1 files changed, 33 insertions, 3 deletions

diff --git a/include/asm-mips/io.h b/include/asm-mips/io.h
index 5a4c8a54b8f4..ba1d7bbc15d2 100644
--- a/include/asm-mips/io.h
+++ b/include/asm-mips/io.h
@@ -4,7 +4,7 @@
  * for more details.
  *
  * Copyright (C) 1994, 1995 Waldorf GmbH
- * Copyright (C) 1994 - 2000 Ralf Baechle
+ * Copyright (C) 1994 - 2000, 06 Ralf Baechle
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  * Copyright (C) 2004, 2005  MIPS Technologies, Inc.  All rights reserved.
  *      Author: Maciej W. Rozycki <macro@mips.com>
@@ -103,8 +103,20 @@
  */
 extern const unsigned long mips_io_port_base;
 
-#define set_io_port_base(base)  \
-        do { * (unsigned long *) &mips_io_port_base = (base); } while (0)
+/*
+ * Gcc will generate code to load the value of mips_io_port_base after each
+ * function call which may be fairly wasteful in some cases.  So we don't
+ * play quite by the book.  We tell gcc mips_io_port_base is a long variable
+ * which solves the code generation issue.  Now we need to violate the
+ * aliasing rules a little to make initialization possible and finally we
+ * will need the barrier() to fight side effects of the aliasing chat.
+ * This trickery will eventually collapse under gcc's optimizer.  Oh well.
+ */
+static inline void set_io_port_base(unsigned long base)
+{
+        * (unsigned long *) &mips_io_port_base = base;
+        barrier();
+}
 
 /*
  * Thanks to James van Artsdalen for a better timing-fix than
@@ -283,6 +295,24 @@ static inline void __iomem * __ioremap_mode(phys_t offset, unsigned long size,
         __ioremap_mode((offset), (size), _CACHE_UNCACHED)
 
 /*
+ * ioremap_cachable -   map bus memory into CPU space
+ * @offset:         bus address of the memory
+ * @size:           size of the resource to map
+ *
+ * ioremap_nocache performs a platform specific sequence of operations to
+ * make bus memory CPU accessible via the readb/readw/readl/writeb/
+ * writew/writel functions and the other mmio helpers. The returned
+ * address is not guaranteed to be usable directly as a virtual
+ * address.
+ *
+ * This version of ioremap ensures that the memory is marked cachable by
+ * the CPU.  Also enables full write-combining.  Useful for some
+ * memory-like regions on I/O busses.
+ */
+#define ioremap_cachable(offset, size)                                  \
+        __ioremap_mode((offset), (size), PAGE_CACHABLE_DEFAULT)
+
+/*
  * These two are MIPS specific ioremap variant.  ioremap_cacheable_cow
  * requests a cachable mapping, ioremap_uncached_accelerated requests a
  * mapping using the uncached accelerated mode which isn't supported on