Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * processor_throttling.c - Throttling submodule of the ACPI processor driver | |
3 | * | |
4 | * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com> | |
5 | * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> | |
6 | * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de> | |
7 | * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> | |
8 | * - Added processor hotplug support | |
9 | * | |
10 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License as published by | |
14 | * the Free Software Foundation; either version 2 of the License, or (at | |
15 | * your option) any later version. | |
16 | * | |
17 | * This program is distributed in the hope that it will be useful, but | |
18 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
20 | * General Public License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License along | |
23 | * with this program; if not, write to the Free Software Foundation, Inc., | |
24 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. | |
25 | * | |
26 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
27 | */ | |
28 | ||
29 | #include <linux/kernel.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/init.h> | |
32 | #include <linux/cpufreq.h> | |
33 | #include <linux/proc_fs.h> | |
34 | #include <linux/seq_file.h> | |
35 | ||
36 | #include <asm/io.h> | |
37 | #include <asm/uaccess.h> | |
38 | ||
39 | #include <acpi/acpi_bus.h> | |
40 | #include <acpi/processor.h> | |
41 | ||
42 | #define ACPI_PROCESSOR_COMPONENT 0x01000000 | |
43 | #define ACPI_PROCESSOR_CLASS "processor" | |
1da177e4 | 44 | #define _COMPONENT ACPI_PROCESSOR_COMPONENT |
f52fd66d | 45 | ACPI_MODULE_NAME("processor_throttling"); |
1da177e4 LT |
46 | |
47 | /* -------------------------------------------------------------------------- | |
48 | Throttling Control | |
49 | -------------------------------------------------------------------------- */ | |
4be44fcd | 50 | static int acpi_processor_get_throttling(struct acpi_processor *pr) |
1da177e4 | 51 | { |
4be44fcd LB |
52 | int state = 0; |
53 | u32 value = 0; | |
54 | u32 duty_mask = 0; | |
55 | u32 duty_value = 0; | |
1da177e4 | 56 | |
1da177e4 LT |
57 | |
58 | if (!pr) | |
d550d98d | 59 | return -EINVAL; |
1da177e4 LT |
60 | |
61 | if (!pr->flags.throttling) | |
d550d98d | 62 | return -ENODEV; |
1da177e4 LT |
63 | |
64 | pr->throttling.state = 0; | |
65 | ||
66 | duty_mask = pr->throttling.state_count - 1; | |
67 | ||
68 | duty_mask <<= pr->throttling.duty_offset; | |
69 | ||
70 | local_irq_disable(); | |
71 | ||
72 | value = inl(pr->throttling.address); | |
73 | ||
74 | /* | |
75 | * Compute the current throttling state when throttling is enabled | |
76 | * (bit 4 is on). | |
77 | */ | |
78 | if (value & 0x10) { | |
79 | duty_value = value & duty_mask; | |
80 | duty_value >>= pr->throttling.duty_offset; | |
81 | ||
82 | if (duty_value) | |
4be44fcd | 83 | state = pr->throttling.state_count - duty_value; |
1da177e4 LT |
84 | } |
85 | ||
86 | pr->throttling.state = state; | |
87 | ||
88 | local_irq_enable(); | |
89 | ||
90 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, | |
4be44fcd LB |
91 | "Throttling state is T%d (%d%% throttling applied)\n", |
92 | state, pr->throttling.states[state].performance)); | |
1da177e4 | 93 | |
d550d98d | 94 | return 0; |
1da177e4 LT |
95 | } |
96 | ||
4be44fcd | 97 | int acpi_processor_set_throttling(struct acpi_processor *pr, int state) |
1da177e4 | 98 | { |
4be44fcd LB |
99 | u32 value = 0; |
100 | u32 duty_mask = 0; | |
101 | u32 duty_value = 0; | |
1da177e4 | 102 | |
1da177e4 LT |
103 | |
104 | if (!pr) | |
d550d98d | 105 | return -EINVAL; |
1da177e4 LT |
106 | |
107 | if ((state < 0) || (state > (pr->throttling.state_count - 1))) | |
d550d98d | 108 | return -EINVAL; |
1da177e4 LT |
109 | |
110 | if (!pr->flags.throttling) | |
d550d98d | 111 | return -ENODEV; |
1da177e4 LT |
112 | |
113 | if (state == pr->throttling.state) | |
d550d98d | 114 | return 0; |
