arch/i386/kernel/cpu/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/slab.h>
  27
  28 #include "speedstep-lib.h"
  29
  30
  31 /* speedstep_chipset:
  32  *   It is necessary to know which chipset is used. As accesses to
  33  * this device occur at various places in this module, we need a
  34  * static struct pci_dev * pointing to that device.
  35  */
  36 static struct pci_dev *speedstep_chipset_dev;
  37
  38
  39 /* speedstep_processor
  40  */
  41 static unsigned int speedstep_processor = 0;
  42
  43 static u32 pmbase;
  44
  45 /*
  46  *   There are only two frequency states for each processor. Values
  47  * are in kHz for the time being.
  48  */
  49 static struct cpufreq_frequency_table speedstep_freqs[] = {
  50         {SPEEDSTEP_HIGH,        0},
  51         {SPEEDSTEP_LOW,         0},
  52         {0,                     CPUFREQ_TABLE_END},
  53 };
  54
  55
  56 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "speedstep-ich", msg)
  57
  58
  59 /**
  60  * speedstep_find_register - read the PMBASE address
  61  *
  62  * Returns: -ENODEV if no register could be found
  63  */
  64 static int speedstep_find_register (void)
  65 {
  66         if (!speedstep_chipset_dev)
  67                 return -ENODEV;
  68
  69         /* get PMBASE */
  70         pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
  71         if (!(pmbase & 0x01)) {
  72                 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
  73                 return -ENODEV;
  74         }
  75
  76         pmbase &= 0xFFFFFFFE;
  77         if (!pmbase) {
  78                 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
  79                 return -ENODEV;
  80         }
  81
  82         dprintk("pmbase is 0x%x\n", pmbase);
  83         return 0;
  84 }
  85
  86 /**
  87  * speedstep_set_state - set the SpeedStep state
  88  * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
  89  *
  90  *   Tries to change the SpeedStep state.
  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         dprintk("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         dprintk("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         dprintk("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
 134
 135         if (state == (value & 0x1)) {
 136                 dprintk("change to %u MHz succeeded\n", (speedstep_get_processor_frequency(speedstep_processor) / 1000));
 137         } else {
 138                 printk (KERN_ERR "cpufreq: change failed - I/O error\n");
 139         }
 140
 141         return;
 142 }
 143
 144
 145 /**
 146  * speedstep_activate - activate SpeedStep control in the chipset
 147  *
 148  *   Tries to activate the SpeedStep status and control registers.
 149  * Returns -EINVAL on an unsupported chipset, and zero on success.
 150  */
 151 static int speedstep_activate (void)
 152 {
 153         u16 value = 0;
 154
 155         if (!speedstep_chipset_dev)
 156                 return -EINVAL;
 157
 158         pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
 159         if (!(value & 0x08)) {
 160                 value |= 0x08;
 161                 dprintk("activating SpeedStep (TM) registers\n");
 162                 pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
 163         }
 164
 165         return 0;
 166 }
 167
 168
 169 /**
 170  * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
 171  *
 172  *   Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
 173  * the LPC bridge / PM module which contains all power-management
 174  * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
 175  * chipset, or zero on failure.
 176  */
 177 static unsigned int speedstep_detect_chipset (void)
 178 {
 179         speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 180                               PCI_DEVICE_ID_INTEL_82801DB_12,
 181                               PCI_ANY_ID,
 182                               PCI_ANY_ID,
 183                               NULL);
 184         if (speedstep_chipset_dev)
 185                 return 4; /* 4-M */
 186
 187         speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 188                               PCI_DEVICE_ID_INTEL_82801CA_12,
 189                               PCI_ANY_ID,
 190                               PCI_ANY_ID,
 191                               NULL);
 192         if (speedstep_chipset_dev)
 193                 return 3; /* 3-M */
 194
 195
 196         speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 197                               PCI_DEVICE_ID_INTEL_82801BA_10,
 198                               PCI_ANY_ID,
 199                               PCI_ANY_ID,
 200                               NULL);
 201         if (speedstep_chipset_dev) {
 202                 /* speedstep.c causes lockups on Dell Inspirons 8000 and
 203                  * 8100 which use a pretty old revision of the 82815
 204                  * host brige. Abort on these systems.
