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   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/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/init.h>
  30 #include <linux/cpufreq.h>
  31 #include <linux/proc_fs.h>
  32 #include <linux/seq_file.h>
  33 #include <linux/compiler.h>
  34 #include <linux/sched.h>        /* current */
  35 #include <asm/io.h>
  36 #include <asm/delay.h>
  37 #include <asm/uaccess.h>
  38
  39 #include <linux/acpi.h>
  40 #include <acpi/processor.h>
  41
  42 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
  43
  44 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
  45 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  46 MODULE_LICENSE("GPL");
  47
  48
  49 struct cpufreq_acpi_io {
  50         struct acpi_processor_performance       *acpi_data;
  51         struct cpufreq_frequency_table          *freq_table;
  52         unsigned int                            resume;
  53 };
  54
  55 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
  56 static struct acpi_processor_performance        *acpi_perf_data[NR_CPUS];
  57
  58 static struct cpufreq_driver acpi_cpufreq_driver;
  59
  60 static unsigned int acpi_pstate_strict;
  61
  62 static int
  63 acpi_processor_write_port(
  64         u16     port,
  65         u8      bit_width,
  66         u32     value)
  67 {
  68         if (bit_width <= 8) {
  69                 outb(value, port);
  70         } else if (bit_width <= 16) {
  71                 outw(value, port);
  72         } else if (bit_width <= 32) {
  73                 outl(value, port);
  74         } else {
  75                 return -ENODEV;
  76         }
  77         return 0;
  78 }
  79
  80 static int
  81 acpi_processor_read_port(
  82         u16     port,
  83         u8      bit_width,
  84         u32     *ret)
  85 {
  86         *ret = 0;
  87         if (bit_width <= 8) {
  88                 *ret = inb(port);
  89         } else if (bit_width <= 16) {
  90                 *ret = inw(port);
  91         } else if (bit_width <= 32) {
  92                 *ret = inl(port);
  93         } else {
  94                 return -ENODEV;
  95         }
  96         return 0;
  97 }
  98
  99 static int
 100 acpi_processor_set_performance (
 101         struct cpufreq_acpi_io  *data,
 102         unsigned int            cpu,
 103         int                     state)
 104 {
 105         u16                     port = 0;
 106         u8                      bit_width = 0;
 107         int                     i = 0;
 108         int                     ret = 0;
 109         u32                     value = 0;
 110         int                     retval;
 111         struct acpi_processor_performance       *perf;
 112
 113         dprintk("acpi_processor_set_performance\n");
 114
 115         retval = 0;
 116         perf = data->acpi_data;
 117         if (state == perf->state) {
 118                 if (unlikely(data->resume)) {
 119                         dprintk("Called after resume, resetting to P%d\n", state);
 120                         data->resume = 0;
 121                 } else {
 122                         dprintk("Already at target state (P%d)\n", state);
 123                         return (retval);
 124                 }
 125         }
 126
 127         dprintk("Transitioning from P%d to P%d\n", perf->state, state);
 128
 129         /*
 130          * First we write the target state's 'control' value to the
 131          * control_register.
 132          */
 133
 134         port = perf->control_register.address;
 135         bit_width = perf->control_register.bit_width;
 136         value = (u32) perf->states[state].control;
 137
 138         dprintk("Writing 0x%08x to port 0x%04x\n", value, port);
 139
 140         ret = acpi_processor_write_port(port, bit_width, value);
 141         if (ret) {
 142                 dprintk("Invalid port width 0x%04x\n", bit_width);
 143                 return (ret);
 144         }
 145
 146         /*
 147          * Assume the write went through when acpi_pstate_strict is not used.
 148          * As read status_register is an expensive operation and there
 149          * are no specific error cases where an IO port write will fail.
 150          */
 151         if (acpi_pstate_strict) {
 152                 /* Then we read the 'status_register' and compare the value
 153                  * with the target state's 'status' to make sure the
 154                  * transition was successful.
 155                  * Note that we'll poll for up to 1ms (100 cycles of 10us)
 156                  * before giving up.
