Dave Jones | b917083 | 2005-05-31 19:03:47 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * drivers/cpufreq/cpufreq_conservative.c |
| 3 | * |
| 4 | * Copyright (C) 2001 Russell King |
| 5 | * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>. |
| 6 | * Jun Nakajima <jun.nakajima@intel.com> |
| 7 | * (C) 2004 Alexander Clouter <alex-kernel@digriz.org.uk> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 as |
| 11 | * published by the Free Software Foundation. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/smp.h> |
| 17 | #include <linux/init.h> |
| 18 | #include <linux/interrupt.h> |
| 19 | #include <linux/ctype.h> |
| 20 | #include <linux/cpufreq.h> |
| 21 | #include <linux/sysctl.h> |
| 22 | #include <linux/types.h> |
| 23 | #include <linux/fs.h> |
| 24 | #include <linux/sysfs.h> |
| 25 | #include <linux/sched.h> |
| 26 | #include <linux/kmod.h> |
| 27 | #include <linux/workqueue.h> |
| 28 | #include <linux/jiffies.h> |
| 29 | #include <linux/kernel_stat.h> |
| 30 | #include <linux/percpu.h> |
| 31 | |
| 32 | /* |
| 33 | * dbs is used in this file as a shortform for demandbased switching |
| 34 | * It helps to keep variable names smaller, simpler |
| 35 | */ |
| 36 | |
| 37 | #define DEF_FREQUENCY_UP_THRESHOLD (80) |
| 38 | #define MIN_FREQUENCY_UP_THRESHOLD (0) |
| 39 | #define MAX_FREQUENCY_UP_THRESHOLD (100) |
| 40 | |
| 41 | #define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
| 42 | #define MIN_FREQUENCY_DOWN_THRESHOLD (0) |
| 43 | #define MAX_FREQUENCY_DOWN_THRESHOLD (100) |
| 44 | |
| 45 | /* |
| 46 | * The polling frequency of this governor depends on the capability of |
| 47 | * the processor. Default polling frequency is 1000 times the transition |
| 48 | * latency of the processor. The governor will work on any processor with |
| 49 | * transition latency <= 10mS, using appropriate sampling |
| 50 | * rate. |
| 51 | * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) |
| 52 | * this governor will not work. |
| 53 | * All times here are in uS. |
| 54 | */ |
| 55 | static unsigned int def_sampling_rate; |
| 56 | #define MIN_SAMPLING_RATE (def_sampling_rate / 2) |
| 57 | #define MAX_SAMPLING_RATE (500 * def_sampling_rate) |
| 58 | #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (100000) |
| 59 | #define DEF_SAMPLING_DOWN_FACTOR (5) |
| 60 | #define TRANSITION_LATENCY_LIMIT (10 * 1000) |
| 61 | |
| 62 | static void do_dbs_timer(void *data); |
| 63 | |
| 64 | struct cpu_dbs_info_s { |
| 65 | struct cpufreq_policy *cur_policy; |
| 66 | unsigned int prev_cpu_idle_up; |
| 67 | unsigned int prev_cpu_idle_down; |
| 68 | unsigned int enable; |
| 69 | }; |
| 70 | static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); |
| 71 | |
| 72 | static unsigned int dbs_enable; /* number of CPUs using this policy */ |
| 73 | |
| 74 | static DECLARE_MUTEX (dbs_sem); |
| 75 | static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); |
| 76 | |
| 77 | struct dbs_tuners { |
| 78 | unsigned int sampling_rate; |