 205                  */
 206                 static struct pci_dev *hostbridge;
 207                 u8 rev = 0;
 208
 209                 hostbridge  = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 210                               PCI_DEVICE_ID_INTEL_82815_MC,
 211                               PCI_ANY_ID,
 212                               PCI_ANY_ID,
 213                               NULL);
 214
 215                 if (!hostbridge)
 216                         return 2; /* 2-M */
 217
 218                 pci_read_config_byte(hostbridge, PCI_REVISION_ID, &rev);
 219                 if (rev < 5) {
 220                         dprintk("hostbridge does not support speedstep\n");
 221                         speedstep_chipset_dev = NULL;
 222                         pci_dev_put(hostbridge);
 223                         return 0;
 224                 }
 225
 226                 pci_dev_put(hostbridge);
 227                 return 2; /* 2-M */
 228         }
 229
 230         return 0;
 231 }
 232
 233 static unsigned int _speedstep_get(cpumask_t cpus)
 234 {
 235         unsigned int speed;
 236         cpumask_t cpus_allowed;
 237
 238         cpus_allowed = current->cpus_allowed;
 239         set_cpus_allowed(current, cpus);
 240         speed = speedstep_get_processor_frequency(speedstep_processor);
 241         set_cpus_allowed(current, cpus_allowed);
 242         dprintk("detected %u kHz as current frequency\n", speed);
 243         return speed;
 244 }
 245
 246 static unsigned int speedstep_get(unsigned int cpu)
 247 {
 248         return _speedstep_get(cpumask_of_cpu(cpu));
 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 (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 256  *
 257  * Sets a new CPUFreq policy.
 258  */
 259 static int speedstep_target (struct cpufreq_policy *policy,
 260                              unsigned int target_freq,
 261                              unsigned int relation)
 262 {
 263         unsigned int newstate = 0;
 264         struct cpufreq_freqs freqs;
 265         cpumask_t cpus_allowed;
 266         int i;
 267
 268         if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], target_freq, relation, &newstate))
 269                 return -EINVAL;
 270
 271         freqs.old = _speedstep_get(policy->cpus);
 272         freqs.new = speedstep_freqs[newstate].frequency;
 273         freqs.cpu = policy->cpu;
 274
 275         dprintk("transiting from %u to %u kHz\n", freqs.old, freqs.new);
 276
 277         /* no transition necessary */
 278         if (freqs.old == freqs.new)
 279                 return 0;
 280
 281         cpus_allowed = current->cpus_allowed;
 282
 283         for_each_cpu_mask(i, policy->cpus) {
 284                 freqs.cpu = i;
 285                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 286         }
 287
 288         /* switch to physical CPU where state is to be changed */
 289         set_cpus_allowed(current, policy->cpus);
 290
 291         speedstep_set_state(newstate);
 292
 293         /* allow to be run on all CPUs */
 294         set_cpus_allowed(current, cpus_allowed);
 295
 296         for_each_cpu_mask(i, policy->cpus) {
 297                 freqs.cpu = i;
 298                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 299         }
 300
 301         return 0;
 302 }
 303
 304
 305 /**
 306  * speedstep_verify - verifies a new CPUFreq policy
 307  * @policy: new policy
 308  *
 309  * Limit must be within speedstep_low_freq and speedstep_high_freq, with
 310  * at least one border included.
