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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/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 <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 #include "speedstep-est-common.h"
  43
  44 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
  45
  46 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
  47 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  48 MODULE_LICENSE("GPL");
  49
  50
  51 struct cpufreq_acpi_io {
  52         struct acpi_processor_performance       acpi_data;
  53         struct cpufreq_frequency_table          *freq_table;
  54         unsigned int                            resume;
  55 };
  56
  57 static struct cpufreq_acpi_io   *acpi_io_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                     ret = 0;
 109         u32                     value = 0;
 110         int                     i = 0;
 111         struct cpufreq_freqs    cpufreq_freqs;
 112         cpumask_t               saved_mask;
 113         int                     retval;
 114
 115         dprintk("acpi_processor_set_performance\n");
 116
 117         /*
 118          * TBD: Use something other than set_cpus_allowed.
 119          * As set_cpus_allowed is a bit racy,
 120          * with any other set_cpus_allowed for this process.
 121          */
 122         saved_mask = current->cpus_allowed;
 123         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 124         if (smp_processor_id() != cpu) {
 125                 return (-EAGAIN);
 126         }
 127
 128         if (state == data->acpi_data.state) {
 129                 if (unlikely(data->resume)) {
 130                         dprintk("Called after resume, resetting to P%d\n", state);
 131                         data->resume = 0;
 132                 } else {
 133                         dprintk("Already at target state (P%d)\n", state);
 134                         retval = 0;
 135                         goto migrate_end;
 136                 }
 137         }
 138
 139         dprintk("Transitioning from P%d to P%d\n",
 140                 data->acpi_data.state, state);
 141
 142         /* cpufreq frequency struct */
 143         cpufreq_freqs.cpu = cpu;
 144         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
 145         cpufreq_freqs.new = data->freq_table[state].frequency;
 146
 147         /* notify cpufreq */
 148         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 149
 150         /*
 151          * First we write the target state's 'control' value to the
 152          * control_register.
 153          */
 154
 155         port = data->acpi_data.control_register.address;
 156         bit_width = data->acpi_data.control_register.bit_width;
 157         value = (u32) data->acpi_data.states[state].control;
 158
 159         dprintk("Writing 0x%08x to port 0x%04x\n", value, port);
 160
 161         ret = acpi_processor_write_port(port, bit_width, value);
 162         if (ret) {
 163                 dprintk("Invalid port width 0x%04x\n", bit_width);
 164                 retval = ret;
 165                 goto migrate_end;
 166         }
 167
 168         /*
 169          * Assume the write went through when acpi_pstate_strict is not used.
 170          * As read status_register is an expensive operation and there
 171          * are no specific error cases where an IO port write will fail.
 172          */
 173         if (acpi_pstate_strict) {
 174                 /* Then we read the 'status_register' and compare the value
 175                  * with the target state's 'status' to make sure the
 176                  * transition was successful.
 177                  * Note that we'll poll for up to 1ms (100 cycles of 10us)
 178                  * before giving up.
 179                  */
 180
 181                 port = data->acpi_data.status_register.address;
 182                 bit_width = data->acpi_data.status_register.bit_width;
 183
 184                 dprintk("Looking for 0x%08x from port 0x%04x\n",
 185                         (u32) data->acpi_data.states[state].status, port);
 186
 187                 for (i=0; i<100; i++) {
 188                         ret = acpi_processor_read_port(port, bit_width, &value);
 189                         if (ret) {
 190                                 dprintk("Invalid port width 0x%04x\n", bit_width);
 191                                 retval = ret;
 192                                 goto migrate_end;
 193                         }
 194                         if (value == (u32) data->acpi_data.states[state].status)
 195                                 break;
 196                         udelay(10);
 197                 }
 198         } else {
 199                 i = 0;
 200                 value = (u32) data->acpi_data.states[state].status;
 201         }
 202
 203         /* notify cpufreq */
 204         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 205
 206         if (unlikely(value != (u32) data->acpi_data.states[state].status)) {
 207                 unsigned int tmp = cpufreq_freqs.new;
 208                 cpufreq_freqs.new = cpufreq_freqs.old;
 209                 cpufreq_freqs.old = tmp;
 210                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 211                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 212                 printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
 213                 retval = -ENODEV;
 214                 goto migrate_end;
 215         }
 216
 217         dprintk("Transition successful after %d microseconds\n", i * 10);
 218
 219         data->acpi_data.state = state;
 220
 221         retval = 0;
 222 migrate_end:
 223         set_cpus_allowed(current, saved_mask);
 224         return (retval);
