arch/i386/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/sched.h>        /* current */
  36 #include <linux/dmi.h>
  37
  38 #include <linux/acpi.h>
  39 #include <acpi/processor.h>
  40
  41 #include <asm/io.h>
  42 #include <asm/msr.h>
  43 #include <asm/processor.h>
  44 #include <asm/cpufeature.h>
  45 #include <asm/delay.h>
  46 #include <asm/uaccess.h>
  47
  48 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
  49
  50 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
  51 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  52 MODULE_LICENSE("GPL");
  53
  54 enum {
  55         UNDEFINED_CAPABLE = 0,
  56         SYSTEM_INTEL_MSR_CAPABLE,
  57         SYSTEM_IO_CAPABLE,
  58 };
  59
  60 #define INTEL_MSR_RANGE         (0xffff)
  61
  62 struct acpi_cpufreq_data {
  63         struct acpi_processor_performance *acpi_data;
  64         struct cpufreq_frequency_table *freq_table;
  65         unsigned int resume;
  66         unsigned int cpu_feature;
  67 };
  68
  69 static struct acpi_cpufreq_data *drv_data[NR_CPUS];
  70 static struct acpi_processor_performance *acpi_perf_data[NR_CPUS];
  71
  72 static struct cpufreq_driver acpi_cpufreq_driver;
  73
  74 static unsigned int acpi_pstate_strict;
  75
  76 static int check_est_cpu(unsigned int cpuid)
  77 {
  78         struct cpuinfo_x86 *cpu = &cpu_data[cpuid];
  79
  80         if (cpu->x86_vendor != X86_VENDOR_INTEL ||
  81             !cpu_has(cpu, X86_FEATURE_EST))
  82                 return 0;
  83
  84         return 1;
  85 }
  86
  87 static unsigned extract_io(u32 value, struct acpi_cpufreq_data *data)
  88 {
  89         struct acpi_processor_performance *perf;
  90         int i;
  91
  92         perf = data->acpi_data;
  93
  94         for (i = 0; i < perf->state_count; i++) {
  95                 if (value == perf->states[i].status)
  96                         return data->freq_table[i].frequency;
  97         }
  98         return 0;
  99 }
 100
 101 static unsigned extract_msr(u32 msr, struct acpi_cpufreq_data *data)
 102 {
 103         int i;
 104         struct acpi_processor_performance *perf;
 105
 106         msr &= INTEL_MSR_RANGE;
 107         perf = data->acpi_data;
 108
 109         for (i = 0; data->freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 110                 if (msr == perf->states[data->freq_table[i].index].status)
 111                         return data->freq_table[i].frequency;
 112         }
 113         return data->freq_table[0].frequency;
 114 }
 115
 116 static unsigned extract_freq(u32 val, struct acpi_cpufreq_data *data)
 117 {
 118         switch (data->cpu_feature) {
 119         case SYSTEM_INTEL_MSR_CAPABLE:
 120                 return extract_msr(val, data);
 121         case SYSTEM_IO_CAPABLE:
 122                 return extract_io(val, data);
 123         default:
 124                 return 0;
 125         }
 126 }
 127
 128 static void wrport(u16 port, u8 bit_width, u32 value)
 129 {
 130         if (bit_width <= 8) {
 131                 outb(value, port);
 132         } else if (bit_width <= 16) {
 133                 outw(value, port);
 134         } else if (bit_width <= 32) {
 135                 outl(value, port);
 136         }
 137 }
 138
 139 static void rdport(u16 port, u8 bit_width, u32 * ret)
 140 {
 141         *ret = 0;
 142         if (bit_width <= 8) {
 143                 *ret = inb(port);
 144         } else if (bit_width <= 16) {
 145                 *ret = inw(port);
 146         } else if (bit_width <= 32) {
 147                 *ret = inl(port);
 148         }
 149 }
 150
 151 struct msr_addr {
 152         u32 reg;
 153 };
 154
 155 struct io_addr {
 156         u16 port;
 157         u8 bit_width;
 158 };
 159
 160 typedef union {
