| 1 | /* $NetBSD: subr_cpufreq.c,v 1.9 2014/02/12 20:20:15 martin Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2011 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Jukka Ruohonen. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * |
| 14 | * 1. Redistributions of source code must retain the above copyright |
| 15 | * notice, this list of conditions and the following disclaimer. |
| 16 | * 2. Redistributions in binary form must reproduce the above copyright |
| 17 | * notice, this list of conditions and the following disclaimer in the |
| 18 | * documentation and/or other materials provided with the distribution. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 21 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 22 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 23 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 24 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 25 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 26 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 27 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 29 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 30 | * POSSIBILITY OF SUCH DAMAGE. |
| 31 | */ |
| 32 | #include <sys/cdefs.h> |
| 33 | __KERNEL_RCSID(0, "$NetBSD: subr_cpufreq.c,v 1.9 2014/02/12 20:20:15 martin Exp $" ); |
| 34 | |
| 35 | #include <sys/param.h> |
| 36 | #include <sys/cpu.h> |
| 37 | #include <sys/cpufreq.h> |
| 38 | #include <sys/kernel.h> |
| 39 | #include <sys/kmem.h> |
| 40 | #include <sys/mutex.h> |
| 41 | #include <sys/time.h> |
| 42 | #include <sys/xcall.h> |
| 43 | |
| 44 | static int cpufreq_latency(void); |
| 45 | static uint32_t cpufreq_get_max(void); |
| 46 | static uint32_t cpufreq_get_min(void); |
| 47 | static uint32_t cpufreq_get_raw(struct cpu_info *); |
| 48 | static void cpufreq_get_state_raw(uint32_t, struct cpufreq_state *); |
| 49 | static void cpufreq_set_raw(struct cpu_info *, uint32_t); |
| 50 | static void cpufreq_set_all_raw(uint32_t); |
| 51 | |
| 52 | static kmutex_t cpufreq_lock __cacheline_aligned; |
| 53 | static struct cpufreq *cf_backend __read_mostly = NULL; |
| 54 | |
| 55 | void |
| 56 | cpufreq_init(void) |
| 57 | { |
| 58 | |
| 59 | mutex_init(&cpufreq_lock, MUTEX_DEFAULT, IPL_NONE); |
| 60 | cf_backend = kmem_zalloc(sizeof(*cf_backend), KM_SLEEP); |
| 61 | } |
| 62 | |
| 63 | int |
| 64 | cpufreq_register(struct cpufreq *cf) |
| 65 | { |
| 66 | uint32_t c, i, j, k, m; |
| 67 | int rv; |
| 68 | |
| 69 | if (cold != 0) |
| 70 | return EBUSY; |
| 71 | |
| 72 | KASSERT(cf != NULL); |
| 73 | KASSERT(cf_backend != NULL); |
| 74 | KASSERT(cf->cf_get_freq != NULL); |
| 75 | KASSERT(cf->cf_set_freq != NULL); |
| 76 | KASSERT(cf->cf_state_count > 0); |
| 77 | KASSERT(cf->cf_state_count < CPUFREQ_STATE_MAX); |
| 78 | |
| 79 | mutex_enter(&cpufreq_lock); |
| 80 | |