 225 }
 226
 227
 228 static int
 229 acpi_cpufreq_target (
 230         struct cpufreq_policy   *policy,
 231         unsigned int target_freq,
 232         unsigned int relation)
 233 {
 234         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 235         unsigned int next_state = 0;
 236         unsigned int result = 0;
 237
 238         dprintk("acpi_cpufreq_setpolicy\n");
 239
 240         result = cpufreq_frequency_table_target(policy,
 241                         data->freq_table,
 242                         target_freq,
 243                         relation,
 244                         &next_state);
 245         if (result)
 246                 return (result);
 247
 248         result = acpi_processor_set_performance (data, policy->cpu, next_state);
 249
 250         return (result);
 251 }
 252
 253
 254 static int
 255 acpi_cpufreq_verify (
 256         struct cpufreq_policy   *policy)
 257 {
 258         unsigned int result = 0;
 259         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 260
 261         dprintk("acpi_cpufreq_verify\n");
 262
 263         result = cpufreq_frequency_table_verify(policy,
 264                         data->freq_table);
 265
 266         return (result);
 267 }
 268
 269
 270 static unsigned long
 271 acpi_cpufreq_guess_freq (
 272         struct cpufreq_acpi_io  *data,
 273         unsigned int            cpu)
 274 {
 275         if (cpu_khz) {
 276                 /* search the closest match to cpu_khz */
 277                 unsigned int i;
 278                 unsigned long freq;
 279                 unsigned long freqn = data->acpi_data.states[0].core_frequency * 1000;
 280
 281                 for (i=0; i < (data->acpi_data.state_count - 1); i++) {
 282                         freq = freqn;
 283                         freqn = data->acpi_data.states[i+1].core_frequency * 1000;
 284                         if ((2 * cpu_khz) > (freqn + freq)) {
 285                                 data->acpi_data.state = i;
 286                                 return (freq);
 287                         }
 288                 }
 289                 data->acpi_data.state = data->acpi_data.state_count - 1;
 290                 return (freqn);
 291         } else
 292                 /* assume CPU is at P0... */
 293                 data->acpi_data.state = 0;
 294                 return data->acpi_data.states[0].core_frequency * 1000;
 295
 296 }
 297
 298
 299 /*
 300  * acpi_processor_cpu_init_pdc_est - let BIOS know about the SMP capabilities
 301  * of this driver
 302  * @perf: processor-specific acpi_io_data struct
 303  * @cpu: CPU being initialized
 304  *
 305  * To avoid issues with legacy OSes, some BIOSes require to be informed of
 306  * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC
 307  * accordingly, for Enhanced Speedstep. Actual call to _PDC is done in
 308  * driver/acpi/processor.c
 309  */
 310 static void
 311 acpi_processor_cpu_init_pdc_est(
 312                 struct acpi_processor_performance *perf,
 313                 unsigned int cpu,
 314                 struct acpi_object_list *obj_list
 315                 )
 316 {
 317         union acpi_object *obj;
 318         u32 *buf;
 319         struct cpuinfo_x86 *c = cpu_data + cpu;
 320         dprintk("acpi_processor_cpu_init_pdc_est\n");
 321
 322         if (!cpu_has(c, X86_FEATURE_EST))
 323                 return;
 324
 325         /* Initialize pdc. It will be used later. */
 326         if (!obj_list)
 327                 return;
 328
 329         if (!(obj_list->count && obj_list->pointer))
 330                 return;
 331
 332         obj = obj_list->pointer;
 333         if ((obj->buffer.length == 12) && obj->buffer.pointer) {
 334                 buf = (u32 *)obj->buffer.pointer;
 335                 buf[0] = ACPI_PDC_REVISION_ID;
 336                 buf[1] = 1;
 337                 buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;
 338                 perf->pdc = obj_list;
 339         }
 340         return;
 341 }
 342
 343
 344 /* CPU specific PDC initialization */
 345 static void
 346 acpi_processor_cpu_init_pdc(
 347                 struct acpi_processor_performance *perf,
 348                 unsigned int cpu,
 349                 struct acpi_object_list *obj_list
 350                 )
 351 {
 352         struct cpuinfo_x86 *c = cpu_data + cpu;
 353         dprintk("acpi_processor_cpu_init_pdc\n");
 354         perf->pdc = NULL;
 355         if (cpu_has(c, X86_FEATURE_EST))
 356                 acpi_processor_cpu_init_pdc_est(perf, cpu, obj_list);
 357         return;
 358 }
 359
 360
 361 static int
 362 acpi_cpufreq_cpu_init (
 363         struct cpufreq_policy   *policy)
 364 {
 365         unsigned int            i;
 366         unsigned int            cpu = policy->cpu;
 367         struct cpufreq_acpi_io  *data;
 368         unsigned int            result = 0;
 369
 370         union acpi_object               arg0 = {ACPI_TYPE_BUFFER};
 371         u32                             arg0_buf[3];
 372         struct acpi_object_list         arg_list = {1, &arg0};
 373
 374         dprintk("acpi_cpufreq_cpu_init\n");
 375         /* setup arg_list for _PDC settings */
 376         arg0.buffer.length = 12;
 377         arg0.buffer.pointer = (u8 *) arg0_buf;
 378
 379         data = kmalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 380         if (!data)
 381                 return (-ENOMEM);
 382         memset(data, 0, sizeof(struct cpufreq_acpi_io));
 383
 384         acpi_io_data[cpu] = data;
 385
 386         acpi_processor_cpu_init_pdc(&data->acpi_data, cpu, &arg_list);
 387         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 388         data->acpi_data.pdc = NULL;
 389
 390         if (result)
 391                 goto err_free;
