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
  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                     ret = 0;
 108         u32                     value = 0;
 109         int                     i = 0;
 110         struct cpufreq_freqs    cpufreq_freqs;
 111         cpumask_t               saved_mask;
 112         int                     retval;
 113
 114         dprintk("acpi_processor_set_performance\n");
 115
 116         /*
 117          * TBD: Use something other than set_cpus_allowed.
 118          * As set_cpus_allowed is a bit racy,
 119          * with any other set_cpus_allowed for this process.
 120          */
 121         saved_mask = current->cpus_allowed;
 122         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 123         if (smp_processor_id() != cpu) {
 124                 return (-EAGAIN);
 125         }
 126
 127         if (state == data->acpi_data.state) {
 128                 if (unlikely(data->resume)) {
 129                         dprintk("Called after resume, resetting to P%d\n", state);
 130                         data->resume = 0;
 131                 } else {
 132                         dprintk("Already at target state (P%d)\n", state);
 133                         retval = 0;
 134                         goto migrate_end;
 135                 }
 136         }
 137
 138         dprintk("Transitioning from P%d to P%d\n",
 139                 data->acpi_data.state, state);
 140
 141         /* cpufreq frequency struct */
 142         cpufreq_freqs.cpu = cpu;
 143         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
 144         cpufreq_freqs.new = data->freq_table[state].frequency;
 145
 146         /* notify cpufreq */
 147         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 148
 149         /*
 150          * First we write the target state's 'control' value to the
 151          * control_register.
 152          */
 153
 154         port = data->acpi_data.control_register.address;
 155         bit_width = data->acpi_data.control_register.bit_width;
 156         value = (u32) data->acpi_data.states[state].control;
 157
 158         dprintk("Writing 0x%08x to port 0x%04x\n", value, port);
 159
 160         ret = acpi_processor_write_port(port, bit_width, value);
 161         if (ret) {
 162                 dprintk("Invalid port width 0x%04x\n", bit_width);
 163                 retval = ret;
 164                 goto migrate_end;
 165         }
 166
 167         /*
 168          * Assume the write went through when acpi_pstate_strict is not used.
 169          * As read status_register is an expensive operation and there
 170          * are no specific error cases where an IO port write will fail.
 171          */
 172         if (acpi_pstate_strict) {
 173                 /* Then we read the 'status_register' and compare the value
 174                  * with the target state's 'status' to make sure the
 175                  * transition was successful.
 176                  * Note that we'll poll for up to 1ms (100 cycles of 10us)
 177                  * before giving up.
 178                  */
 179
 180                 port = data->acpi_data.status_register.address;
 181                 bit_width = data->acpi_data.status_register.bit_width;
 182
 183                 dprintk("Looking for 0x%08x from port 0x%04x\n",
 184                         (u32) data->acpi_data.states[state].status, port);
 185
 186                 for (i=0; i<100; i++) {
 187                         ret = acpi_processor_read_port(port, bit_width, &value);
 188                         if (ret) {
 189                                 dprintk("Invalid port width 0x%04x\n", bit_width);
 190                                 retval = ret;
 191                                 goto migrate_end;
 192                         }
 193                         if (value == (u32) data->acpi_data.states[state].status)
 194                                 break;
 195                         udelay(10);
 196                 }
 197         } else {
 198                 i = 0;
 199                 value = (u32) data->acpi_data.states[state].status;
 200         }
 201
 202         /* notify cpufreq */
 203         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 204
 205         if (unlikely(value != (u32) data->acpi_data.states[state].status)) {
 206                 unsigned int tmp = cpufreq_freqs.new;
 207                 cpufreq_freqs.new = cpufreq_freqs.old;
 208                 cpufreq_freqs.old = tmp;
 209                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 210                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 211                 printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
