[MIPS] Hook for platforms to define cachability of /dev/mem regions

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 17 insertions, 0 deletions

diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index abf99b1eba13..81f925a9a731 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -6,6 +6,8 @@
  * Copyright (C) 1994 - 2003, 07 by Ralf Baechle (ralf@linux-mips.org)
  * Copyright (C) 2007 MIPS Technologies, Inc.
  */
+#include <linux/fs.h>
+#include <linux/fcntl.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -164,3 +166,11 @@ void __init cpu_cache_init(void)
 
         panic(cache_panic);
 }
+
+int __weak __uncached_access(struct file *file, unsigned long addr)
+{
+        if (file->f_flags & O_SYNC)
+                return 1;
+
+        return addr >= __pa(high_memory);
+}
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index cc9a9d0df979..7e082bceed57 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -75,6 +75,13 @@ static inline int uncached_access(struct file *file, unsigned long addr)
          * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases.
          */
         return !(efi_mem_attributes(addr) & EFI_MEMORY_WB);
+#elif defined(CONFIG_MIPS)
+        {
+                extern int __uncached_access(struct file *file,
+                                             unsigned long addr);
+
+                return __uncached_access(file, addr);
+        }
 #else
         /*
          * Accessing memory above the top the kernel knows about or through a file pointer