cpuidle: Single/Global registration of idle states

This patch makes the cpuidle_states structure global (single copy)
instead of per-cpu. The statistics needed on per-cpu basis
by the governor are kept per-cpu. This simplifies the cpuidle
subsystem as state registration is done by single cpu only.
Having single copy of cpuidle_states saves memory. Rare case
of asymmetric C-states can be handled within the cpuidle driver
and architectures such as POWER do not have asymmetric C-states.

Having single/global registration of all the idle states,
dynamic C-state transitions on x86 are handled by
the boot cpu. Here, the boot cpu  would disable all the devices,
re-populate the states and later enable all the devices,
irrespective of the cpu that would receive the notification first.

Reference:
https://lkml.org/lkml/2011/4/25/83

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 67055f180330..610f6fb1bbc2 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -329,6 +329,7 @@ extern void acpi_processor_throttling_init(void);
 int acpi_processor_power_init(struct acpi_processor *pr,
 			      struct acpi_device *device);
 int acpi_processor_cst_has_changed(struct acpi_processor *pr);
+int acpi_processor_hotplug(struct acpi_processor *pr);
 int acpi_processor_power_exit(struct acpi_processor *pr,
 			      struct acpi_device *device);
 int acpi_processor_suspend(struct acpi_device * device, pm_message_t state);