arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c

   1 /*
   2  * acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
   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  *
   8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or (at
  13  *  your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful, but
  16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *  General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  23  *
  24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  25  */
  26
  27 #include <linux/config.h>
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/init.h>
  31 #include <linux/cpufreq.h>
  32 #include <linux/proc_fs.h>
  33 #include <linux/seq_file.h>
  34 #include <linux/compiler.h>
  35 #include <linux/sched.h>        /* current */
  36 #include <asm/io.h>
  37 #include <asm/delay.h>
  38 #include <asm/uaccess.h>
  39
  40 #include <linux/acpi.h>
  41 #include <acpi/processor.h>
  42
  43 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
  44
  45 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
  46 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  47 MODULE_LICENSE("GPL");
  48
  49
  50 struct cpufreq_acpi_io {
  51         struct acpi_processor_performance       *acpi_data;
  52         struct cpufreq_frequency_table          *freq_table;
  53         unsigned int                            resume;
  54 };
  55
  56 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
  57 static struct acpi_processor_performance        *acpi_perf_data[NR_CPUS];
  58
  59 static struct cpufreq_driver acpi_cpufreq_driver;
  60
  61 static unsigned int acpi_pstate_strict;
  62
  63 static int
  64 acpi_processor_write_port(
  65         u16     port,
  66         u8      bit_width,
  67         u32     value)
  68 {
  69         if (bit_width <= 8) {
  70                 outb(value, port);
  71         } else if (bit_width <= 16) {
  72                 outw(value, port);
  73         } else if (bit_width <= 32) {
  74                 outl(value, port);
  75         } else {
  76                 return -ENODEV;
  77         }
  78         return 0;
  79 }
  80
  81 static int
  82 acpi_processor_read_port(
  83         u16     port,
  84         u8      bit_width,
  85         u32     *ret)
  86 {
  87         *ret = 0;
  88         if (bit_width <= 8) {
  89                 *ret = inb(port);
  90         } else if (bit_width <= 16) {
  91                 *ret = inw(port);
  92         } else if (bit_width <= 32) {
  93                 *ret = inl(port);
  94         } else {
  95                 return -ENODEV;
  96         }
  97         return 0;
  98 }
  99
 100 static int
 101 acpi_processor_set_performance (
 102         struct cpufreq_acpi_io  *data,
 103         unsigned int            cpu,
 104         int                     state)
 105 {
 106         u16                     port = 0;
 107         u8                      bit_width = 0;
 108         int                     i = 0;
 109         int                     ret = 0;
 110         u32                     value = 0;
 111         int                     retval;
 112         struct acpi_processor_performance       *perf;
 113
 114         dprintk("acpi_processor_set_performance\n");
 115
 116         retval = 0;
 117         perf = data->acpi_data;
 118         if (state == perf->state) {
 119                 if (unlikely(data->resume)) {
 120                         dprintk("Called after resume, resetting to P%d\n", state);
 121                         data->resume = 0;
 122                 } else {
 123                         dprintk("Already at target state (P%d)\n", state);
 124                         return (retval);
 125                 }
 126         }
 127
 128         dprintk("Transitioning from P%d to P%d\n", perf->state, state);
 129
 130         /*
 131          * First we write the target state's 'control' value to the
 132          * control_register.
 133          */
 134
 135         port = perf->control_register.address;
 136         bit_width = perf->control_register.bit_width;
 137         value = (u32) perf->states[state].control;
 138
 139         dprintk("Writing 0x%08x to port 0x%04x\n", value, port);
 140
 141         ret = acpi_processor_write_port(port, bit_width, value);
 142         if (ret) {
 143                 dprintk("Invalid port width 0x%04x\n", bit_width);
 144                 return (ret);
 145         }
 146
 147         /*
 148          * Assume the write went through when acpi_pstate_strict is not used.
 149          * As read status_register is an expensive operation and there
 150          * are no specific error cases where an IO port write will fail.
 151          */
 152         if (acpi_pstate_strict) {
 153                 /* Then we read the 'status_register' and compare the value
 154                  * with the target state's 'status' to make sure the
 155                  * transition was successful.
 156                  * Note that we'll poll for up to 1ms (100 cycles of 10us)
 157                  * before giving up.
