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 #include "speedstep-est-common.h"
  44
  45 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
  46
  47 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
  48 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  49 MODULE_LICENSE("GPL");
  50
  51
  52 struct cpufreq_acpi_io {
  53         struct acpi_processor_performance       acpi_data;
  54         struct cpufreq_frequency_table          *freq_table;
  55         unsigned int                            resume;
  56 };
  57
  58 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
  59
  60 static struct cpufreq_driver acpi_cpufreq_driver;
  61
  62 static unsigned int acpi_pstate_strict;
  63
  64 static int
  65 acpi_processor_write_port(
  66         u16     port,
  67         u8      bit_width,
  68         u32     value)
  69 {
  70         if (bit_width <= 8) {
  71                 outb(value, port);
  72         } else if (bit_width <= 16) {
  73                 outw(value, port);
  74         } else if (bit_width <= 32) {
  75                 outl(value, port);
  76         } else {
  77                 return -ENODEV;
  78         }
  79         return 0;
  80 }
  81
  82 static int
  83 acpi_processor_read_port(
  84         u16     port,
  85         u8      bit_width,
  86         u32     *ret)
  87 {
  88         *ret = 0;
  89         if (bit_width <= 8) {
  90                 *ret = inb(port);
  91         } else if (bit_width <= 16) {
  92                 *ret = inw(port);
  93         } else if (bit_width <= 32) {
  94                 *ret = inl(port);
  95         } else {
  96                 return -ENODEV;
  97         }
  98         return 0;
  99 }
 100
 101 static int
 102 acpi_processor_set_performance (
 103         struct cpufreq_acpi_io  *data,
 104         unsigned int            cpu,
 105         int                     state)
 106 {
 107         u16                     port = 0;
 108         u8                      bit_width = 0;
 109         int                     ret = 0;
 110         u32                     value = 0;
 111         int                     i = 0;
 112         struct cpufreq_freqs    cpufreq_freqs;
 113         cpumask_t               saved_mask;
 114         int                     retval;
 115
 116         dprintk("acpi_processor_set_performance\n");
 117
 118         /*
 119          * TBD: Use something other than set_cpus_allowed.
 120          * As set_cpus_allowed is a bit racy,
 121          * with any other set_cpus_allowed for this process.
 122          */
 123         saved_mask = current->cpus_allowed;
 124         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 125         if (smp_processor_id() != cpu) {
 126                 return (-EAGAIN);
 127         }
 128
 129         if (state == data->acpi_data.state) {
 130                 if (unlikely(data->resume)) {
 131                         dprintk("Called after resume, resetting to P%d\n", state);
 132                         data->resume = 0;
 133                 } else {
 134                         dprintk("Already at target state (P%d)\n", state);
 135                         retval = 0;
 136                         goto migrate_end;
 137                 }
 138         }
 139
 140         dprintk("Transitioning from P%d to P%d\n",
 141                 data->acpi_data.state, state);
 142
 143         /* cpufreq frequency struct */
 144         cpufreq_freqs.cpu = cpu;
 145         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
 146         cpufreq_freqs.new = data->freq_table[state].frequency;
 147
 148         /* notify cpufreq */
 149         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 150
 151         /*
 152          * First we write the target state's 'control' value to the
 153          * control_register.
 154          */
 155
 156         port = data->acpi_data.control_register.address;
 157         bit_width = data->acpi_data.control_register.bit_width;
 158         value = (u32) data->acpi_data.states[state].control;
 159
 160         dprintk("Writing 0x%08x to port 0x%04x\n", value, port);
 161
 162         ret = acpi_processor_write_port(port, bit_width, value);
 163         if (ret) {
 164                 dprintk("Invalid port width 0x%04x\n", bit_width);
 165                 retval = ret;
 166                 goto migrate_end;
 167         }
 168
 169         /*
 170          * Assume the write went through when acpi_pstate_strict is not used.
 171          * As read status_register is an expensive operation and there
 172          * are no specific error cases where an IO port write will fail.
 173          */
 174         if (acpi_pstate_strict) {
 175                 /* Then we read the 'status_register' and compare the value
 176                  * with the target state's 'status' to make sure the
 177                  * transition was successful.
 178                  * Note that we'll poll for up to 1ms (100 cycles of 10us)
 179                  * before giving up.
