0001 # SPDX-License-Identifier: GPL-2.0-only
0002 menu "CPU Frequency scaling"
0003
0004 config CPU_FREQ
0005 bool "CPU Frequency scaling"
0006 select SRCU
0007 help
0008 CPU Frequency scaling allows you to change the clock speed of
0009 CPUs on the fly. This is a nice method to save power, because
0010 the lower the CPU clock speed, the less power the CPU consumes.
0011
0012 Note that this driver doesn't automatically change the CPU
0013 clock speed, you need to either enable a dynamic cpufreq governor
0014 (see below) after boot, or use a userspace tool.
0015
0016 For details, take a look at
0017 <file:Documentation/admin-guide/pm/cpufreq.rst>.
0018
0019 If in doubt, say N.
0020
0021 if CPU_FREQ
0022
0023 config CPU_FREQ_GOV_ATTR_SET
0024 bool
0025
0026 config CPU_FREQ_GOV_COMMON
0027 select CPU_FREQ_GOV_ATTR_SET
0028 select IRQ_WORK
0029 bool
0030
0031 config CPU_FREQ_STAT
0032 bool "CPU frequency transition statistics"
0033 help
0034 Export CPU frequency statistics information through sysfs.
0035
0036 If in doubt, say N.
0037
0038 choice
0039 prompt "Default CPUFreq governor"
0040 default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ
0041 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if ARM64 || ARM
0042 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if X86_INTEL_PSTATE && SMP
0043 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
0044 help
0045 This option sets which CPUFreq governor shall be loaded at
0046 startup. If in doubt, use the default setting.
0047
0048 config CPU_FREQ_DEFAULT_GOV_PERFORMANCE
0049 bool "performance"
0050 select CPU_FREQ_GOV_PERFORMANCE
0051 help
0052 Use the CPUFreq governor 'performance' as default. This sets
0053 the frequency statically to the highest frequency supported by
0054 the CPU.
0055
0056 config CPU_FREQ_DEFAULT_GOV_POWERSAVE
0057 bool "powersave"
0058 select CPU_FREQ_GOV_POWERSAVE
0059 help
0060 Use the CPUFreq governor 'powersave' as default. This sets
0061 the frequency statically to the lowest frequency supported by
0062 the CPU.
0063
0064 config CPU_FREQ_DEFAULT_GOV_USERSPACE
0065 bool "userspace"
0066 select CPU_FREQ_GOV_USERSPACE
0067 help
0068 Use the CPUFreq governor 'userspace' as default. This allows
0069 you to set the CPU frequency manually or when a userspace
0070 program shall be able to set the CPU dynamically without having
0071 to enable the userspace governor manually.
0072
0073 config CPU_FREQ_DEFAULT_GOV_ONDEMAND
0074 bool "ondemand"
0075 depends on !(X86_INTEL_PSTATE && SMP)
0076 select CPU_FREQ_GOV_ONDEMAND
0077 select CPU_FREQ_GOV_PERFORMANCE
0078 help
0079 Use the CPUFreq governor 'ondemand' as default. This allows
0080 you to get a full dynamic frequency capable system by simply
0081 loading your cpufreq low-level hardware driver.
0082 Be aware that not all cpufreq drivers support the ondemand
0083 governor. If unsure have a look at the help section of the
0084 driver. Fallback governor will be the performance governor.
0085
0086 config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
0087 bool "conservative"
0088 depends on !(X86_INTEL_PSTATE && SMP)
0089 select CPU_FREQ_GOV_CONSERVATIVE
0090 select CPU_FREQ_GOV_PERFORMANCE
0091 help
0092 Use the CPUFreq governor 'conservative' as default. This allows
0093 you to get a full dynamic frequency capable system by simply
0094 loading your cpufreq low-level hardware driver.
0095 Be aware that not all cpufreq drivers support the conservative
0096 governor. If unsure have a look at the help section of the
0097 driver. Fallback governor will be the performance governor.