 157                  */
 158
 159                 port = perf->status_register.address;
 160                 bit_width = perf->status_register.bit_width;
 161
 162                 dprintk("Looking for 0x%08x from port 0x%04x\n",
 163                         (u32) perf->states[state].status, port);
 164
 165                 for (i = 0; i < 100; i++) {
 166                         ret = acpi_processor_read_port(port, bit_width, &value);
 167                         if (ret) {
 168                                 dprintk("Invalid port width 0x%04x\n", bit_width);
 169                                 return (ret);
 170                         }
 171                         if (value == (u32) perf->states[state].status)
 172                                 break;
 173                         udelay(10);
 174                 }
 175         } else {
 176                 value = (u32) perf->states[state].status;
 177         }
 178
 179         if (unlikely(value != (u32) perf->states[state].status)) {
 180                 printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
 181                 retval = -ENODEV;
 182                 return (retval);
 183         }
 184
 185         dprintk("Transition successful after %d microseconds\n", i * 10);
 186
 187         perf->state = state;
 188         return (retval);
 189 }
 190
 191
 192 static int
 193 acpi_cpufreq_target (
 194         struct cpufreq_policy   *policy,
 195         unsigned int target_freq,
 196         unsigned int relation)
 197 {
 198         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 199         struct acpi_processor_performance *perf;
 200         struct cpufreq_freqs freqs;
 201         cpumask_t online_policy_cpus;
 202         cpumask_t saved_mask;
 203         cpumask_t set_mask;
 204         cpumask_t covered_cpus;
 205         unsigned int cur_state = 0;
 206         unsigned int next_state = 0;
 207         unsigned int result = 0;
 208         unsigned int j;
 209         unsigned int tmp;
 210
 211         dprintk("acpi_cpufreq_setpolicy\n");
 212
 213         result = cpufreq_frequency_table_target(policy,
 214                         data->freq_table,
 215                         target_freq,
 216                         relation,
 217                         &next_state);
 218         if (unlikely(result))
 219                 return (result);
 220
 221         perf = data->acpi_data;
 222         cur_state = perf->state;
 223         freqs.old = data->freq_table[cur_state].frequency;
 224         freqs.new = data->freq_table[next_state].frequency;
 225
 226 #ifdef CONFIG_HOTPLUG_CPU
 227         /* cpufreq holds the hotplug lock, so we are safe from here on */
 228         cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
 229 #else
 230         online_policy_cpus = policy->cpus;
 231 #endif
 232
 233         for_each_cpu_mask(j, online_policy_cpus) {
 234                 freqs.cpu = j;
 235                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 236         }
 237
 238         /*
 239          * We need to call driver->target() on all or any CPU in
 240          * policy->cpus, depending on policy->shared_type.
 241          */
 242         saved_mask = current->cpus_allowed;
 243         cpus_clear(covered_cpus);
 244         for_each_cpu_mask(j, online_policy_cpus) {
 245                 /*
 246                  * Support for SMP systems.
 247                  * Make sure we are running on CPU that wants to change freq
 248                  */
 249                 cpus_clear(set_mask);
 250                 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 251                         cpus_or(set_mask, set_mask, online_policy_cpus);
 252                 else
 253                         cpu_set(j, set_mask);
 254
 255                 set_cpus_allowed(current, set_mask);
 256                 if (unlikely(!cpu_isset(smp_processor_id(), set_mask))) {
 257                         dprintk("couldn't limit to CPUs in this domain\n");
 258                         result = -EAGAIN;
 259                         break;
 260                 }
 261
 262                 result = acpi_processor_set_performance (data, j, next_state);
 263                 if (result) {
 264                         result = -EAGAIN;
 265                         break;
 266                 }
 267
 268                 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 269                         break;
 270
 271                 cpu_set(j, covered_cpus);
 272         }
 273
 274         for_each_cpu_mask(j, online_policy_cpus) {
 275                 freqs.cpu = j;
 276                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 277         }
 278
 279         if (unlikely(result)) {
 280                 /*
 281                  * We have failed halfway through the frequency change.
 282                  * We have sent callbacks to online_policy_cpus and
 283                  * acpi_processor_set_performance() has been called on
 284                  * coverd_cpus. Best effort undo..
