drivers/acpi/processor_idle.c

   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, 2005 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/slab.h>
  36 #include <linux/proc_fs.h>
  37 #include <linux/seq_file.h>
  38 #include <linux/acpi.h>
  39 #include <linux/dmi.h>
  40 #include <linux/moduleparam.h>
  41 #include <linux/sched.h>        /* need_resched() */
  42 #include <linux/pm_qos_params.h>
  43 #include <linux/clockchips.h>
  44 #include <linux/cpuidle.h>
  45 #include <linux/irqflags.h>
  46
  47 /*
  48  * Include the apic definitions for x86 to have the APIC timer related defines
  49  * available also for UP (on SMP it gets magically included via linux/smp.h).
  50  * asm/acpi.h is not an option, as it would require more include magic. Also
  51  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
  52  */
  53 #ifdef CONFIG_X86
  54 #include <asm/apic.h>
  55 #endif
  56
  57 #include <asm/io.h>
  58 #include <asm/uaccess.h>
  59
  60 #include <acpi/acpi_bus.h>
  61 #include <acpi/processor.h>
  62 #include <asm/processor.h>
  63
  64 #define PREFIX "ACPI: "
  65
  66 #define ACPI_PROCESSOR_CLASS            "processor"
  67 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  68 ACPI_MODULE_NAME("processor_idle");
  69 #define ACPI_PROCESSOR_FILE_POWER       "power"
  70 #define PM_TIMER_TICK_NS                (1000000000ULL/PM_TIMER_FREQUENCY)
  71 #define C2_OVERHEAD                     1       /* 1us */
  72 #define C3_OVERHEAD                     1       /* 1us */
  73 #define PM_TIMER_TICKS_TO_US(p)         (((p) * 1000)/(PM_TIMER_FREQUENCY/1000))
  74
  75 static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  76 module_param(max_cstate, uint, 0000);
  77 static unsigned int nocst __read_mostly;
  78 module_param(nocst, uint, 0000);
  79
  80 static unsigned int latency_factor __read_mostly = 2;
  81 module_param(latency_factor, uint, 0644);
  82
  83 static u64 us_to_pm_timer_ticks(s64 t)
  84 {
  85         return div64_u64(t * PM_TIMER_FREQUENCY, 1000000);
  86 }
  87 /*
  88  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
  89  * For now disable this. Probably a bug somewhere else.
  90  *
  91  * To skip this limit, boot/load with a large max_cstate limit.
  92  */
  93 static int set_max_cstate(const struct dmi_system_id *id)
  94 {
  95         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  96                 return 0;
  97
  98         printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
  99                " Override with \"processor.max_cstate=%d\"\n", id->ident,
 100                (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
 101
 102         max_cstate = (long)id->driver_data;
 103
 104         return 0;
 105 }
 106
 107 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
 108    callers to only run once -AK */
 109 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
 110         { set_max_cstate, "Clevo 5600D", {
 111           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
 112           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
 113          (void *)2},
 114         { set_max_cstate, "Pavilion zv5000", {
 115           DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 116           DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
 117          (void *)1},
 118         { set_max_cstate, "Asus L8400B", {
 119           DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
 120           DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
 121          (void *)1},
 122         {},
 123 };
 124
 125
 126 /*
 127  * Callers should disable interrupts before the call and enable
 128  * interrupts after return.
 129  */
 130 static void acpi_safe_halt(void)
 131 {
 132         current_thread_info()->status &= ~TS_POLLING;
 133         /*
 134          * TS_POLLING-cleared state must be visible before we
 135          * test NEED_RESCHED:
 136          */
 137         smp_mb();
 138         if (!need_resched()) {
 139                 safe_halt();
 140                 local_irq_disable();
 141         }
 142         current_thread_info()->status |= TS_POLLING;
 143 }
 144
 145 #ifdef ARCH_APICTIMER_STOPS_ON_C3
 146
 147 /*
 148  * Some BIOS implementations switch to C3 in the published C2 state.
 149  * This seems to be a common problem on AMD boxen, but other vendors
 150  * are affected too. We pick the most conservative approach: we assume
 151  * that the local APIC stops in both C2 and C3.
 152  */
 153 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 154                                    struct acpi_processor_cx *cx)
 155 {
 156         struct acpi_processor_power *pwr = &pr->power;
 157         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
 158
 159         if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
 160                 return;
 161
 162         if (boot_cpu_has(X86_FEATURE_AMDC1E))
 163                 type = ACPI_STATE_C1;
 164
 165         /*
 166          * Check, if one of the previous states already marked the lapic
 167          * unstable
 168          */
 169         if (pwr->timer_broadcast_on_state < state)
 170                 return;
 171
 172         if (cx->type >= type)
 173                 pr->power.timer_broadcast_on_state = state;
 174 }
 175
 176 static void __lapic_timer_propagate_broadcast(void *arg)
 177 {
 178         struct acpi_processor *pr = (struct acpi_processor *) arg;
 179         unsigned long reason;
 180
 181         reason = pr->power.timer_broadcast_on_state < INT_MAX ?
