drivers/cpufreq/speedstep-ich.c

   1 /*
   2  * (C) 2001  Dave Jones, Arjan van de ven.
   3  * (C) 2002 - 2003  Dominik Brodowski <linux@brodo.de>
   4  *
   5  *  Licensed under the terms of the GNU GPL License version 2.
   6  *  Based upon reverse engineered information, and on Intel documentation
   7  *  for chipsets ICH2-M and ICH3-M.
   8  *
   9  *  Many thanks to Ducrot Bruno for finding and fixing the last
  10  *  "missing link" for ICH2-M/ICH3-M support, and to Thomas Winkler
  11  *  for extensive testing.
  12  *
  13  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
  14  */
  15
  16
  17 /*********************************************************************
  18  *                        SPEEDSTEP - DEFINITIONS                    *
  19  *********************************************************************/
  20
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/cpufreq.h>
  25 #include <linux/pci.h>
  26 #include <linux/sched.h>
  27
  28 #include <asm/cpu_device_id.h>
  29
  30 #include "speedstep-lib.h"
  31
  32
  33 /* speedstep_chipset:
  34  *   It is necessary to know which chipset is used. As accesses to
  35  * this device occur at various places in this module, we need a
  36  * static struct pci_dev * pointing to that device.
  37  */
  38 static struct pci_dev *speedstep_chipset_dev;
  39
  40
  41 /* speedstep_processor
  42  */
  43 static enum speedstep_processor speedstep_processor;
  44
  45 static u32 pmbase;
  46
  47 /*
  48  *   There are only two frequency states for each processor. Values
  49  * are in kHz for the time being.
  50  */
  51 static struct cpufreq_frequency_table speedstep_freqs[] = {
  52         {SPEEDSTEP_HIGH,        0},
  53         {SPEEDSTEP_LOW,         0},
  54         {0,                     CPUFREQ_TABLE_END},
  55 };
  56
  57
  58 /**
  59  * speedstep_find_register - read the PMBASE address
  60  *
  61  * Returns: -ENODEV if no register could be found
  62  */
  63 static int speedstep_find_register(void)
  64 {
  65         if (!speedstep_chipset_dev)
  66                 return -ENODEV;
  67
  68         /* get PMBASE */
  69         pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
  70         if (!(pmbase & 0x01)) {
  71                 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
  72                 return -ENODEV;
  73         }
  74
  75         pmbase &= 0xFFFFFFFE;
  76         if (!pmbase) {
  77                 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
  78                 return -ENODEV;
  79         }
  80
  81         pr_debug("pmbase is 0x%x\n", pmbase);
  82         return 0;
  83 }
  84
  85 /**
  86  * speedstep_set_state - set the SpeedStep state
  87  * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
  88  *
  89  *   Tries to change the SpeedStep state.  Can be called from
  90  *   smp_call_function_single.
  91  */
  92 static void speedstep_set_state(unsigned int state)
  93 {
  94         u8 pm2_blk;
  95         u8 value;
  96         unsigned long flags;
  97
  98         if (state > 0x1)
  99                 return;
 100
 101         /* Disable IRQs */
 102         local_irq_save(flags);
 103
 104         /* read state */
 105         value = inb(pmbase + 0x50);
 106
 107         pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
 108
 109         /* write new state */
 110         value &= 0xFE;
 111         value |= state;
 112
 113         pr_debug("writing 0x%x to pmbase 0x%x + 0x50\n", value, pmbase);
 114
 115         /* Disable bus master arbitration */
 116         pm2_blk = inb(pmbase + 0x20);
 117         pm2_blk |= 0x01;
 118         outb(pm2_blk, (pmbase + 0x20));
 119
 120         /* Actual transition */
 121         outb(value, (pmbase + 0x50));
 122
 123         /* Restore bus master arbitration */
 124         pm2_blk &= 0xfe;
 125         outb(pm2_blk, (pmbase + 0x20));
 126
 127         /* check if transition was successful */
 128         value = inb(pmbase + 0x50);
 129
 130         /* Enable IRQs */
 131         local_irq_restore(flags);
 132
 133         pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
 134
 135         if (state == (value & 0x1))
 136                 pr_debug("change to %u MHz succeeded\n",
 137                         speedstep_get_frequency(speedstep_processor) / 1000);
 138         else
 139                 printk(KERN_ERR "cpufreq: change failed - I/O error\n");
 140
 141         return;
 142 }
 143
 144 /* Wrapper for smp_call_function_single. */
 145 static void _speedstep_set_state(void *_state)
 146 {
 147         speedstep_set_state(*(unsigned int *)_state);
 148 }
 149
 150 /**
 151  * speedstep_activate - activate SpeedStep control in the chipset
 152  *
 153  *   Tries to activate the SpeedStep status and control registers.
 154  * Returns -EINVAL on an unsupported chipset, and zero on success.
