1 /* 2 * processor_idle - idle state submodule to 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 * Copyright (C) 2005 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> 10 * - Added support for C3 on SMP 11 * 12 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 13 * 14 * This program is free software; you can redistribute it and/or modify 15 * it under the terms of the GNU General Public License as published by 16 * the Free Software Foundation; either version 2 of the License, or (at 17 * your option) any later version. 18 * 19 * This program is distributed in the hope that it will be useful, but 20 * WITHOUT ANY WARRANTY; without even the implied warranty of 21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 22 * General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License along 25 * with this program; if not, write to the Free Software Foundation, Inc., 26 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. 27 * 28 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 29 */ 30 31 #include <linux/kernel.h> 32 #include <linux/module.h> 33 #include <linux/init.h> 34 #include <linux/cpufreq.h> 35 #include <linux/proc_fs.h> 36 #include <linux/seq_file.h> 37 #include <linux/acpi.h> 38 #include <linux/dmi.h> 39 #include <linux/moduleparam.h> 40 #include <linux/sched.h> /* need_resched() */ 41 42 #include <asm/io.h> 43 #include <asm/uaccess.h> 44 45 #include <acpi/acpi_bus.h> 46 #include <acpi/processor.h> 47 48 #define ACPI_PROCESSOR_COMPONENT 0x01000000 49 #define ACPI_PROCESSOR_CLASS "processor" 50 #define ACPI_PROCESSOR_DRIVER_NAME "ACPI Processor Driver" 51 #define _COMPONENT ACPI_PROCESSOR_COMPONENT 52 ACPI_MODULE_NAME("acpi_processor") 53 #define ACPI_PROCESSOR_FILE_POWER "power" 54 #define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000) 55 #define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */ 56 #define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */ 57 static void (*pm_idle_save) (void); 58 module_param(max_cstate, uint, 0644); 59 60 static unsigned int nocst = 0; 61 module_param(nocst, uint, 0000); 62 63 /* 64 * bm_history -- bit-mask with a bit per jiffy of bus-master activity 65 * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms 66 * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms 67 * 100 HZ: 0x0000000F: 4 jiffies = 40ms 68 * reduce history for more aggressive entry into C3 69 */ 70 static unsigned int bm_history = 71 (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1)); 72 module_param(bm_history, uint, 0644); 73 /* -------------------------------------------------------------------------- 74 Power Management 75 -------------------------------------------------------------------------- */ 76 77 /* 78 * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3. 79 * For now disable this. Probably a bug somewhere else. 80 * 81 * To skip this limit, boot/load with a large max_cstate limit. 82 */ 83 static int set_max_cstate(struct dmi_system_id *id) 84 { 85 if (max_cstate > ACPI_PROCESSOR_MAX_POWER) 86 return 0; 87 88 printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate." 89 " Override with \"processor.max_cstate=%d\"\n", id->ident, 90 (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1); 91 92 max_cstate = (long)id->driver_data; 93 94 return 0; 95 } 96 97 static struct dmi_system_id __initdata processor_power_dmi_table[] = { 98 {set_max_cstate, "IBM ThinkPad R40e", { 99 DMI_MATCH(DMI_BIOS_VENDOR, 100 "IBM"), 101 DMI_MATCH(DMI_BIOS_VERSION, 102 "1SET60WW")}, 103 (void *)1}, 104 {set_max_cstate, "Medion 41700", { 105 DMI_MATCH(DMI_BIOS_VENDOR, 106 "Phoenix Technologies LTD"), 107 DMI_MATCH(DMI_BIOS_VERSION, 108 "R01-A1J")}, (void *)1}, 109 {set_max_cstate, "Clevo 5600D", { 110 DMI_MATCH(DMI_BIOS_VENDOR, 111 "Phoenix