 180                  */
 181
 182                 port = data->acpi_data.status_register.address;
 183                 bit_width = data->acpi_data.status_register.bit_width;
 184
 185                 dprintk("Looking for 0x%08x from port 0x%04x\n",
 186                         (u32) data->acpi_data.states[state].status, port);
 187
 188                 for (i=0; i<100; i++) {
 189                         ret = acpi_processor_read_port(port, bit_width, &value);
 190                         if (ret) {
 191                                 dprintk("Invalid port width 0x%04x\n", bit_width);
 192                                 retval = ret;
 193                                 goto migrate_end;
 194                         }
 195                         if (value == (u32) data->acpi_data.states[state].status)
 196                                 break;
 197                         udelay(10);
 198                 }
 199         } else {
 200                 i = 0;
 201                 value = (u32) data->acpi_data.states[state].status;
 202         }
 203
 204         /* notify cpufreq */
 205         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 206
 207         if (unlikely(value != (u32) data->acpi_data.states[state].status)) {
 208                 unsigned int tmp = cpufreq_freqs.new;
 209                 cpufreq_freqs.new = cpufreq_freqs.old;
 210                 cpufreq_freqs.old = tmp;
 211                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 212                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 213                 printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
 214                 retval = -ENODEV;
 215                 goto migrate_end;
 216         }
 217
 218         dprintk("Transition successful after %d microseconds\n", i * 10);
 219
 220         data->acpi_data.state = state;
 221
 222         retval = 0;
 223 migrate_end:
 224         set_cpus_allowed(current, saved_mask);
 225         return (retval);
 226 }
 227
 228
 229 static int
 230 acpi_cpufreq_target (
 231         struct cpufreq_policy   *policy,
 232         unsigned int target_freq,
 233         unsigned int relation)
 234 {
 235         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 236         unsigned int next_state = 0;
 237         unsigned int result = 0;
 238
 239         dprintk("acpi_cpufreq_setpolicy\n");
 240
 241         result = cpufreq_frequency_table_target(policy,
 242                         data->freq_table,
 243                         target_freq,
 244                         relation,
 245                         &next_state);
 246         if (result)
 247                 return (result);
 248
 249         result = acpi_processor_set_performance (data, policy->cpu, next_state);
 250
 251         return (result);
 252 }
 253
 254
 255 static int
 256 acpi_cpufreq_verify (
 257         struct cpufreq_policy   *policy)
 258 {
 259         unsigned int result = 0;
 260         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 261
 262         dprintk("acpi_cpufreq_verify\n");
 263
 264         result = cpufreq_frequency_table_verify(policy,
 265                         data->freq_table);
 266
 267         return (result);
 268 }
 269
 270
 271 static unsigned long
 272 acpi_cpufreq_guess_freq (
 273         struct cpufreq_acpi_io  *data,
 274         unsigned int            cpu)
 275 {
 276         if (cpu_khz) {
 277                 /* search the closest match to cpu_khz */
 278                 unsigned int i;
 279                 unsigned long freq;
 280                 unsigned long freqn = data->acpi_data.states[0].core_frequency * 1000;
 281
 282                 for (i=0; i < (data->acpi_data.state_count - 1); i++) {
 283                         freq = freqn;
 284                         freqn = data->acpi_data.states[i+1].core_frequency * 1000;
 285                         if ((2 * cpu_khz) > (freqn + freq)) {
 286                                 data->acpi_data.state = i;
 287                                 return (freq);
 288                         }
 289                 }
 290                 data->acpi_data.state = data->acpi_data.state_count - 1;
 291                 return (freqn);
 292         } else
 293                 /* assume CPU is at P0... */
 294                 data->acpi_data.state = 0;
 295                 return data->acpi_data.states[0].core_frequency * 1000;
 296
 297 }
 298
 299
 300 static int
 301 acpi_cpufreq_cpu_init (
 302         struct cpufreq_policy   *policy)
 303 {
 304         unsigned int            i;
 305         unsigned int            cpu = policy->cpu;
 306         struct cpufreq_acpi_io  *data;
 307         unsigned int            result = 0;
 308
 309         dprintk("acpi_cpufreq_cpu_init\n");
 310
 311         data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 312         if (!data)
 313                 return (-ENOMEM);
 314
 315         acpi_io_data[cpu] = data;
 316
 317         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 318
 319         if (result)
 320                 goto err_free;
 321
 322         if (is_const_loops_cpu(cpu)) {
 323                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
 324         }
 325
 326         /* capability check */
 327         if (data->acpi_data.state_count <= 1) {
 328                 dprintk("No P-States\n");
 329                 result = -ENODEV;
 330                 goto err_unreg;