 212                 retval = -ENODEV;
 213                 goto migrate_end;
 214         }
 215
 216         dprintk("Transition successful after %d microseconds\n", i * 10);
 217
 218         data->acpi_data.state = state;
 219
 220         retval = 0;
 221 migrate_end:
 222         set_cpus_allowed(current, saved_mask);
 223         return (retval);
 224 }
 225
 226
 227 static int
 228 acpi_cpufreq_target (
 229         struct cpufreq_policy   *policy,
 230         unsigned int target_freq,
 231         unsigned int relation)
 232 {
 233         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 234         unsigned int next_state = 0;
 235         unsigned int result = 0;
 236
 237         dprintk("acpi_cpufreq_setpolicy\n");
 238
 239         result = cpufreq_frequency_table_target(policy,
 240                         data->freq_table,
 241                         target_freq,
 242                         relation,
 243                         &next_state);
 244         if (result)
 245                 return (result);
 246
 247         result = acpi_processor_set_performance (data, policy->cpu, next_state);
 248
 249         return (result);
 250 }
 251
 252
 253 static int
 254 acpi_cpufreq_verify (
 255         struct cpufreq_policy   *policy)
 256 {
 257         unsigned int result = 0;
 258         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 259
 260         dprintk("acpi_cpufreq_verify\n");
 261
 262         result = cpufreq_frequency_table_verify(policy,
 263                         data->freq_table);
 264
 265         return (result);
 266 }
 267
 268
 269 static unsigned long
 270 acpi_cpufreq_guess_freq (
 271         struct cpufreq_acpi_io  *data,
 272         unsigned int            cpu)
 273 {
 274         if (cpu_khz) {
 275                 /* search the closest match to cpu_khz */
 276                 unsigned int i;
 277                 unsigned long freq;
 278                 unsigned long freqn = data->acpi_data.states[0].core_frequency * 1000;
 279
 280                 for (i=0; i < (data->acpi_data.state_count - 1); i++) {
 281                         freq = freqn;
 282                         freqn = data->acpi_data.states[i+1].core_frequency * 1000;
 283                         if ((2 * cpu_khz) > (freqn + freq)) {
 284                                 data->acpi_data.state = i;
 285                                 return (freq);
 286                         }
 287                 }
 288                 data->acpi_data.state = data->acpi_data.state_count - 1;
 289                 return (freqn);
 290         } else
 291                 /* assume CPU is at P0... */
 292                 data->acpi_data.state = 0;
 293                 return data->acpi_data.states[0].core_frequency * 1000;
 294
 295 }
 296
 297
 298 static int
 299 acpi_cpufreq_cpu_init (
 300         struct cpufreq_policy   *policy)
 301 {
 302         unsigned int            i;
 303         unsigned int            cpu = policy->cpu;
 304         struct cpufreq_acpi_io  *data;
 305         unsigned int            result = 0;
 306         struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
 307
 308         dprintk("acpi_cpufreq_cpu_init\n");
 309
 310         data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 311         if (!data)
 312                 return (-ENOMEM);
 313
 314         acpi_io_data[cpu] = data;
 315
 316         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 317
 318         if (result)
 319                 goto err_free;
 320
 321         if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
 322                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
 323         }
 324
 325         /* capability check */
 326         if (data->acpi_data.state_count <= 1) {
 327                 dprintk("No P-States\n");
 328                 result = -ENODEV;
 329                 goto err_unreg;
 330         }
 331         if ((data->acpi_data.control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
 332             (data->acpi_data.status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
 333                 dprintk("Unsupported address space [%d, %d]\n",
 334                         (u32) (data->acpi_data.control_register.space_id),
 335                         (u32) (data->acpi_data.status_register.space_id));
 336                 result = -ENODEV;
 337                 goto err_unreg;
 338         }
 339
 340         /* alloc freq_table */
 341         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (data->acpi_data.state_count + 1), GFP_KERNEL);
 342         if (!data->freq_table) {
 343                 result = -ENOMEM;