 285                  */
 286
 287                 if (!cpus_empty(covered_cpus)) {
 288                         for_each_cpu_mask(j, covered_cpus) {
 289                                 policy->cpu = j;
 290                                 acpi_processor_set_performance (data,
 291                                                 j,
 292                                                 cur_state);
 293                         }
 294                 }
 295
 296                 tmp = freqs.new;
 297                 freqs.new = freqs.old;
 298                 freqs.old = tmp;
 299                 for_each_cpu_mask(j, online_policy_cpus) {
 300                         freqs.cpu = j;
 301                         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 302                         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 303                 }
 304         }
 305
 306         set_cpus_allowed(current, saved_mask);
 307         return (result);
 308 }
 309
 310
 311 static int
 312 acpi_cpufreq_verify (
 313         struct cpufreq_policy   *policy)
 314 {
 315         unsigned int result = 0;
 316         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 317
 318         dprintk("acpi_cpufreq_verify\n");
 319
 320         result = cpufreq_frequency_table_verify(policy,
 321                         data->freq_table);
 322
 323         return (result);
 324 }
 325
 326
 327 static unsigned long
 328 acpi_cpufreq_guess_freq (
 329         struct cpufreq_acpi_io  *data,
 330         unsigned int            cpu)
 331 {
 332         struct acpi_processor_performance       *perf = data->acpi_data;
 333
 334         if (cpu_khz) {
 335                 /* search the closest match to cpu_khz */
 336                 unsigned int i;
 337                 unsigned long freq;
 338                 unsigned long freqn = perf->states[0].core_frequency * 1000;
 339
 340                 for (i = 0; i < (perf->state_count - 1); i++) {
 341                         freq = freqn;
 342                         freqn = perf->states[i+1].core_frequency * 1000;
 343                         if ((2 * cpu_khz) > (freqn + freq)) {
 344                                 perf->state = i;
 345                                 return (freq);
 346                         }
 347                 }
 348                 perf->state = perf->state_count - 1;
 349                 return (freqn);
 350         } else {
 351                 /* assume CPU is at P0... */
 352                 perf->state = 0;
 353                 return perf->states[0].core_frequency * 1000;
 354         }
 355 }
 356
 357
 358 /*
 359  * acpi_cpufreq_early_init - initialize ACPI P-States library
 360  *
 361  * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
 362  * in order to determine correct frequency and voltage pairings. We can
 363  * do _PDC and _PSD and find out the processor dependency for the
 364  * actual init that will happen later...
 365  */
 366 static int acpi_cpufreq_early_init_acpi(void)
 367 {
 368         struct acpi_processor_performance       *data;
 369         unsigned int                            i, j;
 370
 371         dprintk("acpi_cpufreq_early_init\n");
 372
 373         for_each_possible_cpu(i) {
 374                 data = kzalloc(sizeof(struct acpi_processor_performance),
 375                         GFP_KERNEL);
 376                 if (!data) {
 377                         for_each_possible_cpu(j) {
 378                                 kfree(acpi_perf_data[j]);
 379                                 acpi_perf_data[j] = NULL;
 380                         }
 381                         return (-ENOMEM);
 382                 }
 383                 acpi_perf_data[i] = data;
 384         }
 385
 386         /* Do initialization in ACPI core */
 387         return acpi_processor_preregister_performance(acpi_perf_data);
 388 }
 389
 390 static int
 391 acpi_cpufreq_cpu_init (
 392         struct cpufreq_policy   *policy)
 393 {
 394         unsigned int            i;
 395         unsigned int            cpu = policy->cpu;
 396         struct cpufreq_acpi_io  *data;
 397         unsigned int            result = 0;
 398         struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
 399         struct acpi_processor_performance       *perf;
 400
 401         dprintk("acpi_cpufreq_cpu_init\n");
 402
 403         if (!acpi_perf_data[cpu])
 404                 return (-ENODEV);
 405
 406         data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 407         if (!data)
 408                 return (-ENOMEM);
 409
 410         data->acpi_data = acpi_perf_data[cpu];
 411         acpi_io_data[cpu] = data;
 412
 413         result = acpi_processor_register_performance(data->acpi_data, cpu);
 414
 415         if (result)
 416                 goto err_free;
 417
 418         perf = data->acpi_data;
 419         policy->shared_type = perf->shared_type;
 420         /*
 421          * Will let policy->cpus know about dependency only when software
 422          * coordination is required.