 182                 CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;
 183
 184         clockevents_notify(reason, &pr->id);
 185 }
 186
 187 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
 188 {
 189         smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
 190                                  (void *)pr, 1);
 191 }
 192
 193 /* Power(C) State timer broadcast control */
 194 static void lapic_timer_state_broadcast(struct acpi_processor *pr,
 195                                        struct acpi_processor_cx *cx,
 196                                        int broadcast)
 197 {
 198         int state = cx - pr->power.states;
 199
 200         if (state >= pr->power.timer_broadcast_on_state) {
 201                 unsigned long reason;
 202
 203                 reason = broadcast ?  CLOCK_EVT_NOTIFY_BROADCAST_ENTER :
 204                         CLOCK_EVT_NOTIFY_BROADCAST_EXIT;
 205                 clockevents_notify(reason, &pr->id);
 206         }
 207 }
 208
 209 #else
 210
 211 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
 212                                    struct acpi_processor_cx *cstate) { }
 213 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
 214 static void lapic_timer_state_broadcast(struct acpi_processor *pr,
 215                                        struct acpi_processor_cx *cx,
 216                                        int broadcast)
 217 {
 218 }
 219
 220 #endif
 221
 222 /*
 223  * Suspend / resume control
 224  */
 225 static int acpi_idle_suspend;
 226 static u32 saved_bm_rld;
 227
 228 static void acpi_idle_bm_rld_save(void)
 229 {
 230         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &saved_bm_rld);
 231 }
 232 static void acpi_idle_bm_rld_restore(void)
 233 {
 234         u32 resumed_bm_rld;
 235
 236         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &resumed_bm_rld);
 237
 238         if (resumed_bm_rld != saved_bm_rld)
 239                 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, saved_bm_rld);
 240 }
 241
 242 int acpi_processor_suspend(struct acpi_device * device, pm_message_t state)
 243 {
 244         if (acpi_idle_suspend == 1)
 245                 return 0;
 246
 247         acpi_idle_bm_rld_save();
 248         acpi_idle_suspend = 1;
 249         return 0;
 250 }
 251
 252 int acpi_processor_resume(struct acpi_device * device)
 253 {
 254         if (acpi_idle_suspend == 0)
 255                 return 0;
 256
 257         acpi_idle_bm_rld_restore();
 258         acpi_idle_suspend = 0;
 259         return 0;
 260 }
 261
 262 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
 263 static void tsc_check_state(int state)
 264 {
 265         switch (boot_cpu_data.x86_vendor) {
 266         case X86_VENDOR_AMD:
 267         case X86_VENDOR_INTEL:
 268                 /*
 269                  * AMD Fam10h TSC will tick in all
 270                  * C/P/S0/S1 states when this bit is set.
 271                  */
 272                 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
 273                         return;
 274
 275                 /*FALL THROUGH*/
 276         default:
 277                 /* TSC could halt in idle, so notify users */
 278                 if (state > ACPI_STATE_C1)
 279                         mark_tsc_unstable("TSC halts in idle");
 280         }
 281 }
 282 #else
 283 static void tsc_check_state(int state) { return; }
 284 #endif
 285
 286 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 287 {
 288
 289         if (!pr)
 290                 return -EINVAL;
 291
 292         if (!pr->pblk)
 293                 return -ENODEV;
 294
 295         /* if info is obtained from pblk/fadt, type equals state */
 296         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
 297         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
 298
 299 #ifndef CONFIG_HOTPLUG_CPU
 300         /*
 301          * Check for P_LVL2_UP flag before entering C2 and above on
 302          * an SMP system.
 303          */
 304         if ((num_online_cpus() > 1) &&
 305             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
 306                 return -ENODEV;
 307 #endif
 308
 309         /* determine C2 and C3 address from pblk */
 310         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
 311         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
 312
 313         /* determine latencies from FADT */
 314         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.C2latency;
 315         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.C3latency;
 316
 317         /*
 318          * FADT specified C2 latency must be less than or equal to
 319          * 100 microseconds.
 320          */
 321         if (acpi_gbl_FADT.C2latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
 322                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 323                         "C2 latency too large [%d]\n", acpi_gbl_FADT.C2latency));
 324                 /* invalidate C2 */
 325                 pr->power.states[ACPI_STATE_C2].address = 0;
 326         }
 327
 328         /*
 329          * FADT supplied C3 latency must be less than or equal to
 330          * 1000 microseconds.
