[RFC PATCH V1 7/7] cpuidle: (POWER) Handle power_save=off

[Trinabh Gupta]

This patch makes pseries_idle_driver to be not registered when
power_save=off kernel boot option is specified. For this
boot_option_idle_override is used similar to how it is used for x86.

Signed-off-by: Trinabh Gupta <trinabh at linux.vnet.ibm.com>
Signed-off-by: Arun R Bharadwaj <arun at linux.vnet.ibm.com>
---

 arch/powerpc/include/asm/processor.h            |    3 +++
 arch/powerpc/kernel/idle.c                      |    4 ++++
 arch/powerpc/platforms/pseries/processor_idle.c |    4 ++++
 3 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index d50c2b6..0ce167e 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -377,6 +377,9 @@ static inline unsigned long get_clean_sp(struct pt_regs *regs, int is_32)
 }
 #endif
 
+extern unsigned long  boot_option_idle_override;
+enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
+
 #endif /* __KERNEL__ */
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_PROCESSOR_H */
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 932392b..61515f4 100644
--- a/arch/powerpc/kernel/idle.c
+++ b/arch/powerpc/kernel/idle.c
@@ -39,9 +39,13 @@
 #define cpu_should_die()	0
 #endif
 
+unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;
+EXPORT_SYMBOL(boot_option_idle_override);
+
 static int __init powersave_off(char *arg)
 {
 	ppc_md.power_save = NULL;
+	boot_option_idle_override = IDLE_POWERSAVE_OFF;
 	return 0;
 }
 __setup("powersave=off", powersave_off);
diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c
index ff44b49..c4c3383 100644
--- a/arch/powerpc/platforms/pseries/processor_idle.c
+++ b/arch/powerpc/platforms/pseries/processor_idle.c
@@ -288,6 +288,10 @@ static int pseries_idle_probe(void)
 		return -EPERM;
 	}
 
+	if (boot_option_idle_override != IDLE_NO_OVERRIDE) {
+		return -ENODEV;
+	}
+
 	if (!firmware_has_feature(FW_FEATURE_SPLPAR)) {
 		printk(KERN_DEBUG "Using default idle\n");
 		return -ENODEV;