arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c

   1 /*
   2  * acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.4 $)
   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) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
   7  *  Copyright (C) 2006       Denis Sadykov <denis.m.sadykov@intel.com>
   8  *
   9  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License as published by
  13  *  the Free Software Foundation; either version 2 of the License, or (at
  14  *  your option) any later version.
  15  *
  16  *  This program is distributed in the hope that it will be useful, but
  17  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  *  General Public License for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License along
  22  *  with this program; if not, write to the Free Software Foundation, Inc.,
  23  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  24  *
  25  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/init.h>
  31 #include <linux/smp.h>
  32 #include <linux/sched.h>
  33 #include <linux/cpufreq.h>
  34 #include <linux/compiler.h>
  35 #include <linux/dmi.h>
  36
  37 #include <linux/acpi.h>
  38 #include <acpi/processor.h>
  39
  40 #include <asm/io.h>
  41 #include <asm/msr.h>
  42 #include <asm/processor.h>
  43 #include <asm/cpufeature.h>
  44 #include <asm/delay.h>
  45 #include <asm/uaccess.h>
  46
  47 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
  48
  49 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
  50 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  51 MODULE_LICENSE("GPL");
  52
  53 enum {
  54         UNDEFINED_CAPABLE = 0,
  55         SYSTEM_INTEL_MSR_CAPABLE,
  56         SYSTEM_IO_CAPABLE,
  57 };
  58
  59 #define INTEL_MSR_RANGE         (0xffff)
  60 #define CPUID_6_ECX_APERFMPERF_CAPABILITY       (0x1)
  61
  62 struct acpi_cpufreq_data {
  63         struct acpi_processor_performance *acpi_data;
  64         struct cpufreq_frequency_table *freq_table;
  65         unsigned int max_freq;
  66         unsigned int resume;
  67         unsigned int cpu_feature;
  68 };
  69
  70 static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data);
  71
  72 /* acpi_perf_data is a pointer to percpu data. */
  73 static struct acpi_processor_performance *acpi_perf_data;
  74
  75 static struct cpufreq_driver acpi_cpufreq_driver;
  76
  77 static unsigned int acpi_pstate_strict;
  78
  79 static int check_est_cpu(unsigned int cpuid)
  80 {
  81         struct cpuinfo_x86 *cpu = &cpu_data(cpuid);
  82
  83         if (cpu->x86_vendor != X86_VENDOR_INTEL ||
  84             !cpu_has(cpu, X86_FEATURE_EST))
  85                 return 0;
  86
  87         return 1;
  88 }
  89
  90 static unsigned extract_io(u32 value, struct acpi_cpufreq_data *data)
  91 {
  92         struct acpi_processor_performance *perf;
  93         int i;
  94
  95         perf = data->acpi_data;
  96
  97         for (i=0; i<perf->state_count; i++) {
  98                 if (value == perf->states[i].status)
  99                         return data->freq_table[i].frequency;
 100         }
 101         return 0;
 102 }
 103
 104 static unsigned extract_msr(u32 msr, struct acpi_cpufreq_data *data)
 105 {
 106         int i;
 107         struct acpi_processor_performance *perf;
 108
 109         msr &= INTEL_MSR_RANGE;
 110         perf = data->acpi_data;
 111
 112         for (i=0; data->freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 113                 if (msr == perf->states[data->freq_table[i].index].status)
 114                         return data->freq_table[i].frequency;
 115         }
 116         return data->freq_table[0].frequency;
 117 }
 118
 119 static unsigned extract_freq(u32 val, struct acpi_cpufreq_data *data)
 120 {
 121         switch (data->cpu_feature) {
 122         case SYSTEM_INTEL_MSR_CAPABLE:
 123                 return extract_msr(val, data);
 124         case SYSTEM_IO_CAPABLE:
 125                 return extract_io(val, data);
 126         default:
 127                 return 0;
 128         }
 129 }
 130
 131 struct msr_addr {
 132         u32 reg;
 133 };
 134
 135 struct io_addr {
 136         u16 port;
 137         u8 bit_width;
 138 };
 139
 140 typedef union {
 141         struct msr_addr msr;
 142         struct io_addr io;
 143 } drv_addr_union;
 144
 145 struct drv_cmd {
 146         unsigned int type;
 147         cpumask_t mask;
 148         drv_addr_union addr;
 149         u32 val;
 150 };
 151
 152 static void do_drv_read(struct drv_cmd *cmd)
 153 {
 154         u32 h;
 155
 156         switch (cmd->type) {
 157         case SYSTEM_INTEL_MSR_CAPABLE:
 158                 rdmsr(cmd->addr.msr.reg, cmd->val, h);
 159                 break;
 160         case SYSTEM_IO_CAPABLE:
 161                 acpi_os_read_port((acpi_io_address)cmd->addr.io.port,
 162                                 &cmd->val,
 163                                 (u32)cmd->addr.io.bit_width);
 164                 break;
 165         default:
 166                 break;
 167         }
 168 }
 169
 170 static void do_drv_write(struct drv_cmd *cmd)
 171 {
 172         u32 lo, hi;
 173
 174         switch (cmd->type) {
 175         case SYSTEM_INTEL_MSR_CAPABLE:
 176                 rdmsr(cmd->addr.msr.reg, lo, hi);
 177                 lo = (lo & ~INTEL_MSR_RANGE) | (cmd->val & INTEL_MSR_RANGE);
 178                 wrmsr(cmd->addr.msr.reg, lo, hi);
 179                 break;
 180         case SYSTEM_IO_CAPABLE:
 181                 acpi_os_write_port((acpi_io_address)cmd->addr.io.port,
 182                                 cmd->val,
 183                                 (u32)cmd->addr.io.bit_width);
 184                 break;
 185         default:
 186                 break;
 187         }
 188 }
 189
 190 static void drv_read(struct drv_cmd *cmd)
 191 {
 192         cpumask_t saved_mask = current->cpus_allowed;
 193         cmd->val = 0;
 194
 195         set_cpus_allowed(current, cmd->mask);
 196         do_drv_read(cmd);
 197         set_cpus_allowed(current, saved_mask);
 198 }
 199
 200 static void drv_write(struct drv_cmd *cmd)
 201 {
 202         cpumask_t saved_mask = current->cpus_allowed;
 203         unsigned int i;
 204
 205         for_each_cpu_mask(i, cmd->mask) {
 206                 set_cpus_allowed(current, cpumask_of_cpu(i));
 207                 do_drv_write(cmd);
 208         }
 209
 210         set_cpus_allowed(current, saved_mask);
 211         return;
 212 }
 213
 214 static u32 get_cur_val(cpumask_t mask)
 215 {
 216         struct acpi_processor_performance *perf;
 217         struct drv_cmd cmd;
 218
 219         if (unlikely(cpus_empty(mask)))
 220                 return 0;
 221
 222         switch (per_cpu(drv_data, first_cpu(mask))->cpu_feature) {
 223         case SYSTEM_INTEL_MSR_CAPABLE:
 224                 cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
 225                 cmd.addr.msr.reg = MSR_IA32_PERF_STATUS;
 226                 break;
 227         case SYSTEM_IO_CAPABLE:
 228                 cmd.type = SYSTEM_IO_CAPABLE;
 229                 perf = per_cpu(drv_data, first_cpu(mask))->acpi_data;
 230                 cmd.addr.io.port = perf->control_register.address;
 231                 cmd.addr.io.bit_width = perf->control_register.bit_width;
 232                 break;
 233         default:
 234                 return 0;
 235         }
 236
 237         cmd.mask = mask;
 238
 239         drv_read(&cmd);
 240
 241         dprintk("get_cur_val = %u\n", cmd.val);
 242
 243         return cmd.val;
 244 }
 245
 246 /*
 247  * Return the measured active (C0) frequency on this CPU since last call
 248  * to this function.