 331         }
 332         if ((data->acpi_data.control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
 333             (data->acpi_data.status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
 334                 dprintk("Unsupported address space [%d, %d]\n",
 335                         (u32) (data->acpi_data.control_register.space_id),
 336                         (u32) (data->acpi_data.status_register.space_id));
 337                 result = -ENODEV;
 338                 goto err_unreg;
 339         }
 340
 341         /* alloc freq_table */
 342         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (data->acpi_data.state_count + 1), GFP_KERNEL);
 343         if (!data->freq_table) {
 344                 result = -ENOMEM;
 345                 goto err_unreg;
 346         }
 347
 348         /* detect transition latency */
 349         policy->cpuinfo.transition_latency = 0;
 350         for (i=0; i<data->acpi_data.state_count; i++) {
 351                 if ((data->acpi_data.states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
 352                         policy->cpuinfo.transition_latency = data->acpi_data.states[i].transition_latency * 1000;
 353         }
 354         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 355
 356         /* The current speed is unknown and not detectable by ACPI...  */
 357         policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
 358
 359         /* table init */
 360         for (i=0; i<=data->acpi_data.state_count; i++)
 361         {
 362                 data->freq_table[i].index = i;
 363                 if (i<data->acpi_data.state_count)
 364                         data->freq_table[i].frequency = data->acpi_data.states[i].core_frequency * 1000;
 365                 else
 366                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 367         }
 368
 369         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 370         if (result) {
 371                 goto err_freqfree;
 372         }
 373
 374         /* notify BIOS that we exist */
 375         acpi_processor_notify_smm(THIS_MODULE);
 376
 377         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
 378                cpu);
 379         for (i = 0; i < data->acpi_data.state_count; i++)
 380                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
 381                         (i == data->acpi_data.state?'*':' '), i,
 382                         (u32) data->acpi_data.states[i].core_frequency,
 383                         (u32) data->acpi_data.states[i].power,
 384                         (u32) data->acpi_data.states[i].transition_latency);
 385
 386         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 387
 388         /*
 389          * the first call to ->target() should result in us actually
 390          * writing something to the appropriate registers.
 391          */
 392         data->resume = 1;
 393
 394         return (result);
 395
 396  err_freqfree:
 397         kfree(data->freq_table);
 398  err_unreg:
 399         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 400  err_free:
 401         kfree(data);
 402         acpi_io_data[cpu] = NULL;
 403
 404         return (result);
 405 }
 406
 407
 408 static int
 409 acpi_cpufreq_cpu_exit (
 410         struct cpufreq_policy   *policy)
 411 {
 412         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 413
 414
 415         dprintk("acpi_cpufreq_cpu_exit\n");
 416
 417         if (data) {
 418                 cpufreq_frequency_table_put_attr(policy->cpu);
 419                 acpi_io_data[policy->cpu] = NULL;
 420                 acpi_processor_unregister_performance(&data->acpi_data, policy->cpu);
 421                 kfree(data);
 422         }
 423
 424         return (0);
 425 }
 426
 427 static int
 428 acpi_cpufreq_resume (
 429         struct cpufreq_policy   *policy)
 430 {
 431         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 432
 433
 434         dprintk("acpi_cpufreq_resume\n");
 435
 436         data->resume = 1;
 437
 438         return (0);
 439 }
 440
 441
 442 static struct freq_attr* acpi_cpufreq_attr[] = {
 443         &cpufreq_freq_attr_scaling_available_freqs,
 444         NULL,
 445 };
 446
 447 static struct cpufreq_driver acpi_cpufreq_driver = {
 448         .verify         = acpi_cpufreq_verify,
 449         .target         = acpi_cpufreq_target,
 450         .init           = acpi_cpufreq_cpu_init,
 451         .exit           = acpi_cpufreq_cpu_exit,
 452         .resume         = acpi_cpufreq_resume,
 453         .name           = "acpi-cpufreq",
 454         .owner          = THIS_MODULE,
 455         .attr           = acpi_cpufreq_attr,
 456 };
 457
 458
 459 static int __init
 460 acpi_cpufreq_init (void)
 461 {
 462         int                     result = 0;
 463
 464         dprintk("acpi_cpufreq_init\n");
 465
 466         result = cpufreq_register_driver(&acpi_cpufreq_driver);
 467
 468         return (result);
 469 }
 470
 471
 472 static void __exit
 473 acpi_cpufreq_exit (void)
 474 {
 475         dprintk("acpi_cpufreq_exit\n");
 476
 477         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 478
 479         return;
 480 }
 481
 482 module_param(acpi_pstate_strict, uint, 0644);
 483 MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");
 484
 485 late_initcall(acpi_cpufreq_init);
 486 module_exit(acpi_cpufreq_exit);
 487
 488 MODULE_ALIAS("acpi");