[POWERPC] Xserve cpu-meter driver

This is a small driver for the Xserve G5 CPU-meter blue LEDs on the
front-panel. It might work on the Xserve G4 as well though that was
not tested. It's pretty basic and could use some improvements if
somebody cares doing them. :)
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

drivers/macintosh/Kconfig

@@ -228,4 +228,11 @@ config ANSLCD
 	tristate "Support for ANS LCD display"
 	depends on ADB_CUDA && PPC_PMAC
 
+config PMAC_RACKMETER
+	tristate "Support for Apple XServe front panel LEDs"
+	depends on PPC_PMAC
+	help
+	  This driver procides some support to control the front panel
+          blue LEDs "vu-meter" of the XServer macs.
+
 endmenu

drivers/macintosh/Makefile

@@ -42,3 +42,4 @@ obj-$(CONFIG_WINDFARM_PM112)	+= windfarm_pm112.o windfarm_smu_sat.o \
 				   windfarm_smu_sensors.o \
 				   windfarm_max6690_sensor.o \
 				   windfarm_lm75_sensor.o windfarm_pid.o
+obj-$(CONFIG_PMAC_RACKMETER)	+= rack-meter.o

include/asm-powerpc/dbdma.h

@@ -95,7 +95,13 @@ struct dbdma_cmd {
 #define DBDMA_DO_STOP(regs) do {				\
 	out_le32(&((regs)->control), (RUN|FLUSH)<<16);		\
 	while(in_le32(&((regs)->status)) & (ACTIVE|FLUSH))	\
-		;						\
+		; \
+} while(0)
+
+#define DBDMA_DO_RESET(regs) do {				\
+	out_le32(&((regs)->control), (ACTIVE|DEAD|WAKE|FLUSH|PAUSE|RUN)<<16);\
+	while(in_le32(&((regs)->status)) & (RUN)) \
+		; \
 } while(0)
 
 #endif /* _ASM_DBDMA_H_ */