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 <asm/io.h>
  35 #include <asm/delay.h>
  36 #include <asm/uaccess.h>
  37
  38 #include <linux/acpi.h>
  39 #include <acpi/processor.h>
  40
  41 #include "speedstep-est-common.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
  58 static struct cpufreq_driver acpi_cpufreq_driver;
  59
  60 static int
  61 acpi_processor_write_port(
  62         u16     port,
  63         u8      bit_width,
  64         u32     value)
  65 {
  66         if (bit_width <= 8) {
  67                 outb(value, port);
  68         } else if (bit_width <= 16) {
  69                 outw(value, port);
  70         } else if (bit_width <= 32) {
  71                 outl(value, port);
  72         } else {
  73                 return -ENODEV;
  74         }
  75         return 0;
  76 }
  77
  78 static int
  79 acpi_processor_read_port(
  80         u16     port,
  81         u8      bit_width,
  82         u32     *ret)
  83 {
  84         *ret = 0;
  85         if (bit_width <= 8) {
  86                 *ret = inb(port);
  87         } else if (bit_width <= 16) {
  88                 *ret = inw(port);
  89         } else if (bit_width <= 32) {
  90                 *ret = inl(port);
  91         } else {
  92                 return -ENODEV;
  93         }
  94         return 0;
  95 }
  96
  97 static int
  98 acpi_processor_set_performance (
  99         struct cpufreq_acpi_io  *data,
 100         unsigned int            cpu,
 101         int                     state)
 102 {
 103         u16                     port = 0;
 104         u8                      bit_width = 0;
 105         int                     ret = 0;
 106         u32                     value = 0;
 107         int                     i = 0;
 108         struct cpufreq_freqs    cpufreq_freqs;
 109         cpumask_t               saved_mask;
 110         int                     retval;
 111
 112         dprintk("acpi_processor_set_performance\n");
 113
 114         /*
 115          * TBD: Use something other than set_cpus_allowed.
 116          * As set_cpus_allowed is a bit racy,
 117          * with any other set_cpus_allowed for this process.
 118          */
 119         saved_mask = current->cpus_allowed;
 120         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 121         if (smp_processor_id() != cpu) {
 122                 return (-EAGAIN);
 123         }
 124
 125         if (state == data->acpi_data.state) {
 126                 if (unlikely(data->resume)) {
 127                         dprintk("Called after resume, resetting to P%d\n", state);
 128                         data->resume = 0;
 129                 } else {
 130                         dprintk("Already at target state (P%d)\n", state);
 131                         retval = 0;
 132                         goto migrate_end;
 133                 }
 134         }
 135
 136         dprintk("Transitioning from P%d to P%d\n",
 137                 data->acpi_data.state, state);
 138
 139         /* cpufreq frequency struct */
 140         cpufreq_freqs.cpu = cpu;
 141         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
 142         cpufreq_freqs.new = data->freq_table[state].frequency;
 143
 144         /* notify cpufreq */
 145         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 146
 147         /*
 148          * First we write the target state's 'control' value to the
 149          * control_register.
 150          */
 151
 152         port = data->acpi_data.control_register.address;
 153         bit_width = data->acpi_data.control_register.bit_width;
 154         value = (u32) data->acpi_data.states[state].control;
 155
 156         dprintk("Writing 0x%08x to port 0x%04x\n", value, port);
 157
 158         ret = acpi_processor_write_port(port, bit_width, value);
 159         if (ret) {
 160                 dprintk("Invalid port width 0x%04x\n", bit_width);
 161                 retval = ret;
 162                 goto migrate_end;
 163         }
 164
 165         /*
 166          * Then we read the 'status_register' and compare the value with the
 167          * target state's 'status' to make sure the transition was successful.
 168          * Note that we'll poll for up to 1ms (100 cycles of 10us) before
 169          * giving up.