 161         struct msr_addr msr;
 162         struct io_addr io;
 163 } drv_addr_union;
 164
 165 struct drv_cmd {
 166         unsigned int type;
 167         cpumask_t mask;
 168         drv_addr_union addr;
 169         u32 val;
 170 };
 171
 172 static void do_drv_read(struct drv_cmd *cmd)
 173 {
 174         u32 h;
 175
 176         switch (cmd->type) {
 177         case SYSTEM_INTEL_MSR_CAPABLE:
 178                 rdmsr(cmd->addr.msr.reg, cmd->val, h);
 179                 break;
 180         case SYSTEM_IO_CAPABLE:
 181                 rdport(cmd->addr.io.port, cmd->addr.io.bit_width, &cmd->val);
 182                 break;
 183         default:
 184                 break;
 185         }
 186 }
 187
 188 static void do_drv_write(struct drv_cmd *cmd)
 189 {
 190         u32 h = 0;
 191
 192         switch (cmd->type) {
 193         case SYSTEM_INTEL_MSR_CAPABLE:
 194                 wrmsr(cmd->addr.msr.reg, cmd->val, h);
 195                 break;
 196         case SYSTEM_IO_CAPABLE:
 197                 wrport(cmd->addr.io.port, cmd->addr.io.bit_width, cmd->val);
 198                 break;
 199         default:
 200                 break;
 201         }
 202 }
 203
 204 static inline void drv_read(struct drv_cmd *cmd)
 205 {
 206         cpumask_t saved_mask = current->cpus_allowed;
 207         cmd->val = 0;
 208
 209         set_cpus_allowed(current, cmd->mask);
 210         do_drv_read(cmd);
 211         set_cpus_allowed(current, saved_mask);
 212
 213 }
 214
 215 static void drv_write(struct drv_cmd *cmd)
 216 {
 217         cpumask_t saved_mask = current->cpus_allowed;
 218         unsigned int i;
 219
 220         for_each_cpu_mask(i, cmd->mask) {
 221                 set_cpus_allowed(current, cpumask_of_cpu(i));
 222                 do_drv_write(cmd);
 223         }
 224
 225         set_cpus_allowed(current, saved_mask);
 226         return;
 227 }
 228
 229 static u32 get_cur_val(cpumask_t mask)
 230 {
 231         struct acpi_processor_performance *perf;
 232         struct drv_cmd cmd;
 233
 234         if (unlikely(cpus_empty(mask)))
 235                 return 0;
 236
 237         switch (drv_data[first_cpu(mask)]->cpu_feature) {
 238         case SYSTEM_INTEL_MSR_CAPABLE:
 239                 cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
 240                 cmd.addr.msr.reg = MSR_IA32_PERF_STATUS;
 241                 break;
 242         case SYSTEM_IO_CAPABLE:
 243                 cmd.type = SYSTEM_IO_CAPABLE;
 244                 perf = drv_data[first_cpu(mask)]->acpi_data;
 245                 cmd.addr.io.port = perf->control_register.address;
 246                 cmd.addr.io.bit_width = perf->control_register.bit_width;
 247                 break;
 248         default:
 249                 return 0;
 250         }
 251
 252         cmd.mask = mask;
 253
 254         drv_read(&cmd);
 255
 256         dprintk("get_cur_val = %u\n", cmd.val);
 257
 258         return cmd.val;
 259 }
 260
 261 static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
 262 {
 263         struct acpi_cpufreq_data *data = drv_data[cpu];
 264         unsigned int freq;
 265
 266         dprintk("get_cur_freq_on_cpu (%d)\n", cpu);
 267
 268         if (unlikely(data == NULL ||
 269                      data->acpi_data == NULL || data->freq_table == NULL)) {
 270                 return 0;
 271         }
 272
 273         freq = extract_freq(get_cur_val(cpumask_of_cpu(cpu)), data);
 274         dprintk("cur freq = %u\n", freq);
 275
 276         return freq;
 277 }
 278
 279 static unsigned int check_freqs(cpumask_t mask, unsigned int freq,
 280                                 struct acpi_cpufreq_data *data)
 281 {
 282         unsigned int cur_freq;
 283         unsigned int i;
