linux/drivers/acpi/processor_perflib.c
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   1/*
   2 * processor_perflib.c - ACPI Processor P-States Library ($Revision: 71 $)
   3 *
   4 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6 *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
   7 *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   8 *                      - Added processor hotplug support
   9 *
  10 *
  11 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  12 *
  13 *  This program is free software; you can redistribute it and/or modify
  14 *  it under the terms of the GNU General Public License as published by
  15 *  the Free Software Foundation; either version 2 of the License, or (at
  16 *  your option) any later version.
  17 *
  18 *  This program is distributed in the hope that it will be useful, but
  19 *  WITHOUT ANY WARRANTY; without even the implied warranty of
  20 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21 *  General Public License for more details.
  22 *
  23 *  You should have received a copy of the GNU General Public License along
  24 *  with this program; if not, write to the Free Software Foundation, Inc.,
  25 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  26 *
  27 */
  28
  29#include <linux/kernel.h>
  30#include <linux/module.h>
  31#include <linux/init.h>
  32#include <linux/cpufreq.h>
  33
  34#ifdef CONFIG_X86
  35#include <asm/cpufeature.h>
  36#endif
  37
  38#include <acpi/acpi_bus.h>
  39#include <acpi/acpi_drivers.h>
  40#include <acpi/processor.h>
  41
  42#define PREFIX "ACPI: "
  43
  44#define ACPI_PROCESSOR_CLASS            "processor"
  45#define ACPI_PROCESSOR_FILE_PERFORMANCE "performance"
  46#define _COMPONENT              ACPI_PROCESSOR_COMPONENT
  47ACPI_MODULE_NAME("processor_perflib");
  48
  49static DEFINE_MUTEX(performance_mutex);
  50
  51/* Use cpufreq debug layer for _PPC changes. */
  52#define cpufreq_printk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
  53                                                "cpufreq-core", msg)
  54
  55/*
  56 * _PPC support is implemented as a CPUfreq policy notifier:
  57 * This means each time a CPUfreq driver registered also with
  58 * the ACPI core is asked to change the speed policy, the maximum
  59 * value is adjusted so that it is within the platform limit.
  60 *
  61 * Also, when a new platform limit value is detected, the CPUfreq
  62 * policy is adjusted accordingly.
  63 */
  64
  65/* ignore_ppc:
  66 * -1 -> cpufreq low level drivers not initialized -> _PSS, etc. not called yet
  67 *       ignore _PPC
  68 *  0 -> cpufreq low level drivers initialized -> consider _PPC values
  69 *  1 -> ignore _PPC totally -> forced by user through boot param
  70 */
  71static int ignore_ppc = -1;
  72module_param(ignore_ppc, int, 0644);
  73MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \
  74                 "limited by BIOS, this should help");
  75
  76#define PPC_REGISTERED   1
  77#define PPC_IN_USE       2
  78
  79static int acpi_processor_ppc_status;
  80
  81static int acpi_processor_ppc_notifier(struct notifier_block *nb,
  82                                       unsigned long event, void *data)
  83{
  84        struct cpufreq_policy *policy = data;
  85        struct acpi_processor *pr;
  86        unsigned int ppc = 0;
  87
  88        if (event == CPUFREQ_START && ignore_ppc <= 0) {
  89                ignore_ppc = 0;
  90                return 0;
  91        }
  92
  93        if (ignore_ppc)
  94                return 0;
  95
  96        if (event != CPUFREQ_INCOMPATIBLE)
  97                return 0;
  98
  99        mutex_lock(&performance_mutex);
 100
 101        pr = per_cpu(processors, policy->cpu);
 102        if (!pr || !pr->performance)
 103                goto out;
 104
 105        ppc = (unsigned int)pr->performance_platform_limit;
 106
 107        if (ppc >= pr->performance->state_count)
 108                goto out;
 109
 110        cpufreq_verify_within_limits(policy, 0,
 111                                     pr->performance->states[ppc].
