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                 value = (u32) perf->states[state].status;
 178         }
 179
 180         if (unlikely(value != (u32) perf->states[state].status)) {
 181                 printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
 182                 retval = -ENODEV;
 183                 return (retval);
 184         }
 185
 186         dprintk("Transition successful after %d microseconds\n", i * 10);
 187
 188         perf->state = state;
 189         return (retval);
 190 }
 191
 192
 193 static int
 194 acpi_cpufreq_target (
 195         struct cpufreq_policy   *policy,
 196         unsigned int target_freq,
 197         unsigned int relation)
 198 {
 199         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 200         struct acpi_processor_performance *perf;
 201         struct cpufreq_freqs freqs;
 202         cpumask_t online_policy_cpus;
 203         cpumask_t saved_mask;
 204         cpumask_t set_mask;
 205         cpumask_t covered_cpus;
 206         unsigned int cur_state = 0;
 207         unsigned int next_state = 0;
 208         unsigned int result = 0;
 209         unsigned int j;
 210         unsigned int tmp;
 211
 212         dprintk("acpi_cpufreq_setpolicy\n");
 213
 214         result = cpufreq_frequency_table_target(policy,
 215                         data->freq_table,
 216                         target_freq,
 217                         relation,
 218                         &next_state);
 219         if (unlikely(result))
 220                 return (result);
 221
 222         perf = data->acpi_data;
 223         cur_state = perf->state;
 224         freqs.old = data->freq_table[cur_state].frequency;
 225         freqs.new = data->freq_table[next_state].frequency;
 226
 227 #ifdef CONFIG_HOTPLUG_CPU
 228         /* cpufreq holds the hotplug lock, so we are safe from here on */
 229         cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
 230 #else
 231         online_policy_cpus = policy->cpus;
 232 #endif
 233
 234         for_each_cpu_mask(j, online_policy_cpus) {
 235                 freqs.cpu = j;
 236                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 237         }
 238
 239         /*
 240          * We need to call driver->target() on all or any CPU in
 241          * policy->cpus, depending on policy->shared_type.
 242          */
 243         saved_mask = current->cpus_allowed;
 244         cpus_clear(covered_cpus);
 245         for_each_cpu_mask(j, online_policy_cpus) {
 246                 /*
 247                  * Support for SMP systems.
 248                  * Make sure we are running on CPU that wants to change freq
 249                  */
 250                 cpus_clear(set_mask);
 251                 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 252                         cpus_or(set_mask, set_mask, online_policy_cpus);
 253                 else
 254                         cpu_set(j, set_mask);
 255
 256                 set_cpus_allowed(current, set_mask);
 257                 if (unlikely(!cpu_isset(smp_processor_id(), set_mask))) {
 258                         dprintk("couldn't limit to CPUs in this domain\n");
 259                         result = -EAGAIN;
 260                         break;
 261                 }
 262
 263                 result = acpi_processor_set_performance (data, j, next_state);
 264                 if (result) {
 265                         result = -EAGAIN;
 266                         break;
 267                 }
 268
 269                 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 270                         break;
 271
 272                 cpu_set(j, covered_cpus);
 273         }
 274
 275         for_each_cpu_mask(j, online_policy_cpus) {
 276                 freqs.cpu = j;
 277                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 278         }
 279
 280         if (unlikely(result)) {
 281                 /*
 282                  * We have failed halfway through the frequency change.
 283                  * We have sent callbacks to online_policy_cpus and
 284                  * acpi_processor_set_performance() has been called on
 285                  * coverd_cpus. Best effort undo..