 249  * Input: cpu number
 250  * Return: Average CPU frequency in terms of max frequency (zero on error)
 251  *
 252  * We use IA32_MPERF and IA32_APERF MSRs to get the measured performance
 253  * over a period of time, while CPU is in C0 state.
 254  * IA32_MPERF counts at the rate of max advertised frequency
 255  * IA32_APERF counts at the rate of actual CPU frequency
 256  * Only IA32_APERF/IA32_MPERF ratio is architecturally defined and
 257  * no meaning should be associated with absolute values of these MSRs.
 258  */
 259 static unsigned int get_measured_perf(unsigned int cpu)
 260 {
 261         union {
 262                 struct {
 263                         u32 lo;
 264                         u32 hi;
 265                 } split;
 266                 u64 whole;
 267         } aperf_cur, mperf_cur;
 268
 269         cpumask_t saved_mask;
 270         unsigned int perf_percent;
 271         unsigned int retval;
 272
 273         saved_mask = current->cpus_allowed;
 274         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 275         if (get_cpu() != cpu) {
 276                 /* We were not able to run on requested processor */
 277                 put_cpu();
 278                 return 0;
 279         }
 280
 281         rdmsr(MSR_IA32_APERF, aperf_cur.split.lo, aperf_cur.split.hi);
 282         rdmsr(MSR_IA32_MPERF, mperf_cur.split.lo, mperf_cur.split.hi);
 283
 284         wrmsr(MSR_IA32_APERF, 0,0);
 285         wrmsr(MSR_IA32_MPERF, 0,0);
 286
 287 #ifdef __i386__
 288         /*
 289          * We dont want to do 64 bit divide with 32 bit kernel
 290          * Get an approximate value. Return failure in case we cannot get
 291          * an approximate value.
 292          */
 293         if (unlikely(aperf_cur.split.hi || mperf_cur.split.hi)) {
 294                 int shift_count;
 295                 u32 h;
 296
 297                 h = max_t(u32, aperf_cur.split.hi, mperf_cur.split.hi);
 298                 shift_count = fls(h);
 299
 300                 aperf_cur.whole >>= shift_count;
 301                 mperf_cur.whole >>= shift_count;
 302         }
 303
 304         if (((unsigned long)(-1) / 100) < aperf_cur.split.lo) {
 305                 int shift_count = 7;
 306                 aperf_cur.split.lo >>= shift_count;
 307                 mperf_cur.split.lo >>= shift_count;
 308         }
 309
 310         if (aperf_cur.split.lo && mperf_cur.split.lo)
 311                 perf_percent = (aperf_cur.split.lo * 100) / mperf_cur.split.lo;
 312         else
 313                 perf_percent = 0;
 314
 315 #else
 316         if (unlikely(((unsigned long)(-1) / 100) < aperf_cur.whole)) {
 317                 int shift_count = 7;
 318                 aperf_cur.whole >>= shift_count;
 319                 mperf_cur.whole >>= shift_count;
 320         }
 321
 322         if (aperf_cur.whole && mperf_cur.whole)
 323                 perf_percent = (aperf_cur.whole * 100) / mperf_cur.whole;
 324         else
 325                 perf_percent = 0;
 326
 327 #endif
 328
 329         retval = per_cpu(drv_data, cpu)->max_freq * perf_percent / 100;
 330
 331         put_cpu();
 332         set_cpus_allowed(current, saved_mask);
 333
 334         dprintk("cpu %d: performance percent %d\n", cpu, perf_percent);
 335         return retval;
 336 }
 337
 338 static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
 339 {
 340         struct acpi_cpufreq_data *data = per_cpu(drv_data, cpu);
 341         unsigned int freq;
 342
 343         dprintk("get_cur_freq_on_cpu (%d)\n", cpu);
 344
 345         if (unlikely(data == NULL ||
 346                      data->acpi_data == NULL || data->freq_table == NULL)) {
 347                 return 0;
 348         }
 349
 350         freq = extract_freq(get_cur_val(cpumask_of_cpu(cpu)), data);
 351         dprintk("cur freq = %u\n", freq);
 352
 353         return freq;
 354 }
 355
 356 static unsigned int check_freqs(cpumask_t mask, unsigned int freq,
 357                                 struct acpi_cpufreq_data *data)
 358 {
 359         unsigned int cur_freq;
 360         unsigned int i;
 361
 362         for (i=0; i<100; i++) {
 363                 cur_freq = extract_freq(get_cur_val(mask), data);
 364                 if (cur_freq == freq)
 365                         return 1;
 366                 udelay(10);
