1
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 <file:Documentation/cpu-freq>.
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_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ
40 default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if BIG_LITTLE
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 select CPU_FREQ_GOV_ONDEMAND
75 select CPU_FREQ_GOV_PERFORMANCE
76 help
77 Use the CPUFreq governor 'ondemand' as default. This allows
78 you to get a full dynamic frequency capable system by simply
79 loading your cpufreq low-level hardware driver.
80 Be aware that not all cpufreq drivers support the ondemand
81 governor. If unsure have a look at the help section of the
82 driver. Fallback governor will be the performance governor.
83
84config CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
85 bool "conservative"
86 select CPU_FREQ_GOV_CONSERVATIVE
87 select CPU_FREQ_GOV_PERFORMANCE
88 help
89 Use the CPUFreq governor 'conservative' as default. This allows
90 you to get a full dynamic frequency capable system by simply
91 loading your cpufreq low-level hardware driver.
92 Be aware that not all cpufreq drivers support the conservative
93 governor. If unsure have a look at the help section of the
94 driver. Fallback governor will be the performance governor.
95
96config CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
97 bool "schedutil"
98 depends on SMP
99 select CPU_FREQ_GOV_SCHEDUTIL
100 select CPU_FREQ_GOV_PERFORMANCE
101 help
102 Use the 'schedutil' CPUFreq governor by default. If unsure,
103 have a look at the help section of that governor. The fallback
104 governor will be 'performance'.
105
106endchoice
107
108config CPU_FREQ_GOV_PERFORMANCE
109 tristate "'performance' governor"
110 help
111 This cpufreq governor sets the frequency statically to the
112 highest available CPU frequency.
113
114 To compile this driver as a module, choose M here: the
115 module will be called cpufreq_performance.
116
117 If in doubt, say Y.
118
119config CPU_FREQ_GOV_POWERSAVE
120 tristate "'powersave' governor"
121 help
122 This cpufreq governor sets the frequency statically to the
123 lowest available CPU frequency.
124
125 To compile this driver as a module, choose M here: the
126 module will be called cpufreq_powersave.
127
128 If in doubt, say Y.
129
130config CPU_FREQ_GOV_USERSPACE
131 tristate "'userspace' governor for userspace frequency scaling"
132 help
133 Enable this cpufreq governor when you either want to set the
134 CPU frequency manually or when a userspace program shall
135 be able to set the CPU dynamically, like on LART
136 <http://www.lartmaker.nl/>.
137
138 To compile this driver as a module, choose M here: the
139 module will be called cpufreq_userspace.
140
141 For details, take a look at <file:Documentation/cpu-freq/>.
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 linux/Documentation/cpu-freq.
160
161 If in doubt, say N.
162
163config CPU_FREQ_GOV_CONSERVATIVE
164 tristate "'conservative' cpufreq governor"
165 depends on CPU_FREQ
166 select CPU_FREQ_GOV_COMMON
167 help
168 'conservative' - this driver is rather similar to the 'ondemand'
169 governor both in its source code and its purpose, the difference is
170 its optimisation for better suitability in a battery powered
171 environment. The frequency is gracefully increased and decreased
172 rather than jumping to 100% when speed is required.
173
174 If you have a desktop machine then you should really be considering
175 the 'ondemand' governor instead, however if you are using a laptop,
176 PDA or even an AMD64 based computer (due to the unacceptable
177 step-by-step latency issues between the minimum and maximum frequency
178 transitions in the CPU) you will probably want to use this governor.
179
180 To compile this driver as a module, choose M here: the
181 module will be called cpufreq_conservative.