 170          */
 171
 172         port = data->acpi_data.status_register.address;
 173         bit_width = data->acpi_data.status_register.bit_width;
 174
 175         dprintk("Looking for 0x%08x from port 0x%04x\n",
 176                 (u32) data->acpi_data.states[state].status, port);
 177
 178         for (i=0; i<100; i++) {
 179                 ret = acpi_processor_read_port(port, bit_width, &value);
 180                 if (ret) {
 181                         dprintk("Invalid port width 0x%04x\n", bit_width);
 182                         retval = ret;
 183                         goto migrate_end;
 184                 }
 185                 if (value == (u32) data->acpi_data.states[state].status)
 186                         break;
 187                 udelay(10);
 188         }
 189
 190         /* notify cpufreq */
 191         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 192
 193         if (value != (u32) data->acpi_data.states[state].status) {
 194                 unsigned int tmp = cpufreq_freqs.new;
 195                 cpufreq_freqs.new = cpufreq_freqs.old;
 196                 cpufreq_freqs.old = tmp;
 197                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 198                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 199                 printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
 200                 retval = -ENODEV;
 201                 goto migrate_end;
 202         }
 203
 204         dprintk("Transition successful after %d microseconds\n", i * 10);
 205
 206         data->acpi_data.state = state;
 207
 208         retval = 0;
 209 migrate_end:
 210         set_cpus_allowed(current, saved_mask);
 211         return (retval);
 212 }
 213
 214
 215 static int
 216 acpi_cpufreq_target (
 217         struct cpufreq_policy   *policy,
 218         unsigned int target_freq,
 219         unsigned int relation)
 220 {
 221         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 222         unsigned int next_state = 0;
 223         unsigned int result = 0;
 224
 225         dprintk("acpi_cpufreq_setpolicy\n");
 226
 227         result = cpufreq_frequency_table_target(policy,
 228                         data->freq_table,
 229                         target_freq,
 230                         relation,
 231                         &next_state);
 232         if (result)
 233                 return (result);
 234
 235         result = acpi_processor_set_performance (data, policy->cpu, next_state);
 236
 237         return (result);
 238 }
 239
 240
 241 static int
 242 acpi_cpufreq_verify (
 243         struct cpufreq_policy   *policy)
 244 {
 245         unsigned int result = 0;
 246         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 247
 248         dprintk("acpi_cpufreq_verify\n");
 249
 250         result = cpufreq_frequency_table_verify(policy,
 251                         data->freq_table);
 252
 253         return (result);
 254 }
 255
 256
 257 static unsigned long
 258 acpi_cpufreq_guess_freq (
 259         struct cpufreq_acpi_io  *data,
 260         unsigned int            cpu)
 261 {
 262         if (cpu_khz) {
 263                 /* search the closest match to cpu_khz */
 264                 unsigned int i;
 265                 unsigned long freq;
 266                 unsigned long freqn = data->acpi_data.states[0].core_frequency * 1000;
 267
 268                 for (i=0; i < (data->acpi_data.state_count - 1); i++) {
 269                         freq = freqn;
 270                         freqn = data->acpi_data.states[i+1].core_frequency * 1000;
 271                         if ((2 * cpu_khz) > (freqn + freq)) {
 272                                 data->acpi_data.state = i;
 273                                 return (freq);
 274                         }
 275                 }
 276                 data->acpi_data.state = data->acpi_data.state_count - 1;
 277                 return (freqn);
 278         } else
 279                 /* assume CPU is at P0... */
 280                 data->acpi_data.state = 0;
 281                 return data->acpi_data.states[0].core_frequency * 1000;
 282
 283 }
 284
 285
 286 /*
 287  * acpi_processor_cpu_init_pdc_est - let BIOS know about the SMP capabilities
 288  * of this driver
 289  * @perf: processor-specific acpi_io_data struct
