1# SPDX-License-Identifier: GPL-2.0-only 2menu "CPU Frequency scaling" 3 4config CPU_FREQ 5 bool "CPU Frequency scaling" 6 select SRCU 7 help 8 CPU Frequency scaling allows you to change the clock speed of 9 CPUs on the fly. This is a nice method to save power, because 10 the lower the CPU clock speed, the less power the CPU consumes. 11 12 Note that this driver doesn't automatically change the CPU 13 clock speed, you need to either enable a dynamic cpufreq governor 14 (see below) after boot, or use a userspace tool. 15 16 For details, take a look at 17 <file:Documentation/admin-guide/pm/cpufreq.rst>. 18 19 If in doubt, say N. 20 21if CPU_FREQ 22 23config CPU_FREQ_GOV_ATTR_SET 24 bool 25 26config CPU_FREQ_GOV_COMMON 27 select CPU_FREQ_GOV_ATTR_SET 28 select IRQ_WORK 29 bool 30 31config CPU_FREQ_STAT 32 bool "CPU frequency transition statistics" 33 help 34 Export CPU frequency statistics information through sysfs. 35 36 If in doubt, say N. 37 38choice 39 prompt "Default CPUFreq governor" 40 default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ 41 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if ARM64 || ARM 42 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if X86_INTEL_PSTATE && SMP 43 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE 44 help 45 This option sets which CPUFreq governor shall be loaded at 46 startup. If in doubt, use the default setting. 47 48config CPU_FREQ_DEFAULT_GOV_PERFORMANCE 49 bool "performance" 50 select CPU_FREQ_GOV_PERFORMANCE 51 help 52 Use the CPUFreq governor 'performance' as default. This sets 53 the frequency statically to the highest frequency supported by 54 the CPU. 55 56config CPU_FREQ_DEFAULT_GOV_POWERSAVE 57 bool "powersave" 58 select CPU_FREQ_GOV_POWERSAVE 59 help 60 Use the CPUFreq governor 'powersave' as default. This sets 61 the frequency statically to the lowest frequency supported by 62 the CPU. 63 64config CPU_FREQ_DEFAULT_GOV_USERSPACE 65 bool "userspace" 66 select CPU_FREQ_GOV_USERSPACE 67 help 68 Use the CPUFreq governor 'userspace' as default. This allows 69 you to set the CPU frequency manually or when a userspace 70 program shall be able to set the CPU dynamically without having 71 to enable the userspace governor manually. 72 73config CPU_FREQ_DEFAULT_GOV_ONDEMAND 74 bool "ondemand" 75 depends on !(X86_INTEL_PSTATE && SMP) 76 select CPU_FREQ_GOV_ONDEMAND 77 select CPU_FREQ_GOV_PERFORMANCE 78 help 79 Use the CPUFreq governor 'ondemand' as default. This allows 80 you to get a full dynamic frequency capable system by simply 81 loading your cpufreq low-level hardware driver. 82 Be aware that not all cpufreq drivers support the ondemand 83 governor. If unsure have a look at the help section of the 84 driver. Fallback governor will be the performance governor. 85 86config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE 87 bool "conservative" 88 depends on !(X86_INTEL_PSTATE && SMP) 89 select CPU_FREQ_GOV_CONSERVATIVE 90 select CPU_FREQ_GOV_PERFORMANCE 91 help 92 Use the CPUFreq governor 'conservative' as default. This allows 93 you to get a full dynamic frequency capable system by simply 94 loading your cpufreq low-level hardware driver. 95 Be aware that not all cpufreq drivers support the conservative 96 governor. If unsure have a look at the help section of the 97 driver. Fallback governor will be the performance governor. 98 99config CPU_FREQ_DEFAULT_GOV_SCHEDUTIL 100 bool "schedutil" 101 depends on SMP 102 select CPU_FREQ_GOV_SCHEDUTIL 103 select CPU_FREQ_GOV_PERFORMANCE 104 help 105 Use the 'schedutil' CPUFreq governor by default. If unsure, 106 have a look at the help section of that governor. The fallback 107 governor will be 'performance'. 108 109endchoice 110 111config CPU_FREQ_GOV_PERFORMANCE 112 tristate "'performance' governor" 113 help 114 This cpufreq governor sets the frequency statically to the 115 highest available CPU frequency. 116 117 To compile this driver as a module, choose M here: the 118 module will be called cpufreq_performance. 119 120 If in doubt, say Y. 121 122config CPU_FREQ_GOV_POWERSAVE 123 tristate "'powersave' governor" 124 help 125 This cpufreq governor sets the frequency statically to the 126 lowest available CPU frequency. 127 128 To compile this driver as a module, choose M here: the 129 module will be called cpufreq_powersave. 130 131 If in doubt, say Y. 132 133config CPU_FREQ_GOV_USERSPACE 134 tristate "'userspace' governor for userspace frequency scaling" 135 help 136 Enable this cpufreq governor when you either want to set the 137 CPU frequency manually or when a userspace program shall 138 be able to set the CPU dynamically, like on LART 139 <http://www.lartmaker.nl/>. 140 141 To compile this driver as a module, choose M here: the 142 module will be called cpufreq_userspace. 143 144 If in doubt, say Y. 145 146config CPU_FREQ_GOV_ONDEMAND 147 tristate "'ondemand' cpufreq policy governor" 148 select CPU_FREQ_GOV_COMMON 149 help 150 'ondemand' - This driver adds a dynamic cpufreq policy governor. 151 The governor does a periodic polling and 152 changes frequency based on the CPU utilization. 153 The support for this governor depends on CPU capability to 154 do fast frequency switching (i.e, very low latency frequency 155 transitions). 