| 81 | if (cf_backend->cf_init != false) { |
| 82 | mutex_exit(&cpufreq_lock); |
| 83 | return EALREADY; |
| 84 | } |
| 85 | |
| 86 | cf_backend->cf_init = true; |
| 87 | cf_backend->cf_mp = cf->cf_mp; |
| 88 | cf_backend->cf_cookie = cf->cf_cookie; |
| 89 | cf_backend->cf_get_freq = cf->cf_get_freq; |
| 90 | cf_backend->cf_set_freq = cf->cf_set_freq; |
| 91 | |
| 92 | (void)strlcpy(cf_backend->cf_name, cf->cf_name, sizeof(cf->cf_name)); |
| 93 | |
| 94 | /* |
| 95 | * Sanity check the values and verify descending order. |
| 96 | */ |
| 97 | for (c = i = 0; i < cf->cf_state_count; i++) { |
| 98 | |
| 99 | CTASSERT(CPUFREQ_STATE_ENABLED != 0); |
| 100 | CTASSERT(CPUFREQ_STATE_DISABLED != 0); |
| 101 | |
| 102 | if (cf->cf_state[i].cfs_freq == 0) |
| 103 | continue; |
| 104 | |
| 105 | if (cf->cf_state[i].cfs_freq > 9999 && |
| 106 | cf->cf_state[i].cfs_freq != CPUFREQ_STATE_ENABLED && |
| 107 | cf->cf_state[i].cfs_freq != CPUFREQ_STATE_DISABLED) |
| 108 | continue; |
| 109 | |
| 110 | for (j = k = 0; j < i; j++) { |
| 111 | |
| 112 | if (cf->cf_state[i].cfs_freq >= |
| 113 | cf->cf_state[j].cfs_freq) { |
| 114 | k = 1; |
| 115 | break; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | if (k != 0) |
| 120 | continue; |
| 121 | |
| 122 | cf_backend->cf_state[c].cfs_index = c; |
| 123 | cf_backend->cf_state[c].cfs_freq = cf->cf_state[i].cfs_freq; |
| 124 | cf_backend->cf_state[c].cfs_power = cf->cf_state[i].cfs_power; |
| 125 | |
| 126 | c++; |
| 127 | } |
| 128 | |
| 129 | cf_backend->cf_state_count = c; |
| 130 | |
| 131 | if (cf_backend->cf_state_count == 0) { |
| 132 | mutex_exit(&cpufreq_lock); |
| 133 | cpufreq_deregister(); |
| 134 | return EINVAL; |
| 135 | } |
| 136 | |
| 137 | rv = cpufreq_latency(); |
| 138 | |
| 139 | if (rv != 0) { |
| 140 | mutex_exit(&cpufreq_lock); |
| 141 | cpufreq_deregister(); |
| 142 | return rv; |
| 143 | } |
| 144 | |
| 145 | m = cpufreq_get_max(); |
| 146 | cpufreq_set_all_raw(m); |
| 147 | mutex_exit(&cpufreq_lock); |
| 148 | |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | void |
| 153 | cpufreq_deregister(void) |
| 154 | { |
| 155 | |
| 156 | mutex_enter(&cpufreq_lock); |
| 157 | memset(cf_backend, 0, sizeof(*cf_backend)); |
| 158 | mutex_exit(&cpufreq_lock); |
| 159 | } |
| 160 | |
| 161 | static int |
| 162 | cpufreq_latency(void) |
| 163 | { |
| 164 | struct cpufreq *cf = cf_backend; |
| 165 | struct timespec nta, ntb; |
| 166 | const uint32_t n = 10; |
| 167 | uint32_t i, j, l, m; |
| 168 | uint64_t s; |
| 169 | |
| 170 | l = cpufreq_get_min(); |
| 171 | m = cpufreq_get_max(); |
| 172 | |
| 173 | /* |
| 174 | * For each state, sample the average transition |
| 175 | * latency required to set the state for all CPUs. |
| 176 | */ |
| 177 | for (i = 0; i < cf->cf_state_count; i++) { |
| 178 | |
| 179 | for (s = 0, j = 0; j < n; j++) { |
| 180 | |