Technologies LTD"), 112 DMI_MATCH(DMI_BIOS_VERSION, 113 "SHE845M0.86C.0013.D.0302131307")}, 114 (void *)2}, 115 {}, 116 }; 117 118 static inline u32 ticks_elapsed(u32 t1, u32 t2) 119 { 120 if (t2 >= t1) 121 return (t2 - t1); 122 else if (!acpi_fadt.tmr_val_ext) 123 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF); 124 else 125 return ((0xFFFFFFFF - t1) + t2); 126 } 127 128 static void 129 acpi_processor_power_activate(struct acpi_processor *pr, 130 struct acpi_processor_cx *new) 131 { 132 struct acpi_processor_cx *old; 133 134 if (!pr || !new) 135 return; 136 137 old = pr->power.state; 138 139 if (old) 140 old->promotion.count = 0; 141 new->demotion.count = 0; 142 143 /* Cleanup from old state. */ 144 if (old) { 145 switch (old->type) { 146 case ACPI_STATE_C3: 147 /* Disable bus master reload */ 148 if (new->type != ACPI_STATE_C3 && pr->flags.bm_check) 149 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0, 150 ACPI_MTX_DO_NOT_LOCK); 151 break; 152 } 153 } 154 155 /* Prepare to use new state. */ 156 switch (new->type) { 157 case ACPI_STATE_C3: 158 /* Enable bus master reload */ 159 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check) 160 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1, 161 ACPI_MTX_DO_NOT_LOCK); 162 break; 163 } 164 165 pr->power.state = new; 166 167 return; 168 } 169 170 static atomic_t c3_cpu_count; 171 172 static void acpi_processor_idle(void) 173 { 174 struct acpi_processor *pr = NULL; 175 struct acpi_processor_cx *cx = NULL; 176 struct acpi_processor_cx *next_state = NULL; 177 int sleep_ticks = 0; 178 u32 t1, t2 = 0; 179 180 pr = processors[raw_smp_processor_id()]; 181 if (!pr) 182 return; 183 184 /* 185 * Interrupts must be disabled during bus mastering calculations and 186 * for C2/C3 transitions. 187 */ 188 local_irq_disable(); 189 190 /* 191 * Check whether we truly need to go idle, or should 192 * reschedule: 193 */ 194 if (unlikely(need_resched())) { 195 local_irq_enable(); 196 return; 197 } 198 199 cx = pr->power.state; 200 if (!cx) 201 goto easy_out; 202 203 /* 204 * Check BM Activity 205 * ----------------- 206 * Check for bus mastering activity (if required), record, and check 207 * for demotion. 208 */ 209 if (pr->flags.bm_check) { 210 u32 bm_status = 0; 211 unsigned long diff = jiffies - pr->power.bm_check_timestamp; 212 213 if (diff > 32) 214 diff = 32; 215 216 while (diff) { 217 /* if we didn't get called, assume there was busmaster activity */ 218 diff--; 219 if (diff) 220 pr->power.bm_activity |= 0x1; 221 pr->power.bm_activity <<= 1; 222 } 223 224 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, 225 &bm_status, ACPI_MTX_DO_NOT_LOCK); 226 if (bm_status) { 227 pr->power.bm_activity++; 228 acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 229 1, ACPI_MTX_DO_NOT_LOCK); 230 } 231 /* 232 * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect 233 * the true state of bus mastering activity; forcing us to 234 * manually check the BMIDEA bit of each IDE channel. 235 */ 236 else if (errata.piix4.bmisx) { 237 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01) 238 || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01)) 239 pr->power.bm_activity++; 240 } 241 242 pr->power.bm_check_timestamp = jiffies; 243 244 /* 245 * Apply bus mastering demotion policy. Automatically demote 246 * to avoid a faulty transition. Note that the processor 247 * won't enter a low-power state during this call (to this 248 * funciton) but should upon the next. 249 * 250 * TBD: A better policy might be to fallback to the demotion 251 * state (use it for this quantum only) istead of 252 * demoting -- and rely on duration as our sole demotion 253 * qualification. This may, however, introduce DMA 254 * issues (e.g. floppy DMA transfer overrun/underrun). 