 286                  */
 287
 288                 if (!cpus_empty(covered_cpus)) {
 289                         for_each_cpu_mask(j, covered_cpus) {
 290                                 policy->cpu = j;
 291                                 acpi_processor_set_performance (data,
 292                                                 j,
 293                                                 cur_state);
 294                         }
 295                 }
 296
 297                 tmp = freqs.new;
 298                 freqs.new = freqs.old;
 299                 freqs.old = tmp;
 300                 for_each_cpu_mask(j, online_policy_cpus) {
 301                         freqs.cpu = j;
 302                         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 303                         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 304                 }
 305         }
 306
 307         set_cpus_allowed(current, saved_mask);
 308         return (result);
 309 }
 310
 311
 312 static int
 313 acpi_cpufreq_verify (
 314         struct cpufreq_policy   *policy)
 315 {
 316         unsigned int result = 0;
 317         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 318
 319         dprintk("acpi_cpufreq_verify\n");
 320
 321         result = cpufreq_frequency_table_verify(policy,
 322                         data->freq_table);
 323
 324         return (result);
 325 }
 326
 327
 328 static unsigned long
 329 acpi_cpufreq_guess_freq (
 330         struct cpufreq_acpi_io  *data,
 331         unsigned int            cpu)
 332 {
 333         struct acpi_processor_performance       *perf = data->acpi_data;
 334
 335         if (cpu_khz) {
 336                 /* search the closest match to cpu_khz */
 337                 unsigned int i;
 338                 unsigned long freq;
 339                 unsigned long freqn = perf->states[0].core_frequency * 1000;
 340
 341                 for (i = 0; i < (perf->state_count - 1); i++) {
 342                         freq = freqn;
 343                         freqn = perf->states[i+1].core_frequency * 1000;
 344                         if ((2 * cpu_khz) > (freqn + freq)) {
 345                                 perf->state = i;
 346                                 return (freq);
 347                         }
 348                 }
 349                 perf->state = perf->state_count - 1;
 350                 return (freqn);
 351         } else {
 352                 /* assume CPU is at P0... */
 353                 perf->state = 0;
 354                 return perf->states[0].core_frequency * 1000;
 355         }
 356 }
 357
 358
 359 /*
 360  * acpi_cpufreq_early_init - initialize ACPI P-States library
 361  *
 362  * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
 363  * in order to determine correct frequency and voltage pairings. We can
 364  * do _PDC and _PSD and find out the processor dependency for the
 365  * actual init that will happen later...
 366  */
 367 static int acpi_cpufreq_early_init_acpi(void)
 368 {
 369         struct acpi_processor_performance       *data;
 370         unsigned int                            i, j;
 371
 372         dprintk("acpi_cpufreq_early_init\n");
 373
 374         for_each_possible_cpu(i) {
 375                 data = kzalloc(sizeof(struct acpi_processor_performance),
 376                         GFP_KERNEL);
 377                 if (!data) {
 378                         for_each_possible_cpu(j) {
 379                                 kfree(acpi_perf_data[j]);
 380                                 acpi_perf_data[j] = NULL;
 381                         }
 382                         return (-ENOMEM);
 383                 }
 384                 acpi_perf_data[i] = data;
 385         }
 386
 387         /* Do initialization in ACPI core */
 388         acpi_processor_preregister_performance(acpi_perf_data);
 389         return 0;
 390 }
 391
 392 static int
 393 acpi_cpufreq_cpu_init (
 394         struct cpufreq_policy   *policy)
 395 {
 396         unsigned int            i;
 397         unsigned int            cpu = policy->cpu;
 398         struct cpufreq_acpi_io  *data;
 399         unsigned int            result = 0;
 400         struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
 401         struct acpi_processor_performance       *perf;
 402
 403         dprintk("acpi_cpufreq_cpu_init\n");
 404
 405         if (!acpi_perf_data[cpu])
 406                 return (-ENODEV);
 407
 408         data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 409         if (!data)
 410                 return (-ENOMEM);
 411
 412         data->acpi_data = acpi_perf_data[cpu];
 413         acpi_io_data[cpu] = data;
 414
 415         result = acpi_processor_register_performance(data->acpi_data, cpu);
 416
 417         if (result)
 418                 goto err_free;
 419
 420         perf = data->acpi_data;
 421         policy->cpus = perf->shared_cpu_map;
 422         policy->shared_type = perf->shared_type;
 423
