ACPI: register ACPI Processor as generic thermal cooling device

Register ACPI processor as thermal cooling devices.
A combination of processor T-state and P-state are used for thermal throttling.
the processor will reduce the frequency first and then set the T-state.

we use cpufreq_thermal_reduction_pctg to calculate the cpufreq limit,
and call cpufreq_verify_with_limit to set the cpufreq limit.
if cpufreq driver is loaded, then we have four cooling state for cpufreq control.
cooling state 0: cpufreq limit == max_freq
cooling state 1: cpufreq limit == max_freq * 80%
cooling state 2: cpufreq limit == max_freq * 60%
cooling state 3: cpufreq limit == max_freq * 40%

after the cpufreq limit is set to 40 percentage of the max_freq,
we use T-state for cooling.

eg. a processor has P-state support, and it has 8 T-state (T0-T7),
the max_state of the proceesor is 10:

state	cpufreq-limit  T-state
0:	max_freq	T0
1:	max_freq * 80%	T0
2:	max_freq * 60%	T0
3:	max_freq * 40%	T0
4:	max_freq * 40%	T1
5:	max_freq * 40%	T2
6:	max_freq * 40%	T3
7:	max_freq * 40%	T4
8:	max_freq * 40%	T5
9:	max_freq * 40%	T6
10:	max_freq * 40%	T7

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Thomas Sujith <sujith.thomas@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 76411b1fc4fd..0787635a11aa 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -4,7 +4,7 @@
 #include <linux/kernel.h>
 #include <linux/cpu.h>
 #include <linux/cpuidle.h>
-
+#include <linux/thermal.h>
 #include <asm/acpi.h>
 
 #define ACPI_PROCESSOR_BUSY_METRIC      10
@@ -218,7 +218,7 @@ struct acpi_processor {
         struct acpi_processor_performance *performance;
         struct acpi_processor_throttling throttling;
         struct acpi_processor_limit limit;
-
+        struct thermal_cooling_device *cdev;
         /* the _PDC objects for this processor, if any */
         struct acpi_object_list *pdc;
 };
@@ -330,7 +330,7 @@ extern struct cpuidle_driver acpi_idle_driver;
 /* in processor_thermal.c */
 int acpi_processor_get_limit_info(struct acpi_processor *pr);
 extern struct file_operations acpi_processor_limit_fops;
-
+extern struct thermal_cooling_device_ops processor_cooling_ops;
 #ifdef CONFIG_CPU_FREQ
 void acpi_thermal_cpufreq_init(void);
 void acpi_thermal_cpufreq_exit(void);