 112                                     core_frequency * 1000);
 113
 114      out:
 115        mutex_unlock(&performance_mutex);
 116
 117        return 0;
 118}
 119
 120static struct notifier_block acpi_ppc_notifier_block = {
 121        .notifier_call = acpi_processor_ppc_notifier,
 122};
 123
 124static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
 125{
 126        acpi_status status = 0;
 127        unsigned long long ppc = 0;
 128
 129
 130        if (!pr)
 131                return -EINVAL;
 132
 133        /*
 134         * _PPC indicates the maximum state currently supported by the platform
 135         * (e.g. 0 = states 0..n; 1 = states 1..n; etc.
 136         */
 137        status = acpi_evaluate_integer(pr->handle, "_PPC", NULL, &ppc);
 138
 139        if (status != AE_NOT_FOUND)
 140                acpi_processor_ppc_status |= PPC_IN_USE;
 141
 142        if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 143                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PPC"));
 144                return -ENODEV;
 145        }
 146
 147        cpufreq_printk("CPU %d: _PPC is %d - frequency %s limited\n", pr->id,
 148                       (int)ppc, ppc ? "" : "not");
 149
 150        pr->performance_platform_limit = (int)ppc;
 151
 152        return 0;
 153}
 154
 155int acpi_processor_ppc_has_changed(struct acpi_processor *pr)
 156{
 157        int ret;
 158
 159        if (ignore_ppc)
 160                return 0;
 161
 162        ret = acpi_processor_get_platform_limit(pr);
 163
 164        if (ret < 0)
 165                return (ret);
 166        else
 167                return cpufreq_update_policy(pr->id);
 168}
 169
 170void acpi_processor_ppc_init(void)
 171{
 172        if (!cpufreq_register_notifier
 173            (&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER))
 174                acpi_processor_ppc_status |= PPC_REGISTERED;
 175        else
 176                printk(KERN_DEBUG
 177                       "Warning: Processor Platform Limit not supported.\n");
 178}
 179
 180void acpi_processor_ppc_exit(void)
 181{
 182        if (acpi_processor_ppc_status & PPC_REGISTERED)
 183                cpufreq_unregister_notifier(&acpi_ppc_notifier_block,
 184                                            CPUFREQ_POLICY_NOTIFIER);
 185
 186        acpi_processor_ppc_status &= ~PPC_REGISTERED;
 187}
 188
 189static int acpi_processor_get_performance_control(struct acpi_processor *pr)
 190{
 191        int result = 0;
 192        acpi_status status = 0;
 193        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 194        union acpi_object *pct = NULL;
 195        union acpi_object obj = { 0 };
 196
 197
 198        status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
 199        if (ACPI_FAILURE(status)) {
 200                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PCT"));
 201                return -ENODEV;
 202        }
 203
 204        pct = (union acpi_object *)buffer.pointer;
 205        if (!pct || (pct->type != ACPI_TYPE_PACKAGE)
 206            || (pct->package.count != 2)) {
 207                printk(KERN_ERR PREFIX "Invalid _PCT data\n");
 208                result = -EFAULT;
 209                goto end;
 210        }
 211
 212        /*
 213         * control_register
 214         */
 215
 216        obj = pct->package.elements[0];
 217
 218        if ((obj.type != ACPI_TYPE_BUFFER)
 219            || (obj.buffer.length < sizeof(struct acpi_pct_register))
 220            || (obj.buffer.pointer == NULL)) {
 221                printk(KERN_ERR PREFIX "Invalid _PCT data (control_register)\n");
 222                result = -EFAULT;
 223                goto end;
 224        }
 225        memcpy(&pr->performance->control_register, obj.buffer.pointer,
 226               sizeof(struct acpi_pct_register));
 227
 228        /*
 229         * status_register
 230         */
 231
 232        obj = pct->package.elements[1];
 233
 234        if ((obj.type != ACPI_TYPE_BUFFER)
 235            || (obj.buffer.length < sizeof(struct acpi_pct_register))
 236            || (obj.buffer.pointer == NULL)) {