| 79 | unsigned int sampling_down_factor; |
| 80 | unsigned int up_threshold; |
| 81 | unsigned int down_threshold; |
| 82 | unsigned int ignore_nice; |
| 83 | unsigned int freq_step; |
| 84 | }; |
| 85 | |
| 86 | static struct dbs_tuners dbs_tuners_ins = { |
| 87 | .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, |
| 88 | .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD, |
| 89 | .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, |
| 90 | }; |
| 91 | |
| 92 | /************************** sysfs interface ************************/ |
| 93 | static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf) |
| 94 | { |
| 95 | return sprintf (buf, "%u\n", MAX_SAMPLING_RATE); |
| 96 | } |
| 97 | |
| 98 | static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf) |
| 99 | { |
| 100 | return sprintf (buf, "%u\n", MIN_SAMPLING_RATE); |
| 101 | } |
| 102 | |
| 103 | #define define_one_ro(_name) \ |
| 104 | static struct freq_attr _name = \ |
| 105 | __ATTR(_name, 0444, show_##_name, NULL) |
| 106 | |
| 107 | define_one_ro(sampling_rate_max); |
| 108 | define_one_ro(sampling_rate_min); |
| 109 | |
| 110 | /* cpufreq_conservative Governor Tunables */ |
| 111 | #define show_one(file_name, object) \ |
| 112 | static ssize_t show_##file_name \ |
| 113 | (struct cpufreq_policy *unused, char *buf) \ |
| 114 | { \ |
| 115 | return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ |
| 116 | } |
| 117 | show_one(sampling_rate, sampling_rate); |
| 118 | show_one(sampling_down_factor, sampling_down_factor); |
| 119 | show_one(up_threshold, up_threshold); |
| 120 | show_one(down_threshold, down_threshold); |
| 121 | show_one(ignore_nice, ignore_nice); |
| 122 | show_one(freq_step, freq_step); |
| 123 | |
| 124 | static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, |
| 125 | const char *buf, size_t count) |
| 126 | { |
| 127 | unsigned int input; |
| 128 | int ret; |
| 129 | ret = sscanf (buf, "%u", &input); |
| 130 | if (ret != 1 ) |
| 131 | return -EINVAL; |
| 132 | |
| 133 | down(&dbs_sem); |
| 134 | dbs_tuners_ins.sampling_down_factor = input; |
| 135 | up(&dbs_sem); |
| 136 | |
| 137 | return count; |
| 138 | } |
| 139 | |
| 140 | static ssize_t store_sampling_rate(struct cpufreq_policy *unused, |
| 141 | const char *buf, size_t count) |
| 142 | { |
| 143 | unsigned int input; |
| 144 | int ret; |
| 145 | ret = sscanf (buf, "%u", &input); |
| 146 | |
| 147 | down(&dbs_sem); |
| 148 | if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) { |
| 149 | up(&dbs_sem); |
| 150 | return -EINVAL; |
| 151 | } |
| 152 | |
| 153 | dbs_tuners_ins.sampling_rate = input; |
| 154 | up(&dbs_sem); |
| 155 | |
| 156 | return count; |
| 157 | } |
| 158 | |
| 159 | static ssize_t store_up_threshold(struct cpufreq_policy *unused, |
| 160 | const char *buf, size_t count) |
| 161 | { |
| 162 | unsigned int input; |
| 163 | int ret; |
| 164 | ret = sscanf (buf, "%u", &input); |
| 165 | |
| 166 | down(&dbs_sem); |
| 167 | if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || |
| 168 | input < MIN_FREQUENCY_UP_THRESHOLD || |
| 169 | input <= dbs_tuners_ins.down_threshold) { |
| 170 | up(&dbs_sem); |
| 171 | return -EINVAL; |
| 172 | } |
| 173 | |
| 174 | dbs_tuners_ins.up_threshold = input; |
| 175 | up(&dbs_sem); |
| 176 | |
| 177 | return count; |
| 178 | } |
| 179 | |
| 180 | static ssize_t store_down_threshold(struct cpufreq_policy *unused, |
| 181 | const char *buf, size_t count) |
| 182 | { |
| 183 | unsigned int input; |
| 184 | int ret; |
| 185 | ret = sscanf (buf, "%u", &input); |
| 186 | |
| 187 | down(&dbs_sem); |
| 188 | if (ret != 1 || input > MAX_FREQUENCY_DOWN_THRESHOLD || |
| 189 | input < MIN_FREQUENCY_DOWN_THRESHOLD || |
| 190 | input >= dbs_tuners_ins.up_threshold) { |
| 191 | up(&dbs_sem); |
| 192 | return -EINVAL; |
| 193 | } |
| 194 | |
| 195 | dbs_tuners_ins.down_threshold = input; |
| 196 | up(&dbs_sem); |
| 197 | |
| 198 | return count; |
| 199 | } |
| 200 | |
| 201 | static ssize_t store_ignore_nice(struct cpufreq_policy *policy, |
| 202 | const char *buf, size_t count) |
| 203 | { |
| 204 | unsigned int input; |
| 205 | int ret; |
| 206 | |
| 207 | unsigned int j; |
| 208 | |
| 209 | ret = sscanf (buf, "%u", &input); |
| 210 | if ( ret != 1 ) |
| 211 | return -EINVAL; |
| 212 | |
| 213 | if ( input > 1 ) |
| 214 | input = 1; |
| 215 | |
| 216 | down(&dbs_sem); |
| 217 | if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */ |
| 218 | up(&dbs_sem); |
| 219 | return count; |
| 220 | } |
| 221 | dbs_tuners_ins.ignore_nice = input; |
| 222 | |
| 223 | /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */ |
| 224 | for_each_cpu_mask(j, policy->cpus) { |
| 225 | struct cpu_dbs_info_s *j_dbs_info; |
| 226 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 227 | j_dbs_info->cur_policy = policy; |
| 228 | |
| 229 | j_dbs_info->prev_cpu_idle_up = |
| 230 | kstat_cpu(j).cpustat.idle + |
| 231 | kstat_cpu(j).cpustat.iowait + |
| 232 | ( !dbs_tuners_ins.ignore_nice |
| 233 | ? kstat_cpu(j).cpustat.nice : 0 ); |
| 234 | j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up; |
| 235 | } |
| 236 | up(&dbs_sem); |
| 237 | |
| 238 | return count; |
| 239 | } |
| 240 | |
| 241 | static ssize_t store_freq_step(struct cpufreq_policy *policy, |
| 242 | const char *buf, size_t count) |
| 243 | { |
| 244 | unsigned int input; |
| 245 | int ret; |
| 246 | |
| 247 | ret = sscanf (buf, "%u", &input); |
| 248 | |
| 249 | if ( ret != 1 ) |
| 250 | return -EINVAL; |
| 251 | |
| 252 | if ( input > 100 ) |
| 253 | input = 100; |
| 254 | |
| 255 | /* no need to test here if freq_step is zero as the user might actually |
| 256 | * want this, they would be crazy though :) */ |
| 257 | down(&dbs_sem); |
| 258 | dbs_tuners_ins.freq_step = input; |
| 259 | up(&dbs_sem); |
| 260 | |
| 261 | return count; |
| 262 | } |
| 263 | |
| 264 | #define define_one_rw(_name) \ |
| 265 | static struct freq_attr _name = \ |
| 266 | __ATTR(_name, 0644, show_##_name, store_##_name) |
| 267 | |
| 268 | define_one_rw(sampling_rate); |
| 269 | define_one_rw(sampling_down_factor); |
