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Commit 885f925e authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

Merge branch 'pm-cpufreq' 

* pm-cpufreq: (57 commits)
  cpufreq: MAINTAINERS: Add co-maintainer
  cpufreq: pxa2xx: initialize variables
  ARM: S5pv210: compiling issue, ARM_S5PV210_CPUFREQ needs CONFIG_CPU_FREQ_TABLE=y
  cpufreq: cpu0: Put cpu parent node after using it
  cpufreq: ARM big LITTLE: Adapt to latest cpufreq updates
  cpufreq: ARM big LITTLE: put DT nodes after using them
  cpufreq: Don't call __cpufreq_governor() for drivers without target()
  cpufreq: exynos5440: Protect OPP search calls with RCU lock
  cpufreq: dbx500: Round to closest available freq
  cpufreq: Call __cpufreq_governor() with correct policy->cpus mask
  cpufreq / intel_pstate: Optimize intel_pstate_set_policy
  cpufreq: OMAP: instantiate omap-cpufreq as a platform_driver
  arm: exynos: Enable OPP library support for exynos5440
  cpufreq: exynos: Remove error return even if no soc is found
  cpufreq: exynos: Add cpufreq driver for exynos5440
  cpufreq: AMD "frequency sensitivity feedback" powersave bias for ondemand governor
  cpufreq: ondemand: allow custom powersave_bias_target handler to be registered
  cpufreq: convert cpufreq_driver to using RCU
  cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq
  cpufreq: sparc: move cpufreq driver to drivers/cpufreq
  ...

Conflicts:
	MAINTAINERS (with commit a8e39c35 from pm-cpuidle)
	drivers/cpufreq/cpufreq_governor.h (with commit beb0ff39)
parents e4f5a3ad 45c009a9

Documentation/cpu-freq/cpu-drivers.txt

+5 −4
Original line number Diff line number Diff line
@@ -108,8 +108,9 @@ policy->governor must contain the "default policy" for 
				cpufreq_driver.target is called with

				these values.



For setting some of these values, the frequency table helpers might be

helpful. See the section 2 for more information on them.

For setting some of these values (cpuinfo.min[max]_freq, policy->min[max]), the

frequency table helpers might be helpful. See the section 2 for more information

on them.



SMP systems normally have same clock source for a group of cpus. For these the

.init() would be called only once for the first online cpu. Here the .init()
@@ -184,10 +185,10 @@ the reference implementation in drivers/cpufreq/longrun.c 
As most cpufreq processors only allow for being set to a few specific

frequencies, a "frequency table" with some functions might assist in

some work of the processor driver. Such a "frequency table" consists

of an array of struct cpufreq_freq_table entries, with any value in

of an array of struct cpufreq_frequency_table entries, with any value in

"index" you want to use, and the corresponding frequency in

"frequency". At the end of the table, you need to add a

cpufreq_freq_table entry with frequency set to CPUFREQ_TABLE_END. And

cpufreq_frequency_table entry with frequency set to CPUFREQ_TABLE_END. And

if you want to skip one entry in the table, set the frequency to 

CPUFREQ_ENTRY_INVALID. The entries don't need to be in ascending

order.

Documentation/cpu-freq/governors.txt

+27 −0
Original line number Diff line number Diff line
@@ -167,6 +167,27 @@ of load evaluation and helping the CPU stay at its top speed when truly 
busy, rather than shifting back and forth in speed. This tunable has no

effect on behavior at lower speeds/lower CPU loads.



powersave_bias: this parameter takes a value between 0 to 1000. It

defines the percentage (times 10) value of the target frequency that

will be shaved off of the target. For example, when set to 100 -- 10%,

when ondemand governor would have targeted 1000 MHz, it will target

1000 MHz - (10% of 1000 MHz) = 900 MHz instead. This is set to 0

(disabled) by default.

When AMD frequency sensitivity powersave bias driver --

drivers/cpufreq/amd_freq_sensitivity.c is loaded, this parameter

defines the workload frequency sensitivity threshold in which a lower

frequency is chosen instead of ondemand governor's original target.