1da177e4 LT |
115 | |
116 | /* | |
117 | * Calculate the duty_value and duty_mask. | |
118 | */ | |
119 | if (state) { | |
120 | duty_value = pr->throttling.state_count - state; | |
121 | ||
122 | duty_value <<= pr->throttling.duty_offset; | |
123 | ||
124 | /* Used to clear all duty_value bits */ | |
125 | duty_mask = pr->throttling.state_count - 1; | |
126 | ||
cee324b1 | 127 | duty_mask <<= acpi_gbl_FADT.duty_offset; |
1da177e4 LT |
128 | duty_mask = ~duty_mask; |
129 | } | |
130 | ||
131 | local_irq_disable(); | |
132 | ||
133 | /* | |
134 | * Disable throttling by writing a 0 to bit 4. Note that we must | |
135 | * turn it off before you can change the duty_value. | |
136 | */ | |
137 | value = inl(pr->throttling.address); | |
138 | if (value & 0x10) { | |
139 | value &= 0xFFFFFFEF; | |
140 | outl(value, pr->throttling.address); | |
141 | } | |
142 | ||
143 | /* | |
144 | * Write the new duty_value and then enable throttling. Note | |
145 | * that a state value of 0 leaves throttling disabled. | |
146 | */ | |
147 | if (state) { | |
148 | value &= duty_mask; | |
149 | value |= duty_value; | |
150 | outl(value, pr->throttling.address); | |
151 | ||
152 | value |= 0x00000010; | |
153 | outl(value, pr->throttling.address); | |
154 | } | |
155 | ||
156 | pr->throttling.state = state; | |
157 | ||
158 | local_irq_enable(); | |
159 | ||
160 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, | |
4be44fcd LB |
161 | "Throttling state set to T%d (%d%%)\n", state, |
162 | (pr->throttling.states[state].performance ? pr-> | |
163 | throttling.states[state].performance / 10 : 0))); | |
1da177e4 | 164 | |
d550d98d | 165 | return 0; |
1da177e4 LT |
166 | } |
167 | ||
4be44fcd | 168 | int acpi_processor_get_throttling_info(struct acpi_processor *pr) |
1da177e4 | 169 | { |
4be44fcd LB |
170 | int result = 0; |
171 | int step = 0; | |
172 | int i = 0; | |
1da177e4 | 173 | |
1da177e4 LT |
174 | |
175 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, | |
4be44fcd LB |
176 | "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n", |
177 | pr->throttling.address, | |
178 | pr->throttling.duty_offset, | |
179 | pr->throttling.duty_width)); | |
1da177e4 LT |
180 | |
181 | if (!pr) | |
d550d98d | 182 | return -EINVAL; |
1da177e4 LT |
183 | |
184 | /* TBD: Support ACPI 2.0 objects */ | |
185 | ||
186 | if (!pr->throttling.address) { | |
187 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n")); | |
d550d98d | 188 | return 0; |
4be44fcd | 189 | } else if (!pr->throttling.duty_width) { |
1da177e4 | 190 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n")); |
d550d98d | 191 | return 0; |
1da177e4 LT |
192 | } |
193 | /* TBD: Support duty_cycle values that span bit 4. */ | |
4be44fcd | 194 | else if ((pr->throttling.duty_offset + pr->throttling.duty_width) > 4) { |
cece9296 | 195 | printk(KERN_WARNING PREFIX "duty_cycle spans bit 4\n"); |
d550d98d | 196 | return 0; |
1da177e4 LT |
197 | } |
198 | ||
199 | /* | |
200 | * PIIX4 Errata: We don't support throttling on the original PIIX4. | |
201 | * This shouldn't be an issue as few (if any) mobile systems ever | |
202 | * used this part. | |
203 | */ | |
204 | if (errata.piix4.throttle) { | |
205 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, | |
4be44fcd | 206 | "Throttling not supported on PIIX4 A- or B-step\n")); |
d550d98d | 207 | return 0; |
1da177e4 LT |
208 | } |
209 | ||
cee324b1 | 210 | pr->throttling.state_count = 1 << acpi_gbl_FADT.duty_width; |
1da177e4 LT |
211 | |
212 | /* | |
213 | * Compute state values. Note that throttling displays a linear power/ | |
214 | * performance relationship (at 50% performance the CPU will consume | |
215 | * 50% power). Values are in 1/10th of a percent to preserve accuracy. | |
216 | */ | |
217 | ||
218 | step = (1000 / pr->throttling.state_count); | |
219 | ||
4be44fcd | 220 | for (i = 0; i < pr->throttling.state_count; i++) { |
1da177e4 LT |
221 | pr->throttling.states[i].performance = step * i; |
222 | pr->throttling.states[i].power = step * i; | |