| 181 | /* |
| 182 | * Attempt to exclude possible |
| 183 | * caching done by the backend. |
| 184 | */ |
| 185 | if (i == 0) |
| 186 | cpufreq_set_all_raw(l); |
| 187 | else { |
| 188 | cpufreq_set_all_raw(m); |
| 189 | } |
| 190 | |
| 191 | nanotime(&nta); |
| 192 | cpufreq_set_all_raw(cf->cf_state[i].cfs_freq); |
| 193 | nanotime(&ntb); |
| 194 | timespecsub(&ntb, &nta, &ntb); |
| 195 | |
| 196 | if (ntb.tv_sec != 0 || |
| 197 | ntb.tv_nsec > CPUFREQ_LATENCY_MAX) |
| 198 | continue; |
| 199 | |
| 200 | if (s >= UINT64_MAX - CPUFREQ_LATENCY_MAX) |
| 201 | break; |
| 202 | |
| 203 | /* Convert to microseconds to prevent overflow */ |
| 204 | s += ntb.tv_nsec / 1000; |
| 205 | } |
| 206 | |
| 207 | /* |
| 208 | * Consider the backend unsuitable if |
| 209 | * the transition latency was too high. |
| 210 | */ |
| 211 | if (s == 0) |
| 212 | return EMSGSIZE; |
| 213 | |
| 214 | cf->cf_state[i].cfs_latency = s / n; |
| 215 | } |
| 216 | |
| 217 | return 0; |
| 218 | } |
| 219 | |
| 220 | void |
| 221 | cpufreq_suspend(struct cpu_info *ci) |
| 222 | { |
| 223 | struct cpufreq *cf = cf_backend; |
| 224 | uint32_t l, s; |
| 225 | |
| 226 | mutex_enter(&cpufreq_lock); |
| 227 | |
| 228 | if (cf->cf_init != true) { |
| 229 | mutex_exit(&cpufreq_lock); |
| 230 | return; |
| 231 | } |
| 232 | |
| 233 | l = cpufreq_get_min(); |
| 234 | s = cpufreq_get_raw(ci); |
| 235 | |
| 236 | cpufreq_set_raw(ci, l); |
| 237 | cf->cf_state_saved = s; |
| 238 | |
| 239 | mutex_exit(&cpufreq_lock); |
| 240 | } |
| 241 | |
| 242 | void |
| 243 | cpufreq_resume(struct cpu_info *ci) |
| 244 | { |
| 245 | struct cpufreq *cf = cf_backend; |
| 246 | |
| 247 | mutex_enter(&cpufreq_lock); |
| 248 | |
| 249 | if (cf->cf_init != true || cf->cf_state_saved == 0) { |
| 250 | mutex_exit(&cpufreq_lock); |
| 251 | return; |
| 252 | } |
| 253 | |
| 254 | cpufreq_set_raw(ci, cf->cf_state_saved); |
| 255 | mutex_exit(&cpufreq_lock); |
| 256 | } |
| 257 | |
| 258 | uint32_t |
| 259 | cpufreq_get(struct cpu_info *ci) |
| 260 | { |
| 261 | struct cpufreq *cf = cf_backend; |
| 262 | uint32_t freq; |
| 263 | |
| 264 | mutex_enter(&cpufreq_lock); |
| 265 | |
| 266 | if (cf->cf_init != true) { |
| 267 | mutex_exit(&cpufreq_lock); |
| 268 | return 0; |
| 269 | } |
| 270 | |
| 271 | freq = cpufreq_get_raw(ci); |
| 272 | mutex_exit(&cpufreq_lock); |
| 273 | |
| 274 | return freq; |
| 275 | } |
| 276 | |
| 277 | static uint32_t |
| 278 | cpufreq_get_max(void) |
| 279 | { |
| 280 | struct cpufreq *cf = cf_backend; |
| 281 | |
| 282 | KASSERT(cf->cf_init != false); |
| 283 | KASSERT(mutex_owned(&cpufreq_lock) != 0); |
| 284 | |
| 285 | return cf->cf_state[0].cfs_freq; |
| 286 | } |
| 287 | |
| 288 | static uint32_t |
| 289 | cpufreq_get_min(void) |
| 290 | { |
| 291 | struct cpufreq *cf = cf_backend; |
| 292 | |
| 293 | KASSERT(cf->cf_init != false); |