 331          */
 332         if (acpi_gbl_FADT.C3latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
 333                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 334                         "C3 latency too large [%d]\n", acpi_gbl_FADT.C3latency));
 335                 /* invalidate C3 */
 336                 pr->power.states[ACPI_STATE_C3].address = 0;
 337         }
 338
 339         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 340                           "lvl2[0x%08x] lvl3[0x%08x]\n",
 341                           pr->power.states[ACPI_STATE_C2].address,
 342                           pr->power.states[ACPI_STATE_C3].address));
 343
 344         return 0;
 345 }
 346
 347 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
 348 {
 349         if (!pr->power.states[ACPI_STATE_C1].valid) {
 350                 /* set the first C-State to C1 */
 351                 /* all processors need to support C1 */
 352                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
 353                 pr->power.states[ACPI_STATE_C1].valid = 1;
 354                 pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
 355         }
 356         /* the C0 state only exists as a filler in our array */
 357         pr->power.states[ACPI_STATE_C0].valid = 1;
 358         return 0;
 359 }
 360
 361 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
 362 {
 363         acpi_status status = 0;
 364         u64 count;
 365         int current_count;
 366         int i;
 367         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 368         union acpi_object *cst;
 369
 370
 371         if (nocst)
 372                 return -ENODEV;
 373
 374         current_count = 0;
 375
 376         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
 377         if (ACPI_FAILURE(status)) {
 378                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
 379                 return -ENODEV;
 380         }
 381
 382         cst = buffer.pointer;
 383
 384         /* There must be at least 2 elements */
 385         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
 386                 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
 387                 status = -EFAULT;
 388                 goto end;
 389         }
 390
 391         count = cst->package.elements[0].integer.value;
 392
 393         /* Validate number of power states. */
 394         if (count < 1 || count != cst->package.count - 1) {
 395                 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
 396                 status = -EFAULT;
 397                 goto end;
 398         }
 399
 400         /* Tell driver that at least _CST is supported. */
 401         pr->flags.has_cst = 1;
 402
 403         for (i = 1; i <= count; i++) {
 404                 union acpi_object *element;
 405                 union acpi_object *obj;
 406                 struct acpi_power_register *reg;
 407                 struct acpi_processor_cx cx;
 408
 409                 memset(&cx, 0, sizeof(cx));
 410
 411                 element = &(cst->package.elements[i]);
 412                 if (element->type != ACPI_TYPE_PACKAGE)
 413                         continue;
 414
 415                 if (element->package.count != 4)
 416                         continue;
 417
 418                 obj = &(element->package.elements[0]);
 419
 420                 if (obj->type != ACPI_TYPE_BUFFER)
 421                         continue;
 422
 423                 reg = (struct acpi_power_register *)obj->buffer.pointer;
 424
 425                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
 426                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
 427                         continue;
 428
 429                 /* There should be an easy way to extract an integer... */
 430                 obj = &(element->package.elements[1]);
 431                 if (obj->type != ACPI_TYPE_INTEGER)
 432                         continue;
 433
 434                 cx.type = obj->integer.value;
 435                 /*
 436                  * Some buggy BIOSes won't list C1 in _CST -
 437                  * Let acpi_processor_get_power_info_default() handle them later
 438                  */
 439                 if (i == 1 && cx.type != ACPI_STATE_C1)
 440                         current_count++;
 441
 442                 cx.address = reg->address;
 443                 cx.index = current_count + 1;
 444
 445                 cx.entry_method = ACPI_CSTATE_SYSTEMIO;
 446                 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
 447                         if (acpi_processor_ffh_cstate_probe
 448                                         (pr->id, &cx, reg) == 0) {
 449                                 cx.entry_method = ACPI_CSTATE_FFH;
 450                         } else if (cx.type == ACPI_STATE_C1) {
 451                                 /*
 452                                  * C1 is a special case where FIXED_HARDWARE
 453                                  * can be handled in non-MWAIT way as well.
 454                                  * In that case, save this _CST entry info.
 455                                  * Otherwise, ignore this info and continue.
 456                                  */
 457                                 cx.entry_method = ACPI_CSTATE_HALT;
 458                                 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
 459                         } else {
 460                                 continue;
 461                         }
 462                         if (cx.type == ACPI_STATE_C1 &&
 463                                         (idle_halt || idle_nomwait)) {
 464                                 /*
 465                                  * In most cases the C1 space_id obtained from
 466                                  * _CST object is FIXED_HARDWARE access mode.
 467                                  * But when the option of idle=halt is added,
 468                                  * the entry_method type should be changed from
 469                                  * CSTATE_FFH to CSTATE_HALT.
 470                                  * When the option of idle=nomwait is added,
 471                                  * the C1 entry_method type should be
 472                                  * CSTATE_HALT.