 158                  */
 159
 160                 port = perf->status_register.address;
 161                 bit_width = perf->status_register.bit_width;
 162
 163                 dprintk("Looking for 0x%08x from port 0x%04x\n",
 164                         (u32) perf->states[state].status, port);
 165
 166                 for (i = 0; i < 100; i++) {
 167                         ret = acpi_processor_read_port(port, bit_width, &value);
 168                         if (ret) {
 169                                 dprintk("Invalid port width 0x%04x\n", bit_width);
 170                                 return (ret);
 171                         }
 172                         if (value == (u32) perf->states[state].status)
 173                                 break;
 174                         udelay(10);
 175                 }
 176         } else {
 177                 i = 0;
 178                 value = (u32) perf->states[state].status;
 179         }
 180
 181         if (unlikely(value != (u32) perf->states[state].status)) {
 182                 printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
 183                 retval = -ENODEV;
 184                 return (retval);
 185         }
 186
 187         dprintk("Transition successful after %d microseconds\n", i * 10);
 188
 189         perf->state = state;
 190         return (retval);
 191 }
 192
 193
 194 static int
 195 acpi_cpufreq_target (
 196         struct cpufreq_policy   *policy,
 197         unsigned int target_freq,
 198         unsigned int relation)
 199 {
 200         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 201         struct acpi_processor_performance *perf;
 202         struct cpufreq_freqs freqs;
 203         cpumask_t online_policy_cpus;
 204         cpumask_t saved_mask;
 205         cpumask_t set_mask;
 206         cpumask_t covered_cpus;
 207         unsigned int cur_state = 0;
 208         unsigned int next_state = 0;
 209         unsigned int result = 0;
 210         unsigned int j;
 211         unsigned int tmp;
 212
 213         dprintk("acpi_cpufreq_setpolicy\n");
 214
 215         result = cpufreq_frequency_table_target(policy,
 216                         data->freq_table,
 217                         target_freq,
 218                         relation,
 219                         &next_state);
 220         if (unlikely(result))
 221                 return (result);
 222
 223         perf = data->acpi_data;
 224         cur_state = perf->state;
 225         freqs.old = data->freq_table[cur_state].frequency;
 226         freqs.new = data->freq_table[next_state].frequency;
 227
 228 #ifdef CONFIG_HOTPLUG_CPU
 229         /* cpufreq holds the hotplug lock, so we are safe from here on */
 230         cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
 231 #else
 232         online_policy_cpus = policy->cpus;
 233 #endif
 234
 235         for_each_cpu_mask(j, online_policy_cpus) {
 236                 freqs.cpu = j;
 237                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 238         }
 239
 240         /*
 241          * We need to call driver->target() on all or any CPU in
 242          * policy->cpus, depending on policy->shared_type.
 243          */
 244         saved_mask = current->cpus_allowed;
 245         cpus_clear(covered_cpus);
 246         for_each_cpu_mask(j, online_policy_cpus) {
 247                 /*
 248                  * Support for SMP systems.
 249                  * Make sure we are running on CPU that wants to change freq
 250                  */
 251                 cpus_clear(set_mask);
 252                 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 253                         cpus_or(set_mask, set_mask, online_policy_cpus);
 254                 else
 255                         cpu_set(j, set_mask);
 256
 257                 set_cpus_allowed(current, set_mask);
 258                 if (unlikely(!cpu_isset(smp_processor_id(), set_mask))) {
 259                         dprintk("couldn't limit to CPUs in this domain\n");
 260                         result = -EAGAIN;
 261                         break;
 262                 }
 263
 264                 result = acpi_processor_set_performance (data, j, next_state);
 265                 if (result) {
 266                         result = -EAGAIN;
 267                         break;
 268                 }
 269
 270                 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 271                         break;
 272
 273                 cpu_set(j, covered_cpus);
 274         }
 275
 276         for_each_cpu_mask(j, online_policy_cpus) {
 277                 freqs.cpu = j;
 278                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 279         }
 280
 281         if (unlikely(result)) {
 282                 /*
 283                  * We have failed halfway through the frequency change.
 284                  * We have sent callbacks to online_policy_cpus and
 285                  * acpi_processor_set_performance() has been called on
 286                  * coverd_cpus. Best effort undo..
