ACPI: Split out ACPI PSS from ACPI Processor driver

The ACPI processor driver is currently tied too closely
to the ACPI P-states (PSS) and other related constructs
for controlling CPU performance.

The newer ACPI specification (v5.1 onwards) introduces
alternative methods to PSS. These new mechanisms are
described within each ACPI Processor object and so they
need to be scanned whenever a new Processor object is detected.
This patch introduces a new Kconfig symbol to allow for
finer configurability among the two options for controlling
performance states. There is no change in functionality and
the option is auto-selected by the architectures which support it.

A future commit will introduce support for CPPC: A newer method of
controlling CPU performance. The OS is not expected to support
CPPC and PSS at the same time, so the Kconfig option lets us make
the two mutually exclusive at compile time.

Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 26 insertions, 2 deletions

diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 4188a4d3b597..b6c917835805 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -318,6 +318,7 @@ int acpi_get_cpuid(acpi_handle, int type, u32 acpi_id);
 void acpi_processor_set_pdc(acpi_handle handle);
 
 /* in processor_throttling.c */
+#ifdef CONFIG_ACPI_CPU_FREQ_PSS
 int acpi_processor_tstate_has_changed(struct acpi_processor *pr);
 int acpi_processor_get_throttling_info(struct acpi_processor *pr);
 extern int acpi_processor_set_throttling(struct acpi_processor *pr,
@@ -330,6 +331,29 @@ extern void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
 			unsigned long action);
 extern const struct file_operations acpi_processor_throttling_fops;
 extern void acpi_processor_throttling_init(void);
+#else
+static inline int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
+{
+	return 0;
+}
+
+static inline int acpi_processor_get_throttling_info(struct acpi_processor *pr)
+{
+	return -ENODEV;
+}
+
+static inline int acpi_processor_set_throttling(struct acpi_processor *pr,
+					 int state, bool force)
+{
+	return -ENODEV;
+}
+
+static inline void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
+			unsigned long action) {}
+
+static inline void acpi_processor_throttling_init(void) {}
+#endif	/* CONFIG_ACPI_CPU_FREQ_PSS */
+
 /* in processor_idle.c */
 int acpi_processor_power_init(struct acpi_processor *pr);
 int acpi_processor_power_exit(struct acpi_processor *pr);
@@ -348,7 +372,7 @@ static inline void acpi_processor_syscore_exit(void) {}
 /* in processor_thermal.c */
 int acpi_processor_get_limit_info(struct acpi_processor *pr);
 extern const struct thermal_cooling_device_ops processor_cooling_ops;
-#ifdef CONFIG_CPU_FREQ
+#if defined(CONFIG_ACPI_CPU_FREQ_PSS) & defined(CONFIG_CPU_FREQ)
 void acpi_thermal_cpufreq_init(void);
 void acpi_thermal_cpufreq_exit(void);
 #else
@@ -360,6 +384,6 @@ static inline void acpi_thermal_cpufreq_exit(void)
 {
 	return;
 }
-#endif
+#endif	/* CONFIG_ACPI_CPU_FREQ_PSS */
 
 #endif