 423          */
 424         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
 425             policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 426                 policy->cpus = perf->shared_cpu_map;
 427
 428         if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
 429                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
 430         }
 431
 432         /* capability check */
 433         if (perf->state_count <= 1) {
 434                 dprintk("No P-States\n");
 435                 result = -ENODEV;
 436                 goto err_unreg;
 437         }
 438
 439         if ((perf->control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
 440             (perf->status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
 441                 dprintk("Unsupported address space [%d, %d]\n",
 442                         (u32) (perf->control_register.space_id),
 443                         (u32) (perf->status_register.space_id));
 444                 result = -ENODEV;
 445                 goto err_unreg;
 446         }
 447
 448         /* alloc freq_table */
 449         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (perf->state_count + 1), GFP_KERNEL);
 450         if (!data->freq_table) {
 451                 result = -ENOMEM;
 452                 goto err_unreg;
 453         }
 454
 455         /* detect transition latency */
 456         policy->cpuinfo.transition_latency = 0;
 457         for (i=0; i<perf->state_count; i++) {
 458                 if ((perf->states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
 459                         policy->cpuinfo.transition_latency = perf->states[i].transition_latency * 1000;
 460         }
 461         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 462
 463         /* The current speed is unknown and not detectable by ACPI...  */
 464         policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
 465
 466         /* table init */
 467         for (i=0; i<=perf->state_count; i++)
 468         {
 469                 data->freq_table[i].index = i;
 470                 if (i<perf->state_count)
 471                         data->freq_table[i].frequency = perf->states[i].core_frequency * 1000;
 472                 else
 473                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 474         }
 475
 476         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 477         if (result) {
 478                 goto err_freqfree;
 479         }
 480
 481         /* notify BIOS that we exist */
 482         acpi_processor_notify_smm(THIS_MODULE);
 483
 484         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
 485                cpu);
 486         for (i = 0; i < perf->state_count; i++)
 487                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
 488                         (i == perf->state?'*':' '), i,
 489                         (u32) perf->states[i].core_frequency,
 490                         (u32) perf->states[i].power,
 491                         (u32) perf->states[i].transition_latency);
 492
 493         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 494
 495         /*
 496          * the first call to ->target() should result in us actually
 497          * writing something to the appropriate registers.
 498          */
 499         data->resume = 1;
 500
 501         return (result);
 502
 503  err_freqfree:
 504         kfree(data->freq_table);
 505  err_unreg:
 506         acpi_processor_unregister_performance(perf, cpu);
 507  err_free:
 508         kfree(data);
 509         acpi_io_data[cpu] = NULL;
 510
 511         return (result);
 512 }
 513
 514
 515 static int
 516 acpi_cpufreq_cpu_exit (
 517         struct cpufreq_policy   *policy)
 518 {
 519         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 520
 521
 522         dprintk("acpi_cpufreq_cpu_exit\n");
 523
 524         if (data) {
 525                 cpufreq_frequency_table_put_attr(policy->cpu);
 526                 acpi_io_data[policy->cpu] = NULL;
 527                 acpi_processor_unregister_performance(data->acpi_data, policy->cpu);
 528                 kfree(data);
 529         }
 530
 531         return (0);
 532 }
 533
 534 static int
 535 acpi_cpufreq_resume (
 536         struct cpufreq_policy   *policy)
 537 {
 538         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 539
 540
 541         dprintk("acpi_cpufreq_resume\n");
 542
 543         data->resume = 1;
 544
 545         return (0);
 546 }
 547
 548
 549 static struct freq_attr* acpi_cpufreq_attr[] = {
 550         &cpufreq_freq_attr_scaling_available_freqs,
 551         NULL,
 552 };
 553
 554 static struct cpufreq_driver acpi_cpufreq_driver = {
 555         .verify = acpi_cpufreq_verify,
 556         .target = acpi_cpufreq_target,
 557         .init   = acpi_cpufreq_cpu_init,
 558         .exit   = acpi_cpufreq_cpu_exit,
 559         .resume = acpi_cpufreq_resume,
 560         .name   = "acpi-cpufreq",
 561         .owner  = THIS_MODULE,
 562         .attr   = acpi_cpufreq_attr,
 563         .flags  = CPUFREQ_STICKY,
 564 };
 565
 566
 567 static int __init
 568 acpi_cpufreq_init (void)
 569 {
 570         int                     result = 0;
 571
 572         dprintk("acpi_cpufreq_init\n");
 573
 574         result = acpi_cpufreq_early_init_acpi();
 575
 576         if (!result)
 577                 result = cpufreq_register_driver(&acpi_cpufreq_driver);
 578
 579         return (result);
 580 }
 581
 582
 583 static void __exit
 584 acpi_cpufreq_exit (void)
 585 {
 586         unsigned int    i;
 587         dprintk("acpi_cpufreq_exit\n");
 588
 589         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 590
 591         for_each_possible_cpu(i) {
 592                 kfree(acpi_perf_data[i]);
 593                 acpi_perf_data[i] = NULL;
 594         }
 595         return;
 596 }
 597
 598 module_param(acpi_pstate_strict, uint, 0644);
 599 MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");
 600
 601 late_initcall(acpi_cpufreq_init);
 602 module_exit(acpi_cpufreq_exit);
 603
 604 MODULE_ALIAS("acpi");