 284
 285         for (i = 0; i < 100; i++) {
 286                 cur_freq = extract_freq(get_cur_val(mask), data);
 287                 if (cur_freq == freq)
 288                         return 1;
 289                 udelay(10);
 290         }
 291         return 0;
 292 }
 293
 294 static int acpi_cpufreq_target(struct cpufreq_policy *policy,
 295                                unsigned int target_freq, unsigned int relation)
 296 {
 297         struct acpi_cpufreq_data *data = drv_data[policy->cpu];
 298         struct acpi_processor_performance *perf;
 299         struct cpufreq_freqs freqs;
 300         cpumask_t online_policy_cpus;
 301         struct drv_cmd cmd;
 302         unsigned int msr;
 303         unsigned int next_state = 0;
 304         unsigned int next_perf_state = 0;
 305         unsigned int i;
 306         int result = 0;
 307
 308         dprintk("acpi_cpufreq_target %d (%d)\n", target_freq, policy->cpu);
 309
 310         if (unlikely(data == NULL ||
 311                      data->acpi_data == NULL || data->freq_table == NULL)) {
 312                 return -ENODEV;
 313         }
 314
 315         perf = data->acpi_data;
 316         result = cpufreq_frequency_table_target(policy,
 317                                                 data->freq_table,
 318                                                 target_freq,
 319                                                 relation, &next_state);
 320         if (unlikely(result))
 321                 return -ENODEV;
 322
 323 #ifdef CONFIG_HOTPLUG_CPU
 324         /* cpufreq holds the hotplug lock, so we are safe from here on */
 325         cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
 326 #else
 327         online_policy_cpus = policy->cpus;
 328 #endif
 329
 330         next_perf_state = data->freq_table[next_state].index;
 331         if (perf->state == next_perf_state) {
 332                 if (unlikely(data->resume)) {
 333                         dprintk("Called after resume, resetting to P%d\n",
 334                                 next_perf_state);
 335                         data->resume = 0;
 336                 } else {
 337                         dprintk("Already at target state (P%d)\n",
 338                                 next_perf_state);
 339                         return 0;
 340                 }
 341         }
 342
 343         switch (data->cpu_feature) {
 344         case SYSTEM_INTEL_MSR_CAPABLE:
 345                 cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
 346                 cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
 347                 msr =
 348                     (u32) perf->states[next_perf_state].
 349                     control & INTEL_MSR_RANGE;
 350                 cmd.val = (cmd.val & ~INTEL_MSR_RANGE) | msr;
 351                 break;
 352         case SYSTEM_IO_CAPABLE:
 353                 cmd.type = SYSTEM_IO_CAPABLE;
 354                 cmd.addr.io.port = perf->control_register.address;
 355                 cmd.addr.io.bit_width = perf->control_register.bit_width;
 356                 cmd.val = (u32) perf->states[next_perf_state].control;
 357                 break;
 358         default:
 359                 return -ENODEV;
 360         }
 361
 362         cpus_clear(cmd.mask);
 363
 364         if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
 365                 cmd.mask = online_policy_cpus;
 366         else
 367                 cpu_set(policy->cpu, cmd.mask);
 368
 369         freqs.old = data->freq_table[perf->state].frequency;
 370         freqs.new = data->freq_table[next_perf_state].frequency;
 371         for_each_cpu_mask(i, cmd.mask) {
 372                 freqs.cpu = i;