| 270 | define_one_rw(up_threshold); |
| 271 | define_one_rw(down_threshold); |
| 272 | define_one_rw(ignore_nice); |
| 273 | define_one_rw(freq_step); |
| 274 | |
| 275 | static struct attribute * dbs_attributes[] = { |
| 276 | &sampling_rate_max.attr, |
| 277 | &sampling_rate_min.attr, |
| 278 | &sampling_rate.attr, |
| 279 | &sampling_down_factor.attr, |
| 280 | &up_threshold.attr, |
| 281 | &down_threshold.attr, |
| 282 | &ignore_nice.attr, |
| 283 | &freq_step.attr, |
| 284 | NULL |
| 285 | }; |
| 286 | |
| 287 | static struct attribute_group dbs_attr_group = { |
| 288 | .attrs = dbs_attributes, |
| 289 | .name = "conservative", |
| 290 | }; |
| 291 | |
| 292 | /************************** sysfs end ************************/ |
| 293 | |
| 294 | static void dbs_check_cpu(int cpu) |
| 295 | { |
| 296 | unsigned int idle_ticks, up_idle_ticks, down_idle_ticks; |
| 297 | unsigned int total_idle_ticks; |
| 298 | unsigned int freq_step; |
| 299 | unsigned int freq_down_sampling_rate; |
| 300 | static int down_skip[NR_CPUS]; |
| 301 | static int requested_freq[NR_CPUS]; |
| 302 | static unsigned short init_flag = 0; |
| 303 | struct cpu_dbs_info_s *this_dbs_info; |
| 304 | struct cpu_dbs_info_s *dbs_info; |
| 305 | |
| 306 | struct cpufreq_policy *policy; |
| 307 | unsigned int j; |
| 308 | |
| 309 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| 310 | if (!this_dbs_info->enable) |
| 311 | return; |
| 312 | |
| 313 | policy = this_dbs_info->cur_policy; |
| 314 | |
| 315 | if ( init_flag == 0 ) { |
| 316 | for ( /* NULL */; init_flag < NR_CPUS; init_flag++ ) { |
| 317 | dbs_info = &per_cpu(cpu_dbs_info, init_flag); |
| 318 | requested_freq[cpu] = dbs_info->cur_policy->cur; |
| 319 | } |
| 320 | init_flag = 1; |
| 321 | } |
| 322 | |
| 323 | /* |
| 324 | * The default safe range is 20% to 80% |
| 325 | * Every sampling_rate, we check |
| 326 | * - If current idle time is less than 20%, then we try to |
| 327 | * increase frequency |
| 328 | * Every sampling_rate*sampling_down_factor, we check |
| 329 | * - If current idle time is more than 80%, then we try to |
| 330 | * decrease frequency |
| 331 | * |
| 332 | * Any frequency increase takes it to the maximum frequency. |
| 333 | * Frequency reduction happens at minimum steps of |
| 334 | * 5% (default) of max_frequency |
| 335 | */ |
| 336 | |
| 337 | /* Check for frequency increase */ |
| 338 | total_idle_ticks = kstat_cpu(cpu).cpustat.idle + |
| 339 | kstat_cpu(cpu).cpustat.iowait; |
| 340 | /* consider 'nice' tasks as 'idle' time too if required */ |
| 341 | if (dbs_tuners_ins.ignore_nice == 0) |
| 342 | total_idle_ticks += kstat_cpu(cpu).cpustat.nice; |
| 343 | idle_ticks = total_idle_ticks - |
| 344 | this_dbs_info->prev_cpu_idle_up; |
| 345 | this_dbs_info->prev_cpu_idle_up = total_idle_ticks; |
| 346 | |
| 347 | |
| 348 | for_each_cpu_mask(j, policy->cpus) { |
| 349 | unsigned int tmp_idle_ticks; |
| 350 | struct cpu_dbs_info_s *j_dbs_info; |
| 351 | |
| 352 | if (j == cpu) |
