1 # SPDX-License-Identifier: GPL-2.0-only
2 menu "CPU Frequency scaling"
3 
4 config 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 
21 if CPU_FREQ
22 
23 config CPU_FREQ_GOV_ATTR_SET
24 	bool
25 
26 config CPU_FREQ_GOV_COMMON
27 	select CPU_FREQ_GOV_ATTR_SET
28 	select IRQ_WORK
29 	bool
30 
31 config 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 
38 choice
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 
48 config 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 
56 config 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 
64 config 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 
73 config 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 
86 config 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 
99 config 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 
109 endchoice
110 
111 config 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 
122 config 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 
133 config 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 
146 config 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 
165 config 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 
190 config 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 
207 comment "CPU frequency scaling drivers"
208 
209 config 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 
221 config 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 
230 if X86
231 source "drivers/cpufreq/Kconfig.x86"
232 endif
233 
234 if ARM || ARM64
235 source "drivers/cpufreq/Kconfig.arm"
236 endif
237 
238 if PPC32 || PPC64
239 source "drivers/cpufreq/Kconfig.powerpc"
240 endif
241 
242 if IA64
243 config 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.
251 endif
252 
253 if MIPS
254 config 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 
264 config 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 
275 config 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.
283 endif
284 
285 if SPARC64
286 config 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 
293 config 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.
299 endif
300 
301 if SUPERH
302 config 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.
313 endif
314 
315 config 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 
324 endif
325 endmenu
326