 373                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 374         }
 375
 376         drv_write(&cmd);
 377
 378         if (acpi_pstate_strict) {
 379                 if (!check_freqs(cmd.mask, freqs.new, data)) {
 380                         dprintk("acpi_cpufreq_target failed (%d)\n",
 381                                 policy->cpu);
 382                         return -EAGAIN;
 383                 }
 384         }
 385
 386         for_each_cpu_mask(i, cmd.mask) {
 387                 freqs.cpu = i;
 388                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 389         }
 390         perf->state = next_perf_state;
 391
 392         return result;
 393 }
 394
 395 static int acpi_cpufreq_verify(struct cpufreq_policy *policy)
 396 {
 397         struct acpi_cpufreq_data *data = drv_data[policy->cpu];
 398
 399         dprintk("acpi_cpufreq_verify\n");
 400
 401         return cpufreq_frequency_table_verify(policy, data->freq_table);
 402 }
 403
 404 static unsigned long
 405 acpi_cpufreq_guess_freq(struct acpi_cpufreq_data *data, unsigned int cpu)
 406 {
 407         struct acpi_processor_performance *perf = data->acpi_data;
 408
 409         if (cpu_khz) {
 410                 /* search the closest match to cpu_khz */
 411                 unsigned int i;
 412                 unsigned long freq;
 413                 unsigned long freqn = perf->states[0].core_frequency * 1000;
 414
 415                 for (i = 0; i < (perf->state_count - 1); i++) {
 416                         freq = freqn;
 417                         freqn = perf->states[i + 1].core_frequency * 1000;
 418                         if ((2 * cpu_khz) > (freqn + freq)) {
 419                                 perf->state = i;
 420                                 return freq;
 421                         }
 422                 }
 423                 perf->state = perf->state_count - 1;
 424                 return freqn;
 425         } else {
 426                 /* assume CPU is at P0... */
 427                 perf->state = 0;
 428                 return perf->states[0].core_frequency * 1000;
 429         }
 430 }
 431
 432 /*
 433  * acpi_cpufreq_early_init - initialize ACPI P-States library
 434  *
 435  * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
 436  * in order to determine correct frequency and voltage pairings. We can
 437  * do _PDC and _PSD and find out the processor dependency for the
 438  * actual init that will happen later...
 439  */
 440 static int acpi_cpufreq_early_init(void)
 441 {
 442         struct acpi_processor_performance *data;
 443         cpumask_t covered;
 444         unsigned int i, j;
 445
 446         dprintk("acpi_cpufreq_early_init\n");
 447
 448         for_each_possible_cpu(i) {
 449                 data = kzalloc(sizeof(struct acpi_processor_performance),
 450                                GFP_KERNEL);
 451                 if (!data) {
 452                         for_each_cpu_mask(j, covered) {
 453                                 kfree(acpi_perf_data[j]);
 454                                 acpi_perf_data[j] = NULL;
 455                         }
 456                         return -ENOMEM;
 457                 }
 458                 acpi_perf_data[i] = data;
 459                 cpu_set(i, covered);
 460         }
 461
 462         /* Do initialization in ACPI core */
 463         acpi_processor_preregister_performance(acpi_perf_data);
 464         return 0;
 465 }
 466
 467 /*
 468  * Some BIOSes do SW_ANY coordination internally, either set it up in hw
 469  * or do it in BIOS firmware and won't inform about it to OS. If not
 470  * detected, this has a side effect of making CPU run at a different speed
 471  * than OS intended it to run at. Detect it and handle it cleanly.
