MIPS: Remove SLOW_DOWN_IO

CONF_SLOWDOWN_IO is never set for any target, so remove the dead code in
the SLOW_DOWN_IO macro. This is done in preparation for changes to
mips_io_port_base which can be avoided in this path by removing it
entirely.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>

arch/mips/include/asm/io.h

@@ -25,11 +25,6 @@
 #include <mangle-port.h>
 #include <spaces.h>
 
-/*
- * Slowdown I/O port space accesses for antique hardware.
- */
-#undef CONF_SLOWDOWN_IO
-
 /*
  * Raw operations are never swapped in software.  OTOH values that raw
  * operations are working on may or may not have been swapped by the bus
@@ -71,33 +66,6 @@ static inline void set_io_port_base(unsigned long base)
 	barrier();
 }
 
-/*
- * Thanks to James van Artsdalen for a better timing-fix than
- * the two short jumps: using outb's to a nonexistent port seems
- * to guarantee better timings even on fast machines.
- *
- * On the other hand, I'd like to be sure of a non-existent port:
- * I feel a bit unsafe about using 0x80 (should be safe, though)
- *
- *		Linus
- *
- */
-
-#define __SLOW_DOWN_IO \
-	__asm__ __volatile__( \
-		"sb\t$0,0x80(%0)" \
-		: : "r" (mips_io_port_base));
-
-#ifdef CONF_SLOWDOWN_IO
-#ifdef REALLY_SLOW_IO
-#define SLOW_DOWN_IO { __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; }
-#else
-#define SLOW_DOWN_IO __SLOW_DOWN_IO
-#endif
-#else
-#define SLOW_DOWN_IO
-#endif
-
 /*
  *     virt_to_phys    -       map virtual addresses to physical
  *     @address: address to remap
@@ -316,7 +284,7 @@ static inline type pfx##read##bwlq(const volatile void __iomem *mem)	\
 	return pfx##ioswab##bwlq(__mem, __val);				\
 }
 
-#define __BUILD_IOPORT_SINGLE(pfx, bwlq, type, p, slow)			\
+#define __BUILD_IOPORT_SINGLE(pfx, bwlq, type, p)			\
 									\
 static inline void pfx##out##bwlq##p(type val, unsigned long port)	\
 {									\
@@ -333,7 +301,6 @@ static inline void pfx##out##bwlq##p(type val, unsigned long port)	\
 	BUILD_BUG_ON(sizeof(type) > sizeof(unsigned long));		\
 									\
 	*__addr = __val;						\
-	slow;								\
 }									\
 									\
 static inline type pfx##in##bwlq##p(unsigned long port)			\
@@ -346,7 +313,6 @@ static inline type pfx##in##bwlq##p(unsigned long port)			\
 	BUILD_BUG_ON(sizeof(type) > sizeof(unsigned long));		\
 									\
 	__val = *__addr;						\
-	slow;								\
 									\
 	return pfx##ioswab##bwlq(__addr, __val);			\
 }
@@ -367,8 +333,8 @@ BUILDIO_MEM(l, u32)
 BUILDIO_MEM(q, u64)
 
 #define __BUILD_IOPORT_PFX(bus, bwlq, type)				\
-	__BUILD_IOPORT_SINGLE(bus, bwlq, type, ,)			\
-	__BUILD_IOPORT_SINGLE(bus, bwlq, type, _p, SLOW_DOWN_IO)
+	__BUILD_IOPORT_SINGLE(bus, bwlq, type, )			\
+	__BUILD_IOPORT_SINGLE(bus, bwlq, type, _p)
 
 #define BUILDIO_IOPORT(bwlq, type)					\
 	__BUILD_IOPORT_PFX(, bwlq, type)				\