 424         if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
 425                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
 426         }
 427
 428         /* capability check */
 429         if (perf->state_count <= 1) {
 430                 dprintk("No P-States\n");
 431                 result = -ENODEV;
 432                 goto err_unreg;
 433         }
 434
 435         if ((perf->control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
 436             (perf->status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
 437                 dprintk("Unsupported address space [%d, %d]\n",
 438                         (u32) (perf->control_register.space_id),
 439                         (u32) (perf->status_register.space_id));
 440                 result = -ENODEV;
 441                 goto err_unreg;
 442         }
 443
 444         /* alloc freq_table */
 445         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (perf->state_count + 1), GFP_KERNEL);
 446         if (!data->freq_table) {
 447                 result = -ENOMEM;
 448                 goto err_unreg;
 449         }
 450
 451         /* detect transition latency */
 452         policy->cpuinfo.transition_latency = 0;
 453         for (i=0; i<perf->state_count; i++) {
 454                 if ((perf->states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
 455                         policy->cpuinfo.transition_latency = perf->states[i].transition_latency * 1000;
 456         }
 457         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 458
 459         /* The current speed is unknown and not detectable by ACPI...  */
 460         policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
 461
 462         /* table init */
 463         for (i=0; i<=perf->state_count; i++)
 464         {
 465                 data->freq_table[i].index = i;
 466                 if (i<perf->state_count)
 467                         data->freq_table[i].frequency = perf->states[i].core_frequency * 1000;
 468                 else
 469                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 470         }
 471
 472         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 473         if (result) {
 474                 goto err_freqfree;
 475         }
 476
 477         /* notify BIOS that we exist */
 478         acpi_processor_notify_smm(THIS_MODULE);
 479
 480         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
 481                cpu);
 482         for (i = 0; i < perf->state_count; i++)
 483                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
 484                         (i == perf->state?'*':' '), i,
 485                         (u32) perf->states[i].core_frequency,
 486                         (u32) perf->states[i].power,
 487                         (u32) perf->states[i].transition_latency);
 488
 489         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 490
 491         /*
 492          * the first call to ->target() should result in us actually
 493          * writing something to the appropriate registers.
 494          */
 495         data->resume = 1;
 496
 497         return (result);
 498
 499  err_freqfree:
 500         kfree(data->freq_table);
 501  err_unreg:
 502         acpi_processor_unregister_performance(perf, cpu);
 503  err_free:
 504         kfree(data);
 505         acpi_io_data[cpu] = NULL;
 506
 507         return (result);
 508 }
 509
 510
 511 static int
 512 acpi_cpufreq_cpu_exit (
 513         struct cpufreq_policy   *policy)
 514 {
 515         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 516
 517
 518         dprintk("acpi_cpufreq_cpu_exit\n");
 519
 520         if (data) {
 521                 cpufreq_frequency_table_put_attr(policy->cpu);
 522                 acpi_io_data[policy->cpu] = NULL;
 523                 acpi_processor_unregister_performance(data->acpi_data, policy->cpu);
 524                 kfree(data);
 525         }
 526
 527         return (0);
 528 }
 529
 530 static int
 531 acpi_cpufreq_resume (
 532         struct cpufreq_policy   *policy)
 533 {
 534         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 535
 536
 537         dprintk("acpi_cpufreq_resume\n");
 538
 539         data->resume = 1;
 540
 541         return (0);
 542 }
 543
 544
 545 static struct freq_attr* acpi_cpufreq_attr[] = {
 546         &cpufreq_freq_attr_scaling_available_freqs,
 547         NULL,
 548 };
 549
 550 static struct cpufreq_driver acpi_cpufreq_driver = {
 551         .verify = acpi_cpufreq_verify,
 552         .target = acpi_cpufreq_target,
 553         .init   = acpi_cpufreq_cpu_init,
 554         .exit   = acpi_cpufreq_cpu_exit,
 555         .resume = acpi_cpufreq_resume,
 556         .name   = "acpi-cpufreq",
 557         .owner  = THIS_MODULE,
 558         .attr   = acpi_cpufreq_attr,
 559         .flags  = CPUFREQ_STICKY,
 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_possible_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");