1# SPDX-License-Identifier: GPL-2.0-only 2menu "CPU Frequency scaling" 3 4config CPU_FREQ 5 bool "CPU Frequency scaling" 6 help 7 CPU Frequency scaling allows you to change the clock speed of 8 CPUs on the fly. This is a nice method to save power, because 9 the lower the CPU clock speed, the less power the CPU consumes. 10 11 Note that this driver doesn't automatically change the CPU 12 clock speed, you need to either enable a dynamic cpufreq governor 13 (see below) after boot, or use a userspace tool. 14 15 For details, take a look at 16 <file:Documentation/admin-guide/pm/cpufreq.rst>. 17 18 If in doubt, say N. 19 20if CPU_FREQ 21 22config CPU_FREQ_GOV_ATTR_SET 23 bool 24 25config CPU_FREQ_GOV_COMMON 26 select CPU_FREQ_GOV_ATTR_SET 27 select IRQ_WORK 28 bool 29 30config CPU_FREQ_STAT 31 bool "CPU frequency transition statistics" 32 help 33 Export CPU frequency statistics information through sysfs. 34 35 If in doubt, say N. 36 37choice 38 prompt "Default CPUFreq governor" 39 default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1110_CPUFREQ 40 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if ARM64 || ARM 41 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if (X86_INTEL_PSTATE || X86_AMD_PSTATE) && SMP 42 default CPU_FREQ_DEFAULT_GOV_PERFORMANCE 43 help 44 This option sets which CPUFreq governor shall be loaded at 45 startup. If in doubt, use the default setting. 46 47config CPU_FREQ_DEFAULT_GOV_PERFORMANCE 48 bool "performance" 49 select CPU_FREQ_GOV_PERFORMANCE 50 help 51 Use the CPUFreq governor 'performance' as default. This sets 52 the frequency statically to the highest frequency supported by 53 the CPU. 54 55config CPU_FREQ_DEFAULT_GOV_POWERSAVE 56 bool "powersave" 57 select CPU_FREQ_GOV_POWERSAVE 58 help 59 Use the CPUFreq governor 'powersave' as default. This sets 60 the frequency statically to the lowest frequency supported by 61 the CPU. 62 63config CPU_FREQ_DEFAULT_GOV_USERSPACE 64 bool "userspace" 65 select CPU_FREQ_GOV_USERSPACE 66 help 67 Use the CPUFreq governor 'userspace' as default. This allows 68 you to set the CPU frequency manually or when a userspace 69 program shall be able to set the CPU dynamically without having 70 to enable the userspace governor manually. 71 72config CPU_FREQ_DEFAULT_GOV_ONDEMAND 73 bool "ondemand" 74 depends on !(X86_INTEL_PSTATE && SMP) 75 select CPU_FREQ_GOV_ONDEMAND 76 select CPU_FREQ_GOV_PERFORMANCE 77 help 78 Use the CPUFreq governor 'ondemand' as default. This allows 79 you to get a full dynamic frequency capable system by simply 80 loading your cpufreq low-level hardware driver. 81 Be aware that not all cpufreq drivers support the ondemand 82 governor. If unsure have a look at the help section of the 83 driver. Fallback governor will be the performance governor. 84 85config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE 86 bool "conservative" 87 depends on !(X86_INTEL_PSTATE && SMP) 88 select CPU_FREQ_GOV_CONSERVATIVE 89 select CPU_FREQ_GOV_PERFORMANCE 90 help 91 Use the CPUFreq governor 'conservative' as default. This allows 92 you to get a full dynamic frequency capable system by simply 93 loading your cpufreq low-level hardware driver. 94 Be aware that not all cpufreq drivers support the conservative 95 governor. If unsure have a look at the help section of the 96 driver. Fallback governor will be the performance governor. 97 98config CPU_FREQ_DEFAULT_GOV_SCHEDUTIL 99 bool "schedutil" 100 depends on SMP 101 select CPU_FREQ_GOV_SCHEDUTIL 102 select CPU_FREQ_GOV_PERFORMANCE 103 help 104 Use the 'schedutil' CPUFreq governor by default. If unsure, 105 have a look at the help section of that governor. The fallback 106 governor will be 'performance'. 107 108endchoice 109 110config CPU_FREQ_GOV_PERFORMANCE 111 tristate "'performance' governor" 112 help 113 This cpufreq governor sets the frequency statically to the 114 highest available CPU frequency. 115 116 To compile this driver as a module, choose M here: the 117 module will be called cpufreq_performance. 118 119 If in doubt, say Y. 120 121config CPU_FREQ_GOV_POWERSAVE 122 tristate "'powersave' governor" 123 help 124 This cpufreq governor sets the frequency statically to the 125 lowest available CPU frequency. 126 127 To compile this driver as a module, choose M here: the 128 module will be called cpufreq_powersave. 129 130 If in doubt, say Y. 131 132config CPU_FREQ_GOV_USERSPACE 133 tristate "'userspace' governor for userspace frequency scaling" 134 help 135 Enable this cpufreq governor when you either want to set the 136 CPU frequency manually or when a userspace program shall 137 be able to set the CPU dynamically, like on LART 138 <http://www.lartmaker.nl/>. 139 140 To compile this driver as a module, choose M here: the 141 module will be called cpufreq_userspace. 