 344                 goto err_unreg;
 345         }
 346
 347         /* detect transition latency */
 348         policy->cpuinfo.transition_latency = 0;
 349         for (i=0; i<data->acpi_data.state_count; i++) {
 350                 if ((data->acpi_data.states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
 351                         policy->cpuinfo.transition_latency = data->acpi_data.states[i].transition_latency * 1000;
 352         }
 353         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 354
 355         /* The current speed is unknown and not detectable by ACPI...  */
 356         policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
 357
 358         /* table init */
 359         for (i=0; i<=data->acpi_data.state_count; i++)
 360         {
 361                 data->freq_table[i].index = i;
 362                 if (i<data->acpi_data.state_count)
 363                         data->freq_table[i].frequency = data->acpi_data.states[i].core_frequency * 1000;
 364                 else
 365                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 366         }
 367
 368         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 369         if (result) {
 370                 goto err_freqfree;
 371         }
 372
 373         /* notify BIOS that we exist */
 374         acpi_processor_notify_smm(THIS_MODULE);
 375
 376         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
 377                cpu);
 378         for (i = 0; i < data->acpi_data.state_count; i++)
 379                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
 380                         (i == data->acpi_data.state?'*':' '), i,
 381                         (u32) data->acpi_data.states[i].core_frequency,
 382                         (u32) data->acpi_data.states[i].power,
 383                         (u32) data->acpi_data.states[i].transition_latency);
 384
 385         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 386
 387         /*
 388          * the first call to ->target() should result in us actually
 389          * writing something to the appropriate registers.
 390          */
 391         data->resume = 1;
 392
 393         return (result);
 394
 395  err_freqfree:
 396         kfree(data->freq_table);
 397  err_unreg:
 398         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 399  err_free:
 400         kfree(data);
 401         acpi_io_data[cpu] = NULL;
 402
 403         return (result);
 404 }
 405
 406
 407 static int
 408 acpi_cpufreq_cpu_exit (
 409         struct cpufreq_policy   *policy)
 410 {
 411         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 412
 413
 414         dprintk("acpi_cpufreq_cpu_exit\n");
 415
 416         if (data) {
 417                 cpufreq_frequency_table_put_attr(policy->cpu);
 418                 acpi_io_data[policy->cpu] = NULL;
 419                 acpi_processor_unregister_performance(&data->acpi_data, policy->cpu);
 420                 kfree(data);
 421         }
 422
 423         return (0);
 424 }
 425
 426 static int
 427 acpi_cpufreq_resume (
 428         struct cpufreq_policy   *policy)
 429 {
 430         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 431
 432
 433         dprintk("acpi_cpufreq_resume\n");
 434
 435         data->resume = 1;
 436
 437         return (0);
 438 }
 439
 440
 441 static struct freq_attr* acpi_cpufreq_attr[] = {
 442         &cpufreq_freq_attr_scaling_available_freqs,
 443         NULL,
 444 };
 445
 446 static struct cpufreq_driver acpi_cpufreq_driver = {
 447         .verify         = acpi_cpufreq_verify,
 448         .target         = acpi_cpufreq_target,
 449         .init           = acpi_cpufreq_cpu_init,
 450         .exit           = acpi_cpufreq_cpu_exit,
 451         .resume         = acpi_cpufreq_resume,
 452         .name           = "acpi-cpufreq",
 453         .owner          = THIS_MODULE,
 454         .attr           = acpi_cpufreq_attr,
 455 };
 456
 457
 458 static int __init
 459 acpi_cpufreq_init (void)
 460 {
 461         int                     result = 0;
 462
 463         dprintk("acpi_cpufreq_init\n");
 464
 465         result = cpufreq_register_driver(&acpi_cpufreq_driver);
 466
 467         return (result);
 468 }
 469
 470
 471 static void __exit
 472 acpi_cpufreq_exit (void)
 473 {
 474         dprintk("acpi_cpufreq_exit\n");
 475
 476         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 477
 478         return;
 479 }
 480
 481 module_param(acpi_pstate_strict, uint, 0644);
 482 MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");
 483
 484 late_initcall(acpi_cpufreq_init);
 485 module_exit(acpi_cpufreq_exit);
 486
 487 MODULE_ALIAS("acpi");