 392
 393         if (is_const_loops_cpu(cpu)) {
 394                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
 395         }
 396
 397         /* capability check */
 398         if (data->acpi_data.state_count <= 1) {
 399                 dprintk("No P-States\n");
 400                 result = -ENODEV;
 401                 goto err_unreg;
 402         }
 403         if ((data->acpi_data.control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
 404             (data->acpi_data.status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
 405                 dprintk("Unsupported address space [%d, %d]\n",
 406                         (u32) (data->acpi_data.control_register.space_id),
 407                         (u32) (data->acpi_data.status_register.space_id));
 408                 result = -ENODEV;
 409                 goto err_unreg;
 410         }
 411
 412         /* alloc freq_table */
 413         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (data->acpi_data.state_count + 1), GFP_KERNEL);
 414         if (!data->freq_table) {
 415                 result = -ENOMEM;
 416                 goto err_unreg;
 417         }
 418
 419         /* detect transition latency */
 420         policy->cpuinfo.transition_latency = 0;
 421         for (i=0; i<data->acpi_data.state_count; i++) {
 422                 if ((data->acpi_data.states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
 423                         policy->cpuinfo.transition_latency = data->acpi_data.states[i].transition_latency * 1000;
 424         }
 425         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 426
 427         /* The current speed is unknown and not detectable by ACPI...  */
 428         policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
 429
 430         /* table init */
 431         for (i=0; i<=data->acpi_data.state_count; i++)
 432         {
 433                 data->freq_table[i].index = i;
 434                 if (i<data->acpi_data.state_count)
 435                         data->freq_table[i].frequency = data->acpi_data.states[i].core_frequency * 1000;
 436                 else
 437                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 438         }
 439
 440         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 441         if (result) {
 442                 goto err_freqfree;
 443         }
 444
 445         /* notify BIOS that we exist */
 446         acpi_processor_notify_smm(THIS_MODULE);
 447
 448         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
 449                cpu);
 450         for (i = 0; i < data->acpi_data.state_count; i++)
 451                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
 452                         (i == data->acpi_data.state?'*':' '), i,
 453                         (u32) data->acpi_data.states[i].core_frequency,
 454                         (u32) data->acpi_data.states[i].power,
 455                         (u32) data->acpi_data.states[i].transition_latency);
 456
 457         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 458
 459         /*
 460          * the first call to ->target() should result in us actually
 461          * writing something to the appropriate registers.
 462          */
 463         data->resume = 1;
 464
 465         return (result);
 466
 467  err_freqfree:
 468         kfree(data->freq_table);
 469  err_unreg:
 470         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 471  err_free:
 472         kfree(data);
 473         acpi_io_data[cpu] = NULL;
 474
 475         return (result);
 476 }
 477
 478
 479 static int
 480 acpi_cpufreq_cpu_exit (
 481         struct cpufreq_policy   *policy)
 482 {
 483         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 484
 485
 486         dprintk("acpi_cpufreq_cpu_exit\n");
 487
 488         if (data) {
 489                 cpufreq_frequency_table_put_attr(policy->cpu);
 490                 acpi_io_data[policy->cpu] = NULL;
 491                 acpi_processor_unregister_performance(&data->acpi_data, policy->cpu);
 492                 kfree(data);
 493         }
 494
 495         return (0);
 496 }
 497
 498 static int
 499 acpi_cpufreq_resume (
 500         struct cpufreq_policy   *policy)
 501 {
 502         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 503
 504
 505         dprintk("acpi_cpufreq_resume\n");
 506
 507         data->resume = 1;
 508
 509         return (0);
 510 }
 511
 512
 513 static struct freq_attr* acpi_cpufreq_attr[] = {
 514         &cpufreq_freq_attr_scaling_available_freqs,
 515         NULL,
 516 };
 517
 518 static struct cpufreq_driver acpi_cpufreq_driver = {
 519         .verify         = acpi_cpufreq_verify,
 520         .target         = acpi_cpufreq_target,
 521         .init           = acpi_cpufreq_cpu_init,
 522         .exit           = acpi_cpufreq_cpu_exit,
 523         .resume         = acpi_cpufreq_resume,
 524         .name           = "acpi-cpufreq",
 525         .owner          = THIS_MODULE,
 526         .attr           = acpi_cpufreq_attr,
 527 };
 528
 529
 530 static int __init
 531 acpi_cpufreq_init (void)
 532 {
 533         int                     result = 0;
 534
 535         dprintk("acpi_cpufreq_init\n");
 536
 537         result = cpufreq_register_driver(&acpi_cpufreq_driver);
 538
 539         return (result);
 540 }
 541
 542
 543 static void __exit
 544 acpi_cpufreq_exit (void)
 545 {
 546         dprintk("acpi_cpufreq_exit\n");
 547
 548         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 549
 550         return;
 551 }
 552
 553 module_param(acpi_pstate_strict, uint, 0644);
 554 MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");
 555
 556 late_initcall(acpi_cpufreq_init);
 557 module_exit(acpi_cpufreq_exit);
 558
 559 MODULE_ALIAS("acpi");