255 */ 256 if (pr->power.bm_activity & cx->demotion.threshold.bm) { 257 local_irq_enable(); 258 next_state = cx->demotion.state; 259 goto end; 260 } 261 } 262 263 cx->usage++; 264 265 /* 266 * Sleep: 267 * ------ 268 * Invoke the current Cx state to put the processor to sleep. 269 */ 270 switch (cx->type) { 271 272 case ACPI_STATE_C1: 273 /* 274 * Invoke C1. 275 * Use the appropriate idle routine, the one that would 276 * be used without acpi C-states. 277 */ 278 if (pm_idle_save) 279 pm_idle_save(); 280 else 281 safe_halt(); 282 /* 283 * TBD: Can't get time duration while in C1, as resumes 284 * go to an ISR rather than here. Need to instrument 285 * base interrupt handler. 286 */ 287 sleep_ticks = 0xFFFFFFFF; 288 break; 289 290 case ACPI_STATE_C2: 291 /* Get start time (ticks) */ 292 t1 = inl(acpi_fadt.xpm_tmr_blk.address); 293 /* Invoke C2 */ 294 inb(cx->address); 295 /* Dummy op - must do something useless after P_LVL2 read */ 296 t2 = inl(acpi_fadt.xpm_tmr_blk.address); 297 /* Get end time (ticks) */ 298 t2 = inl(acpi_fadt.xpm_tmr_blk.address); 299 /* Re-enable interrupts */ 300 local_irq_enable(); 301 /* Compute time (ticks) that we were actually asleep */ 302 sleep_ticks = 303 ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD; 304 break; 305 306 case ACPI_STATE_C3: 307 308 if (pr->flags.bm_check) { 309 if (atomic_inc_return(&c3_cpu_count) == 310 num_online_cpus()) { 311 /* 312 * All CPUs are trying to go to C3 313 * Disable bus master arbitration 314 */ 315 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1, 316 ACPI_MTX_DO_NOT_LOCK); 317 } 318 } else { 319 /* SMP with no shared cache... Invalidate cache */ 320 ACPI_FLUSH_CPU_CACHE(); 321 } 322 323 /* Get start time (ticks) */ 324 t1 = inl(acpi_fadt.xpm_tmr_blk.address); 325 /* Invoke C3 */ 326 inb(cx->address); 327 /* Dummy op - must do something useless after P_LVL3 read */ 328 t2 = inl(acpi_fadt.xpm_tmr_blk.address); 329 /* Get end time (ticks) */ 330 t2 = inl(acpi_fadt.xpm_tmr_blk.address); 331 if (pr->flags.bm_check) { 332 /* Enable bus master arbitration */ 333 atomic_dec(&c3_cpu_count); 334 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0, 335 ACPI_MTX_DO_NOT_LOCK); 336 } 337 338 /* Re-enable interrupts */ 339 local_irq_enable(); 340 /* Compute time (ticks) that we were actually asleep */ 341 sleep_ticks = 342 ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD; 343 break; 344 345 default: 346 local_irq_enable(); 347 return; 348 } 349 350 next_state = pr->power.state; 351 352 /* 353 * Promotion? 354 * ---------- 355 * Track the number of longs (time asleep is greater than threshold) 356 * and promote when the count threshold is reached. Note that bus 357 * mastering activity may prevent promotions. 358 * Do not promote above max_cstate. 359 */ 360 if (cx->promotion.state && 361 ((cx->promotion.state - pr->power.states) <= max_cstate)) { 362 if (sleep_ticks > cx->promotion.threshold.ticks) { 363 cx->promotion.count++; 364 cx->demotion.count = 0; 365 if (cx->promotion.count >= 366 cx->promotion.threshold.count) { 367 if (pr->flags.bm_check) { 368 if (! 369 (pr->power.bm_activity & cx-> 370 promotion.threshold.bm)) { 371 next_state = 372 cx->promotion.state; 373 goto end; 374 } 375 } else { 376 next_state = cx->promotion.state; 377 goto end; 378 } 379 } 380 } 381 } 382 383 /* 384 * Demotion? 385 * --------- 386 * Track the number of shorts (time asleep is less than time threshold) 387 * and demote when the usage threshold is reached. 388 */ 389 if (cx->demotion.state) { 390 if (sleep_ticks < cx->demotion.threshold.ticks) { 391 cx->demotion.count++; 392 cx->promotion.count = 0; 393 if (cx->demotion.count >= cx->demotion.threshold.count) { 394 next_state = cx->demotion.state; 395 goto end; 396 } 397 } 398 } 399 400 end: 401 /* 402 * Demote if current state exceeds max_cstate 403 */ 404 if ((pr->power.state - pr->power.states) > max_cstate) { 405 if (cx->demotion.state) 406 next_state = cx->demotion.state; 407 } 408 409 /* 410 * New Cx State? 