223 | } | |
224 | ||
225 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n", | |
4be44fcd | 226 | pr->throttling.state_count)); |
1da177e4 LT |
227 | |
228 | pr->flags.throttling = 1; | |
229 | ||
230 | /* | |
231 | * Disable throttling (if enabled). We'll let subsequent policy (e.g. | |
232 | * thermal) decide to lower performance if it so chooses, but for now | |
233 | * we'll crank up the speed. | |
234 | */ | |
235 | ||
236 | result = acpi_processor_get_throttling(pr); | |
237 | if (result) | |
238 | goto end; | |
239 | ||
240 | if (pr->throttling.state) { | |
4be44fcd LB |
241 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, |
242 | "Disabling throttling (was T%d)\n", | |
243 | pr->throttling.state)); | |
1da177e4 LT |
244 | result = acpi_processor_set_throttling(pr, 0); |
245 | if (result) | |
246 | goto end; | |
247 | } | |
248 | ||
4be44fcd | 249 | end: |
1da177e4 LT |
250 | if (result) |
251 | pr->flags.throttling = 0; | |
252 | ||
d550d98d | 253 | return result; |
1da177e4 LT |
254 | } |
255 | ||
1da177e4 LT |
256 | /* proc interface */ |
257 | ||
4be44fcd LB |
258 | static int acpi_processor_throttling_seq_show(struct seq_file *seq, |
259 | void *offset) | |
1da177e4 | 260 | { |
50dd0969 | 261 | struct acpi_processor *pr = seq->private; |
4be44fcd LB |
262 | int i = 0; |
263 | int result = 0; | |
1da177e4 | 264 | |
1da177e4 LT |
265 | |
266 | if (!pr) | |
267 | goto end; | |
268 | ||
269 | if (!(pr->throttling.state_count > 0)) { | |
270 | seq_puts(seq, "<not supported>\n"); | |
271 | goto end; | |
272 | } | |
273 | ||
274 | result = acpi_processor_get_throttling(pr); | |
275 | ||
276 | if (result) { | |
4be44fcd LB |
277 | seq_puts(seq, |
278 | "Could not determine current throttling state.\n"); | |
1da177e4 LT |
279 | goto end; |
280 | } | |
281 | ||
282 | seq_printf(seq, "state count: %d\n" | |
4be44fcd LB |
283 | "active state: T%d\n", |
284 | pr->throttling.state_count, pr->throttling.state); | |
1da177e4 LT |
285 | |
286 | seq_puts(seq, "states:\n"); | |
287 | for (i = 0; i < pr->throttling.state_count; i++) | |
288 | seq_printf(seq, " %cT%d: %02d%%\n", | |
4be44fcd LB |
289 | (i == pr->throttling.state ? '*' : ' '), i, |
290 | (pr->throttling.states[i].performance ? pr-> | |
291 | throttling.states[i].performance / 10 : 0)); | |
1da177e4 | 292 | |
4be44fcd | 293 | end: |
d550d98d | 294 | return 0; |
1da177e4 LT |
295 | } |
296 | ||
4be44fcd LB |
297 | static int acpi_processor_throttling_open_fs(struct inode *inode, |
298 | struct file *file) | |
1da177e4 LT |
299 | { |
300 | return single_open(file, acpi_processor_throttling_seq_show, | |
4be44fcd | 301 | PDE(inode)->data); |
1da177e4 LT |
302 | } |
303 | ||
757b1866 AB |
304 | static ssize_t acpi_processor_write_throttling(struct file * file, |
305 | const char __user * buffer, | |
306 | size_t count, loff_t * data) | |
1da177e4 | 307 | { |
4be44fcd | 308 | int result = 0; |
50dd0969 JE |
309 | struct seq_file *m = file->private_data; |
310 | struct acpi_processor *pr = m->private; | |
4be44fcd | 311 | char state_string[12] = { '\0' }; |
1da177e4 | 312 | |
1da177e4 LT |
313 | |
314 | if (!pr || (count > sizeof(state_string) - 1)) | |
d550d98d | 315 | return -EINVAL; |
1da177e4 LT |
316 | |
317 | if (copy_from_user(state_string, buffer, count)) | |
d550d98d | 318 | return -EFAULT; |
1da177e4 LT |
319 | |
320 | state_string[count] = '\0'; | |
321 | ||
322 | result = acpi_processor_set_throttling(pr, | |
4be44fcd LB |
323 | simple_strtoul(state_string, |
324 | NULL, 0)); | |
1da177e4 | 325 | if (result) |
d550d98d | 326 | return result; |
1da177e4 | 327 | |
d550d98d | 328 | return count; |
1da177e4 LT |
329 | } |
330 | ||
331 | struct file_operations acpi_processor_throttling_fops = { | |
4be44fcd LB |
332 | .open = acpi_processor_throttling_open_fs, |
333 | .read = seq_read, | |
d479e908 | 334 | .write = acpi_processor_write_throttling, |
4be44fcd LB |
335 | .llseek = seq_lseek, |
336 | .release = single_release, | |
1da177e4 | 337 | }; |