1 /* 2 * processor_thermal.c - Passive cooling 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/uaccess.h> 37 38 #include <acpi/acpi_bus.h> 39 #include <acpi/processor.h> 40 #include <acpi/acpi_drivers.h> 41 42 #define ACPI_PROCESSOR_COMPONENT 0x01000000 43 #define ACPI_PROCESSOR_CLASS "processor" 44 #define ACPI_PROCESSOR_DRIVER_NAME "ACPI Processor Driver" 45 #define _COMPONENT ACPI_PROCESSOR_COMPONENT 46 ACPI_MODULE_NAME("acpi_processor") 47 48 /* -------------------------------------------------------------------------- 49 Limit Interface 50 -------------------------------------------------------------------------- */ 51 static int acpi_processor_apply_limit(struct acpi_processor *pr) 52 { 53 int result = 0; 54 u16 px = 0; 55 u16 tx = 0; 56 57 58 if (!pr) 59 return -EINVAL; 60 61 if (!pr->flags.limit) 62 return -ENODEV; 63 64 if (pr->flags.throttling) { 65 if (pr->limit.user.tx > tx) 66 tx = pr->limit.user.tx; 67 if (pr->limit.thermal.tx > tx) 68 tx = pr->limit.thermal.tx; 69 70 result = acpi_processor_set_throttling(pr, tx); 71 if (result) 72 goto end; 73 } 74 75 pr->limit.state.px = px; 76 pr->limit.state.tx = tx; 77 78 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 79 "Processor [%d] limit set to (P%d:T%d)\n", pr->id, 80 pr->limit.state.px, pr->limit.state.tx)); 81 82 end: 83 if (result) 84 printk(KERN_ERR PREFIX "Unable to set limit\n"); 85 86 return result; 87 } 88 89 #ifdef CONFIG_CPU_FREQ 90 91 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it 92 * offers (in most cases) voltage scaling in addition to frequency scaling, and 93 * thus a cubic (instead of linear) reduction of energy. Also, we allow for 94 * _any_ cpufreq driver and not only the acpi-cpufreq driver. 95 */ 96 97 static unsigned int cpufreq_thermal_reduction_pctg[NR_CPUS]; 98 static unsigned int acpi_thermal_cpufreq_is_init = 0; 99 100 static int cpu_has_cpufreq(unsigned int cpu) 101 { 102 struct cpufreq_policy policy; 103 if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu)) 104 return 0; 105 return 1; 106 } 107 108 static int acpi_thermal_cpufreq_increase(unsigned int cpu) 109 { 110 if (!cpu_has_cpufreq(cpu)) 111 return -ENODEV; 112 113 if (cpufreq_thermal_reduction_pctg[cpu] < 60) { 114 cpufreq_thermal_reduction_pctg[cpu] += 20; 115 cpufreq_update_policy(cpu); 116 return 0; 117 } 118 119 return -ERANGE; 120 } 121 122 static int acpi_thermal_cpufreq_decrease(unsigned int cpu) 123 { 124 if (!cpu_has_cpufreq(cpu)) 125 return -ENODEV; 126 127 if (cpufreq_thermal_reduction_pctg[cpu] > 20) 128 cpufreq_thermal_reduction_pctg[cpu] -= 20; 129 else 130 cpufreq_thermal_reduction_pctg[cpu] = 0; 131 cpufreq_update_policy(cpu); 132 /* We reached max freq again and can leave passive mode */ 133 return !cpufreq_thermal_reduction_pctg[cpu]; 134 } 135 136 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb, 137 unsigned long event, void *data) 138 { 139 struct cpufreq_policy *policy = data; 140 unsigned long max_freq = 0; 141 142 if (event != CPUFREQ_ADJUST) 143 goto out; 144 145 max_freq = 146 (policy->cpuinfo.max_freq * 147 (100 - cpufreq_thermal_reduction_pctg[policy->cpu])) / 100; 148 149 cpufreq_verify_within_limits(policy, 0, max_freq); 150 151 out: 152 return 0; 153 } 154 155 static struct notifier_block acpi_thermal_cpufreq_notifier_block = { 156 .notifier_call = acpi_thermal_cpufreq_notifier, 157 }; 158 159 void acpi_thermal_cpufreq_init(void) 160 { 161 int i; 162 163 for (i = 0; i < NR_CPUS; i++) 164 cpufreq_thermal_reduction_pctg[i] = 0; 165 166 i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block, 167 CPUFREQ_POLICY_NOTIFIER); 168 if (!i) 169 acpi_thermal_cpufreq_is_init = 1; 170 } 171 172 void acpi_thermal_cpufreq_exit(void) 173 { 174 if (acpi_thermal_cpufreq_is_init) 175 cpufreq_unregister_notifier 176 (&acpi_thermal_cpufreq_notifier_block, 177 CPUFREQ_POLICY_NOTIFIER); 178 179 acpi_thermal_cpufreq_is_init = 0; 180 } 181 182 #else /* ! CONFIG_CPU_FREQ */ 183 184 static int acpi_thermal_cpufreq_increase(unsigned int cpu) 185 { 186 return -ENODEV; 187 } 188 static int acpi_thermal_cpufreq_decrease(unsigned int cpu) 189 { 190 return -ENODEV; 191 } 192 193 #endif 194 195 int acpi_processor_set_thermal_limit(acpi_handle handle, int type) 196 { 197 int result = 0; 198 struct acpi_processor *pr = NULL; 199 struct acpi_device *device = NULL; 200 int tx = 0, max_tx_px = 0; 201 202 203 if ((type < ACPI_PROCESSOR_LIMIT_NONE) 204 || (type > ACPI_PROCESSOR_LIMIT_DECREMENT)) 205 return -EINVAL; 206 207 result = acpi_bus_get_device(handle, &device); 208 if (result) 209 return result; 210 211 pr = acpi_driver_data(device); 212 if (!pr) 213 return -ENODEV; 214 215 /* Thermal limits are always relative to the current Px/Tx state. */ 216 if (pr->flags.throttling) 217 pr->limit.thermal.tx = pr->throttling.state; 218 219 /* 220 * Our default policy is to only use throttling at the lowest 221 * performance state. 