The frequency sensitivity is a hardware reported (on AMD Family 16h

Processors and above) value between 0 to 100% that tells software how

the performance of the workload running on a CPU will change when

frequency changes. A workload with sensitivity of 0% (memory/IO-bound)

will not perform any better on higher core frequency, whereas a

workload with sensitivity of 100% (CPU-bound) will perform better

higher the frequency. When the driver is loaded, this is set to 400

by default -- for CPUs running workloads with sensitivity value below

40%, a lower frequency is chosen. Unloading the driver or writing 0

will disable this feature.





2.5 Conservative

----------------
@@ -191,6 +212,12 @@ governor but for the opposite direction. For example when set to its 
default value of '20' it means that if the CPU usage needs to be below

20% between samples to have the frequency decreased.



sampling_down_factor: similar functionality as in "ondemand" governor.

But in "conservative", it controls the rate at which the kernel makes

a decision on when to decrease the frequency while running in any

speed. Load for frequency increase is still evaluated every

sampling rate.



3. The Governor Interface in the CPUfreq Core

=============================================

Documentation/devicetree/bindings/cpufreq/arm_big_little_dt.txt

0 → 100644
+65 −0
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Generic ARM big LITTLE cpufreq driver's DT glue

-----------------------------------------------



This is DT specific glue layer for generic cpufreq driver for big LITTLE

systems.



Both required and optional properties listed below must be defined

under node /cpus/cpu@x. Where x is the first cpu inside a cluster.



FIXME: Cpus should boot in the order specified in DT and all cpus for a cluster

must be present contiguously. Generic DT driver will check only node 'x' for

cpu:x.



Required properties:

- operating-points: Refer to Documentation/devicetree/bindings/power/opp.txt

  for details



Optional properties:

- clock-latency: Specify the possible maximum transition latency for clock,

  in unit of nanoseconds.



Examples:



cpus {

	#address-cells = <1>;

	#size-cells = <0>;



	cpu@0 {

		compatible = "arm,cortex-a15";

		reg = <0>;

		next-level-cache = <&L2>;

		operating-points = <

			/* kHz    uV */

			792000  1100000

			396000  950000

			198000  850000

		>;

		clock-latency = <61036>; /* two CLK32 periods */

	};



	cpu@1 {

		compatible = "arm,cortex-a15";

		reg = <1>;

		next-level-cache = <&L2>;

	};



	cpu@100 {

		compatible = "arm,cortex-a7";

		reg = <100>;

		next-level-cache = <&L2>;

		operating-points = <

			/* kHz    uV */

			792000  950000

			396000  750000

			198000  450000

		>;

		clock-latency = <61036>; /* two CLK32 periods */

	};



	cpu@101 {

		compatible = "arm,cortex-a7";

		reg = <101>;

		next-level-cache = <&L2>;

	};

};

Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt

+1 −1
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ cpus { 
			396000  950000

			198000  850000

		>;

		transition-latency = <61036>; /* two CLK32 periods */

		clock-latency = <61036>; /* two CLK32 periods */

	};



	cpu@1 {

Documentation/devicetree/bindings/cpufreq/cpufreq-exynos5440.txt

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+28 −0
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Exynos5440 cpufreq driver

-------------------



Exynos5440 SoC cpufreq driver for CPU frequency scaling.



Required properties:

- interrupts: Interrupt to know the completion of cpu frequency change.

- operating-points: Table of frequencies and voltage CPU could be transitioned into,

	in the decreasing order. Frequency should be in KHz units and voltage

	should be in microvolts.



Optional properties:

- clock-latency: Clock monitor latency in microsecond.



All the required listed above must be defined under node cpufreq.



Example:

--------

	cpufreq@160000 {

		compatible = "samsung,exynos5440-cpufreq";

		reg = <0x160000 0x1000>;

		interrupts = <0 57 0>;

		operating-points = <

				1000000 975000

				800000  925000>;

		clock-latency = <100000>;

	};