forked from Minki/linux
996133119f
This patch adds the new passive governor for DEVFREQ framework. The following governors are already present and used for DVFS (Dynamic Voltage and Frequency Scaling) drivers. The following governors are independently used for one device driver which don't give the influence to other device drviers and also don't receive the effect from other device drivers. - ondemand / performance / powersave / userspace The passive governor depends on operation of parent driver with specific governos extremely and is not able to decide the new frequency by oneself. According to the decided new frequency of parent driver with governor, the passive governor uses it to decide the appropriate frequency for own device driver. The passive governor must need the following information from device tree: - the source clock and OPP tables - the instance of parent device For exameple, there are one more devfreq device drivers which need to change their source clock according to their utilization on runtime. But, they share the same power line (e.g., regulator). So, specific device driver is operated as parent with ondemand governor and then the rest device driver with passive governor is influenced by parent device. Suggested-by: Myungjoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> [tjakobi: Reported RCU locking issue and cw00.choi fix it] Reported-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de> [linux.amoon: Reported possible recursive locking and cw00.choi fix it] Reported-by: Anand Moon <linux.amoon@gmail.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
127 lines
4.8 KiB
Plaintext
127 lines
4.8 KiB
Plaintext
menuconfig PM_DEVFREQ
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bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
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select SRCU
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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 frequency
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given at the initialization.
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config DEVFREQ_GOV_PASSIVE
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tristate "Passive"
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help
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Sets the frequency based on the frequency of its parent devfreq
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device. This governor does not change the frequency by itself
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through sysfs entries. The passive governor recommends that
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devfreq device uses the OPP table to get the frequency/voltage.
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comment "DEVFREQ Drivers"
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config ARM_EXYNOS_BUS_DEVFREQ
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bool "ARM EXYNOS Generic Memory Bus DEVFREQ Driver"
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depends on ARCH_EXYNOS
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select DEVFREQ_GOV_SIMPLE_ONDEMAND
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select DEVFREQ_EVENT_EXYNOS_PPMU
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select PM_DEVFREQ_EVENT
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select PM_OPP
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help
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This adds the common DEVFREQ driver for Exynos Memory bus. Exynos
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Memory bus has one more group of memory bus (e.g, MIF and INT block).
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Each memory bus group could contain many memoby bus block. It reads
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PPMU counters of memory controllers by using DEVFREQ-event device
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and adjusts 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_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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