| 353 | continue; |
| 354 | |
| 355 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 356 | /* Check for frequency increase */ |
| 357 | total_idle_ticks = kstat_cpu(j).cpustat.idle + |
| 358 | kstat_cpu(j).cpustat.iowait; |
| 359 | /* consider 'nice' too? */ |
| 360 | if (dbs_tuners_ins.ignore_nice == 0) |
| 361 | total_idle_ticks += kstat_cpu(j).cpustat.nice; |
| 362 | tmp_idle_ticks = total_idle_ticks - |
| 363 | j_dbs_info->prev_cpu_idle_up; |
| 364 | j_dbs_info->prev_cpu_idle_up = total_idle_ticks; |
| 365 | |
| 366 | if (tmp_idle_ticks < idle_ticks) |
| 367 | idle_ticks = tmp_idle_ticks; |
| 368 | } |
| 369 | |
| 370 | /* Scale idle ticks by 100 and compare with up and down ticks */ |
| 371 | idle_ticks *= 100; |
| 372 | up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) * |
| 373 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate); |
| 374 | |
| 375 | if (idle_ticks < up_idle_ticks) { |
| 376 | /* if we are already at full speed then break out early */ |
| 377 | if (requested_freq[cpu] == policy->max) |
| 378 | return; |
| 379 | |
| 380 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; |
| 381 | |
| 382 | /* max freq cannot be less than 100. But who knows.... */ |
| 383 | if (unlikely(freq_step == 0)) |
| 384 | freq_step = 5; |
| 385 | |
| 386 | requested_freq[cpu] += freq_step; |
| 387 | if (requested_freq[cpu] > policy->max) |
| 388 | requested_freq[cpu] = policy->max; |
| 389 | |
| 390 | __cpufreq_driver_target(policy, requested_freq[cpu], |
| 391 | CPUFREQ_RELATION_H); |
| 392 | down_skip[cpu] = 0; |
| 393 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; |
| 394 | return; |
| 395 | } |
| 396 | |
| 397 | /* Check for frequency decrease */ |
| 398 | down_skip[cpu]++; |
| 399 | if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor) |
| 400 | return; |
| 401 | |
| 402 | total_idle_ticks = kstat_cpu(cpu).cpustat.idle + |
| 403 | kstat_cpu(cpu).cpustat.iowait; |
| 404 | /* consider 'nice' too? */ |
| 405 | if (dbs_tuners_ins.ignore_nice == 0) |
| 406 | total_idle_ticks += kstat_cpu(cpu).cpustat.nice; |
| 407 | idle_ticks = total_idle_ticks - |
| 408 | this_dbs_info->prev_cpu_idle_down; |
| 409 | this_dbs_info->prev_cpu_idle_down = total_idle_ticks; |
| 410 | |
| 411 | for_each_cpu_mask(j, policy->cpus) { |
| 412 | unsigned int tmp_idle_ticks; |
| 413 | struct cpu_dbs_info_s *j_dbs_info; |
| 414 | |
| 415 | if (j == cpu) |
| 416 | continue; |
| 417 | |
| 418 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 419 | /* Check for frequency increase */ |
| 420 | total_idle_ticks = kstat_cpu(j).cpustat.idle + |
| 421 | kstat_cpu(j).cpustat.iowait; |
| 422 | /* consider 'nice' too? */ |
| 423 | if (dbs_tuners_ins.ignore_nice == 0) |
| 424 | total_idle_ticks += kstat_cpu(j).cpustat.nice; |
| 425 | tmp_idle_ticks = total_idle_ticks - |
| 426 | j_dbs_info->prev_cpu_idle_down; |
| 427 | j_dbs_info->prev_cpu_idle_down = total_idle_ticks; |
| 428 | |
| 429 | if (tmp_idle_ticks < idle_ticks) |
| 430 | idle_ticks = tmp_idle_ticks; |
| 431 | } |