 155  */
 156 static int speedstep_activate(void)
 157 {
 158         u16 value = 0;
 159
 160         if (!speedstep_chipset_dev)
 161                 return -EINVAL;
 162
 163         pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
 164         if (!(value & 0x08)) {
 165                 value |= 0x08;
 166                 pr_debug("activating SpeedStep (TM) registers\n");
 167                 pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
 168         }
 169
 170         return 0;
 171 }
 172
 173
 174 /**
 175  * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
 176  *
 177  *   Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
 178  * the LPC bridge / PM module which contains all power-management
 179  * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
 180  * chipset, or zero on failure.
 181  */
 182 static unsigned int speedstep_detect_chipset(void)
 183 {
 184         speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 185                               PCI_DEVICE_ID_INTEL_82801DB_12,
 186                               PCI_ANY_ID, PCI_ANY_ID,
 187                               NULL);
 188         if (speedstep_chipset_dev)
 189                 return 4; /* 4-M */
 190
 191         speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 192                               PCI_DEVICE_ID_INTEL_82801CA_12,
 193                               PCI_ANY_ID, PCI_ANY_ID,
 194                               NULL);
 195         if (speedstep_chipset_dev)
 196                 return 3; /* 3-M */
 197
 198
 199         speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 200                               PCI_DEVICE_ID_INTEL_82801BA_10,
 201                               PCI_ANY_ID, PCI_ANY_ID,
 202                               NULL);
 203         if (speedstep_chipset_dev) {
 204                 /* speedstep.c causes lockups on Dell Inspirons 8000 and
 205                  * 8100 which use a pretty old revision of the 82815
 206                  * host bridge. Abort on these systems.
 207                  */
 208                 static struct pci_dev *hostbridge;
 209
 210                 hostbridge  = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 211                               PCI_DEVICE_ID_INTEL_82815_MC,
 212                               PCI_ANY_ID, PCI_ANY_ID,
 213                               NULL);
 214
 215                 if (!hostbridge)
 216                         return 2; /* 2-M */
 217
 218                 if (hostbridge->revision < 5) {
 219                         pr_debug("hostbridge does not support speedstep\n");
 220                         speedstep_chipset_dev = NULL;
 221                         pci_dev_put(hostbridge);
 222                         return 0;
 223                 }
 224
 225                 pci_dev_put(hostbridge);
 226                 return 2; /* 2-M */
 227         }
 228
 229         return 0;
 230 }
 231
 232 static void get_freq_data(void *_speed)
 233 {
 234         unsigned int *speed = _speed;
 235
 236         *speed = speedstep_get_frequency(speedstep_processor);
 237 }
 238
 239 static unsigned int speedstep_get(unsigned int cpu)
 240 {
 241         unsigned int speed;
 242
 243         /* You're supposed to ensure CPU is online. */
 244         if (smp_call_function_single(cpu, get_freq_data, &speed, 1) != 0)
 245                 BUG();
 246
 247         pr_debug("detected %u kHz as current frequency\n", speed);
 248         return speed;
 249 }
 250
 251 /**
 252  * speedstep_target - set a new CPUFreq policy
 253  * @policy: new policy
 254  * @target_freq: the target frequency
 255  * @relation: how that frequency relates to achieved frequency
 256  *      (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 257  *
 258  * Sets a new CPUFreq policy.
 259  */
 260 static int speedstep_target(struct cpufreq_policy *policy,
 261                              unsigned int target_freq,
 262                              unsigned int relation)
 263 {
 264         unsigned int newstate = 0, policy_cpu;
 265         struct cpufreq_freqs freqs;
 266         int i;
 267
 268         if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
 269                                 target_freq, relation, &newstate))
 270                 return -EINVAL;
 271
 272         policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
 273         freqs.old = speedstep_get(policy_cpu);
 274         freqs.new = speedstep_freqs[newstate].frequency;
 275         freqs.cpu = policy->cpu;
 276
 277         pr_debug("transiting from %u to %u kHz\n", freqs.old, freqs.new);
 278
 279         /* no transition necessary */
 280         if (freqs.old == freqs.new)
 281                 return 0;
 282
 283         for_each_cpu(i, policy->cpus) {
 284                 freqs.cpu = i;
 285                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 286         }
 287
 288         smp_call_function_single(policy_cpu, _speedstep_set_state, &newstate,
 289                                  true);
 290
 291         for_each_cpu(i, policy->cpus) {
 292                 freqs.cpu = i;
 293                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 294         }
 295
 296         return 0;
 297 }
 298
 299
 300 /**
 301  * speedstep_verify - verifies a new CPUFreq policy
 302  * @policy: new policy
 303  *
 304  * Limit must be within speedstep_low_freq and speedstep_high_freq, with
 305  * at least one border included.