 472  */
 473 static int bios_with_sw_any_bug;
 474
 475 static int sw_any_bug_found(struct dmi_system_id *d)
 476 {
 477         bios_with_sw_any_bug = 1;
 478         return 0;
 479 }
 480
 481 static struct dmi_system_id sw_any_bug_dmi_table[] = {
 482         {
 483                 .callback = sw_any_bug_found,
 484                 .ident = "Supermicro Server X6DLP",
 485                 .matches = {
 486                         DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
 487                         DMI_MATCH(DMI_BIOS_VERSION, "080010"),
 488                         DMI_MATCH(DMI_PRODUCT_NAME, "X6DLP"),
 489                 },
 490         },
 491         { }
 492 };
 493
 494 static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
 495 {
 496         unsigned int i;
 497         unsigned int valid_states = 0;
 498         unsigned int cpu = policy->cpu;
 499         struct acpi_cpufreq_data *data;
 500         unsigned int l, h;
 501         unsigned int result = 0;
 502         struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
 503         struct acpi_processor_performance *perf;
 504
 505         dprintk("acpi_cpufreq_cpu_init\n");
 506
 507         if (!acpi_perf_data[cpu])
 508                 return -ENODEV;
 509
 510         data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
 511         if (!data)
 512                 return -ENOMEM;
 513
 514         data->acpi_data = acpi_perf_data[cpu];
 515         drv_data[cpu] = data;
 516
 517         if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
 518                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
 519         }
 520
 521         result = acpi_processor_register_performance(data->acpi_data, cpu);
 522         if (result)
 523                 goto err_free;
 524
 525         perf = data->acpi_data;
 526         policy->shared_type = perf->shared_type;
 527         /*
 528          * Will let policy->cpus know about dependency only when software
 529          * coordination is required.
 530          */
 531         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
 532             policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
 533                 policy->cpus = perf->shared_cpu_map;
 534         }
 535
 536 #ifdef CONFIG_SMP
 537         dmi_check_system(sw_any_bug_dmi_table);
 538         if (bios_with_sw_any_bug && cpus_weight(policy->cpus) == 1) {
 539                 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 540                 policy->cpus = cpu_core_map[cpu];
 541         }
 542 #endif
 543
 544         /* capability check */
 545         if (perf->state_count <= 1) {
 546                 dprintk("No P-States\n");
 547                 result = -ENODEV;
 548                 goto err_unreg;
 549         }
 550
 551         if (perf->control_register.space_id != perf->status_register.space_id) {
 552                 result = -ENODEV;
 553                 goto err_unreg;
 554         }
 555
 556         switch (perf->control_register.space_id) {
 557         case ACPI_ADR_SPACE_SYSTEM_IO:
 558                 dprintk("SYSTEM IO addr space\n");
 559                 data->cpu_feature = SYSTEM_IO_CAPABLE;
 560                 break;
 561         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 562                 dprintk("HARDWARE addr space\n");
 563                 if (!check_est_cpu(cpu)) {
 564                         result = -ENODEV;
 565                         goto err_unreg;
 566                 }
 567                 data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
 568                 break;
 569         default:
 570                 dprintk("Unknown addr space %d\n",
 571                         (u32) (perf->control_register.space_id));
 572                 result = -ENODEV;
 573                 goto err_unreg;
 574         }
 575
 576         data->freq_table =
 577             kmalloc(sizeof(struct cpufreq_frequency_table) *
 578                     (perf->state_count + 1), GFP_KERNEL);
 579         if (!data->freq_table) {
 580                 result = -ENOMEM;
 581                 goto err_unreg;
 582         }
 583
 584         /* detect transition latency */
 585         policy->cpuinfo.transition_latency = 0;
 586         for (i = 0; i < perf->state_count; i++) {
 587                 if ((perf->states[i].transition_latency * 1000) >
 588                     policy->cpuinfo.transition_latency)
 589                         policy->cpuinfo.transition_latency =
 590                             perf->states[i].transition_latency * 1000;
 591         }
 592         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 593
 594         /* table init */
 595         for (i = 0; i < perf->state_count; i++) {
 596                 if (i > 0 && perf->states[i].core_frequency ==
 597                     perf->states[i - 1].core_frequency)
 598                         continue;
 599
 600                 data->freq_table[valid_states].index = i;
 601                 data->freq_table[valid_states].frequency =
 602                     perf->states[i].core_frequency * 1000;
 603                 valid_states++;
 604         }
 605         data->freq_table[perf->state_count].frequency = CPUFREQ_TABLE_END;
 606
 607         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 608         if (result) {
 609                 goto err_freqfree;
 610         }
 611
 612         switch (data->cpu_feature) {
 613         case ACPI_ADR_SPACE_SYSTEM_IO:
 614                 /* Current speed is unknown and not detectable by IO port */
 615                 policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
 616                 break;
 617         case ACPI_ADR_SPACE_FIXED_HARDWARE:
 618                 acpi_cpufreq_driver.get = get_cur_freq_on_cpu;
 619                 get_cur_freq_on_cpu(cpu);
 620                 break;
 621         default:
 622                 break;
 623         }
 624
 625         /* notify BIOS that we exist */
 626         acpi_processor_notify_smm(THIS_MODULE);
 627
 628         dprintk("CPU%u - ACPI performance management activated.\n", cpu);
 629         for (i = 0; i < perf->state_count; i++)
 630                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
 631                         (i == perf->state ? '*' : ' '), i,
 632                         (u32) perf->states[i].core_frequency,
 633                         (u32) perf->states[i].power,
 634                         (u32) perf->states[i].transition_latency);
 635
 636         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 637
 638         /*
 639          * the first call to ->target() should result in us actually
 640          * writing something to the appropriate registers.