411 * ------------- 412 * If we're going to start using a new Cx state we must clean up 413 * from the previous and prepare to use the new. 414 */ 415 if (next_state != pr->power.state) 416 acpi_processor_power_activate(pr, next_state); 417 418 return; 419 420 easy_out: 421 /* do C1 instead of busy loop */ 422 if (pm_idle_save) 423 pm_idle_save(); 424 else 425 safe_halt(); 426 return; 427 } 428 429 static int acpi_processor_set_power_policy(struct acpi_processor *pr) 430 { 431 unsigned int i; 432 unsigned int state_is_set = 0; 433 struct acpi_processor_cx *lower = NULL; 434 struct acpi_processor_cx *higher = NULL; 435 struct acpi_processor_cx *cx; 436 437 ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy"); 438 439 if (!pr) 440 return_VALUE(-EINVAL); 441 442 /* 443 * This function sets the default Cx state policy (OS idle handler). 444 * Our scheme is to promote quickly to C2 but more conservatively 445 * to C3. We're favoring C2 for its characteristics of low latency 446 * (quick response), good power savings, and ability to allow bus 447 * mastering activity. Note that the Cx state policy is completely 448 * customizable and can be altered dynamically. 449 */ 450 451 /* startup state */ 452 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 453 cx = &pr->power.states[i]; 454 if (!cx->valid) 455 continue; 456 457 if (!state_is_set) 458 pr->power.state = cx; 459 state_is_set++; 460 break; 461 } 462 463 if (!state_is_set) 464 return_VALUE(-ENODEV); 465 466 /* demotion */ 467 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 468 cx = &pr->power.states[i]; 469 if (!cx->valid) 470 continue; 471 472 if (lower) { 473 cx->demotion.state = lower; 474 cx->demotion.threshold.ticks = cx->latency_ticks; 475 cx->demotion.threshold.count = 1; 476 if (cx->type == ACPI_STATE_C3) 477 cx->demotion.threshold.bm = bm_history; 478 } 479 480 lower = cx; 481 } 482 483 /* promotion */ 484 for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) { 485 cx = &pr->power.states[i]; 486 if (!cx->valid) 487 continue; 488 489 if (higher) { 490 cx->promotion.state = higher; 491 cx->promotion.threshold.ticks = cx->latency_ticks; 492 if (cx->type >= ACPI_STATE_C2) 493 cx->promotion.threshold.count = 4; 494 else 495 cx->promotion.threshold.count = 10; 496 if (higher->type == ACPI_STATE_C3) 497 cx->promotion.threshold.bm = bm_history; 498 } 499 500 higher = cx; 501 } 502 503 return_VALUE(0); 504 } 505 506 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr) 507 { 508 int i; 509 510 ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt"); 511 512 if (!pr) 513 return_VALUE(-EINVAL); 514 515 if (!pr->pblk) 516 return_VALUE(-ENODEV); 517 518 for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++) 519 memset(pr->power.states, 0, sizeof(struct acpi_processor_cx)); 520 521 /* if info is obtained from pblk/fadt, type equals state */ 522 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1; 523 pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2; 524 pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3; 525 526 /* the C0 state only exists as a filler in our array, 527 * and all processors need to support C1 */ 528 pr->power.states[ACPI_STATE_C0].valid = 1; 529 pr->power.states[ACPI_STATE_C1].valid = 1; 530 531 /* determine C2 and C3 address from pblk */ 532 pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4; 533 pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5; 534 535 /* determine latencies from FADT */ 536 pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat; 537 pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat; 