 287                  */
 288
 289                 if (!cpus_empty(covered_cpus)) {
 290                         for_each_cpu_mask(j, covered_cpus) {
 291                                 policy->cpu = j;
 292                                 acpi_processor_set_performance (data,
 293                                                 j,
 294                                                 cur_state);
 295                         }
 296                 }
 297
 298                 tmp = freqs.new;
 299                 freqs.new = freqs.old;
 300                 freqs.old = tmp;
 301                 for_each_cpu_mask(j, online_policy_cpus) {
 302                         freqs.cpu = j;
 303                         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 304                         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 305                 }
 306         }
 307
 308         set_cpus_allowed(current, saved_mask);
 309         return (result);
 310 }
 311
 312
 313 static int
 314 acpi_cpufreq_verify (
 315         struct cpufreq_policy   *policy)
 316 {
 317         unsigned int result = 0;
 318         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 319
 320         dprintk("acpi_cpufreq_verify\n");
 321
 322         result = cpufreq_frequency_table_verify(policy,
 323                         data->freq_table);
 324
 325         return (result);
 326 }
 327
 328
 329 static unsigned long
 330 acpi_cpufreq_guess_freq (
 331         struct cpufreq_acpi_io  *data,
 332         unsigned int            cpu)
 333 {
 334         struct acpi_processor_performance       *perf = data->acpi_data;
 335
 336         if (cpu_khz) {
 337                 /* search the closest match to cpu_khz */
 338                 unsigned int i;
 339                 unsigned long freq;
 340                 unsigned long freqn = perf->states[0].core_frequency * 1000;
 341
 342                 for (i = 0; i < (perf->state_count - 1); i++) {
 343                         freq = freqn;
 344                         freqn = perf->states[i+1].core_frequency * 1000;
 345                         if ((2 * cpu_khz) > (freqn + freq)) {
 346                                 perf->state = i;
 347                                 return (freq);
 348                         }
 349                 }
 350                 perf->state = perf->state_count - 1;
 351                 return (freqn);
 352         } else {
 353                 /* assume CPU is at P0... */
 354                 perf->state = 0;
 355                 return perf->states[0].core_frequency * 1000;
 356         }
 357 }
 358
 359
 360 /*
 361  * acpi_cpufreq_early_init - initialize ACPI P-States library
 362  *
 363  * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
 364  * in order to determine correct frequency and voltage pairings. We can
 365  * do _PDC and _PSD and find out the processor dependency for the
 366  * actual init that will happen later...
 367  */
 368 static int acpi_cpufreq_early_init_acpi(void)
 369 {
 370         struct acpi_processor_performance       *data;
 371         unsigned int                            i, j;
 372
 373         dprintk("acpi_cpufreq_early_init\n");
 374
 375         for_each_cpu(i) {
 376                 data = kzalloc(sizeof(struct acpi_processor_performance),
 377                         GFP_KERNEL);
 378                 if (!data) {
 379                         for_each_cpu(j) {
 380                                 kfree(acpi_perf_data[j]);
 381                                 acpi_perf_data[j] = NULL;
 382                         }
 383                         return (-ENOMEM);
 384                 }
 385                 acpi_perf_data[i] = data;
 386         }
 387
 388         /* Do initialization in ACPI core */
 389         acpi_processor_preregister_performance(acpi_perf_data);
 390         return 0;
 391 }
 392
 393 static int
 394 acpi_cpufreq_cpu_init (
 395         struct cpufreq_policy   *policy)
 396 {
 397         unsigned int            i;
 398         unsigned int            cpu = policy->cpu;
 399         struct cpufreq_acpi_io  *data;
 400         unsigned int            result = 0;
 401         struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
 402         struct acpi_processor_performance       *perf;
 403
 404         dprintk("acpi_cpufreq_cpu_init\n");
 405
 406         if (!acpi_perf_data[cpu])
 407                 return (-ENODEV);
 408
 409         data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 410         if (!data)
 411                 return (-ENOMEM);
 412
 413         data->acpi_data = acpi_perf_data[cpu];
 414         acpi_io_data[cpu] = data;
 415
 416         result = acpi_processor_register_performance(data->acpi_data, cpu);
 417
 418         if (result)
 419                 goto err_free;
 420
 421         perf = data->acpi_data;
 422         policy->cpus = perf->shared_cpu_map;
 423         policy->shared_type = perf->shared_type;
 424
 425         if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
 426                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
 427         }
 428
 429         /* capability check */
 430         if (perf->state_count <= 1) {
 431                 dprintk("No P-States\n");
 432                 result = -ENODEV;
 433                 goto err_unreg;
 434         }
 435
 436         if ((perf->control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
