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Subject[patch 12/13] x86: PAT Add ioremap_wc() interface
Introduce ioremap_wc for wc remap. There is also a generic ioremap_wc
aliased to ioremap_uc so that drivers can use this interface transparently.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>

Index: linux-2.6-x86.git/arch/x86/mm/ioremap.c
===================================================================
--- linux-2.6-x86.git.orig/arch/x86/mm/ioremap.c 2008-03-18 03:21:25.000000000 -0700
+++ linux-2.6-x86.git/arch/x86/mm/ioremap.c 2008-03-18 09:20:21.000000000 -0700
@@ -98,6 +98,9 @@
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;
@@ -168,8 +171,13 @@
* 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;
@@ -182,6 +190,9 @@
default:
prot = PAGE_KERNEL_NOCACHE;
break;
+ case _PAGE_CACHE_WC:
+ prot = PAGE_KERNEL_WC;
+ break;
case _PAGE_CACHE_WB:
prot = PAGE_KERNEL;
break;
@@ -240,6 +251,25 @@
}
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(unsigned long phys_addr, unsigned long size)
{
return __ioremap(phys_addr, size, _PAGE_CACHE_WB);
Index: linux-2.6-x86.git/include/asm-generic/iomap.h
===================================================================
--- linux-2.6-x86.git.orig/include/asm-generic/iomap.h 2008-03-18 02:16:03.000000000 -0700
+++ linux-2.6-x86.git/include/asm-generic/iomap.h 2008-03-18 03:54:39.000000000 -0700
@@ -60,6 +60,10 @@
extern void __iomem *ioport_map(unsigned long port, unsigned int nr);
extern void ioport_unmap(void __iomem *);

+#ifndef ARCH_HAS_IOREMAP_WC
+#define ioremap_wc ioremap_nocache
+#endif
+
/* Create a virtual mapping cookie for a PCI BAR (memory or IO) */
struct pci_dev;
extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
Index: linux-2.6-x86.git/include/asm-x86/io.h
===================================================================
--- linux-2.6-x86.git.orig/include/asm-x86/io.h 2008-03-18 03:14:09.000000000 -0700
+++ linux-2.6-x86.git/include/asm-x86/io.h 2008-03-18 03:54:39.000000000 -0700
@@ -1,6 +1,8 @@
#ifndef _ASM_X86_IO_H
#define _ASM_X86_IO_H

+#define ARCH_HAS_IOREMAP_WC
+
#ifdef CONFIG_X86_32
# include "io_32.h"
#else
@@ -9,6 +11,7 @@

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);

extern void *xlate_dev_mem_ptr(unsigned long phys);
extern void unxlate_dev_mem_ptr(unsigned long phys, void *addr);
Index: linux-2.6-x86.git/include/asm-x86/pgtable.h
===================================================================
--- linux-2.6-x86.git.orig/include/asm-x86/pgtable.h 2008-03-18 03:33:01.000000000 -0700
+++ linux-2.6-x86.git/include/asm-x86/pgtable.h 2008-03-18 03:54:39.000000000 -0700
@@ -90,6 +90,7 @@
#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_VSYSCALL (__PAGE_KERNEL_RX | _PAGE_USER)
#define __PAGE_KERNEL_VSYSCALL_NOCACHE (__PAGE_KERNEL_VSYSCALL | _PAGE_PCD | _PAGE_PWT)
@@ -106,6 +107,7 @@
#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_EXEC_NOCACHE MAKE_GLOBAL(__PAGE_KERNEL_EXEC_NOCACHE)
#define PAGE_KERNEL_LARGE MAKE_GLOBAL(__PAGE_KERNEL_LARGE)
--


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