 237                printk(KERN_ERR PREFIX "Invalid _PCT data (status_register)\n");
 238                result = -EFAULT;
 239                goto end;
 240        }
 241
 242        memcpy(&pr->performance->status_register, obj.buffer.pointer,
 243               sizeof(struct acpi_pct_register));
 244
 245      end:
 246        kfree(buffer.pointer);
 247
 248        return result;
 249}
 250
 251static int acpi_processor_get_performance_states(struct acpi_processor *pr)
 252{
 253        int result = 0;
 254        acpi_status status = AE_OK;
 255        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 256        struct acpi_buffer format = { sizeof("NNNNNN"), "NNNNNN" };
 257        struct acpi_buffer state = { 0, NULL };
 258        union acpi_object *pss = NULL;
 259        int i;
 260
 261
 262        status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
 263        if (ACPI_FAILURE(status)) {
 264                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PSS"));
 265                return -ENODEV;
 266        }
 267
 268        pss = buffer.pointer;
 269        if (!pss || (pss->type != ACPI_TYPE_PACKAGE)) {
 270                printk(KERN_ERR PREFIX "Invalid _PSS data\n");
 271                result = -EFAULT;
 272                goto end;
 273        }
 274
 275        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d performance states\n",
 276                          pss->package.count));
 277
 278        pr->performance->state_count = pss->package.count;
 279        pr->performance->states =
 280            kmalloc(sizeof(struct acpi_processor_px) * pss->package.count,
 281                    GFP_KERNEL);
 282        if (!pr->performance->states) {
 283                result = -ENOMEM;
 284                goto end;
 285        }
 286
 287        for (i = 0; i < pr->performance->state_count; i++) {
 288
 289                struct acpi_processor_px *px = &(pr->performance->states[i]);
 290
 291                state.length = sizeof(struct acpi_processor_px);
 292                state.pointer = px;
 293
 294                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
 295
 296                status = acpi_extract_package(&(pss->package.elements[i]),
 297                                              &format, &state);
 298                if (ACPI_FAILURE(status)) {
 299                        ACPI_EXCEPTION((AE_INFO, status, "Invalid _PSS data"));
 300                        result = -EFAULT;
 301                        kfree(pr->performance->states);
 302                        goto end;
 303                }
 304
 305                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 306                                  "State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]\n",
 307                                  i,
 308                                  (u32) px->core_frequency,
 309                                  (u32) px->power,
 310                                  (u32) px->transition_latency,
 311                                  (u32) px->bus_master_latency,
 312                                  (u32) px->control, (u32) px->status));
 313
 314                /*
 315                 * Check that ACPI's u64 MHz will be valid as u32 KHz in cpufreq
 316                 */
 317                if (!px->core_frequency ||
 318                    ((u32)(px->core_frequency * 1000) !=
 319                     (px->core_frequency * 1000))) {
 320                        printk(KERN_ERR FW_BUG PREFIX
 321                               "Invalid BIOS _PSS frequency: 0x%llx MHz\n",
 322                               px->core_frequency);
 323                        result = -EFAULT;
 324                        kfree(pr->performance->states);
 325                        goto end;
 326                }
 327        }
 328
 329      end:
 330        kfree(buffer.pointer);
 331
 332        return result;
 333}
 334
 335static int acpi_processor_get_performance_info(struct acpi_processor *pr)
 336{
 337        int result = 0;
 338        acpi_status status = AE_OK;
 339        acpi_handle handle = NULL;
 340