| 432 | |
| 433 | /* Scale idle ticks by 100 and compare with up and down ticks */ |
| 434 | idle_ticks *= 100; |
| 435 | down_skip[cpu] = 0; |
| 436 | |
| 437 | freq_down_sampling_rate = dbs_tuners_ins.sampling_rate * |
| 438 | dbs_tuners_ins.sampling_down_factor; |
| 439 | down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) * |
| 440 | usecs_to_jiffies(freq_down_sampling_rate); |
| 441 | |
| 442 | if (idle_ticks > down_idle_ticks ) { |
| 443 | /* if we are already at the lowest speed then break out early |
| 444 | * or if we 'cannot' reduce the speed as the user might want |
| 445 | * freq_step to be zero */ |
| 446 | if (requested_freq[cpu] == policy->min |
| 447 | || dbs_tuners_ins.freq_step == 0) |
| 448 | return; |
| 449 | |
| 450 | freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100; |
| 451 | |
| 452 | /* max freq cannot be less than 100. But who knows.... */ |
| 453 | if (unlikely(freq_step == 0)) |
| 454 | freq_step = 5; |
| 455 | |
| 456 | requested_freq[cpu] -= freq_step; |
| 457 | if (requested_freq[cpu] < policy->min) |
| 458 | requested_freq[cpu] = policy->min; |
| 459 | |
| 460 | __cpufreq_driver_target(policy, |
| 461 | requested_freq[cpu], |
| 462 | CPUFREQ_RELATION_H); |
| 463 | return; |
| 464 | } |
| 465 | } |
| 466 | |
| 467 | static void do_dbs_timer(void *data) |
| 468 | { |
| 469 | int i; |
| 470 | down(&dbs_sem); |
| 471 | for_each_online_cpu(i) |
| 472 | dbs_check_cpu(i); |
| 473 | schedule_delayed_work(&dbs_work, |
| 474 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
| 475 | up(&dbs_sem); |
| 476 | } |
| 477 | |
| 478 | static inline void dbs_timer_init(void) |
| 479 | { |
| 480 | INIT_WORK(&dbs_work, do_dbs_timer, NULL); |
| 481 | schedule_delayed_work(&dbs_work, |
| 482 | usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); |
| 483 | return; |
| 484 | } |
| 485 | |
| 486 | static inline void dbs_timer_exit(void) |
| 487 | { |
| 488 | cancel_delayed_work(&dbs_work); |
| 489 | return; |
| 490 | } |
| 491 | |
| 492 | static int cpufreq_governor_dbs(struct cpufreq_policy *policy, |
| 493 | unsigned int event) |
| 494 | { |
| 495 | unsigned int cpu = policy->cpu; |
| 496 | struct cpu_dbs_info_s *this_dbs_info; |
| 497 | unsigned int j; |
| 498 | |
| 499 | this_dbs_info = &per_cpu(cpu_dbs_info, cpu); |
| 500 | |
| 501 | switch (event) { |
| 502 | case CPUFREQ_GOV_START: |
| 503 | if ((!cpu_online(cpu)) || |
| 504 | (!policy->cur)) |
| 505 | return -EINVAL; |
| 506 | |
| 507 | if (policy->cpuinfo.transition_latency > |
| 508 | (TRANSITION_LATENCY_LIMIT * 1000)) |
| 509 | return -EINVAL; |
| 510 | if (this_dbs_info->enable) /* Already enabled */ |
| 511 | break; |
| 512 | |
| 513 | down(&dbs_sem); |
| 514 | for_each_cpu_mask(j, policy->cpus) { |
| 515 | struct cpu_dbs_info_s *j_dbs_info; |
| 516 | j_dbs_info = &per_cpu(cpu_dbs_info, j); |
| 517 | j_dbs_info->cur_policy = policy; |
| 518 | |
| 519 | j_dbs_info->prev_cpu_idle_up = |
| 520 | kstat_cpu(j).cpustat.idle + |
| 521 | kstat_cpu(j).cpustat.iowait + |
