKE_GLOBAL(__PAGE_KERNEL_RX)
#define PAGE_KERNEL_WC MAKE_GLOBAL(__PAGE_KERNEL_WC)
#define PAGE_KERNEL_NOCACHE MAKE_GLOBAL(__PAGE_KERNEL_NOCACHE)
#define PAGE_KERNEL_UC_MINUS MAKE_GLOBAL(__PAGE_KERNEL_UC_MINUS)
#define PAGE_KERNEL_EXEC_NOCACHE MAKE_GLOBAL(__PAGE_KERNEL_EXEC_NOCACHE)