PM / devfreq: event: Add devfreq_event class
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>
2015-01-26 12:16:27 +08:00
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menuconfig PM_DEVFREQ_EVENT
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bool "DEVFREQ-Event device Support"
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help
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The devfreq-event device provide the raw data and events which
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indicate the current state of devfreq-event device. The provided
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data from devfreq-event device is used to monitor the state of
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device and determine the suitable size of resource to reduce the
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wasted resource.
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The devfreq-event device can support the various type of events
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(e.g., raw data, utilization, latency, bandwidth). The events
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may be used by devfreq governor and other subsystem.
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if PM_DEVFREQ_EVENT
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2016-04-07 10:29:11 +08:00
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config DEVFREQ_EVENT_EXYNOS_NOCP
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bool "EXYNOS NoC (Network On Chip) Probe DEVFREQ event Driver"
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depends on ARCH_EXYNOS
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select PM_OPP
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help
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This add the devfreq-event driver for Exynos SoC. It provides NoC
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(Network on Chip) Probe counters to measure the bandwidth of AXI bus.
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PM / devfreq: event: Add devfreq_event class
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>
2015-01-26 12:16:27 +08:00
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config DEVFREQ_EVENT_EXYNOS_PPMU
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bool "EXYNOS PPMU (Platform Performance Monitoring Unit) DEVFREQ event Driver"
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depends on ARCH_EXYNOS
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select PM_OPP
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help
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This add the devfreq-event driver for Exynos SoC. It provides PPMU
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(Platform Performance Monitoring Unit) counters to estimate the
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utilization of each module.
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endif # PM_DEVFREQ_EVENT
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