ARM: document and update UNCACHEABLE_ADDR definitions

Document the UNCACHEABLE_ADDR definitions for footbridge and SA1100
so that we know where they're located and/or what they're accessing.
Change RiscPC to calculate the UNCACHEABLE_ADDR value from FLUSH_BASE
as that's where we locate that.

UNCACHEABLE_ADDR is used to perform an uncached access (ARMv4
terminology) necessary to force a CPU clock-switch to the memory-
speed clock, as required for entering WFI.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

arch/arm/mach-footbridge/include/mach/hardware.h

@@ -59,7 +59,7 @@
 #define XBUS_SWITCH_J17_11	((*XBUS_SWITCH) & (1 << 5))
 #define XBUS_SWITCH_J17_9	((*XBUS_SWITCH) & (1 << 6))
 
-#define UNCACHEABLE_ADDR	(ARMCSR_BASE + 0x108)
+#define UNCACHEABLE_ADDR	(ARMCSR_BASE + 0x108)	/* CSR_ROMBASEMASK */
 
 
 /* PIC irq control */

arch/arm/mach-rpc/include/mach/hardware.h

@@ -40,7 +40,7 @@
 #define SCREEN_END		0xdfc00000
 #define SCREEN_BASE		0xdf800000
 
-#define UNCACHEABLE_ADDR	0xdf010000
+#define UNCACHEABLE_ADDR	(FLUSH_BASE + 0x10000)
 
 /*
  * IO Addresses

arch/arm/mach-sa1100/include/mach/hardware.h

@@ -13,7 +13,7 @@
 #define __ASM_ARCH_HARDWARE_H
 
 
-#define UNCACHEABLE_ADDR	0xfa050000
+#define UNCACHEABLE_ADDR	0xfa050000	/* ICIP */
 
 
 /*