0098
0099 config CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
0100 bool "schedutil"
0101 depends on SMP
0102 select CPU_FREQ_GOV_SCHEDUTIL
0103 select CPU_FREQ_GOV_PERFORMANCE
0104 help
0105 Use the 'schedutil' CPUFreq governor by default. If unsure,
0106 have a look at the help section of that governor. The fallback
0107 governor will be 'performance'.
0108
0109 endchoice
0110
0111 config CPU_FREQ_GOV_PERFORMANCE
0112 tristate "'performance' governor"
0113 help
0114 This cpufreq governor sets the frequency statically to the
0115 highest available CPU frequency.
0116
0117 To compile this driver as a module, choose M here: the
0118 module will be called cpufreq_performance.
0119
0120 If in doubt, say Y.
0121
0122 config CPU_FREQ_GOV_POWERSAVE
0123 tristate "'powersave' governor"
0124 help
0125 This cpufreq governor sets the frequency statically to the
0126 lowest available CPU frequency.
0127
0128 To compile this driver as a module, choose M here: the
0129 module will be called cpufreq_powersave.
0130
0131 If in doubt, say Y.
0132
0133 config CPU_FREQ_GOV_USERSPACE
0134 tristate "'userspace' governor for userspace frequency scaling"
0135 help
0136 Enable this cpufreq governor when you either want to set the
0137 CPU frequency manually or when a userspace program shall
0138 be able to set the CPU dynamically, like on LART
0139 <http://www.lartmaker.nl/>.
0140
0141 To compile this driver as a module, choose M here: the
0142 module will be called cpufreq_userspace.
0143
0144 If in doubt, say Y.
0145
0146 config CPU_FREQ_GOV_ONDEMAND
0147 tristate "'ondemand' cpufreq policy governor"
0148 select CPU_FREQ_GOV_COMMON
0149 help
0150 'ondemand' - This driver adds a dynamic cpufreq policy governor.
0151 The governor does a periodic polling and
0152 changes frequency based on the CPU utilization.
0153 The support for this governor depends on CPU capability to
0154 do fast frequency switching (i.e, very low latency frequency
0155 transitions).
0156
0157 To compile this driver as a module, choose M here: the
0158 module will be called cpufreq_ondemand.
0159
0160 For details, take a look at
0161 <file:Documentation/admin-guide/pm/cpufreq.rst>.
0162
0163 If in doubt, say N.
0164
0165 config CPU_FREQ_GOV_CONSERVATIVE
0166 tristate "'conservative' cpufreq governor"
0167 depends on CPU_FREQ
0168 select CPU_FREQ_GOV_COMMON
0169 help
0170 'conservative' - this driver is rather similar to the 'ondemand'
0171 governor both in its source code and its purpose, the difference is
0172 its optimisation for better suitability in a battery powered
0173 environment. The frequency is gracefully increased and decreased
0174 rather than jumping to 100% when speed is required.
0175
0176 If you have a desktop machine then you should really be considering
0177 the 'ondemand' governor instead, however if you are using a laptop,
0178 PDA or even an AMD64 based computer (due to the unacceptable
0179 step-by-step latency issues between the minimum and maximum frequency
0180 transitions in the CPU) you will probably want to use this governor.
0181
0182 To compile this driver as a module, choose M here: the
0183 module will be called cpufreq_conservative.
0184
0185 For details, take a look at
0186 <file:Documentation/admin-guide/pm/cpufreq.rst>.
0187
0188 If in doubt, say N.
0189
0190 config CPU_FREQ_GOV_SCHEDUTIL
0191 bool "'schedutil' cpufreq policy governor"
0192 depends on CPU_FREQ && SMP
0193 select CPU_FREQ_GOV_ATTR_SET
0194 select IRQ_WORK
0195 help
0196 This governor makes decisions based on the utilization data provided
0197 by the scheduler. It sets the CPU frequency to be proportional to
0198 the utilization/capacity ratio coming from the scheduler. If the
0199 utilization is frequency-invariant, the new frequency is also
0200 proportional to the maximum available frequency. If that is not the
0201 case, it is proportional to the current frequency of the CPU. The
0202 frequency tipping point is at utilization/capacity equal to 80% in
0203 both cases.