156 157 To compile this driver as a module, choose M here: the 158 module will be called cpufreq_ondemand. 159 160 For details, take a look at 161 <file:Documentation/admin-guide/pm/cpufreq.rst>. 162 163 If in doubt, say N. 164 165config CPU_FREQ_GOV_CONSERVATIVE 166 tristate "'conservative' cpufreq governor" 167 depends on CPU_FREQ 168 select CPU_FREQ_GOV_COMMON 169 help 170 'conservative' - this driver is rather similar to the 'ondemand' 171 governor both in its source code and its purpose, the difference is 172 its optimisation for better suitability in a battery powered 173 environment. The frequency is gracefully increased and decreased 174 rather than jumping to 100% when speed is required. 175 176 If you have a desktop machine then you should really be considering 177 the 'ondemand' governor instead, however if you are using a laptop, 178 PDA or even an AMD64 based computer (due to the unacceptable 179 step-by-step latency issues between the minimum and maximum frequency 180 transitions in the CPU) you will probably want to use this governor. 181 182 To compile this driver as a module, choose M here: the 183 module will be called cpufreq_conservative. 184 185 For details, take a look at 186 <file:Documentation/admin-guide/pm/cpufreq.rst>. 187 188 If in doubt, say N. 189 190config CPU_FREQ_GOV_SCHEDUTIL 191 bool "'schedutil' cpufreq policy governor" 192 depends on CPU_FREQ && SMP 193 select CPU_FREQ_GOV_ATTR_SET 194 select IRQ_WORK 195 help 196 This governor makes decisions based on the utilization data provided 197 by the scheduler. It sets the CPU frequency to be proportional to 198 the utilization/capacity ratio coming from the scheduler. If the 199 utilization is frequency-invariant, the new frequency is also 200 proportional to the maximum available frequency. If that is not the 201 case, it is proportional to the current frequency of the CPU. The 202 frequency tipping point is at utilization/capacity equal to 80% in 203 both cases. 204 205 If in doubt, say N. 206 207comment "CPU frequency scaling drivers" 208 209config CPUFREQ_DT 210 tristate "Generic DT based cpufreq driver" 211 depends on HAVE_CLK && OF 212 select CPUFREQ_DT_PLATDEV 213 select PM_OPP 214 help 215 This adds a generic DT based cpufreq driver for frequency management. 216 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP) 217 systems. 218 219 If in doubt, say N. 220 221config CPUFREQ_DT_PLATDEV 222 bool 223 help 224 This adds a generic DT based cpufreq platdev driver for frequency 225 management. This creates a 'cpufreq-dt' platform device, on the 226 supported platforms. 227 228 If in doubt, say N. 229 230if X86 231source "drivers/cpufreq/Kconfig.x86" 232endif 233 234if ARM || ARM64 235source "drivers/cpufreq/Kconfig.arm" 236endif 237 238if PPC32 || PPC64 239source "drivers/cpufreq/Kconfig.powerpc" 240endif 241 242if IA64 243config IA64_ACPI_CPUFREQ 244 tristate "ACPI Processor P-States driver" 245 depends on ACPI_PROCESSOR 246 help 247 This driver adds a CPUFreq driver which utilizes the ACPI 248 Processor Performance States. 249 250 If in doubt, say N. 251endif 252 253if MIPS 254config BMIPS_CPUFREQ 255 tristate "BMIPS CPUfreq Driver" 256 help 257 This option adds a CPUfreq driver for BMIPS processors with 258 support for configurable CPU frequency. 259 260 For now, BMIPS5 chips are supported (such as the Broadcom 7425). 261 262 If in doubt, say N. 263 264config LOONGSON2_CPUFREQ 265 tristate "Loongson2 CPUFreq Driver" 266 depends on LEMOTE_MACH2F 267 help 268 This option adds a CPUFreq driver for loongson processors which 269 support software configurable cpu frequency. 270 271 Loongson2F and it's successors support this feature. 272 273 If in doubt, say N. 274 275config LOONGSON1_CPUFREQ 276 tristate "Loongson1 CPUFreq Driver" 277 depends on LOONGSON1_LS1B 278 help 279 This option adds a CPUFreq driver for loongson1 processors which 280 support software configurable cpu frequency. 281 282 If in doubt, say N. 283endif 284 285if SPARC64 286config SPARC_US3_CPUFREQ 287 tristate "UltraSPARC-III CPU Frequency driver" 288 help 289 This adds the CPUFreq driver for UltraSPARC-III processors. 290 291 If in doubt, say N. 292 293config SPARC_US2E_CPUFREQ 294 tristate "UltraSPARC-IIe CPU Frequency driver" 295 help 296 This adds the CPUFreq driver for UltraSPARC-IIe processors. 297 298 If in doubt, say N. 299endif 300 301if SUPERH 302config SH_CPU_FREQ 303 tristate "SuperH CPU Frequency driver" 304 help 305 This adds the cpufreq driver for SuperH. Any CPU that supports 306 clock rate rounding through the clock framework can use this 307 driver. While it will make the kernel slightly larger, this is 308 harmless for CPUs that don't support rate rounding. The driver 309 will also generate a notice in the boot log before disabling 310 itself if the CPU in question is not capable of rate rounding. 311 312 If unsure, say N. 313endif 314 315config QORIQ_CPUFREQ 316 tristate "CPU frequency scaling driver for Freescale QorIQ SoCs" 317 depends on OF && COMMON_CLK 318 depends on PPC_E500MC || SOC_LS1021A || ARCH_LAYERSCAPE || COMPILE_TEST 319 select CLK_QORIQ 320 help 321 This adds the CPUFreq driver support for Freescale QorIQ SoCs 322 which are capable of changing the CPU's frequency dynamically. 323 324endif 325endmenu 326