142 143 If in doubt, say Y. 144 145config CPU_FREQ_GOV_ONDEMAND 146 tristate "'ondemand' cpufreq policy governor" 147 select CPU_FREQ_GOV_COMMON 148 help 149 'ondemand' - This driver adds a dynamic cpufreq policy governor. 150 The governor does a periodic polling and 151 changes frequency based on the CPU utilization. 152 The support for this governor depends on CPU capability to 153 do fast frequency switching (i.e, very low latency frequency 154 transitions). 155 156 To compile this driver as a module, choose M here: the 157 module will be called cpufreq_ondemand. 158 159 For details, take a look at 160 <file:Documentation/admin-guide/pm/cpufreq.rst>. 161 162 If in doubt, say N. 163 164config CPU_FREQ_GOV_CONSERVATIVE 165 tristate "'conservative' cpufreq governor" 166 depends on CPU_FREQ 167 select CPU_FREQ_GOV_COMMON 168 help 169 'conservative' - this driver is rather similar to the 'ondemand' 170 governor both in its source code and its purpose, the difference is 171 its optimisation for better suitability in a battery powered 172 environment. The frequency is gracefully increased and decreased 173 rather than jumping to 100% when speed is required. 174 175 If you have a desktop machine then you should really be considering 176 the 'ondemand' governor instead, however if you are using a laptop, 177 PDA or even an AMD64 based computer (due to the unacceptable 178 step-by-step latency issues between the minimum and maximum frequency 179 transitions in the CPU) you will probably want to use this governor. 180 181 To compile this driver as a module, choose M here: the 182 module will be called cpufreq_conservative. 183 184 For details, take a look at 185 <file:Documentation/admin-guide/pm/cpufreq.rst>. 186 187 If in doubt, say N. 188 189config CPU_FREQ_GOV_SCHEDUTIL 190 bool "'schedutil' cpufreq policy governor" 191 depends on CPU_FREQ && SMP 192 select CPU_FREQ_GOV_ATTR_SET 193 select IRQ_WORK 194 help 195 This governor makes decisions based on the utilization data provided 196 by the scheduler. It sets the CPU frequency to be proportional to 197 the utilization/capacity ratio coming from the scheduler. If the 198 utilization is frequency-invariant, the new frequency is also 199 proportional to the maximum available frequency. If that is not the 200 case, it is proportional to the current frequency of the CPU. The 201 frequency tipping point is at utilization/capacity equal to 80% in 202 both cases. 203 204 If in doubt, say N. 205 206comment "CPU frequency scaling drivers" 207 208config CPUFREQ_DT 209 tristate "Generic DT based cpufreq driver" 210 depends on HAVE_CLK && OF 211 select CPUFREQ_DT_PLATDEV 212 select PM_OPP 213 help 214 This adds a generic DT based cpufreq driver for frequency management. 215 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP) 216 systems. 217 218 If in doubt, say N. 219 220config CPUFREQ_DT_PLATDEV 221 tristate "Generic DT based cpufreq platdev driver" 222 depends on OF 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 MIPS 243config BMIPS_CPUFREQ 244 tristate "BMIPS CPUfreq Driver" 245 help 246 This option adds a CPUfreq driver for BMIPS processors with 247 support for configurable CPU frequency. 248 249 For now, BMIPS5 chips are supported (such as the Broadcom 7425). 250 251 If in doubt, say N. 252 253config LOONGSON2_CPUFREQ 254 tristate "Loongson2 CPUFreq Driver" 255 depends on LEMOTE_MACH2F 256 help 257 This option adds a CPUFreq driver for loongson processors which 258 support software configurable cpu frequency. 259 260 Loongson2F and its successors support this feature. 261 262 If in doubt, say N. 263endif 264 265if SPARC64 266config SPARC_US3_CPUFREQ 267 tristate "UltraSPARC-III CPU Frequency driver" 268 help 269 This adds the CPUFreq driver for UltraSPARC-III processors. 270 271 If in doubt, say N. 272 273config SPARC_US2E_CPUFREQ 274 tristate "UltraSPARC-IIe CPU Frequency driver" 275 help 276 This adds the CPUFreq driver for UltraSPARC-IIe processors. 277 278 If in doubt, say N. 279endif 280 281if SUPERH 282config SH_CPU_FREQ 283 tristate "SuperH CPU Frequency driver" 284 help 285 This adds the cpufreq driver for SuperH. Any CPU that supports 286 clock rate rounding through the clock framework can use this 287 driver. While it will make the kernel slightly larger, this is 288 harmless for CPUs that don't support rate rounding. The driver 289 will also generate a notice in the boot log before disabling 290 itself if the CPU in question is not capable of rate rounding. 291 292 If unsure, say N. 293endif 294 295config QORIQ_CPUFREQ 296 tristate "CPU frequency scaling driver for Freescale QorIQ SoCs" 297 depends on OF && COMMON_CLK 298 depends on PPC_E500MC || SOC_LS1021A || ARCH_LAYERSCAPE || COMPILE_TEST 299 select CLK_QORIQ 300 help 301 This adds the CPUFreq driver support for Freescale QorIQ SoCs 302 which are capable of changing the CPU's frequency dynamically. 303 304endif 305endmenu 306