 341        if (!pr || !pr->performance || !pr->handle)
 342                return -EINVAL;
 343
 344        status = acpi_get_handle(pr->handle, "_PCT", &handle);
 345        if (ACPI_FAILURE(status)) {
 346                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 347                                  "ACPI-based processor performance control unavailable\n"));
 348                return -ENODEV;
 349        }
 350
 351        result = acpi_processor_get_performance_control(pr);
 352        if (result)
 353                goto update_bios;
 354
 355        result = acpi_processor_get_performance_states(pr);
 356        if (result)
 357                goto update_bios;
 358
 359        return 0;
 360
 361        /*
 362         * Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that
 363         * the BIOS is older than the CPU and does not know its frequencies
 364         */
 365 update_bios:
 366#ifdef CONFIG_X86
 367        if (ACPI_SUCCESS(acpi_get_handle(pr->handle, "_PPC", &handle))){
 368                if(boot_cpu_has(X86_FEATURE_EST))
 369                        printk(KERN_WARNING FW_BUG "BIOS needs update for CPU "
 370                               "frequency support\n");
 371        }
 372#endif
 373        return result;
 374}
 375
 376int acpi_processor_notify_smm(struct module *calling_module)
 377{
 378        acpi_status status;
 379        static int is_done = 0;
 380
 381
 382        if (!(acpi_processor_ppc_status & PPC_REGISTERED))
 383                return -EBUSY;
 384
 385        if (!try_module_get(calling_module))
 386                return -EINVAL;
 387
 388        /* is_done is set to negative if an error occured,
 389         * and to postitive if _no_ error occured, but SMM
 390         * was already notified. This avoids double notification
 391         * which might lead to unexpected results...
 392         */
 393        if (is_done > 0) {
 394                module_put(calling_module);
 395                return 0;
 396        } else if (is_done < 0) {
 397                module_put(calling_module);
 398                return is_done;
 399        }
 400
 401        is_done = -EIO;
 402
 403        /* Can't write pstate_control to smi_command if either value is zero */
 404        if ((!acpi_gbl_FADT.smi_command) || (!acpi_gbl_FADT.pstate_control)) {
 405                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No SMI port or pstate_control\n"));
 406                module_put(calling_module);
 407                return 0;
 408        }
 409
 410        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 411                          "Writing pstate_control [0x%x] to smi_command [0x%x]\n",
 412                          acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command));
 413
 414        status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
 415                                    (u32) acpi_gbl_FADT.pstate_control, 8);
 416        if (ACPI_FAILURE(status)) {
 417                ACPI_EXCEPTION((AE_INFO, status,
 418                                "Failed to write pstate_control [0x%x] to "
 419                                "smi_command [0x%x]", acpi_gbl_FADT.pstate_control,
 420                                acpi_gbl_FADT.smi_command));
 421                module_put(calling_module);
 422                return status;
 423        }
 424
 425        /* Success. If there's no _PPC, we need to fear nothing, so
 426         * we can allow the cpufreq driver to be rmmod'ed. */
 427        is_done = 1;
 428
 429        if (!(acpi_processor_ppc_status & PPC_IN_USE))
 430                module_put(calling_module);
 431
 432        return 0;
 433}
 434
 435EXPORT_SYMBOL(acpi_processor_notify_smm);
 436
 437static int acpi_processor_get_psd(struct acpi_processor *pr)
 438{
 439        int result = 0;
 440        acpi_status status = AE_OK;
 441        struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 442        struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
 443        struct acpi_buffer state = {0, NULL};
 444        union acpi_object  *psd = NULL;