 473                                  */
 474                                 cx.entry_method = ACPI_CSTATE_HALT;
 475                                 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
 476                         }
 477                 } else {
 478                         snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
 479                                  cx.address);
 480                 }
 481
 482                 if (cx.type == ACPI_STATE_C1) {
 483                         cx.valid = 1;
 484                 }
 485
 486                 obj = &(element->package.elements[2]);
 487                 if (obj->type != ACPI_TYPE_INTEGER)
 488                         continue;
 489
 490                 cx.latency = obj->integer.value;
 491
 492                 obj = &(element->package.elements[3]);
 493                 if (obj->type != ACPI_TYPE_INTEGER)
 494                         continue;
 495
 496                 cx.power = obj->integer.value;
 497
 498                 current_count++;
 499                 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
 500
 501                 /*
 502                  * We support total ACPI_PROCESSOR_MAX_POWER - 1
 503                  * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
 504                  */
 505                 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
 506                         printk(KERN_WARNING
 507                                "Limiting number of power states to max (%d)\n",
 508                                ACPI_PROCESSOR_MAX_POWER);
 509                         printk(KERN_WARNING
 510                                "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
 511                         break;
 512                 }
 513         }
 514
 515         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
 516                           current_count));
 517
 518         /* Validate number of power states discovered */
 519         if (current_count < 2)
 520                 status = -EFAULT;
 521
 522       end:
 523         kfree(buffer.pointer);
 524
 525         return status;
 526 }
 527
 528 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
 529                                            struct acpi_processor_cx *cx)
 530 {
 531         static int bm_check_flag = -1;
 532         static int bm_control_flag = -1;
 533
 534
 535         if (!cx->address)
 536                 return;
 537
 538         /*
 539          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
 540          * DMA transfers are used by any ISA device to avoid livelock.
 541          * Note that we could disable Type-F DMA (as recommended by
 542          * the erratum), but this is known to disrupt certain ISA
 543          * devices thus we take the conservative approach.
 544          */
 545         else if (errata.piix4.fdma) {
 546                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 547                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
 548                 return;
 549         }
 550
 551         /* All the logic here assumes flags.bm_check is same across all CPUs */
 552         if (bm_check_flag == -1) {
 553                 /* Determine whether bm_check is needed based on CPU  */
 554                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
 555                 bm_check_flag = pr->flags.bm_check;
 556                 bm_control_flag = pr->flags.bm_control;
 557         } else {
 558                 pr->flags.bm_check = bm_check_flag;
 559                 pr->flags.bm_control = bm_control_flag;
 560         }
 561
 562         if (pr->flags.bm_check) {
 563                 if (!pr->flags.bm_control) {
 564                         if (pr->flags.has_cst != 1) {
 565                                 /* bus mastering control is necessary */
 566                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 567                                         "C3 support requires BM control\n"));
 568                                 return;
 569                         } else {
 570                                 /* Here we enter C3 without bus mastering */
 571                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 572                                         "C3 support without BM control\n"));
 573                         }
 574                 }
 575         } else {
 576                 /*
 577                  * WBINVD should be set in fadt, for C3 state to be
 578                  * supported on when bm_check is not required.
 579                  */
 580                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
 581                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 582                                           "Cache invalidation should work properly"
 583                                           " for C3 to be enabled on SMP systems\n"));
 584                         return;
 585                 }
 586         }
 587
 588         /*
 589          * Otherwise we've met all of our C3 requirements.
 590          * Normalize the C3 latency to expidite policy.  Enable
 591          * checking of bus mastering status (bm_check) so we can
 592          * use this in our C3 policy
 593          */
 594         cx->valid = 1;
 595
 596         cx->latency_ticks = cx->latency;
 597         /*
 598          * On older chipsets, BM_RLD needs to be set
 599          * in order for Bus Master activity to wake the
 600          * system from C3.  Newer chipsets handle DMA
 601          * during C3 automatically and BM_RLD is a NOP.
 602          * In either case, the proper way to
 603          * handle BM_RLD is to set it and leave it set.
 604          */
 605         acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
 606
 607         return;
 608 }
 609
 610 static int acpi_processor_power_verify(struct acpi_processor *pr)
 611 {
 612         unsigned int i;
 613         unsigned int working = 0;
 614
 615         pr->power.timer_broadcast_on_state = INT_MAX;
 616
 617         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
 618                 struct acpi_processor_cx *cx = &pr->power.states[i];
 619
 620                 switch (cx->type) {
 621                 case ACPI_STATE_C1:
 622                         cx->valid = 1;
 623                         break;
 624
 625                 case ACPI_STATE_C2:
 626                         if (!cx->address)
 627                                 break;
 628                         cx->valid = 1;
 629                         cx->latency_ticks = cx->latency; /* Normalize latency */
 630                         break;
 631