538 539 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 540 "lvl2[0x%08x] lvl3[0x%08x]\n", 541 pr->power.states[ACPI_STATE_C2].address, 542 pr->power.states[ACPI_STATE_C3].address)); 543 544 return_VALUE(0); 545 } 546 547 static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr) 548 { 549 int i; 550 551 ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1"); 552 553 for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++) 554 memset(&(pr->power.states[i]), 0, 555 sizeof(struct acpi_processor_cx)); 556 557 /* if info is obtained from pblk/fadt, type equals state */ 558 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1; 559 pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2; 560 pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3; 561 562 /* the C0 state only exists as a filler in our array, 563 * and all processors need to support C1 */ 564 pr->power.states[ACPI_STATE_C0].valid = 1; 565 pr->power.states[ACPI_STATE_C1].valid = 1; 566 567 return_VALUE(0); 568 } 569 570 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr) 571 { 572 acpi_status status = 0; 573 acpi_integer count; 574 int i; 575 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; 576 union acpi_object *cst; 577 578 ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_cst"); 579 580 if (nocst) 581 return_VALUE(-ENODEV); 582 583 pr->power.count = 0; 584 for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++) 585 memset(&(pr->power.states[i]), 0, 586 sizeof(struct acpi_processor_cx)); 587 588 status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer); 589 if (ACPI_FAILURE(status)) { 590 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n")); 591 return_VALUE(-ENODEV); 592 } 593 594 cst = (union acpi_object *)buffer.pointer; 595 596 /* There must be at least 2 elements */ 597 if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) { 598 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 599 "not enough elements in _CST\n")); 600 status = -EFAULT; 601 goto end; 602 } 603 604 count = cst->package.elements[0].integer.value; 605 606 /* Validate number of power states. */ 607 if (count < 1 || count != cst->package.count - 1) { 608 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 609 "count given by _CST is not valid\n")); 610 status = -EFAULT; 611 goto end; 612 } 613 614 /* We support up to ACPI_PROCESSOR_MAX_POWER. */ 615 if (count > ACPI_PROCESSOR_MAX_POWER) { 616 printk(KERN_WARNING 617 "Limiting number of power states to max (%d)\n", 618 ACPI_PROCESSOR_MAX_POWER); 619 printk(KERN_WARNING 620 "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n"); 621 count = ACPI_PROCESSOR_MAX_POWER; 622 } 623 624 /* Tell driver that at least _CST is supported. */ 625 pr->flags.has_cst = 1; 626 627 for (i = 1; i <= count; i++) { 628 union acpi_object *element; 629 union acpi_object *obj; 630 struct acpi_power_register *reg; 631 struct acpi_processor_cx cx; 632 633 memset(&cx, 0, sizeof(cx)); 634 635 element = (union acpi_object *)&(cst->package.elements[i]); 636 if (element->type != ACPI_TYPE_PACKAGE) 637 continue; 638 639 if (element->package.count != 4) 640 continue; 641 642 obj = (union acpi_object *)&(element->package.elements[0]); 643 644 if (obj->type != ACPI_TYPE_BUFFER) 645 continue; 646 647 reg = (struct acpi_power_register *)obj->buffer.pointer; 648 649 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO && 650 (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) 651 continue; 652 653 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ? 