 445        struct acpi_psd_package *pdomain;
 446
 447        status = acpi_evaluate_object(pr->handle, "_PSD", NULL, &buffer);
 448        if (ACPI_FAILURE(status)) {
 449                return -ENODEV;
 450        }
 451
 452        psd = buffer.pointer;
 453        if (!psd || (psd->type != ACPI_TYPE_PACKAGE)) {
 454                printk(KERN_ERR PREFIX "Invalid _PSD data\n");
 455                result = -EFAULT;
 456                goto end;
 457        }
 458
 459        if (psd->package.count != 1) {
 460                printk(KERN_ERR PREFIX "Invalid _PSD data\n");
 461                result = -EFAULT;
 462                goto end;
 463        }
 464
 465        pdomain = &(pr->performance->domain_info);
 466
 467        state.length = sizeof(struct acpi_psd_package);
 468        state.pointer = pdomain;
 469
 470        status = acpi_extract_package(&(psd->package.elements[0]),
 471                &format, &state);
 472        if (ACPI_FAILURE(status)) {
 473                printk(KERN_ERR PREFIX "Invalid _PSD data\n");
 474                result = -EFAULT;
 475                goto end;
 476        }
 477
 478        if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
 479                printk(KERN_ERR PREFIX "Unknown _PSD:num_entries\n");
 480                result = -EFAULT;
 481                goto end;
 482        }
 483
 484        if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
 485                printk(KERN_ERR PREFIX "Unknown _PSD:revision\n");
 486                result = -EFAULT;
 487                goto end;
 488        }
 489
 490        if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
 491            pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
 492            pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
 493                printk(KERN_ERR PREFIX "Invalid _PSD:coord_type\n");
 494                result = -EFAULT;
 495                goto end;
 496        }
 497end:
 498        kfree(buffer.pointer);
 499        return result;
 500}
 501
 502int acpi_processor_preregister_performance(
 503                struct acpi_processor_performance *performance)
 504{
 505        int count, count_target;
 506        int retval = 0;
 507        unsigned int i, j;
 508        cpumask_var_t covered_cpus;
 509        struct acpi_processor *pr;
 510        struct acpi_psd_package *pdomain;
 511        struct acpi_processor *match_pr;
 512        struct acpi_psd_package *match_pdomain;
 513
 514        if (!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))
 515                return -ENOMEM;
 516
 517        mutex_lock(&performance_mutex);
 518
 519        /*
 520         * Check if another driver has already registered, and abort before
 521         * changing pr->performance if it has. Check input data as well.
 522         */
 523        for_each_possible_cpu(i) {
 524                pr = per_cpu(processors, i);
 525                if (!pr) {
 526                        /* Look only at processors in ACPI namespace */
 527                        continue;
 528                }
 529
 530                if (pr->performance) {
 531                        retval = -EBUSY;
 532                        goto err_out;
 533                }
 534
 535                if (!performance || !per_cpu_ptr(performance, i)) {
 536                        retval = -EINVAL;
 537                        goto err_out;
 538                }
 539        }
 540
 541        /* Call _PSD for all CPUs */
 542        for_each_possible_cpu(i) {
 543                pr = per_cpu(processors, i);
 544                if (!pr)
 545                        continue;
 546
 547                pr->performance = per_cpu_ptr(performance, i);
 548                cpumask_set_cpu(i, pr->performance->shared_cpu_map);
 549                if (acpi_processor_get_psd(pr)) {
 550                        retval = -EINVAL;
 551                        continue;
 552                }
 553        }
 554        if (retval)
 555                goto err_ret;
 556
 557        /*
 558         * Now that we have _PSD data from all CPUs, lets setup P-state 
 559         * domain info.