 632                 case ACPI_STATE_C3:
 633                         acpi_processor_power_verify_c3(pr, cx);
 634                         break;
 635                 }
 636                 if (!cx->valid)
 637                         continue;
 638
 639                 lapic_timer_check_state(i, pr, cx);
 640                 tsc_check_state(cx->type);
 641                 working++;
 642         }
 643
 644         lapic_timer_propagate_broadcast(pr);
 645
 646         return (working);
 647 }
 648
 649 static int acpi_processor_get_power_info(struct acpi_processor *pr)
 650 {
 651         unsigned int i;
 652         int result;
 653
 654
 655         /* NOTE: the idle thread may not be running while calling
 656          * this function */
 657
 658         /* Zero initialize all the C-states info. */
 659         memset(pr->power.states, 0, sizeof(pr->power.states));
 660
 661         result = acpi_processor_get_power_info_cst(pr);
 662         if (result == -ENODEV)
 663                 result = acpi_processor_get_power_info_fadt(pr);
 664
 665         if (result)
 666                 return result;
 667
 668         acpi_processor_get_power_info_default(pr);
 669
 670         pr->power.count = acpi_processor_power_verify(pr);
 671
 672         /*
 673          * if one state of type C2 or C3 is available, mark this
 674          * CPU as being "idle manageable"
 675          */
 676         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 677                 if (pr->power.states[i].valid) {
 678                         pr->power.count = i;
 679                         if (pr->power.states[i].type >= ACPI_STATE_C2)
 680                                 pr->flags.power = 1;
 681                 }
 682         }
 683
 684         return 0;
 685 }
 686
 687 #ifdef CONFIG_ACPI_PROCFS
 688 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
 689 {
 690         struct acpi_processor *pr = seq->private;
 691         unsigned int i;
 692
 693
 694         if (!pr)
 695                 goto end;
 696
 697         seq_printf(seq, "active state:            C%zd\n"
 698                    "max_cstate:              C%d\n"
 699                    "maximum allowed latency: %d usec\n",
 700                    pr->power.state ? pr->power.state - pr->power.states : 0,
 701                    max_cstate, pm_qos_request(PM_QOS_CPU_DMA_LATENCY));
 702
 703         seq_puts(seq, "states:\n");
 704
 705         for (i = 1; i <= pr->power.count; i++) {
 706                 seq_printf(seq, "   %cC%d:                  ",
 707                            (&pr->power.states[i] ==
 708                             pr->power.state ? '*' : ' '), i);
 709
 710                 if (!pr->power.states[i].valid) {
 711                         seq_puts(seq, "<not supported>\n");
 712                         continue;
 713                 }
 714
 715                 switch (pr->power.states[i].type) {
 716                 case ACPI_STATE_C1:
 717                         seq_printf(seq, "type[C1] ");
 718                         break;
 719                 case ACPI_STATE_C2:
 720                         seq_printf(seq, "type[C2] ");
 721                         break;
 722                 case ACPI_STATE_C3:
 723                         seq_printf(seq, "type[C3] ");
 724                         break;
 725                 default:
 726                         seq_printf(seq, "type[--] ");
 727                         break;
 728                 }
 729
 730                 seq_puts(seq, "promotion[--] ");
 731
 732                 seq_puts(seq, "demotion[--] ");
 733
 734                 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020Lu]\n",
 735                            pr->power.states[i].latency,
 736                            pr->power.states[i].usage,
 737                            us_to_pm_timer_ticks(pr->power.states[i].time));
 738         }
 739
 740       end:
 741         return 0;
 742 }
 743
 744 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
 745 {
 746         return single_open(file, acpi_processor_power_seq_show,
 747                            PDE(inode)->data);
 748 }
 749
 750 static const struct file_operations acpi_processor_power_fops = {
 751         .owner = THIS_MODULE,
 752         .open = acpi_processor_power_open_fs,
 753         .read = seq_read,
 754         .llseek = seq_lseek,
 755         .release = single_release,
 756 };
 757 #endif
 758
 759 /**
 760  * acpi_idle_bm_check - checks if bus master activity was detected
 761  */
 762 static int acpi_idle_bm_check(void)
 763 {
 764         u32 bm_status = 0;
 765
 766         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
 767         if (bm_status)
 768                 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
 769         /*
 770          * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
 771          * the true state of bus mastering activity; forcing us to
 772          * manually check the BMIDEA bit of each IDE channel.
 773          */
 774         else if (errata.piix4.bmisx) {
 775                 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
 776                     || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
 777                         bm_status = 1;
 778         }
 779         return bm_status;
 780 }
 781
 782 /**
 783  * acpi_idle_do_entry - a helper function that does C2 and C3 type entry
 784  * @cx: cstate data
 785  *
 786  * Caller disables interrupt before call and enables interrupt after return.
 787  */
 788 static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx)
 789 {
 790         /* Don't trace irqs off for idle */
 791         stop_critical_timings();
 792         if (cx->entry_method == ACPI_CSTATE_FFH) {
 793                 /* Call into architectural FFH based C-state */
 794                 acpi_processor_ffh_cstate_enter(cx);
 795         } else if (cx->entry_method == ACPI_CSTATE_HALT) {
 796                 acpi_safe_halt();
 797         } else {
 798                 int unused;
 799                 /* IO port based C-state */
 800                 inb(cx->address);
 801                 /* Dummy wait op - must do something useless after P_LVL2 read
 802                    because chipsets cannot guarantee that STPCLK# signal
 803                    gets asserted in time to freeze execution properly. */
 804                 unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
 805         }
 806         start_critical_timings();
 807 }
 808
 809 /**
 810  * acpi_idle_enter_c1 - enters an ACPI C1 state-type
 811  * @dev: the target CPU
 812  * @state: the state data
 813  *
 814  * This is equivalent to the HALT instruction.
