From: venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com>
Date: Thu, 18 Dec 2008 19:41:32 +0000 (-0800)
Subject: x86: PAT: add pgprot_writecombine() interface for drivers - v3
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2520bd3123c00272f818a176c92d03c7d0a113d6;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

x86: PAT: add pgprot_writecombine() interface for drivers - v3

Impact: New mm functionality.

Add pgprot_writecombine. pgprot_writecombine will be aliased to
pgprot_noncached when not supported by the architecture.

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

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 6968d4f6be3e..579f8ceee948 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -168,6 +168,9 @@
 
 #ifndef __ASSEMBLY__
 
+#define pgprot_writecombine	pgprot_writecombine
+extern pgprot_t pgprot_writecombine(pgprot_t prot);
+
 /*
  * ZERO_PAGE is a global shared page that is always zero: used
  * for zero-mapped memory areas etc..
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 1069ffecf77d..d5254bae84f4 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -832,6 +832,14 @@ void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
 	}
 }
 
+pgprot_t pgprot_writecombine(pgprot_t prot)
+{
+	if (pat_enabled)
+		return __pgprot(pgprot_val(prot) | _PAGE_CACHE_WC);
+	else
+		return pgprot_noncached(prot);
+}
+
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
 
 /* get Nth element of the linked list */
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index ef87f889ef62..b84633801fb6 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -129,6 +129,10 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
 #define move_pte(pte, prot, old_addr, new_addr)	(pte)
 #endif
 
+#ifndef pgprot_writecombine
+#define pgprot_writecombine pgprot_noncached
+#endif
+
 /*
  * When walking page tables, get the address of the next boundary,
  * or the end address of the range if that comes earlier.  Although no