 367         }
 368         return 0;
 369 }
 370
 371 static int acpi_cpufreq_target(struct cpufreq_policy *policy,
 372                                unsigned int target_freq, unsigned int relation)
 373 {
 374         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
 375         struct acpi_processor_performance *perf;
 376         struct cpufreq_freqs freqs;
 377         cpumask_t online_policy_cpus;
 378         struct drv_cmd cmd;
 379         unsigned int next_state = 0; /* Index into freq_table */
 380         unsigned int next_perf_state = 0; /* Index into perf table */
 381         unsigned int i;
 382         int result = 0;
 383
 384         dprintk("acpi_cpufreq_target %d (%d)\n", target_freq, policy->cpu);
 385
 386         if (unlikely(data == NULL ||
 387              data->acpi_data == NULL || data->freq_table == NULL)) {
 388                 return -ENODEV;
 389         }
 390
 391         perf = data->acpi_data;
 392         result = cpufreq_frequency_table_target(policy,
 393                                                 data->freq_table,
 394                                                 target_freq,
 395                                                 relation, &next_state);
 396         if (unlikely(result))
 397                 return -ENODEV;
 398
 399 #ifdef CONFIG_HOTPLUG_CPU
 400         /* cpufreq holds the hotplug lock, so we are safe from here on */
 401         cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
 402 #else
 403         online_policy_cpus = policy->cpus;
 404 #endif
 405
 406         next_perf_state = data->freq_table[next_state].index;
 407         if (perf->state == next_perf_state) {
 408                 if (unlikely(data->resume)) {
 409                         dprintk("Called after resume, resetting to P%d\n",
 410                                 next_perf_state);
 411                         data->resume = 0;
 412                 } else {
 413                         dprintk("Already at target state (P%d)\n",
 414                                 next_perf_state);
 415                         return 0;
 416                 }
 417         }
 418
 419         switch (data->cpu_feature) {
 420         case SYSTEM_INTEL_MSR_CAPABLE:
 421                 cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
 422                 cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
 423                 cmd.val = (u32) perf->states[next_perf_state].control;
 424                 break;
 425         case SYSTEM_IO_CAPABLE:
 426                 cmd.type = SYSTEM_IO_CAPABLE;
 427                 cmd.addr.io.port = perf->control_register.address;
 428                 cmd.addr.io.bit_width = perf->control_register.bit_width;
 429                 cmd.val = (u32) perf->states[next_perf_state].control;
 430                 break;
 431         default:
 432                 return -ENODEV;
 433         }
 434
 435         cpus_clear(cmd.mask);
 436
 437         if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
 438                 cmd.mask = online_policy_cpus;
 439         else
 440                 cpu_set(policy->cpu, cmd.mask);
 441
 442         freqs.old = perf->states[perf->state].core_frequency * 1000;
 443         freqs.new = data->freq_table[next_state].frequency;
 444         for_each_cpu_mask(i, cmd.mask) {
 445                 freqs.cpu = i;
 446                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 447         }
 448
 449         drv_write(&cmd);
 450
 451         if (acpi_pstate_strict) {
 452                 if (!check_freqs(cmd.mask, freqs.new, data)) {
 453                         dprintk("acpi_cpufreq_target failed (%d)\n",
 454                                 policy->cpu);
 455                         return -EAGAIN;
 456                 }
 457         }
 458
 459         for_each_cpu_mask(i, cmd.mask) {
 460                 freqs.cpu = i;
 461                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 462         }
 463         perf->state = next_perf_state;
 464
 465         return result;
 466 }
 467
 468 static int acpi_cpufreq_verify(struct cpufreq_policy *policy)
 469 {
 470         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
 471
 472         dprintk("acpi_cpufreq_verify\n");
 473
 474         return cpufreq_frequency_table_verify(policy, data->freq_table);