 815  */
 816 static int acpi_idle_enter_c1(struct cpuidle_device *dev,
 817                               struct cpuidle_state *state)
 818 {
 819         ktime_t  kt1, kt2;
 820         s64 idle_time;
 821         struct acpi_processor *pr;
 822         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
 823
 824         pr = __get_cpu_var(processors);
 825
 826         if (unlikely(!pr))
 827                 return 0;
 828
 829         local_irq_disable();
 830
 831         /* Do not access any ACPI IO ports in suspend path */
 832         if (acpi_idle_suspend) {
 833                 local_irq_enable();
 834                 cpu_relax();
 835                 return 0;
 836         }
 837
 838         lapic_timer_state_broadcast(pr, cx, 1);
 839         kt1 = ktime_get_real();
 840         acpi_idle_do_entry(cx);
 841         kt2 = ktime_get_real();
 842         idle_time =  ktime_to_us(ktime_sub(kt2, kt1));
 843
 844         local_irq_enable();
 845         cx->usage++;
 846         lapic_timer_state_broadcast(pr, cx, 0);
 847
 848         return idle_time;
 849 }
 850
 851 /**
 852  * acpi_idle_enter_simple - enters an ACPI state without BM handling
 853  * @dev: the target CPU
 854  * @state: the state data
 855  */
 856 static int acpi_idle_enter_simple(struct cpuidle_device *dev,
 857                                   struct cpuidle_state *state)
 858 {
 859         struct acpi_processor *pr;
 860         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
 861         ktime_t  kt1, kt2;
 862         s64 idle_time_ns;
 863         s64 idle_time;
 864
 865         pr = __get_cpu_var(processors);
 866
 867         if (unlikely(!pr))
 868                 return 0;
 869
 870         if (acpi_idle_suspend)
 871                 return(acpi_idle_enter_c1(dev, state));
 872
 873         local_irq_disable();
 874
 875         if (cx->entry_method != ACPI_CSTATE_FFH) {
 876                 current_thread_info()->status &= ~TS_POLLING;
 877                 /*
 878                  * TS_POLLING-cleared state must be visible before we test
 879                  * NEED_RESCHED:
 880                  */
 881                 smp_mb();
 882
 883                 if (unlikely(need_resched())) {
 884                         current_thread_info()->status |= TS_POLLING;
 885                         local_irq_enable();
 886                         return 0;
 887                 }
 888         }
 889
 890         /*
 891          * Must be done before busmaster disable as we might need to
 892          * access HPET !
 893          */
 894         lapic_timer_state_broadcast(pr, cx, 1);
 895
 896         if (cx->type == ACPI_STATE_C3)
 897                 ACPI_FLUSH_CPU_CACHE();
 898
 899         kt1 = ktime_get_real();
 900         /* Tell the scheduler that we are going deep-idle: */
 901         sched_clock_idle_sleep_event();
 902         acpi_idle_do_entry(cx);
 903         kt2 = ktime_get_real();
 904         idle_time_ns = ktime_to_ns(ktime_sub(kt2, kt1));
 905         idle_time = idle_time_ns;
 906         do_div(idle_time, NSEC_PER_USEC);
 907
 908         /* Tell the scheduler how much we idled: */
 909         sched_clock_idle_wakeup_event(idle_time_ns);
 910
 911         local_irq_enable();
 912         if (cx->entry_method != ACPI_CSTATE_FFH)
 913                 current_thread_info()->status |= TS_POLLING;
 914
 915         cx->usage++;
 916
 917         lapic_timer_state_broadcast(pr, cx, 0);
 918         cx->time += idle_time;
 919         return idle_time;
 920 }
 921
 922 static int c3_cpu_count;
 923 static DEFINE_SPINLOCK(c3_lock);
 924
 925 /**
 926  * acpi_idle_enter_bm - enters C3 with proper BM handling
 927  * @dev: the target CPU
 928  * @state: the state data
 929  *
 930  * If BM is detected, the deepest non-C3 idle state is entered instead.