 437             (perf->status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
 438                 dprintk("Unsupported address space [%d, %d]\n",
 439                         (u32) (perf->control_register.space_id),
 440                         (u32) (perf->status_register.space_id));
 441                 result = -ENODEV;
 442                 goto err_unreg;
 443         }
 444
 445         /* alloc freq_table */
 446         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (perf->state_count + 1), GFP_KERNEL);
 447         if (!data->freq_table) {
 448                 result = -ENOMEM;
 449                 goto err_unreg;
 450         }
 451
 452         /* detect transition latency */
 453         policy->cpuinfo.transition_latency = 0;
 454         for (i=0; i<perf->state_count; i++) {
 455                 if ((perf->states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
 456                         policy->cpuinfo.transition_latency = perf->states[i].transition_latency * 1000;
 457         }
 458         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 459
 460         /* The current speed is unknown and not detectable by ACPI...  */
 461         policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
 462
 463         /* table init */
 464         for (i=0; i<=perf->state_count; i++)
 465         {
 466                 data->freq_table[i].index = i;
 467                 if (i<perf->state_count)
 468                         data->freq_table[i].frequency = perf->states[i].core_frequency * 1000;
 469                 else
 470                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 471         }
 472
 473         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 474         if (result) {
 475                 goto err_freqfree;
 476         }
 477
 478         /* notify BIOS that we exist */
 479         acpi_processor_notify_smm(THIS_MODULE);
 480
 481         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
 482                cpu);
 483         for (i = 0; i < perf->state_count; i++)
 484                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
 485                         (i == perf->state?'*':' '), i,
 486                         (u32) perf->states[i].core_frequency,
 487                         (u32) perf->states[i].power,
 488                         (u32) perf->states[i].transition_latency);
 489
 490         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 491
 492         /*
 493          * the first call to ->target() should result in us actually
 494          * writing something to the appropriate registers.
 495          */
 496         data->resume = 1;
 497
 498         return (result);
 499
 500  err_freqfree:
 501         kfree(data->freq_table);
 502  err_unreg:
 503         acpi_processor_unregister_performance(perf, cpu);
 504  err_free:
 505         kfree(data);
 506         acpi_io_data[cpu] = NULL;
 507
 508         return (result);
 509 }
 510
 511
 512 static int
 513 acpi_cpufreq_cpu_exit (
 514         struct cpufreq_policy   *policy)
 515 {
 516         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 517
 518
 519         dprintk("acpi_cpufreq_cpu_exit\n");
 520
 521         if (data) {
 522                 cpufreq_frequency_table_put_attr(policy->cpu);
 523                 acpi_io_data[policy->cpu] = NULL;
 524                 acpi_processor_unregister_performance(data->acpi_data, policy->cpu);
 525                 kfree(data);
 526         }
 527
 528         return (0);
 529 }
 530
 531 static int
 532 acpi_cpufreq_resume (
 533         struct cpufreq_policy   *policy)
 534 {
 535         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 536
 537
 538         dprintk("acpi_cpufreq_resume\n");
 539
 540         data->resume = 1;
 541
 542         return (0);
 543 }
 544
 545
 546 static struct freq_attr* acpi_cpufreq_attr[] = {
 547         &cpufreq_freq_attr_scaling_available_freqs,
 548         NULL,
 549 };
 550
 551 static struct cpufreq_driver acpi_cpufreq_driver = {
 552         .verify         = acpi_cpufreq_verify,
 553         .target         = acpi_cpufreq_target,
 554         .init           = acpi_cpufreq_cpu_init,
 555         .exit           = acpi_cpufreq_cpu_exit,
 556         .resume         = acpi_cpufreq_resume,
 557         .name           = "acpi-cpufreq",
 558         .owner          = THIS_MODULE,
 559         .attr           = acpi_cpufreq_attr,
 560 };
 561
 562
 563 static int __init
 564 acpi_cpufreq_init (void)
 565 {
 566         int                     result = 0;
 567
 568         dprintk("acpi_cpufreq_init\n");
 569
 570         result = acpi_cpufreq_early_init_acpi();
 571
 572         if (!result)
 573                 result = cpufreq_register_driver(&acpi_cpufreq_driver);
 574
 575         return (result);
 576 }
 577
 578
 579 static void __exit
 580 acpi_cpufreq_exit (void)
 581 {
 582         unsigned int    i;
 583         dprintk("acpi_cpufreq_exit\n");
 584
 585         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 586
 587         for_each_cpu(i) {
 588                 kfree(acpi_perf_data[i]);
 589                 acpi_perf_data[i] = NULL;
 590         }
 591         return;
 592 }
 593
 594 module_param(acpi_pstate_strict, uint, 0644);
 595 MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");
 596
 597 late_initcall(acpi_cpufreq_init);
 598 module_exit(acpi_cpufreq_exit);
 599
 600 MODULE_ALIAS("acpi");