182
183 For details, take a look at linux/Documentation/cpu-freq.
184
185 If in doubt, say N.
186
187config CPU_FREQ_GOV_SCHEDUTIL
188 bool "'schedutil' cpufreq policy governor"
189 depends on CPU_FREQ && SMP
190 select CPU_FREQ_GOV_ATTR_SET
191 select IRQ_WORK
192 help
193 This governor makes decisions based on the utilization data provided
194 by the scheduler. It sets the CPU frequency to be proportional to
195 the utilization/capacity ratio coming from the scheduler. If the
196 utilization is frequency-invariant, the new frequency is also
197 proportional to the maximum available frequency. If that is not the
198 case, it is proportional to the current frequency of the CPU. The
199 frequency tipping point is at utilization/capacity equal to 80% in
200 both cases.
201
202 If in doubt, say N.
203
204comment "CPU frequency scaling drivers"
205
206config CPUFREQ_DT
207 tristate "Generic DT based cpufreq driver"
208 depends on HAVE_CLK && OF
209 select CPUFREQ_DT_PLATDEV
210 select PM_OPP
211 help
212 This adds a generic DT based cpufreq driver for frequency management.
213 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
214 systems.
215
216 If in doubt, say N.
217
218config CPUFREQ_DT_PLATDEV
219 bool
220 help
221 This adds a generic DT based cpufreq platdev driver for frequency
222 management. This creates a 'cpufreq-dt' platform device, on the
223 supported platforms.
224
225 If in doubt, say N.
226
227if X86
228source "drivers/cpufreq/Kconfig.x86"
229endif
230
231if ARM || ARM64
232source "drivers/cpufreq/Kconfig.arm"
233endif
234
235if PPC32 || PPC64
236source "drivers/cpufreq/Kconfig.powerpc"
237endif
238
239if IA64
240config IA64_ACPI_CPUFREQ
241 tristate "ACPI Processor P-States driver"
242 depends on ACPI_PROCESSOR
243 help
244 This driver adds a CPUFreq driver which utilizes the ACPI
245 Processor Performance States.
246
247 For details, take a look at <file:Documentation/cpu-freq/>.
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 it's successors support this feature.
271
272 For details, take a look at <file:Documentation/cpu-freq/>.
273
274 If in doubt, say N.
275
276config LOONGSON1_CPUFREQ
277 tristate "Loongson1 CPUFreq Driver"
278 depends on LOONGSON1_LS1B
279 help
280 This option adds a CPUFreq driver for loongson1 processors which
281 support software configurable cpu frequency.
282
283 For details, take a look at <file:Documentation/cpu-freq/>.
284
285 If in doubt, say N.
286endif
287
288if SPARC64
289config SPARC_US3_CPUFREQ
290 tristate "UltraSPARC-III CPU Frequency driver"
291 help
292 This adds the CPUFreq driver for UltraSPARC-III processors.
293
294 For details, take a look at <file:Documentation/cpu-freq>.
295
296 If in doubt, say N.
297
298config SPARC_US2E_CPUFREQ
299 tristate "UltraSPARC-IIe CPU Frequency driver"
300 help
301 This adds the CPUFreq driver for UltraSPARC-IIe processors.
302
303 For details, take a look at <file:Documentation/cpu-freq>.
304
305 If in doubt, say N.
306endif
307
308if SUPERH
309config SH_CPU_FREQ
310 tristate "SuperH CPU Frequency driver"
311 help
312 This adds the cpufreq driver for SuperH. Any CPU that supports
313 clock rate rounding through the clock framework can use this
314 driver. While it will make the kernel slightly larger, this is
315 harmless for CPUs that don't support rate rounding. The driver
316 will also generate a notice in the boot log before disabling
317 itself if the CPU in question is not capable of rate rounding.
318
319 For details, take a look at <file:Documentation/cpu-freq>.
320
321 If unsure, say N.
322endif
323
324config QORIQ_CPUFREQ
325 tristate "CPU frequency scaling driver for Freescale QorIQ SoCs"
326 depends on OF && COMMON_CLK && (PPC_E500MC || ARM || ARM64)
327 select CLK_QORIQ
328 help
329 This adds the CPUFreq driver support for Freescale QorIQ SoCs
330 which are capable of changing the CPU's frequency dynamically.
331
332endif
333endmenu
334
