[PATCH] ppc64: cleanup iseries runlight support

The iseries has a bar graph on the front panel that shows how busy it is.
The operating system sets and clears a bit in the CTRL register to control
it.

Instead of going to the complexity of using a thread info bit, just set and
clear it in the idle loop.

Also create two helper functions, ppc64_runlatch_on and ppc64_runlatch_off.

Finally don't use the short form of the SPR defines.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 21 insertions, 6 deletions

diff --git a/include/asm-ppc64/processor.h b/include/asm-ppc64/processor.h
index 5ba6aa45e1e2..809c634ba1df 100644
--- a/include/asm-ppc64/processor.h
+++ b/include/asm-ppc64/processor.h
@@ -164,6 +164,9 @@
 #define SPRN_USIA       0x3AB   /* User Sampled Instruction Address Register */
 #define SPRN_XER        0x001   /* Fixed Point Exception Register */
 #define SPRN_VRSAVE     0x100   /* Vector save */
+#define SPRN_CTRLF      0x088
+#define SPRN_CTRLT      0x098
+#define   CTRL_RUNLATCH 0x1
 
 /* Performance monitor SPRs */
 #define SPRN_SIAR       780
@@ -279,12 +282,6 @@
 #define XGLUE(a,b) a##b
 #define GLUE(a,b) XGLUE(a,b)
 
-/* iSeries CTRL register (for runlatch) */
-
-#define CTRLT           0x098
-#define CTRLF           0x088
-#define RUNLATCH        0x0001
-
 #ifdef __ASSEMBLY__
 
 #define _GLOBAL(name) \
@@ -499,6 +496,24 @@ static inline void prefetchw(const void *x)
 
 #define HAVE_ARCH_PICK_MMAP_LAYOUT
 
+static inline void ppc64_runlatch_on(void)
+{
+        unsigned long ctrl;
+
+        ctrl = mfspr(SPRN_CTRLF);
+        ctrl |= CTRL_RUNLATCH;
+        mtspr(SPRN_CTRLT, ctrl);
+}
+
+static inline void ppc64_runlatch_off(void)
+{
+        unsigned long ctrl;
+
+        ctrl = mfspr(SPRN_CTRLF);
+        ctrl &= ~CTRL_RUNLATCH;
+        mtspr(SPRN_CTRLT, ctrl);
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */