2 files changed, 30 insertions, 0 deletions

diff --git a/arch/arm/include/asm/smp_scu.h b/arch/arm/include/asm/smp_scu.h
index 2376835015d6..4eb6d005ffaa 100644
--- a/arch/arm/include/asm/smp_scu.h
+++ b/arch/arm/include/asm/smp_scu.h
@@ -1,7 +1,14 @@
 #ifndef __ASMARM_ARCH_SCU_H
 #define __ASMARM_ARCH_SCU_H
 
+#define SCU_PM_NORMAL   0
+#define SCU_PM_DORMANT  2
+#define SCU_PM_POWEROFF 3
+
+#ifndef __ASSEMBLER__
 unsigned int scu_get_core_count(void __iomem *);
 void scu_enable(void __iomem *);
+int scu_power_mode(void __iomem *, unsigned int);
+#endif
 
 #endif
diff --git a/arch/arm/kernel/smp_scu.c b/arch/arm/kernel/smp_scu.c
index 9ab4149bd983..a1e757c3439b 100644
--- a/arch/arm/kernel/smp_scu.c
+++ b/arch/arm/kernel/smp_scu.c
@@ -50,3 +50,26 @@ void __init scu_enable(void __iomem *scu_base)
          */
         flush_cache_all();
 }
+
+/*
+ * Set the executing CPUs power mode as defined.  This will be in
+ * preparation for it executing a WFI instruction.
+ *
+ * This function must be called with preemption disabled, and as it
+ * has the side effect of disabling coherency, caches must have been
+ * flushed.  Interrupts must also have been disabled.
+ */
+int scu_power_mode(void __iomem *scu_base, unsigned int mode)
+{
+        unsigned int val;
+        int cpu = smp_processor_id();
+
+        if (mode > 3 || mode == 1 || cpu > 3)
+                return -EINVAL;
+
+        val = __raw_readb(scu_base + SCU_CPU_STATUS + cpu) & ~0x03;
+        val |= mode;
+        __raw_writeb(val, scu_base + SCU_CPU_STATUS + cpu);
+
+        return 0;
+}