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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 && 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 bool
222 help
223 This adds a generic DT based cpufreq platdev driver for frequency
224 management. This creates a 'cpufreq-dt' platform device, on the
225 supported platforms.
226
227 If in doubt, say N.
228
229if X86
230source "drivers/cpufreq/Kconfig.x86"
231endif
232
233if ARM || ARM64
234source "drivers/cpufreq/Kconfig.arm"
235endif
236
237if PPC32 || PPC64
238source "drivers/cpufreq/Kconfig.powerpc"
239endif
240
241if IA64
242config IA64_ACPI_CPUFREQ
243 tristate "ACPI Processor P-States driver"
244 depends on ACPI_PROCESSOR
245 help
246 This driver adds a CPUFreq driver which utilizes the ACPI
247 Processor Performance States.
248
249 If in doubt, say N.
250endif
251
252if MIPS
253config BMIPS_CPUFREQ
254 tristate "BMIPS CPUfreq Driver"
255 help
256 This option adds a CPUfreq driver for BMIPS processors with
257 support for configurable CPU frequency.
258
259 For now, BMIPS5 chips are supported (such as the Broadcom 7425).
260
261 If in doubt, say N.
262
263config LOONGSON2_CPUFREQ
264 tristate "Loongson2 CPUFreq Driver"
265 depends on LEMOTE_MACH2F
266 help
267 This option adds a CPUFreq driver for loongson processors which
268 support software configurable cpu frequency.
269
270 Loongson2F and its successors support this feature.
271
272 If in doubt, say N.
273endif
274
275if SPARC64
276config SPARC_US3_CPUFREQ
277 tristate "UltraSPARC-III CPU Frequency driver"
278 help
279 This adds the CPUFreq driver for UltraSPARC-III processors.
280
281 If in doubt, say N.
282
283config SPARC_US2E_CPUFREQ
284 tristate "UltraSPARC-IIe CPU Frequency driver"
285 help
286 This adds the CPUFreq driver for UltraSPARC-IIe processors.
287
288 If in doubt, say N.
289endif
290
291if SUPERH
292config SH_CPU_FREQ
293 tristate "SuperH CPU Frequency driver"
294 help
295 This adds the cpufreq driver for SuperH. Any CPU that supports
296 clock rate rounding through the clock framework can use this
297 driver. While it will make the kernel slightly larger, this is
298 harmless for CPUs that don't support rate rounding. The driver
299 will also generate a notice in the boot log before disabling
300 itself if the CPU in question is not capable of rate rounding.
301
302 If unsure, say N.
303endif
304
305config QORIQ_CPUFREQ
306 tristate "CPU frequency scaling driver for Freescale QorIQ SoCs"
307 depends on OF && COMMON_CLK
308 depends on PPC_E500MC || SOC_LS1021A || ARCH_LAYERSCAPE || COMPILE_TEST
309 select CLK_QORIQ
310 help
311 This adds the CPUFreq driver support for Freescale QorIQ SoCs
312 which are capable of changing the CPU's frequency dynamically.
313
314endif
315endmenu