222 */ 223 224 tx = pr->limit.thermal.tx; 225 226 switch (type) { 227 228 case ACPI_PROCESSOR_LIMIT_NONE: 229 do { 230 result = acpi_thermal_cpufreq_decrease(pr->id); 231 } while (!result); 232 tx = 0; 233 break; 234 235 case ACPI_PROCESSOR_LIMIT_INCREMENT: 236 /* if going up: P-states first, T-states later */ 237 238 result = acpi_thermal_cpufreq_increase(pr->id); 239 if (!result) 240 goto end; 241 else if (result == -ERANGE) 242 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 243 "At maximum performance state\n")); 244 245 if (pr->flags.throttling) { 246 if (tx == (pr->throttling.state_count - 1)) 247 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 248 "At maximum throttling state\n")); 249 else 250 tx++; 251 } 252 break; 253 254 case ACPI_PROCESSOR_LIMIT_DECREMENT: 255 /* if going down: T-states first, P-states later */ 256 257 if (pr->flags.throttling) { 258 if (tx == 0) { 259 max_tx_px = 1; 260 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 261 "At minimum throttling state\n")); 262 } else { 263 tx--; 264 goto end; 265 } 266 } 267 268 result = acpi_thermal_cpufreq_decrease(pr->id); 269 if (result) { 270 /* 271 * We only could get -ERANGE, 1 or 0. 272 * In the first two cases we reached max freq again. 273 */ 274 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 275 "At minimum performance state\n")); 276 max_tx_px = 1; 277 } else 278 max_tx_px = 0; 279 280 break; 281 } 282 283 end: 284 if (pr->flags.throttling) { 285 pr->limit.thermal.px = 0; 286 pr->limit.thermal.tx = tx; 287 288 result = acpi_processor_apply_limit(pr); 289 if (result) 290 printk(KERN_ERR PREFIX "Unable to set thermal limit\n"); 291 292 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n", 293 pr->limit.thermal.px, pr->limit.thermal.tx)); 294 } else 295 result = 0; 296 if (max_tx_px) 297 return 1; 298 else 299 return result; 300 } 301 302 int acpi_processor_get_limit_info(struct acpi_processor *pr) 303 { 304 305 if (!pr) 306 return -EINVAL; 307 308 if (pr->flags.throttling) 309 pr->flags.limit = 1; 310 311 return 0; 312 } 313 314 /* /proc interface */ 315 316 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset) 317 { 318 struct acpi_processor *pr = (struct acpi_processor *)seq->private; 319 320 321 if (!pr) 322 goto end; 323 324 if (!pr->flags.limit) { 325 seq_puts(seq, "<not supported>\n"); 326 goto end; 327 } 328 329 seq_printf(seq, "active limit: P%d:T%d\n" 330 "user limit: P%d:T%d\n" 331 "thermal limit: P%d:T%d\n", 332 pr->limit.state.px, pr->limit.state.tx, 333 pr->limit.user.px, pr->limit.user.tx, 334 pr->limit.thermal.px, pr->limit.thermal.tx); 335 336 end: 337 return 0; 338 } 339 340 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file) 341 { 342 return single_open(file, acpi_processor_limit_seq_show, 343 PDE(inode)->data); 344 } 345 346 static ssize_t acpi_processor_write_limit(struct file * file, 347 const char __user * buffer, 348 size_t count, loff_t * data) 349 { 350 int result = 0; 351 struct seq_file *m = file->private_data; 352 struct acpi_processor *pr = m->private; 353 char limit_string[25] = { '\0' }; 354 int px = 0; 355 int tx = 0; 356 357 358 if (!pr || (count > sizeof(limit_string) - 1)) { 359 return -EINVAL; 360 } 361 362 if (copy_from_user(limit_string, buffer, count)) { 363 return -EFAULT; 364 } 365 366 limit_string[count] = '\0'; 367 368 if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) { 369 printk(KERN_ERR PREFIX "Invalid data format\n"); 370 return -EINVAL; 371 } 372 373 if (pr->flags.throttling) { 374 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) { 375 printk(KERN_ERR PREFIX "Invalid tx\n"); 376 return -EINVAL; 377 } 378 pr->limit.user.tx = tx; 379 } 380 381 result = acpi_processor_apply_limit(pr); 382 383 return count; 384 } 385 386 struct file_operations acpi_processor_limit_fops = { 387 .open = acpi_processor_limit_open_fs, 388 .read = seq_read, 389 .write = acpi_processor_write_limit, 390 .llseek = seq_lseek, 391 .release = single_release, 392 }; 393