 311  */
 312 static int speedstep_verify (struct cpufreq_policy *policy)
 313 {
 314         return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
 315 }
 316
 317
 318 static int speedstep_cpu_init(struct cpufreq_policy *policy)
 319 {
 320         int result = 0;
 321         unsigned int speed;
 322         cpumask_t cpus_allowed;
 323
 324         /* only run on CPU to be set, or on its sibling */
 325 #ifdef CONFIG_SMP
 326         policy->cpus = cpu_sibling_map[policy->cpu];
 327 #endif
 328
 329         cpus_allowed = current->cpus_allowed;
 330         set_cpus_allowed(current, policy->cpus);
 331
 332         /* detect low and high frequency and transition latency */
 333         result = speedstep_get_freqs(speedstep_processor,
 334                                      &speedstep_freqs[SPEEDSTEP_LOW].frequency,
 335                                      &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
 336                                      &policy->cpuinfo.transition_latency,
 337                                      &speedstep_set_state);
 338         set_cpus_allowed(current, cpus_allowed);
 339         if (result)
 340                 return result;
 341
 342         /* get current speed setting */
 343         speed = _speedstep_get(policy->cpus);
 344         if (!speed)
 345                 return -EIO;
 346
 347         dprintk("currently at %s speed setting - %i MHz\n",
 348                 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency) ? "low" : "high",
 349                 (speed / 1000));
 350
 351         /* cpuinfo and default policy values */
 352         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 353         policy->cur = speed;
 354
 355         result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
 356         if (result)
 357                 return (result);
 358
 359         cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
 360
 361         return 0;
 362 }
 363
 364
 365 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
 366 {
 367         cpufreq_frequency_table_put_attr(policy->cpu);
 368         return 0;
 369 }
 370
 371 static struct freq_attr* speedstep_attr[] = {
 372         &cpufreq_freq_attr_scaling_available_freqs,
 373         NULL,
 374 };
 375
 376
 377 static struct cpufreq_driver speedstep_driver = {
 378         .name   = "speedstep-ich",
 379         .verify = speedstep_verify,
 380         .target = speedstep_target,
 381         .init   = speedstep_cpu_init,
 382         .exit   = speedstep_cpu_exit,
 383         .get    = speedstep_get,
 384         .owner  = THIS_MODULE,
 385         .attr   = speedstep_attr,
 386 };
 387
 388
 389 /**
 390  * speedstep_init - initializes the SpeedStep CPUFreq driver
 391  *
 392  *   Initializes the SpeedStep support. Returns -ENODEV on unsupported
 393  * devices, -EINVAL on problems during initiatization, and zero on
 394  * success.
 395  */
 396 static int __init speedstep_init(void)
 397 {
 398         /* detect processor */
 399         speedstep_processor = speedstep_detect_processor();
 400         if (!speedstep_processor) {
 401                 dprintk("Intel(R) SpeedStep(TM) capable processor not found\n");
 402                 return -ENODEV;
 403         }
 404
 405         /* detect chipset */
 406         if (!speedstep_detect_chipset()) {
 407                 dprintk("Intel(R) SpeedStep(TM) for this chipset not (yet) available.\n");
 408                 return -ENODEV;
 409         }
 410
 411         /* activate speedstep support */
 412         if (speedstep_activate()) {
 413                 pci_dev_put(speedstep_chipset_dev);
 414                 return -EINVAL;
 415         }
 416
 417         if (speedstep_find_register())
 418                 return -ENODEV;
 419
 420         return cpufreq_register_driver(&speedstep_driver);
 421 }
 422
 423
 424 /**
 425  * speedstep_exit - unregisters SpeedStep support
 426  *
 427  *   Unregisters SpeedStep support.
 428  */
 429 static void __exit speedstep_exit(void)
 430 {
 431         pci_dev_put(speedstep_chipset_dev);
 432         cpufreq_unregister_driver(&speedstep_driver);
 433 }
 434
 435
 436 MODULE_AUTHOR ("Dave Jones <davej@codemonkey.org.uk>, Dominik Brodowski <linux@brodo.de>");
 437 MODULE_DESCRIPTION ("Speedstep driver for Intel mobile processors on chipsets with ICH-M southbridges.");
 438 MODULE_LICENSE ("GPL");
 439
 440 module_init(speedstep_init);
 441 module_exit(speedstep_exit);