 931  */
 932 static int acpi_idle_enter_bm(struct cpuidle_device *dev,
 933                               struct cpuidle_state *state)
 934 {
 935         struct acpi_processor *pr;
 936         struct acpi_processor_cx *cx = cpuidle_get_statedata(state);
 937         ktime_t  kt1, kt2;
 938         s64 idle_time_ns;
 939         s64 idle_time;
 940
 941
 942         pr = __get_cpu_var(processors);
 943
 944         if (unlikely(!pr))
 945                 return 0;
 946
 947         if (acpi_idle_suspend)
 948                 return(acpi_idle_enter_c1(dev, state));
 949
 950         if (acpi_idle_bm_check()) {
 951                 if (dev->safe_state) {
 952                         dev->last_state = dev->safe_state;
 953                         return dev->safe_state->enter(dev, dev->safe_state);
 954                 } else {
 955                         local_irq_disable();
 956                         acpi_safe_halt();
 957                         local_irq_enable();
 958                         return 0;
 959                 }
 960         }
 961
 962         local_irq_disable();
 963
 964         if (cx->entry_method != ACPI_CSTATE_FFH) {
 965                 current_thread_info()->status &= ~TS_POLLING;
 966                 /*
 967                  * TS_POLLING-cleared state must be visible before we test
 968                  * NEED_RESCHED:
 969                  */
 970                 smp_mb();
 971
 972                 if (unlikely(need_resched())) {
 973                         current_thread_info()->status |= TS_POLLING;
 974                         local_irq_enable();
 975                         return 0;
 976                 }
 977         }
 978
 979         acpi_unlazy_tlb(smp_processor_id());
 980
 981         /* Tell the scheduler that we are going deep-idle: */
 982         sched_clock_idle_sleep_event();
 983         /*
 984          * Must be done before busmaster disable as we might need to
 985          * access HPET !
 986          */
 987         lapic_timer_state_broadcast(pr, cx, 1);
 988
 989         kt1 = ktime_get_real();
 990         /*
 991          * disable bus master
 992          * bm_check implies we need ARB_DIS
 993          * !bm_check implies we need cache flush
 994          * bm_control implies whether we can do ARB_DIS
 995          *
 996          * That leaves a case where bm_check is set and bm_control is
 997          * not set. In that case we cannot do much, we enter C3
 998          * without doing anything.
 999          */
1000         if (pr->flags.bm_check && pr->flags.bm_control) {
1001                 spin_lock(&c3_lock);
1002                 c3_cpu_count++;
1003                 /* Disable bus master arbitration when all CPUs are in C3 */
1004                 if (c3_cpu_count == num_online_cpus())
1005                         acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
1006                 spin_unlock(&c3_lock);
1007         } else if (!pr->flags.bm_check) {
1008                 ACPI_FLUSH_CPU_CACHE();
1009         }
1010
1011         acpi_idle_do_entry(cx);
1012
1013         /* Re-enable bus master arbitration */
1014         if (pr->flags.bm_check && pr->flags.bm_control) {
1015                 spin_lock(&c3_lock);
1016                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
1017                 c3_cpu_count--;
1018                 spin_unlock(&c3_lock);
1019         }
1020         kt2 = ktime_get_real();
1021         idle_time_ns = ktime_to_ns(ktime_sub(kt2, kt1));
1022         idle_time = idle_time_ns;
1023         do_div(idle_time, NSEC_PER_USEC);
1024
1025         /* Tell the scheduler how much we idled: */
1026         sched_clock_idle_wakeup_event(idle_time_ns);
1027
1028         local_irq_enable();
1029         if (cx->entry_method != ACPI_CSTATE_FFH)
1030                 current_thread_info()->status |= TS_POLLING;
1031
1032         cx->usage++;
1033
1034         lapic_timer_state_broadcast(pr, cx, 0);
1035         cx->time += idle_time;
1036         return idle_time;
1037 }
1038
1039 struct cpuidle_driver acpi_idle_driver = {
1040         .name =         "acpi_idle",
1041         .owner =        THIS_MODULE,
1042 };
1043
1044 /**
1045  * acpi_processor_setup_cpuidle - prepares and configures CPUIDLE
1046  * @pr: the ACPI processor
1047  */
1048 static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
1049 {
1050         int i, count = CPUIDLE_DRIVER_STATE_START;
1051         struct acpi_processor_cx *cx;
1052         struct cpuidle_state *state;
1053         struct cpuidle_device *dev = &pr->power.dev;
1054
1055         if (!pr->flags.power_setup_done)
1056                 return -EINVAL;
1057
1058         if (pr->flags.power == 0) {
1059                 return -EINVAL;
1060         }
1061
1062         dev->cpu = pr->id;
1063         for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
1064                 dev->states[i].name[0] = '\0';
1065                 dev->states[i].desc[0] = '\0';
1066         }
1067
1068         if (max_cstate == 0)
1069                 max_cstate = 1;
1070
1071         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
1072                 cx = &pr->power.states[i];
1073                 state = &dev->states[count];
1074
1075                 if (!cx->valid)
1076                         continue;
1077
1078 #ifdef CONFIG_HOTPLUG_CPU
1079                 if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
1080                     !pr->flags.has_cst &&
1081                     !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
1082                         continue;
1083 #endif
1084                 cpuidle_set_statedata(state, cx);
1085
1086                 snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
1087                 strncpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
1088                 state->exit_latency = cx->latency;
1089                 state->target_residency = cx->latency * latency_factor;
1090                 state->power_usage = cx->power;
1091
1092                 state->flags = 0;
1093                 switch (cx->type) {
1094                         case ACPI_STATE_C1:
1095                         state->flags |= CPUIDLE_FLAG_SHALLOW;
1096                         if (cx->entry_method == ACPI_CSTATE_FFH)
1097                                 state->flags |= CPUIDLE_FLAG_TIME_VALID;
1098
1099                         state->enter = acpi_idle_enter_c1;
1100                         dev->safe_state = state;
1101                         break;
1102
1103                         case ACPI_STATE_C2:
1104                         state->flags |= CPUIDLE_FLAG_BALANCED;
1105                         state->flags |= CPUIDLE_FLAG_TIME_VALID;
1106                         state->enter = acpi_idle_enter_simple;
1107                         dev->safe_state = state;
1108                         break;
1109
1110                         case ACPI_STATE_C3:
1111                         state->flags |= CPUIDLE_FLAG_DEEP;
1112                         state->flags |= CPUIDLE_FLAG_TIME_VALID;
1113                         state->flags |= CPUIDLE_FLAG_CHECK_BM;
1114                         state->enter = pr->flags.bm_check ?