0204
0205 If in doubt, say N.
0206
0207 comment "CPU frequency scaling drivers"
0208
0209 config CPUFREQ_DT
0210 tristate "Generic DT based cpufreq driver"
0211 depends on HAVE_CLK && OF
0212 select CPUFREQ_DT_PLATDEV
0213 select PM_OPP
0214 help
0215 This adds a generic DT based cpufreq driver for frequency management.
0216 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
0217 systems.
0218
0219 If in doubt, say N.
0220
0221 config CPUFREQ_DT_PLATDEV
0222 bool
0223 help
0224 This adds a generic DT based cpufreq platdev driver for frequency
0225 management. This creates a 'cpufreq-dt' platform device, on the
0226 supported platforms.
0227
0228 If in doubt, say N.
0229
0230 if X86
0231 source "drivers/cpufreq/Kconfig.x86"
0232 endif
0233
0234 if ARM || ARM64
0235 source "drivers/cpufreq/Kconfig.arm"
0236 endif
0237
0238 if PPC32 || PPC64
0239 source "drivers/cpufreq/Kconfig.powerpc"
0240 endif
0241
0242 if IA64
0243 config IA64_ACPI_CPUFREQ
0244 tristate "ACPI Processor P-States driver"
0245 depends on ACPI_PROCESSOR
0246 help
0247 This driver adds a CPUFreq driver which utilizes the ACPI
0248 Processor Performance States.
0249
0250 If in doubt, say N.
0251 endif
0252
0253 if MIPS
0254 config BMIPS_CPUFREQ
0255 tristate "BMIPS CPUfreq Driver"
0256 help
0257 This option adds a CPUfreq driver for BMIPS processors with
0258 support for configurable CPU frequency.
0259
0260 For now, BMIPS5 chips are supported (such as the Broadcom 7425).
0261
0262 If in doubt, say N.
0263
0264 config LOONGSON2_CPUFREQ
0265 tristate "Loongson2 CPUFreq Driver"
0266 depends on LEMOTE_MACH2F
0267 help
0268 This option adds a CPUFreq driver for loongson processors which
0269 support software configurable cpu frequency.
0270
0271 Loongson2F and its successors support this feature.
0272
0273 If in doubt, say N.
0274
0275 config LOONGSON1_CPUFREQ
0276 tristate "Loongson1 CPUFreq Driver"
0277 depends on LOONGSON1_LS1B
0278 help
0279 This option adds a CPUFreq driver for loongson1 processors which
0280 support software configurable cpu frequency.
0281
0282 If in doubt, say N.
0283 endif
0284
0285 if SPARC64
0286 config SPARC_US3_CPUFREQ
0287 tristate "UltraSPARC-III CPU Frequency driver"
0288 help
0289 This adds the CPUFreq driver for UltraSPARC-III processors.
0290
0291 If in doubt, say N.
0292
0293 config SPARC_US2E_CPUFREQ
0294 tristate "UltraSPARC-IIe CPU Frequency driver"
0295 help
0296 This adds the CPUFreq driver for UltraSPARC-IIe processors.
0297
0298 If in doubt, say N.
0299 endif
0300
0301 if SUPERH
0302 config SH_CPU_FREQ
0303 tristate "SuperH CPU Frequency driver"
0304 help
0305 This adds the cpufreq driver for SuperH. Any CPU that supports
0306 clock rate rounding through the clock framework can use this
0307 driver. While it will make the kernel slightly larger, this is
0308 harmless for CPUs that don't support rate rounding. The driver
0309 will also generate a notice in the boot log before disabling
0310 itself if the CPU in question is not capable of rate rounding.
0311
0312 If unsure, say N.
0313 endif
0314
0315 config QORIQ_CPUFREQ
0316 tristate "CPU frequency scaling driver for Freescale QorIQ SoCs"
0317 depends on OF && COMMON_CLK
0318 depends on PPC_E500MC || SOC_LS1021A || ARCH_LAYERSCAPE || COMPILE_TEST
0319 select CLK_QORIQ
0320 help
0321 This adds the CPUFreq driver support for Freescale QorIQ SoCs
0322 which are capable of changing the CPU's frequency dynamically.
0323
0324 endif
0325 endmenu
