This patch provides cpu_idle_wait() routine required
by the cpuidle subsystem. Almost all the code is borrowed
from x86.
Signed-off-by: Trinabh Gupta <trinabh@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Arun R Bharadwaj <arun@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/Kconfig | 4 ++++
arch/powerpc/include/asm/system.h | 1 +
arch/powerpc/kernel/idle.c | 18 ++++++++++++++++++
3 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2729c66..518beda 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -87,6 +87,10 @@ config ARCH_HAS_ILOG2_U64
bool
default y if 64BIT
+config ARCH_HAS_CPU_IDLE_WAIT
+ bool
+ default y
+
config GENERIC_HWEIGHT
bool
default y
diff --git a/arch/powerpc/include/asm/system.h b/arch/powerpc/include/asm/system.h
index 2dc595d..811cdf1 100644
--- a/arch/powerpc/include/asm/system.h
+++ b/arch/powerpc/include/asm/system.h
@@ -222,6 +222,7 @@ extern unsigned long klimit;
extern void *zalloc_maybe_bootmem(size_t size, gfp_t mask);
extern int powersave_nap; /* set if nap mode can be used in idle loop */
+void cpu_idle_wait(void);
/*
* Atomic exchange
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 39a2baa..932392b 100644
--- a/arch/powerpc/kernel/idle.c
+++ b/arch/powerpc/kernel/idle.c
@@ -102,6 +102,24 @@ void cpu_idle(void)
}
}
+static void do_nothing(void *unused)
+{
+}
+
+/*
+ * cpu_idle_wait - Used to ensure that all the CPUs come out of the old
+ * idle loop and start using the new idle loop.
+ * Required while changing idle handler on SMP systems.
+ * Caller must have changed idle handler to the new value before the call.
+ */
+void cpu_idle_wait(void)
+{
+ smp_mb();
+ /* kick all the CPUs so that they exit out of old idle routine */
+ smp_call_function(do_nothing, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(cpu_idle_wait);
+
int powersave_nap;
#ifdef CONFIG_SYSCTL
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