 475 }
 476
 477 static unsigned long
 478 acpi_cpufreq_guess_freq(struct acpi_cpufreq_data *data, unsigned int cpu)
 479 {
 480         struct acpi_processor_performance *perf = data->acpi_data;
 481
 482         if (cpu_khz) {
 483                 /* search the closest match to cpu_khz */
 484                 unsigned int i;
 485                 unsigned long freq;
 486                 unsigned long freqn = perf->states[0].core_frequency * 1000;
 487
 488                 for (i=0; i<(perf->state_count-1); i++) {
 489                         freq = freqn;
 490                         freqn = perf->states[i+1].core_frequency * 1000;
 491                         if ((2 * cpu_khz) > (freqn + freq)) {
 492                                 perf->state = i;
 493                                 return freq;
 494                         }
 495                 }
 496                 perf->state = perf->state_count-1;
 497                 return freqn;
 498         } else {
 499                 /* assume CPU is at P0... */
 500                 perf->state = 0;
 501                 return perf->states[0].core_frequency * 1000;
 502         }
 503 }
 504
 505 /*
 506  * acpi_cpufreq_early_init - initialize ACPI P-States library
 507  *
 508  * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
 509  * in order to determine correct frequency and voltage pairings. We can
 510  * do _PDC and _PSD and find out the processor dependency for the
 511  * actual init that will happen later...
 512  */
 513 static int __init acpi_cpufreq_early_init(void)
 514 {
 515         dprintk("acpi_cpufreq_early_init\n");
 516
 517         acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
 518         if (!acpi_perf_data) {
 519                 dprintk("Memory allocation error for acpi_perf_data.\n");
 520                 return -ENOMEM;
 521         }
 522
 523         /* Do initialization in ACPI core */
 524         acpi_processor_preregister_performance(acpi_perf_data);
 525         return 0;
 526 }
 527
 528 #ifdef CONFIG_SMP
 529 /*
 530  * Some BIOSes do SW_ANY coordination internally, either set it up in hw
 531  * or do it in BIOS firmware and won't inform about it to OS. If not
 532  * detected, this has a side effect of making CPU run at a different speed
 533  * than OS intended it to run at. Detect it and handle it cleanly.
 534  */
 535 static int bios_with_sw_any_bug;
 536
 537 static int sw_any_bug_found(const struct dmi_system_id *d)
 538 {
 539         bios_with_sw_any_bug = 1;
 540         return 0;
 541 }
 542
 543 static const struct dmi_system_id sw_any_bug_dmi_table[] = {
 544         {
 545                 .callback = sw_any_bug_found,
 546                 .ident = "Supermicro Server X6DLP",
 547                 .matches = {
 548                         DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
 549                         DMI_MATCH(DMI_BIOS_VERSION, "080010"),
 550                         DMI_MATCH(DMI_PRODUCT_NAME, "X6DLP"),
 551                 },
 552         },
 553         { }
 554 };
 555 #endif
 556
 557 static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 558 {
 559         unsigned int i;
 560         unsigned int valid_states = 0;
 561         unsigned int cpu = policy->cpu;
 562         struct acpi_cpufreq_data *data;
 563         unsigned int result = 0;
 564         struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
 565         struct acpi_processor_performance *perf;
 566
 567         dprintk("acpi_cpufreq_cpu_init\n");
 568
 569         data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
 570         if (!data)
 571                 return -ENOMEM;
 572
 573         data->acpi_data = percpu_ptr(acpi_perf_data, cpu);
 574         per_cpu(drv_data, cpu) = data;
 575
 576         if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))
 577                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
 578
 579         result = acpi_processor_register_performance(data->acpi_data, cpu);
 580         if (result)
 581                 goto err_free;
 582
 583         perf = data->acpi_data;
 584         policy->shared_type = perf->shared_type;
 585
 586         /*
 587          * Will let policy->cpus know about dependency only when software
 588          * coordination is required.