 306  */
 307 static int speedstep_verify(struct cpufreq_policy *policy)
 308 {
 309         return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
 310 }
 311
 312 struct get_freqs {
 313         struct cpufreq_policy *policy;
 314         int ret;
 315 };
 316
 317 static void get_freqs_on_cpu(void *_get_freqs)
 318 {
 319         struct get_freqs *get_freqs = _get_freqs;
 320
 321         get_freqs->ret =
 322                 speedstep_get_freqs(speedstep_processor,
 323                             &speedstep_freqs[SPEEDSTEP_LOW].frequency,
 324                             &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
 325                             &get_freqs->policy->cpuinfo.transition_latency,
 326                             &speedstep_set_state);
 327 }
 328
 329 static int speedstep_cpu_init(struct cpufreq_policy *policy)
 330 {
 331         int result;
 332         unsigned int policy_cpu, speed;
 333         struct get_freqs gf;
 334
 335         /* only run on CPU to be set, or on its sibling */
 336 #ifdef CONFIG_SMP
 337         cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
 338 #endif
 339         policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
 340
 341         /* detect low and high frequency and transition latency */
 342         gf.policy = policy;
 343         smp_call_function_single(policy_cpu, get_freqs_on_cpu, &gf, 1);
 344         if (gf.ret)
 345                 return gf.ret;
 346
 347         /* get current speed setting */
 348         speed = speedstep_get(policy_cpu);
 349         if (!speed)
 350                 return -EIO;
 351
 352         pr_debug("currently at %s speed setting - %i MHz\n",
 353                 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
 354                 ? "low" : "high",
 355                 (speed / 1000));
 356
 357         /* cpuinfo and default policy values */
 358         policy->cur = speed;
 359
 360         result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
 361         if (result)
 362                 return result;
 363
 364         cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
 365
 366         return 0;
 367 }
 368
 369
 370 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
 371 {
 372         cpufreq_frequency_table_put_attr(policy->cpu);
 373         return 0;
 374 }
 375
 376 static struct freq_attr *speedstep_attr[] = {
 377         &cpufreq_freq_attr_scaling_available_freqs,
 378         NULL,
 379 };
 380
 381
 382 static struct cpufreq_driver speedstep_driver = {
 383         .name   = "speedstep-ich",
 384         .verify = speedstep_verify,
 385         .target = speedstep_target,
 386         .init   = speedstep_cpu_init,
 387         .exit   = speedstep_cpu_exit,
 388         .get    = speedstep_get,
 389         .owner  = THIS_MODULE,
 390         .attr   = speedstep_attr,
 391 };
 392
 393 static const struct x86_cpu_id ss_smi_ids[] = {
 394         { X86_VENDOR_INTEL, 6, 0xb, },
 395         { X86_VENDOR_INTEL, 6, 0x8, },
 396         { X86_VENDOR_INTEL, 15, 2 },
 397         {}
 398 };
 399 #if 0
 400 /* Autoload or not? Do not for now. */
 401 MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
 402 #endif
 403
 404 /**
 405  * speedstep_init - initializes the SpeedStep CPUFreq driver
 406  *
 407  *   Initializes the SpeedStep support. Returns -ENODEV on unsupported
 408  * devices, -EINVAL on problems during initiatization, and zero on
 409  * success.
 410  */
 411 static int __init speedstep_init(void)
 412 {
 413         if (!x86_match_cpu(ss_smi_ids))
 414                 return -ENODEV;
 415
 416         /* detect processor */
 417         speedstep_processor = speedstep_detect_processor();
 418         if (!speedstep_processor) {
 419                 pr_debug("Intel(R) SpeedStep(TM) capable processor "
 420                                 "not found\n");
 421                 return -ENODEV;
 422         }
 423
 424         /* detect chipset */
 425         if (!speedstep_detect_chipset()) {
 426                 pr_debug("Intel(R) SpeedStep(TM) for this chipset not "
 427                                 "(yet) available.\n");
 428                 return -ENODEV;
 429         }
 430
 431         /* activate speedstep support */
 432         if (speedstep_activate()) {
 433                 pci_dev_put(speedstep_chipset_dev);
 434                 return -EINVAL;
 435         }
 436
 437         if (speedstep_find_register())
 438                 return -ENODEV;
 439
 440         return cpufreq_register_driver(&speedstep_driver);
 441 }
 442
 443
 444 /**
 445  * speedstep_exit - unregisters SpeedStep support
 446  *
 447  *   Unregisters SpeedStep support.
 448  */
 449 static void __exit speedstep_exit(void)
 450 {
 451         pci_dev_put(speedstep_chipset_dev);
 452         cpufreq_unregister_driver(&speedstep_driver);
 453 }
 454
 455
 456 MODULE_AUTHOR("Dave Jones <davej@redhat.com>, "
 457                 "Dominik Brodowski <linux@brodo.de>");
 458 MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
 459                 "with ICH-M southbridges.");
 460 MODULE_LICENSE("GPL");
 461
 462 module_init(speedstep_init);
 463 module_exit(speedstep_exit);