 290  * @cpu: CPU being initialized
 291  *
 292  * To avoid issues with legacy OSes, some BIOSes require to be informed of
 293  * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC
 294  * accordingly, for Enhanced Speedstep. Actual call to _PDC is done in
 295  * driver/acpi/processor.c
 296  */
 297 static void
 298 acpi_processor_cpu_init_pdc_est(
 299                 struct acpi_processor_performance *perf,
 300                 unsigned int cpu,
 301                 struct acpi_object_list *obj_list
 302                 )
 303 {
 304         union acpi_object *obj;
 305         u32 *buf;
 306         struct cpuinfo_x86 *c = cpu_data + cpu;
 307         dprintk("acpi_processor_cpu_init_pdc_est\n");
 308
 309         if (!cpu_has(c, X86_FEATURE_EST))
 310                 return;
 311
 312         /* Initialize pdc. It will be used later. */
 313         if (!obj_list)
 314                 return;
 315
 316         if (!(obj_list->count && obj_list->pointer))
 317                 return;
 318
 319         obj = obj_list->pointer;
 320         if ((obj->buffer.length == 12) && obj->buffer.pointer) {
 321                 buf = (u32 *)obj->buffer.pointer;
 322                 buf[0] = ACPI_PDC_REVISION_ID;
 323                 buf[1] = 1;
 324                 buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;
 325                 perf->pdc = obj_list;
 326         }
 327         return;
 328 }
 329
 330
 331 /* CPU specific PDC initialization */
 332 static void
 333 acpi_processor_cpu_init_pdc(
 334                 struct acpi_processor_performance *perf,
 335                 unsigned int cpu,
 336                 struct acpi_object_list *obj_list
 337                 )
 338 {
 339         struct cpuinfo_x86 *c = cpu_data + cpu;
 340         dprintk("acpi_processor_cpu_init_pdc\n");
 341         perf->pdc = NULL;
 342         if (cpu_has(c, X86_FEATURE_EST))
 343                 acpi_processor_cpu_init_pdc_est(perf, cpu, obj_list);
 344         return;
 345 }
 346
 347
 348 static int
 349 acpi_cpufreq_cpu_init (
 350         struct cpufreq_policy   *policy)
 351 {
 352         unsigned int            i;
 353         unsigned int            cpu = policy->cpu;
 354         struct cpufreq_acpi_io  *data;
 355         unsigned int            result = 0;
 356
 357         union acpi_object               arg0 = {ACPI_TYPE_BUFFER};
 358         u32                             arg0_buf[3];
 359         struct acpi_object_list         arg_list = {1, &arg0};
 360
 361         dprintk("acpi_cpufreq_cpu_init\n");
 362         /* setup arg_list for _PDC settings */
 363         arg0.buffer.length = 12;
 364         arg0.buffer.pointer = (u8 *) arg0_buf;
 365
 366         data = kmalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 367         if (!data)
 368                 return (-ENOMEM);
 369         memset(data, 0, sizeof(struct cpufreq_acpi_io));
 370
 371         acpi_io_data[cpu] = data;
 372
 373         acpi_processor_cpu_init_pdc(&data->acpi_data, cpu, &arg_list);
 374         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 375         data->acpi_data.pdc = NULL;
 376
 377         if (result)
 378                 goto err_free;
 379
 380         if (is_const_loops_cpu(cpu)) {
 381                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
 382         }
 383
 384         /* capability check */
 385         if (data->acpi_data.state_count <= 1) {
 386                 dprintk("No P-States\n");
 387                 result = -ENODEV;
 388                 goto err_unreg;
 389         }
 390         if ((data->acpi_data.control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
 391             (data->acpi_data.status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
 392                 dprintk("Unsupported address space [%d, %d]\n",
 393                         (u32) (data->acpi_data.control_register.space_id),
 394                         (u32) (data->acpi_data.status_register.space_id));
 395                 result = -ENODEV;
 396                 goto err_unreg;
 397         }
 398
 399         /* alloc freq_table */
 400         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (data->acpi_data.state_count + 1), GFP_KERNEL);
 401         if (!data->freq_table) {
 402                 result = -ENOMEM;
 403                 goto err_unreg;