654 0 : reg->address; 655 656 /* There should be an easy way to extract an integer... */ 657 obj = (union acpi_object *)&(element->package.elements[1]); 658 if (obj->type != ACPI_TYPE_INTEGER) 659 continue; 660 661 cx.type = obj->integer.value; 662 663 if ((cx.type != ACPI_STATE_C1) && 664 (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO)) 665 continue; 666 667 if ((cx.type < ACPI_STATE_C1) || (cx.type > ACPI_STATE_C3)) 668 continue; 669 670 obj = (union acpi_object *)&(element->package.elements[2]); 671 if (obj->type != ACPI_TYPE_INTEGER) 672 continue; 673 674 cx.latency = obj->integer.value; 675 676 obj = (union acpi_object *)&(element->package.elements[3]); 677 if (obj->type != ACPI_TYPE_INTEGER) 678 continue; 679 680 cx.power = obj->integer.value; 681 682 (pr->power.count)++; 683 memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx)); 684 } 685 686 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n", 687 pr->power.count)); 688 689 /* Validate number of power states discovered */ 690 if (pr->power.count < 2) 691 status = -ENODEV; 692 693 end: 694 acpi_os_free(buffer.pointer); 695 696 return_VALUE(status); 697 } 698 699 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx) 700 { 701 ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c2"); 702 703 if (!cx->address) 704 return_VOID; 705 706 /* 707 * C2 latency must be less than or equal to 100 708 * microseconds. 709 */ 710 else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) { 711 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 712 "latency too large [%d]\n", cx->latency)); 713 return_VOID; 714 } 715 716 /* 717 * Otherwise we've met all of our C2 requirements. 718 * Normalize the C2 latency to expidite policy 719 */ 720 cx->valid = 1; 721 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency); 722 723 return_VOID; 724 } 725 726 static void acpi_processor_power_verify_c3(struct acpi_processor *pr, 727 struct acpi_processor_cx *cx) 728 { 729 static int bm_check_flag; 730 731 ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c3"); 732 733 if (!cx->address) 734 return_VOID; 735 736 /* 737 * C3 latency must be less than or equal to 1000 738 * microseconds. 739 */ 740 else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) { 741 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 742 "latency too large [%d]\n", cx->latency)); 743 return_VOID; 744 } 745 746 /* 747 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast) 748 * DMA transfers are used by any ISA device to avoid livelock. 749 * Note that we could disable Type-F DMA (as recommended by 750 * the erratum), but this is known to disrupt certain ISA 751 * devices thus we take the conservative approach. 752 */ 753 else if (errata.piix4.fdma) { 754 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 755 "C3 not supported on PIIX4 with Type-F DMA\n")); 756 return_VOID; 757 } 758 759 /* All the logic here assumes flags.bm_check is same across all CPUs */ 760 if (!bm_check_flag) { 761 /* Determine whether bm_check is needed based on CPU */ 762 acpi_processor_power_init_bm_check(&(pr->flags), pr->id); 763 bm_check_flag = pr->flags.bm_check; 764 } else { 765 pr->flags.bm_check = bm_check_flag; 766 } 767 768 if (pr->flags.bm_check) { 769 /* bus mastering control is necessary */ 770 if (!pr->flags.bm_control) { 771 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 772 "C3 support requires bus mastering control\n")); 773 return_VOID; 774 } 775 } else { 776 /* 777 * WBINVD should be set in fadt, for C3 state to be 778 * supported on when bm_check is not required. 779 */ 780 if (acpi_fadt.wb_invd != 1) { 781 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 782 "Cache invalidation should work properly" 783 " for C3 to be enabled on SMP systems\n")); 784 return_VOID; 785 } 786 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 787 0, ACPI_MTX_DO_NOT_LOCK); 788 } 789 790 /* 791 * Otherwise we've met all of our C3 requirements. 