[IA64] Add ACPI based P-state support

Patch to support P-state transitions on ia64. This driver is based on ACPI,
and uses the ACPI processor driver interface to find out the P-state support
information for the processor. This driver plugs into generic cpufreq
infrastructure.

Once this driver is loaded successfully, ondemand/userspace governor can be
used to change the CPU frequency dynamically based on load or on request from
userspace process.

Refer :
ACPI specification -
      http://www.acpi.info
P-state related PAL calls -
      http://developer.intel.com/design/itanium/downloads/24869909.pdf

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/asm-ia64/acpi.h b/include/asm-ia64/acpi.h
index 4c06d455139c..3a544ffc5008 100644
--- a/include/asm-ia64/acpi.h
+++ b/include/asm-ia64/acpi.h
@@ -116,6 +116,11 @@ extern int __initdata nid_to_pxm_map[MAX_NUMNODES];
 
 extern u16 ia64_acpiid_to_sapicid[];
 
+/*
+ * Refer Intel ACPI _PDC support document for bit definitions
+ */
+#define ACPI_PDC_EST_CAPABILITY_SMP     0x8
+
 #endif /*__KERNEL__*/
 
 #endif /*_ASM_ACPI_H*/