 404         }
 405
 406         /* detect transition latency */
 407         policy->cpuinfo.transition_latency = 0;
 408         for (i=0; i<data->acpi_data.state_count; i++) {
 409                 if ((data->acpi_data.states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
 410                         policy->cpuinfo.transition_latency = data->acpi_data.states[i].transition_latency * 1000;
 411         }
 412         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 413
 414         /* The current speed is unknown and not detectable by ACPI...  */
 415         policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
 416
 417         /* table init */
 418         for (i=0; i<=data->acpi_data.state_count; i++)
 419         {
 420                 data->freq_table[i].index = i;
 421                 if (i<data->acpi_data.state_count)
 422                         data->freq_table[i].frequency = data->acpi_data.states[i].core_frequency * 1000;
 423                 else
 424                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 425         }
 426
 427         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 428         if (result) {
 429                 goto err_freqfree;
 430         }
 431
 432         /* notify BIOS that we exist */
 433         acpi_processor_notify_smm(THIS_MODULE);
 434
 435         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
 436                cpu);
 437         for (i = 0; i < data->acpi_data.state_count; i++)
 438                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
 439                         (i == data->acpi_data.state?'*':' '), i,
 440                         (u32) data->acpi_data.states[i].core_frequency,
 441                         (u32) data->acpi_data.states[i].power,
 442                         (u32) data->acpi_data.states[i].transition_latency);
 443
 444         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 445         return (result);
 446
 447  err_freqfree:
 448         kfree(data->freq_table);
 449  err_unreg:
 450         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 451  err_free:
 452         kfree(data);
 453         acpi_io_data[cpu] = NULL;
 454
 455         return (result);
 456 }
 457
 458
 459 static int
 460 acpi_cpufreq_cpu_exit (
 461         struct cpufreq_policy   *policy)
 462 {
 463         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 464
 465
 466         dprintk("acpi_cpufreq_cpu_exit\n");
 467
 468         if (data) {
 469                 cpufreq_frequency_table_put_attr(policy->cpu);
 470                 acpi_io_data[policy->cpu] = NULL;
 471                 acpi_processor_unregister_performance(&data->acpi_data, policy->cpu);
 472                 kfree(data);
 473         }
 474
 475         return (0);
 476 }
 477
 478 static int
 479 acpi_cpufreq_resume (
 480         struct cpufreq_policy   *policy)
 481 {
 482         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 483
 484
 485         dprintk("acpi_cpufreq_resume\n");
 486
 487         data->resume = 1;
 488
 489         return (0);
 490 }
 491
 492
 493 static struct freq_attr* acpi_cpufreq_attr[] = {
 494         &cpufreq_freq_attr_scaling_available_freqs,
 495         NULL,
 496 };
 497
 498 static struct cpufreq_driver acpi_cpufreq_driver = {
 499         .verify         = acpi_cpufreq_verify,
 500         .target         = acpi_cpufreq_target,
 501         .init           = acpi_cpufreq_cpu_init,
 502         .exit           = acpi_cpufreq_cpu_exit,
 503         .resume         = acpi_cpufreq_resume,
 504         .name           = "acpi-cpufreq",
 505         .owner          = THIS_MODULE,
 506         .attr           = acpi_cpufreq_attr,
 507 };
 508
 509
 510 static int __init
 511 acpi_cpufreq_init (void)
 512 {
 513         int                     result = 0;
 514
 515         dprintk("acpi_cpufreq_init\n");
 516
 517         result = cpufreq_register_driver(&acpi_cpufreq_driver);
 518
 519         return (result);
 520 }
 521
 522
 523 static void __exit
 524 acpi_cpufreq_exit (void)
 525 {
 526         dprintk("acpi_cpufreq_exit\n");
 527
 528         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 529
 530         return;
 531 }
 532
 533
 534 late_initcall(acpi_cpufreq_init);
 535 module_exit(acpi_cpufreq_exit);
 536
 537 MODULE_ALIAS("acpi");