| 294 | KASSERT(mutex_owned(&cpufreq_lock) != 0); |
| 295 | |
| 296 | return cf->cf_state[cf->cf_state_count - 1].cfs_freq; |
| 297 | } |
| 298 | |
| 299 | static uint32_t |
| 300 | cpufreq_get_raw(struct cpu_info *ci) |
| 301 | { |
| 302 | struct cpufreq *cf = cf_backend; |
| 303 | uint32_t freq = 0; |
| 304 | uint64_t xc; |
| 305 | |
| 306 | KASSERT(cf->cf_init != false); |
| 307 | KASSERT(mutex_owned(&cpufreq_lock) != 0); |
| 308 | |
| 309 | xc = xc_unicast(0, (*cf->cf_get_freq), cf->cf_cookie, &freq, ci); |
| 310 | xc_wait(xc); |
| 311 | |
| 312 | return freq; |
| 313 | } |
| 314 | |
| 315 | int |
| 316 | cpufreq_get_backend(struct cpufreq *dst) |
| 317 | { |
| 318 | struct cpufreq *cf = cf_backend; |
| 319 | |
| 320 | mutex_enter(&cpufreq_lock); |
| 321 | |
| 322 | if (cf->cf_init != true || dst == NULL) { |
| 323 | mutex_exit(&cpufreq_lock); |
| 324 | return ENODEV; |
| 325 | } |
| 326 | |
| 327 | memcpy(dst, cf, sizeof(*cf)); |
| 328 | mutex_exit(&cpufreq_lock); |
| 329 | |
| 330 | return 0; |
| 331 | } |
| 332 | |
| 333 | int |
| 334 | cpufreq_get_state(uint32_t freq, struct cpufreq_state *cfs) |
| 335 | { |
| 336 | struct cpufreq *cf = cf_backend; |
| 337 | |
| 338 | mutex_enter(&cpufreq_lock); |
| 339 | |
| 340 | if (cf->cf_init != true || cfs == NULL) { |
| 341 | mutex_exit(&cpufreq_lock); |
| 342 | return ENODEV; |
| 343 | } |
| 344 | |
| 345 | cpufreq_get_state_raw(freq, cfs); |
| 346 | mutex_exit(&cpufreq_lock); |
| 347 | |
| 348 | return 0; |
| 349 | } |
| 350 | |
| 351 | int |
| 352 | cpufreq_get_state_index(uint32_t index, struct cpufreq_state *cfs) |
| 353 | { |
| 354 | struct cpufreq *cf = cf_backend; |
| 355 | |
| 356 | mutex_enter(&cpufreq_lock); |
| 357 | |
| 358 | if (cf->cf_init != true || cfs == NULL) { |
| 359 | mutex_exit(&cpufreq_lock); |
| 360 | return ENODEV; |
| 361 | } |
| 362 | |
| 363 | if (index >= cf->cf_state_count) { |
| 364 | mutex_exit(&cpufreq_lock); |
| 365 | return EINVAL; |
| 366 | } |
| 367 | |
| 368 | memcpy(cfs, &cf->cf_state[index], sizeof(*cfs)); |
| 369 | mutex_exit(&cpufreq_lock); |
| 370 | |
| 371 | return 0; |
| 372 | } |
| 373 | |
| 374 | static void |
| 375 | cpufreq_get_state_raw(uint32_t freq, struct cpufreq_state *cfs) |
| 376 | { |
| 377 | struct cpufreq *cf = cf_backend; |
| 378 | uint32_t f, hi, i = 0, lo = 0; |
| 379 | |
| 380 | KASSERT(mutex_owned(&cpufreq_lock) != 0); |
| 381 | KASSERT(cf->cf_init != false && cfs != NULL); |
| 382 | |
| 383 | hi = cf->cf_state_count; |
| 384 | |
| 385 | while (lo < hi) { |
| 386 | |
| 387 | i = (lo + hi) >> 1; |
| 388 | f = cf->cf_state[i].cfs_freq; |
| 389 | |
| 390 | if (freq == f) |
| 391 | break; |
| 392 | else if (freq > f) |
| 393 | hi = i; |
| 394 | else { |
| 395 | lo = i + 1; |
| 396 | } |
| 397 | } |
| 398 | |
| 399 | memcpy(cfs, &cf->cf_state[i], sizeof(*cfs)); |
| 400 | } |