1115                                         acpi_idle_enter_bm :
1116                                         acpi_idle_enter_simple;
1117                         break;
1118                 }
1119
1120                 count++;
1121                 if (count == CPUIDLE_STATE_MAX)
1122                         break;
1123         }
1124
1125         dev->state_count = count;
1126
1127         if (!count)
1128                 return -EINVAL;
1129
1130         return 0;
1131 }
1132
1133 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
1134 {
1135         int ret = 0;
1136
1137         if (boot_option_idle_override)
1138                 return 0;
1139
1140         if (!pr)
1141                 return -EINVAL;
1142
1143         if (nocst) {
1144                 return -ENODEV;
1145         }
1146
1147         if (!pr->flags.power_setup_done)
1148                 return -ENODEV;
1149
1150         cpuidle_pause_and_lock();
1151         cpuidle_disable_device(&pr->power.dev);
1152         acpi_processor_get_power_info(pr);
1153         if (pr->flags.power) {
1154                 acpi_processor_setup_cpuidle(pr);
1155                 ret = cpuidle_enable_device(&pr->power.dev);
1156         }
1157         cpuidle_resume_and_unlock();
1158
1159         return ret;
1160 }
1161
1162 int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
1163                               struct acpi_device *device)
1164 {
1165         acpi_status status = 0;
1166         static int first_run;
1167 #ifdef CONFIG_ACPI_PROCFS
1168         struct proc_dir_entry *entry = NULL;
1169 #endif
1170
1171         if (boot_option_idle_override)
1172                 return 0;
1173
1174         if (!first_run) {
1175                 if (idle_halt) {
1176                         /*
1177                          * When the boot option of "idle=halt" is added, halt
1178                          * is used for CPU IDLE.
1179                          * In such case C2/C3 is meaningless. So the max_cstate
1180                          * is set to one.
1181                          */
1182                         max_cstate = 1;
1183                 }
1184                 dmi_check_system(processor_power_dmi_table);
1185                 max_cstate = acpi_processor_cstate_check(max_cstate);
1186                 if (max_cstate < ACPI_C_STATES_MAX)
1187                         printk(KERN_NOTICE
1188                                "ACPI: processor limited to max C-state %d\n",
1189                                max_cstate);
1190                 first_run++;
1191         }
1192
1193         if (!pr)
1194                 return -EINVAL;
1195
1196         if (acpi_gbl_FADT.cst_control && !nocst) {
1197                 status =
1198                     acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8);
1199                 if (ACPI_FAILURE(status)) {
1200                         ACPI_EXCEPTION((AE_INFO, status,
1201                                         "Notifying BIOS of _CST ability failed"));
1202                 }
1203         }
1204
1205         acpi_processor_get_power_info(pr);
1206         pr->flags.power_setup_done = 1;
1207
1208         /*
1209          * Install the idle handler if processor power management is supported.
1210          * Note that we use previously set idle handler will be used on
1211          * platforms that only support C1.
1212          */
1213         if (pr->flags.power) {
1214                 acpi_processor_setup_cpuidle(pr);
1215                 if (cpuidle_register_device(&pr->power.dev))
1216                         return -EIO;
1217         }
1218 #ifdef CONFIG_ACPI_PROCFS
1219         /* 'power' [R] */
1220         entry = proc_create_data(ACPI_PROCESSOR_FILE_POWER,
1221                                  S_IRUGO, acpi_device_dir(device),
1222                                  &acpi_processor_power_fops,
1223                                  acpi_driver_data(device));
1224         if (!entry)
1225                 return -EIO;
1226 #endif
1227         return 0;
1228 }
1229
1230 int acpi_processor_power_exit(struct acpi_processor *pr,
1231                               struct acpi_device *device)
1232 {
1233         if (boot_option_idle_override)
1234                 return 0;
1235
1236         cpuidle_unregister_device(&pr->power.dev);
1237         pr->flags.power_setup_done = 0;
1238
1239 #ifdef CONFIG_ACPI_PROCFS
1240         if (acpi_device_dir(device))
1241                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1242                                   acpi_device_dir(device));
1243 #endif
1244
1245         return 0;
1246 }