 589          */
 590         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
 591             policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
 592                 policy->cpus = perf->shared_cpu_map;
 593         }
 594
 595 #ifdef CONFIG_SMP
 596         dmi_check_system(sw_any_bug_dmi_table);
 597         if (bios_with_sw_any_bug && cpus_weight(policy->cpus) == 1) {
 598                 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 599                 policy->cpus = per_cpu(cpu_core_map, cpu);
 600         }
 601 #endif
 602
 603         /* capability check */
 604         if (perf->state_count <= 1) {
 605                 dprintk("No P-States\n");
 606                 result = -ENODEV;
 607                 goto err_unreg;
 608         }
 609
 610         if (perf->control_register.space_id != perf->status_register.space_id) {
 611                 result = -ENODEV;
 612                 goto err_unreg;
 613         }
 614
 615         switch (perf->control_register.space_id) {
 616         case ACPI_ADR_SPACE_SYSTEM_IO:
 617                 dprintk("SYSTEM IO addr space\n");
 618                 data->cpu_feature = SYSTEM_IO_CAPABLE;
 619                 break;
 620         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 621                 dprintk("HARDWARE addr space\n");
 622                 if (!check_est_cpu(cpu)) {
 623                         result = -ENODEV;
 624                         goto err_unreg;
 625                 }
 626                 data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
 627                 break;
 628         default:
 629                 dprintk("Unknown addr space %d\n",
 630                         (u32) (perf->control_register.space_id));
 631                 result = -ENODEV;
 632                 goto err_unreg;
 633         }
 634
 635         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
 636                     (perf->state_count+1), GFP_KERNEL);
 637         if (!data->freq_table) {
 638                 result = -ENOMEM;
 639                 goto err_unreg;
 640         }
 641
 642         /* detect transition latency */
 643         policy->cpuinfo.transition_latency = 0;
 644         for (i=0; i<perf->state_count; i++) {
 645                 if ((perf->states[i].transition_latency * 1000) >
 646                     policy->cpuinfo.transition_latency)
 647                         policy->cpuinfo.transition_latency =
 648                             perf->states[i].transition_latency * 1000;
 649         }
 650
 651         data->max_freq = perf->states[0].core_frequency * 1000;
 652         /* table init */
 653         for (i=0; i<perf->state_count; i++) {
 654                 if (i>0 && perf->states[i].core_frequency >=
 655                     data->freq_table[valid_states-1].frequency / 1000)
 656                         continue;
 657
 658                 data->freq_table[valid_states].index = i;
 659                 data->freq_table[valid_states].frequency =
 660                     perf->states[i].core_frequency * 1000;
 661                 valid_states++;
 662         }
 663         data->freq_table[valid_states].frequency = CPUFREQ_TABLE_END;
 664         perf->state = 0;
 665
 666         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 667         if (result)
 668                 goto err_freqfree;
 669
 670         switch (perf->control_register.space_id) {
 671         case ACPI_ADR_SPACE_SYSTEM_IO:
 672                 /* Current speed is unknown and not detectable by IO port */
 673                 policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
 674                 break;
 675         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 676                 acpi_cpufreq_driver.get = get_cur_freq_on_cpu;
 677                 policy->cur = get_cur_freq_on_cpu(cpu);
 678                 break;
 679         default:
 680                 break;
 681         }
 682
 683         /* notify BIOS that we exist */
 684         acpi_processor_notify_smm(THIS_MODULE);
 685
 686         /* Check for APERF/MPERF support in hardware */
 687         if (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6) {
 688                 unsigned int ecx;
 689                 ecx = cpuid_ecx(6);
 690                 if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY)
 691                         acpi_cpufreq_driver.getavg = get_measured_perf;
 692         }
 693
 694         dprintk("CPU%u - ACPI performance management activated.\n", cpu);
 695         for (i = 0; i < perf->state_count; i++)
 696                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
 697                         (i == perf->state ? '*' : ' '), i,
 698                         (u32) perf->states[i].core_frequency,
 699                         (u32) perf->states[i].power,
 700                         (u32) perf->states[i].transition_latency);
 701
 702         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 703
 704         /*
 705          * the first call to ->target() should result in us actually
 706          * writing something to the appropriate registers.