792 * Normalize the C3 latency to expidite policy. Enable 793 * checking of bus mastering status (bm_check) so we can 794 * use this in our C3 policy 795 */ 796 cx->valid = 1; 797 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency); 798 799 return_VOID; 800 } 801 802 static int acpi_processor_power_verify(struct acpi_processor *pr) 803 { 804 unsigned int i; 805 unsigned int working = 0; 806 807 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 808 struct acpi_processor_cx *cx = &pr->power.states[i]; 809 810 switch (cx->type) { 811 case ACPI_STATE_C1: 812 cx->valid = 1; 813 break; 814 815 case ACPI_STATE_C2: 816 acpi_processor_power_verify_c2(cx); 817 break; 818 819 case ACPI_STATE_C3: 820 acpi_processor_power_verify_c3(pr, cx); 821 break; 822 } 823 824 if (cx->valid) 825 working++; 826 } 827 828 return (working); 829 } 830 831 static int acpi_processor_get_power_info(struct acpi_processor *pr) 832 { 833 unsigned int i; 834 int result; 835 836 ACPI_FUNCTION_TRACE("acpi_processor_get_power_info"); 837 838 /* NOTE: the idle thread may not be running while calling 839 * this function */ 840 841 result = acpi_processor_get_power_info_cst(pr); 842 if ((result) || (acpi_processor_power_verify(pr) < 2)) { 843 result = acpi_processor_get_power_info_fadt(pr); 844 if ((result) || (acpi_processor_power_verify(pr) < 2)) 845 result = acpi_processor_get_power_info_default_c1(pr); 846 } 847 848 /* 849 * Set Default Policy 850 * ------------------ 851 * Now that we know which states are supported, set the default 852 * policy. Note that this policy can be changed dynamically 853 * (e.g. encourage deeper sleeps to conserve battery life when 854 * not on AC). 855 */ 856 result = acpi_processor_set_power_policy(pr); 857 if (result) 858 return_VALUE(result); 859 860 /* 861 * if one state of type C2 or C3 is available, mark this 862 * CPU as being "idle manageable" 863 */ 864 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) { 865 if (pr->power.states[i].valid) { 866 pr->power.count = i; 867 pr->flags.power = 1; 868 } 869 } 870 871 return_VALUE(0); 872 } 873 874 int acpi_processor_cst_has_changed(struct acpi_processor *pr) 875 { 876 int result = 0; 877 878 ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed"); 879 880 if (!pr) 881 return_VALUE(-EINVAL); 882 883 if (nocst) { 884 return_VALUE(-ENODEV); 885 } 886 887 if (!pr->flags.power_setup_done) 888 return_VALUE(-ENODEV); 889 890 /* Fall back to the default idle loop */ 891 pm_idle = pm_idle_save; 892 synchronize_sched(); /* Relies on interrupts forcing exit from idle. */ 893 894 pr->flags.power = 0; 895 result = acpi_processor_get_power_info(pr); 896 if ((pr->flags.power == 1) && (pr->flags.power_setup_done)) 897 pm_idle = acpi_processor_idle; 898 899 return_VALUE(result); 900 } 901 902 /* proc interface */ 903 904 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset) 905 { 906 struct acpi_processor *pr = (struct acpi_processor *)seq->private; 907 unsigned int i; 908 909 ACPI_FUNCTION_TRACE("acpi_processor_power_seq_show"); 910 911 if (!pr) 912 goto end; 913 914 seq_printf(seq, "active state: C%zd\n" 915 "max_cstate: C%d\n" 916 "bus master activity: %08x\n", 917 pr->power.state ? pr->power.state - pr->power.states : 0, 918 max_cstate, (unsigned)pr->power.bm_activity); 919 920 seq_puts(seq, "states:\n"); 921 922 for (i = 1; i <= pr->power.count; i++) { 923 seq_printf(seq, " %cC%d: ", 924 (&pr->power.states[i] == 925 pr->power.state ? '*' : ' '), i); 926 927 if (!pr->power.states[i].valid) { 928 seq_puts(seq, "<not supported>\n"); 929 continue; 930 } 931 932 switch (pr->power.states[i].type) { 933 case ACPI_STATE_C1: 934 seq_printf(seq, "type[C1] "); 935 break; 936 case ACPI_STATE_C2: 937 seq_printf(seq, "type[C2] "); 938 break; 939 case ACPI_STATE_C3: 940 seq_printf(seq, "type[C3] "); 941 break; 942 default: 943 