 641          */
 642         data->resume = 1;
 643
 644         return result;
 645
 646       err_freqfree:
 647         kfree(data->freq_table);
 648       err_unreg:
 649         acpi_processor_unregister_performance(perf, cpu);
 650       err_free:
 651         kfree(data);
 652         drv_data[cpu] = NULL;
 653
 654         return result;
 655 }
 656
 657 static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 658 {
 659         struct acpi_cpufreq_data *data = drv_data[policy->cpu];
 660
 661         dprintk("acpi_cpufreq_cpu_exit\n");
 662
 663         if (data) {
 664                 cpufreq_frequency_table_put_attr(policy->cpu);
 665                 drv_data[policy->cpu] = NULL;
 666                 acpi_processor_unregister_performance(data->acpi_data,
 667                                                       policy->cpu);
 668                 kfree(data);
 669         }
 670
 671         return 0;
 672 }
 673
 674 static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
 675 {
 676         struct acpi_cpufreq_data *data = drv_data[policy->cpu];
 677
 678         dprintk("acpi_cpufreq_resume\n");
 679
 680         data->resume = 1;
 681
 682         return 0;
 683 }
 684
 685 static struct freq_attr *acpi_cpufreq_attr[] = {
 686         &cpufreq_freq_attr_scaling_available_freqs,
 687         NULL,
 688 };
 689
 690 static struct cpufreq_driver acpi_cpufreq_driver = {
 691         .verify = acpi_cpufreq_verify,
 692         .target = acpi_cpufreq_target,
 693         .init = acpi_cpufreq_cpu_init,
 694         .exit = acpi_cpufreq_cpu_exit,
 695         .resume = acpi_cpufreq_resume,
 696         .name = "acpi-cpufreq",
 697         .owner = THIS_MODULE,
 698         .attr = acpi_cpufreq_attr,
 699 };
 700
 701 static int __init acpi_cpufreq_init(void)
 702 {
 703         dprintk("acpi_cpufreq_init\n");
 704
 705         acpi_cpufreq_early_init();
 706
 707         return cpufreq_register_driver(&acpi_cpufreq_driver);
 708 }
 709
 710 static void __exit acpi_cpufreq_exit(void)
 711 {
 712         unsigned int i;
 713         dprintk("acpi_cpufreq_exit\n");
 714
 715         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 716
 717         for_each_possible_cpu(i) {
 718                 kfree(acpi_perf_data[i]);
 719                 acpi_perf_data[i] = NULL;
 720         }
 721         return;
 722 }
 723
 724 module_param(acpi_pstate_strict, uint, 0644);
 725 MODULE_PARM_DESC(acpi_pstate_strict,
 726                  "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");
 727
 728 late_initcall(acpi_cpufreq_init);
 729 module_exit(acpi_cpufreq_exit);
 730
 731 MODULE_ALIAS("acpi");