 707          */
 708         data->resume = 1;
 709
 710         return result;
 711
 712 err_freqfree:
 713         kfree(data->freq_table);
 714 err_unreg:
 715         acpi_processor_unregister_performance(perf, cpu);
 716 err_free:
 717         kfree(data);
 718         per_cpu(drv_data, cpu) = NULL;
 719
 720         return result;
 721 }
 722
 723 static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 724 {
 725         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
 726
 727         dprintk("acpi_cpufreq_cpu_exit\n");
 728
 729         if (data) {
 730                 cpufreq_frequency_table_put_attr(policy->cpu);
 731                 per_cpu(drv_data, policy->cpu) = NULL;
 732                 acpi_processor_unregister_performance(data->acpi_data,
 733                                                       policy->cpu);
 734                 kfree(data);
 735         }
 736
 737         return 0;
 738 }
 739
 740 static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
 741 {
 742         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
 743
 744         dprintk("acpi_cpufreq_resume\n");
 745
 746         data->resume = 1;
 747
 748         return 0;
 749 }
 750
 751 static struct freq_attr *acpi_cpufreq_attr[] = {
 752         &cpufreq_freq_attr_scaling_available_freqs,
 753         NULL,
 754 };
 755
 756 static struct cpufreq_driver acpi_cpufreq_driver = {
 757         .verify = acpi_cpufreq_verify,
 758         .target = acpi_cpufreq_target,
 759         .init = acpi_cpufreq_cpu_init,
 760         .exit = acpi_cpufreq_cpu_exit,
 761         .resume = acpi_cpufreq_resume,
 762         .name = "acpi-cpufreq",
 763         .owner = THIS_MODULE,
 764         .attr = acpi_cpufreq_attr,
 765 };
 766
 767 static int __init acpi_cpufreq_init(void)
 768 {
 769         int ret;
 770
 771         dprintk("acpi_cpufreq_init\n");
 772
 773         ret = acpi_cpufreq_early_init();
 774         if (ret)
 775                 return ret;
 776
 777         return cpufreq_register_driver(&acpi_cpufreq_driver);
 778 }
 779
 780 static void __exit acpi_cpufreq_exit(void)
 781 {
 782         dprintk("acpi_cpufreq_exit\n");
 783
 784         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 785
 786         free_percpu(acpi_perf_data);
 787
 788         return;
 789 }
 790
 791 module_param(acpi_pstate_strict, uint, 0644);
 792 MODULE_PARM_DESC(acpi_pstate_strict,
 793         "value 0 or non-zero. non-zero -> strict ACPI checks are "
 794         "performed during frequency changes.");
 795
 796 late_initcall(acpi_cpufreq_init);
 797 module_exit(acpi_cpufreq_exit);
 798
 799 MODULE_ALIAS("acpi");