 560         */
 561        for_each_possible_cpu(i) {
 562                pr = per_cpu(processors, i);
 563                if (!pr)
 564                        continue;
 565
 566                if (cpumask_test_cpu(i, covered_cpus))
 567                        continue;
 568
 569                pdomain = &(pr->performance->domain_info);
 570                cpumask_set_cpu(i, pr->performance->shared_cpu_map);
 571                cpumask_set_cpu(i, covered_cpus);
 572                if (pdomain->num_processors <= 1)
 573                        continue;
 574
 575                /* Validate the Domain info */
 576                count_target = pdomain->num_processors;
 577                count = 1;
 578                if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
 579                        pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 580                else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
 581                        pr->performance->shared_type = CPUFREQ_SHARED_TYPE_HW;
 582                else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
 583                        pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 584
 585                for_each_possible_cpu(j) {
 586                        if (i == j)
 587                                continue;
 588
 589                        match_pr = per_cpu(processors, j);
 590                        if (!match_pr)
 591                                continue;
 592
 593                        match_pdomain = &(match_pr->performance->domain_info);
 594                        if (match_pdomain->domain != pdomain->domain)
 595                                continue;
 596
 597                        /* Here i and j are in the same domain */
 598
 599                        if (match_pdomain->num_processors != count_target) {
 600                                retval = -EINVAL;
 601                                goto err_ret;
 602                        }
 603
 604                        if (pdomain->coord_type != match_pdomain->coord_type) {
 605                                retval = -EINVAL;
 606                                goto err_ret;
 607                        }
 608
 609                        cpumask_set_cpu(j, covered_cpus);
 610                        cpumask_set_cpu(j, pr->performance->shared_cpu_map);
 611                        count++;
 612                }
 613
 614                for_each_possible_cpu(j) {
 615                        if (i == j)
 616                                continue;
 617
 618                        match_pr = per_cpu(processors, j);
 619                        if (!match_pr)
 620                                continue;
 621
 622                        match_pdomain = &(match_pr->performance->domain_info);
 623                        if (match_pdomain->domain != pdomain->domain)
 624                                continue;
 625
 626                        match_pr->performance->shared_type = 
 627                                        pr->performance->shared_type;
 628                        cpumask_copy(match_pr->performance->shared_cpu_map,
 629                                     pr->performance->shared_cpu_map);
 630                }
 631        }
 632
 633err_ret:
 634        for_each_possible_cpu(i) {
 635                pr = per_cpu(processors, i);
 636                if (!pr || !pr->performance)
 637                        continue;
 638
 639                /* Assume no coordination on any error parsing domain info */
 640                if (retval) {
 641                        cpumask_clear(pr->performance->shared_cpu_map);
 642                        cpumask_set_cpu(i, pr->performance->shared_cpu_map);
 643                        pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 644                }
 645                pr->performance = NULL; /* Will be set for real in register */
 646        }
 647
 648err_out:
 649        mutex_unlock(&performance_mutex);
 650        free_cpumask_var(covered_cpus);
 651        return retval;
 652}
 653EXPORT_SYMBOL(acpi_processor_preregister_performance);
 654
 655int
 656acpi_processor_register_performance(struct acpi_processor_performance
 657                                    *performance, unsigned int cpu)
 658{
 659        struct acpi_processor *pr;
 660
 661        if (!(acpi_processor_ppc_status & PPC_REGISTERED))
 662                return -EINVAL;
 663
 664        mutex_lock(&performance_mutex);
 665
 666        pr = per_cpu(processors, cpu);
 667        if (!pr) {
 668                mutex_unlock(&performance_mutex);
 669                return -ENODEV;
 670        }
 671
 672        if (pr->performance) {
 673                mutex_unlock(&performance_mutex);
 674                return -EBUSY;
 675        }
 676
 677        WARN_ON(!performance);
 678
 679        pr->performance = performance;
 680
 681        if (acpi_processor_get_performance_info(pr)) {
 682                pr->performance = NULL;
 683                mutex_unlock(&performance_mutex);
 684                return -EIO;
 685        }
 686
 687        mutex_unlock(&performance_mutex);
 688        return 0;
 689}
 690
 691EXPORT_SYMBOL(acpi_processor_register_performance);
 692
 693void
 694acpi_processor_unregister_performance(struct acpi_processor_performance
 695                                      *performance, unsigned int cpu)
 696{
 697        struct acpi_processor *pr;
 698
 699        mutex_lock(&performance_mutex);
 700
 701        pr = per_cpu(processors, cpu);
 702        if (!pr) {
 703                mutex_unlock(&performance_mutex);
 704                return;
 705        }
 706
 707        if (pr->performance)
 708                kfree(pr->performance->states);
 709        pr->performance = NULL;
 710
 711        mutex_unlock(&performance_mutex);
 712
 713        return;
 714}
 715
 716EXPORT_SYMBOL(acpi_processor_unregister_performance);
 717