| 522 | ( !dbs_tuners_ins.ignore_nice |
| 523 | ? kstat_cpu(j).cpustat.nice : 0 ); |
| 524 | j_dbs_info->prev_cpu_idle_down |
| 525 | = j_dbs_info->prev_cpu_idle_up; |
| 526 | } |
| 527 | this_dbs_info->enable = 1; |
| 528 | sysfs_create_group(&policy->kobj, &dbs_attr_group); |
| 529 | dbs_enable++; |
| 530 | /* |
| 531 | * Start the timerschedule work, when this governor |
| 532 | * is used for first time |
| 533 | */ |
| 534 | if (dbs_enable == 1) { |
| 535 | unsigned int latency; |
| 536 | /* policy latency is in nS. Convert it to uS first */ |
| 537 | |
| 538 | latency = policy->cpuinfo.transition_latency; |
| 539 | if (latency < 1000) |
| 540 | latency = 1000; |
| 541 | |
| 542 | def_sampling_rate = (latency / 1000) * |
| 543 | DEF_SAMPLING_RATE_LATENCY_MULTIPLIER; |
| 544 | dbs_tuners_ins.sampling_rate = def_sampling_rate; |
| 545 | dbs_tuners_ins.ignore_nice = 0; |
| 546 | dbs_tuners_ins.freq_step = 5; |
| 547 | |
| 548 | dbs_timer_init(); |
| 549 | } |
| 550 | |
| 551 | up(&dbs_sem); |
| 552 | break; |
| 553 | |
| 554 | case CPUFREQ_GOV_STOP: |
| 555 | down(&dbs_sem); |
| 556 | this_dbs_info->enable = 0; |
| 557 | sysfs_remove_group(&policy->kobj, &dbs_attr_group); |
| 558 | dbs_enable--; |
| 559 | /* |
| 560 | * Stop the timerschedule work, when this governor |
| 561 | * is used for first time |
| 562 | */ |
| 563 | if (dbs_enable == 0) |
| 564 | dbs_timer_exit(); |
| 565 | |
| 566 | up(&dbs_sem); |
| 567 | |
| 568 | break; |
| 569 | |
| 570 | case CPUFREQ_GOV_LIMITS: |
| 571 | down(&dbs_sem); |
| 572 | if (policy->max < this_dbs_info->cur_policy->cur) |
| 573 | __cpufreq_driver_target( |
| 574 | this_dbs_info->cur_policy, |
| 575 | policy->max, CPUFREQ_RELATION_H); |
| 576 | else if (policy->min > this_dbs_info->cur_policy->cur) |
| 577 | __cpufreq_driver_target( |
| 578 | this_dbs_info->cur_policy, |
| 579 | policy->min, CPUFREQ_RELATION_L); |
| 580 | up(&dbs_sem); |
| 581 | break; |
| 582 | } |
| 583 | return 0; |
| 584 | } |
| 585 | |
| 586 | static struct cpufreq_governor cpufreq_gov_dbs = { |
| 587 | .name = "conservative", |
| 588 | .governor = cpufreq_governor_dbs, |
| 589 | .owner = THIS_MODULE, |
| 590 | }; |
| 591 | |
| 592 | static int __init cpufreq_gov_dbs_init(void) |
| 593 | { |
| 594 | return cpufreq_register_governor(&cpufreq_gov_dbs); |
| 595 | } |
| 596 | |
| 597 | static void __exit cpufreq_gov_dbs_exit(void) |
| 598 | { |
| 599 | /* Make sure that the scheduled work is indeed not running */ |
| 600 | flush_scheduled_work(); |
| 601 | |
| 602 | cpufreq_unregister_governor(&cpufreq_gov_dbs); |
| 603 | } |
| 604 | |
| 605 | |
| 606 | MODULE_AUTHOR ("Alexander Clouter <alex-kernel@digriz.org.uk>"); |
| 607 | MODULE_DESCRIPTION ("'cpufreq_conservative' - A dynamic cpufreq governor for " |
| 608 | "Low Latency Frequency Transition capable processors " |
| 609 | "optimised for use in a battery environment"); |
| 610 | MODULE_LICENSE ("GPL"); |
| 611 | |
| 612 | module_init(cpufreq_gov_dbs_init); |
| 613 | module_exit(cpufreq_gov_dbs_exit); |