| 401 | |
| 402 | void |
| 403 | cpufreq_set(struct cpu_info *ci, uint32_t freq) |
| 404 | { |
| 405 | struct cpufreq *cf = cf_backend; |
| 406 | |
| 407 | mutex_enter(&cpufreq_lock); |
| 408 | |
| 409 | if (__predict_false(cf->cf_init != true)) { |
| 410 | mutex_exit(&cpufreq_lock); |
| 411 | return; |
| 412 | } |
| 413 | |
| 414 | cpufreq_set_raw(ci, freq); |
| 415 | mutex_exit(&cpufreq_lock); |
| 416 | } |
| 417 | |
| 418 | static void |
| 419 | cpufreq_set_raw(struct cpu_info *ci, uint32_t freq) |
| 420 | { |
| 421 | struct cpufreq *cf = cf_backend; |
| 422 | uint64_t xc; |
| 423 | |
| 424 | KASSERT(cf->cf_init != false); |
| 425 | KASSERT(mutex_owned(&cpufreq_lock) != 0); |
| 426 | |
| 427 | xc = xc_unicast(0, (*cf->cf_set_freq), cf->cf_cookie, &freq, ci); |
| 428 | xc_wait(xc); |
| 429 | } |
| 430 | |
| 431 | void |
| 432 | cpufreq_set_all(uint32_t freq) |
| 433 | { |
| 434 | struct cpufreq *cf = cf_backend; |
| 435 | |
| 436 | mutex_enter(&cpufreq_lock); |
| 437 | |
| 438 | if (__predict_false(cf->cf_init != true)) { |
| 439 | mutex_exit(&cpufreq_lock); |
| 440 | return; |
| 441 | } |
| 442 | |
| 443 | cpufreq_set_all_raw(freq); |
| 444 | mutex_exit(&cpufreq_lock); |
| 445 | } |
| 446 | |
| 447 | static void |
| 448 | cpufreq_set_all_raw(uint32_t freq) |
| 449 | { |
| 450 | struct cpufreq *cf = cf_backend; |
| 451 | uint64_t xc; |
| 452 | |
| 453 | KASSERT(cf->cf_init != false); |
| 454 | KASSERT(mutex_owned(&cpufreq_lock) != 0); |
| 455 | |
| 456 | xc = xc_broadcast(0, (*cf->cf_set_freq), cf->cf_cookie, &freq); |
| 457 | xc_wait(xc); |
| 458 | } |
| 459 | |
| 460 | #ifdef notyet |
| 461 | void |
| 462 | cpufreq_set_higher(struct cpu_info *ci) |
| 463 | { |
| 464 | cpufreq_set_step(ci, -1); |
| 465 | } |
| 466 | |
| 467 | void |
| 468 | cpufreq_set_lower(struct cpu_info *ci) |
| 469 | { |
| 470 | cpufreq_set_step(ci, 1); |
| 471 | } |
| 472 | |
| 473 | static void |
| 474 | cpufreq_set_step(struct cpu_info *ci, int32_t step) |
| 475 | { |
| 476 | struct cpufreq *cf = cf_backend; |
| 477 | struct cpufreq_state cfs; |
| 478 | uint32_t freq; |
| 479 | int32_t index; |
| 480 | |
| 481 | mutex_enter(&cpufreq_lock); |
| 482 | |
| 483 | if (__predict_false(cf->cf_init != true)) { |
| 484 | mutex_exit(&cpufreq_lock); |
| 485 | return; |
| 486 | } |
| 487 | |
| 488 | freq = cpufreq_get_raw(ci); |
| 489 | |
| 490 | if (__predict_false(freq == 0)) { |
| 491 | mutex_exit(&cpufreq_lock); |
| 492 | return; |
| 493 | } |
| 494 | |
| 495 | cpufreq_get_state_raw(freq, &cfs); |
| 496 | index = cfs.cfs_index + step; |
| 497 | |
| 498 | if (index < 0 || index >= (int32_t)cf->cf_state_count) { |
| 499 | mutex_exit(&cpufreq_lock); |
| 500 | return; |
| 501 | } |
| 502 | |
| 503 | cpufreq_set_raw(ci, cf->cf_state[index].cfs_freq); |
| 504 | mutex_exit(&cpufreq_lock); |
| 505 | } |
| 506 | #endif |
| 507 | |