arch/frv/include/asm/io.h: accept const void pointers for read{b,w,l}()

The SMD driver is reading and writing chunks of data to iomem, and
there's an __iowrite32_copy() function for the writing part, but no
__ioread32_copy() function for the reading part.  This series adds
__ioread32_copy() and uses it in two places.

This patch (of 4):

The frv port uses compiler builtins, __builtin_read*(), for the I/O read
routines.  Unfortunately, these don't accept const void pointers although
the generic ASM implementations do, so generic code passing const pointers
to these APIs cause compilers to emit warnings.  Add wrapper functions
that cast away the const to avoid the warnings.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: David Howells <dhowells@redhat.com>
Cc: <zajec5@gmail.com>
Cc: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/frv/include/asm/io.h

@@ -43,9 +43,20 @@ static inline unsigned long _swapl(unsigned long v)
 //#define __iormb() asm volatile("membar")
 //#define __iowmb() asm volatile("membar")
 
-#define __raw_readb __builtin_read8
-#define __raw_readw __builtin_read16
-#define __raw_readl __builtin_read32
+static inline u8 __raw_readb(const volatile void __iomem *addr)
+{
+	return __builtin_read8((volatile void __iomem *)addr);
+}
+
+static inline u16 __raw_readw(const volatile void __iomem *addr)
+{
+	return __builtin_read16((volatile void __iomem *)addr);
+}
+
+static inline u32 __raw_readl(const volatile void __iomem *addr)
+{
+	return __builtin_read32((volatile void __iomem *)addr);
+}
 
 #define __raw_writeb(datum, addr) __builtin_write8(addr, datum)
 #define __raw_writew(datum, addr) __builtin_write16(addr, datum)