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f262f28c14
This patch adds a new class in devfreq, devfreq_event, which provides raw data (e.g., memory bus utilization, GPU utilization) for devfreq governors. - devfreq_event device : Provides raw data for a governor of a devfreq device - devfreq device : Monitors device state and changes frequency/voltage of the device using the raw data from its devfreq_event device. A devfreq device dertermines performance states (normally the frequency and the voltage vlues) based on the results its designtated devfreq governor: e.g., ondemand, performance, powersave. In order to give such results required by a devfreq device, the devfreq governor requires data that indicates the performance requirement given to the devfreq device. The conventional (previous) implementatino of devfreq subsystem requires a devfreq device driver to implement its own mechanism to acquire performance requirement for its governor. However, there had been issues with such requirements: 1. Although performance requirement of such devices is usually acquired from common devices (PMU/PPMU), we do not have any abstract structure to represent them properly. 2. Such performance requirement devices (PMU/PPMU) are actual hardware pieces that may be represented by Device Tree directly while devfreq device itself is a virtual entity that are not considered to be represented by Device Tree according to Device Tree folks. In order to address such issues, a devferq_event device (represented by this patch) provides a template for device drivers representing performance monitoring unit, which gives the basic or raw data for preformance requirement, which in turn, is required by devfreq governors. The following description explains the feature of two kind of devfreq class: - devfreq class (existing) : devfreq consumer device use raw data from devfreq_event device for determining proper current system state and change voltage/frequency dynamically using various governors. - devfreq_event class (new) : Provide measured raw data to devfreq device for governor Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> [Commit message rewritten & conflict resolved by MyungJoo] Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
103 lines
3.9 KiB
Plaintext
103 lines
3.9 KiB
Plaintext
menuconfig PM_DEVFREQ
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bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
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help
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A device may have a list of frequencies and voltages available.
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devfreq, a generic DVFS framework can be registered for a device
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in order to let the governor provided to devfreq choose an
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operating frequency based on the device driver's policy.
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Each device may have its own governor and policy. Devfreq can
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reevaluate the device state periodically and/or based on the
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notification to "nb", a notifier block, of devfreq.
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Like some CPUs with CPUfreq, a device may have multiple clocks.
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However, because the clock frequencies of a single device are
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determined by the single device's state, an instance of devfreq
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is attached to a single device and returns a "representative"
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clock frequency of the device, which is also attached
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to a device by 1-to-1. The device registering devfreq takes the
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responsibility to "interpret" the representative frequency and
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to set its every clock accordingly with the "target" callback
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given to devfreq.
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When OPP is used with the devfreq device, it is recommended to
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register devfreq's nb to the OPP's notifier head. If OPP is
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used with the devfreq device, you may use OPP helper
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functions defined in devfreq.h.
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if PM_DEVFREQ
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comment "DEVFREQ Governors"
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config DEVFREQ_GOV_SIMPLE_ONDEMAND
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tristate "Simple Ondemand"
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help
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Chooses frequency based on the recent load on the device. Works
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similar as ONDEMAND governor of CPUFREQ does. A device with
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Simple-Ondemand should be able to provide busy/total counter
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values that imply the usage rate. A device may provide tuned
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values to the governor with data field at devfreq_add_device().
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config DEVFREQ_GOV_PERFORMANCE
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tristate "Performance"
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help
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Sets the frequency at the maximum available frequency.
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This governor always returns UINT_MAX as frequency so that
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the DEVFREQ framework returns the highest frequency available
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at any time.
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config DEVFREQ_GOV_POWERSAVE
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tristate "Powersave"
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help
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Sets the frequency at the minimum available frequency.
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This governor always returns 0 as frequency so that
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the DEVFREQ framework returns the lowest frequency available
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at any time.
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config DEVFREQ_GOV_USERSPACE
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tristate "Userspace"
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help
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Sets the frequency at the user specified one.
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This governor returns the user configured frequency if there
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has been an input to /sys/devices/.../power/devfreq_set_freq.
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Otherwise, the governor does not change the frequnecy
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given at the initialization.
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comment "DEVFREQ Drivers"
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config ARM_EXYNOS4_BUS_DEVFREQ
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bool "ARM Exynos4210/4212/4412 Memory Bus DEVFREQ Driver"
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depends on (CPU_EXYNOS4210 || SOC_EXYNOS4212 || SOC_EXYNOS4412) && !ARCH_MULTIPLATFORM
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select DEVFREQ_GOV_SIMPLE_ONDEMAND
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select PM_OPP
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help
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This adds the DEVFREQ driver for Exynos4210 memory bus (vdd_int)
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and Exynos4212/4412 memory interface and bus (vdd_mif + vdd_int).
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It reads PPMU counters of memory controllers and adjusts
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the operating frequencies and voltages with OPP support.
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This does not yet operate with optimal voltages.
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config ARM_EXYNOS5_BUS_DEVFREQ
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tristate "ARM Exynos5250 Bus DEVFREQ Driver"
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depends on SOC_EXYNOS5250
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select DEVFREQ_GOV_SIMPLE_ONDEMAND
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select PM_OPP
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help
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This adds the DEVFREQ driver for Exynos5250 bus interface (vdd_int).
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It reads PPMU counters of memory controllers and adjusts the
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operating frequencies and voltages with OPP support.
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config ARM_TEGRA_DEVFREQ
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tristate "Tegra DEVFREQ Driver"
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depends on ARCH_TEGRA_124_SOC
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select DEVFREQ_GOV_SIMPLE_ONDEMAND
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select PM_OPP
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help
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This adds the DEVFREQ driver for the Tegra family of SoCs.
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It reads ACTMON counters of memory controllers and adjusts the
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operating frequencies and voltages with OPP support.
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source "drivers/devfreq/event/Kconfig"
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endif # PM_DEVFREQ
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