seq_printf(seq, "type[--] "); 944 break; 945 } 946 947 if (pr->power.states[i].promotion.state) 948 seq_printf(seq, "promotion[C%zd] ", 949 (pr->power.states[i].promotion.state - 950 pr->power.states)); 951 else 952 seq_puts(seq, "promotion[--] "); 953 954 if (pr->power.states[i].demotion.state) 955 seq_printf(seq, "demotion[C%zd] ", 956 (pr->power.states[i].demotion.state - 957 pr->power.states)); 958 else 959 seq_puts(seq, "demotion[--] "); 960 961 seq_printf(seq, "latency[%03d] usage[%08d]\n", 962 pr->power.states[i].latency, 963 pr->power.states[i].usage); 964 } 965 966 end: 967 return_VALUE(0); 968 } 969 970 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file) 971 { 972 return single_open(file, acpi_processor_power_seq_show, 973 PDE(inode)->data); 974 } 975 976 static struct file_operations acpi_processor_power_fops = { 977 .open = acpi_processor_power_open_fs, 978 .read = seq_read, 979 .llseek = seq_lseek, 980 .release = single_release, 981 }; 982 983 int acpi_processor_power_init(struct acpi_processor *pr, 984 struct acpi_device *device) 985 { 986 acpi_status status = 0; 987 static int first_run = 0; 988 struct proc_dir_entry *entry = NULL; 989 unsigned int i; 990 991 ACPI_FUNCTION_TRACE("acpi_processor_power_init"); 992 993 if (!first_run) { 994 dmi_check_system(processor_power_dmi_table); 995 if (max_cstate < ACPI_C_STATES_MAX) 996 printk(KERN_NOTICE 997 "ACPI: processor limited to max C-state %d\n", 998 max_cstate); 999 first_run++; 1000 } 1001 1002 if (!pr) 1003 return_VALUE(-EINVAL); 1004 1005 if (acpi_fadt.cst_cnt && !nocst) { 1006 status = 1007 acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8); 1008 if (ACPI_FAILURE(status)) { 1009 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 1010 "Notifying BIOS of _CST ability failed\n")); 1011 } 1012 } 1013 1014 acpi_processor_power_init_pdc(&(pr->power), pr->id); 1015 acpi_processor_set_pdc(pr, pr->power.pdc); 1016 acpi_processor_get_power_info(pr); 1017 1018 /* 1019 * Install the idle handler if processor power management is supported. 1020 * Note that we use previously set idle handler will be used on 1021 * platforms that only support C1. 1022 */ 1023 if ((pr->flags.power) && (!boot_option_idle_override)) { 1024 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id); 1025 for (i = 1; i <= pr->power.count; i++) 1026 if (pr->power.states[i].valid) 1027 printk(" C%d[C%d]", i, 1028 pr->power.states[i].type); 1029 printk(")\n"); 1030 1031 if (pr->id == 0) { 1032 pm_idle_save = pm_idle; 1033 pm_idle = acpi_processor_idle; 1034 } 1035 } 1036 1037 /* 'power' [R] */ 1038 entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER, 1039 S_IRUGO, acpi_device_dir(device)); 1040 if (!entry) 1041 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 1042 "Unable to create '%s' fs entry\n", 1043 ACPI_PROCESSOR_FILE_POWER)); 1044 else { 1045 entry->proc_fops = &acpi_processor_power_fops; 1046 entry->data = acpi_driver_data(device); 1047 entry->owner = THIS_MODULE; 1048 } 1049 1050 pr->flags.power_setup_done = 1; 1051 1052 return_VALUE(0); 1053 } 1054 1055 int acpi_processor_power_exit(struct acpi_processor *pr, 1056 struct acpi_device *device) 1057 { 1058 ACPI_FUNCTION_TRACE("acpi_processor_power_exit"); 1059 1060 pr->flags.power_setup_done = 0; 1061 1062 if (acpi_device_dir(device)) 1063 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER, 1064 acpi_device_dir(device)); 1065 1066 /* Unregister the idle handler when processor #0 is removed. */ 1067 if (pr->id == 0) { 1068 pm_idle = pm_idle_save; 1069 1070 /* 1071 * We are about to unload the current idle thread pm callback 1072 * (pm_idle), Wait for all processors to update cached/local 1073 * copies of pm_idle before proceeding. 1074 */ 1075 cpu_idle_wait(); 1076 } 1077 1078 return_VALUE(0); 1079 } 1080