arch/x86/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 #include <linux/sched.h>
  28
  29 #include "speedstep-lib.h"
  30
  31
  32 /* speedstep_chipset:
  33  *   It is necessary to know which chipset is used. As accesses to
  34  * this device occur at various places in this module, we need a
  35  * static struct pci_dev * pointing to that device.
  36  */
  37 static struct pci_dev *speedstep_chipset_dev;
  38
  39
  40 /* speedstep_processor
  41  */
  42 static unsigned int speedstep_processor;
  43
  44 static u32 pmbase;
  45
  46 /*
  47  *   There are only two frequency states for each processor. Values
  48  * are in kHz for the time being.
  49  */
  50 static struct cpufreq_frequency_table speedstep_freqs[] = {
  51         {SPEEDSTEP_HIGH,        0},
  52         {SPEEDSTEP_LOW,         0},
  53         {0,                     CPUFREQ_TABLE_END},
  54 };
  55
  56
  57 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
  58                 "speedstep-ich", msg)
  59
  60
  61 /**
  62  * speedstep_find_register - read the PMBASE address
  63  *
  64  * Returns: -ENODEV if no register could be found
  65  */
  66 static int speedstep_find_register(void)
  67 {
  68         if (!speedstep_chipset_dev)
  69                 return -ENODEV;
  70
  71         /* get PMBASE */
  72         pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
  73         if (!(pmbase & 0x01)) {
  74                 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
  75                 return -ENODEV;
  76         }
  77
  78         pmbase &= 0xFFFFFFFE;
  79         if (!pmbase) {
  80                 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
  81                 return -ENODEV;
  82         }
  83
  84         dprintk("pmbase is 0x%x\n", pmbase);
  85         return 0;
  86 }
  87
  88 /**
  89  * speedstep_set_state - set the SpeedStep state
  90  * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
  91  *
  92  *   Tries to change the SpeedStep state.
  93  */
  94 static void speedstep_set_state(unsigned int state)
  95 {
  96         u8 pm2_blk;
  97         u8 value;
  98         unsigned long flags;
  99
 100         if (state > 0x1)
 101                 return;
 102
 103         /* Disable IRQs */
 104         local_irq_save(flags);
 105
 106         /* read state */
 107         value = inb(pmbase + 0x50);
 108
 109         dprintk("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
 110
 111         /* write new state */
 112         value &= 0xFE;
 113         value |= state;
 114
 115         dprintk("writing 0x%x to pmbase 0x%x + 0x50\n", value, pmbase);
 116
 117         /* Disable bus master arbitration */
 118         pm2_blk = inb(pmbase + 0x20);
 119         pm2_blk |= 0x01;
 120         outb(pm2_blk, (pmbase + 0x20));
 121
 122         /* Actual transition */
 123         outb(value, (pmbase + 0x50));
 124
 125         /* Restore bus master arbitration */
 126         pm2_blk &= 0xfe;
 127         outb(pm2_blk, (pmbase + 0x20));
 128
 129         /* check if transition was successful */
 130         value = inb(pmbase + 0x50);
 131
 132         /* Enable IRQs */
 133         local_irq_restore(flags);
 134
 135         dprintk("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
 136
 137         if (state == (value & 0x1))
 138                 dprintk("change to %u MHz succeeded\n",
 139                         speedstep_get_frequency(speedstep_processor) / 1000);
 140         else
 141                 printk(KERN_ERR "cpufreq: change failed - I/O error\n");
 142
 143         return;
 144 }
 145
 146
 147 /**
 148  * speedstep_activate - activate SpeedStep control in the chipset
 149  *
 150  *   Tries to activate the SpeedStep status and control registers.
 151  * Returns -EINVAL on an unsupported chipset, and zero on success.
 152  */
 153 static int speedstep_activate(void)
 154 {
 155         u16 value = 0;
 156
 157         if (!speedstep_chipset_dev)
 158                 return -EINVAL;
 159
 160         pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
 161         if (!(value & 0x08)) {
 162                 value |= 0x08;
 163                 dprintk("activating SpeedStep (TM) registers\n");
 164                 pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
 165         }
 166
 167         return 0;
 168 }
 169
 170
 171 /**
 172  * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
 173  *
 174  *   Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
 175  * the LPC bridge / PM module which contains all power-management
 176  * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
 177  * chipset, or zero on failure.
 178  */
 179 static unsigned int speedstep_detect_chipset(void)
 180 {
 181         speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 182                               PCI_DEVICE_ID_INTEL_82801DB_12,
 183                               PCI_ANY_ID, PCI_ANY_ID,
 184                               NULL);
 185         if (speedstep_chipset_dev)
 186                 return 4; /* 4-M */
 187
 188         speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 189                               PCI_DEVICE_ID_INTEL_82801CA_12,
 190                               PCI_ANY_ID, 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, PCI_ANY_ID,
 199                               NULL);
 200         if (speedstep_chipset_dev) {
 201                 /* speedstep.c causes lockups on Dell Inspirons 8000 and
 202                  * 8100 which use a pretty old revision of the 82815
 203                  * host brige. Abort on these systems.
 204                  */
 205                 static struct pci_dev *hostbridge;
 206
 207                 hostbridge  = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 208                               PCI_DEVICE_ID_INTEL_82815_MC,
 209                               PCI_ANY_ID, PCI_ANY_ID,
 210                               NULL);
 211
 212                 if (!hostbridge)
 213                         return 2; /* 2-M */
 214
 215                 if (hostbridge->revision < 5) {
 216                         dprintk("hostbridge does not support speedstep\n");
 217                         speedstep_chipset_dev = NULL;
 218                         pci_dev_put(hostbridge);
 219                         return 0;
 220                 }
 221
 222                 pci_dev_put(hostbridge);
 223                 return 2; /* 2-M */
 224         }
 225
 226         return 0;
 227 }
 228
 229 static unsigned int _speedstep_get(const struct cpumask *cpus)
 230 {
 231         unsigned int speed;
 232         cpumask_t cpus_allowed;
 233
 234         cpus_allowed = current->cpus_allowed;
 235         set_cpus_allowed_ptr(current, cpus);
 236         speed = speedstep_get_frequency(speedstep_processor);
 237         set_cpus_allowed_ptr(current, &cpus_allowed);
 238         dprintk("detected %u kHz as current frequency\n", speed);
 239         return speed;
 240 }
 241
 242 static unsigned int speedstep_get(unsigned int cpu)
 243 {
 244         return _speedstep_get(cpumask_of(cpu));
 245 }
 246
 247 /**
 248  * speedstep_target - set a new CPUFreq policy
 249  * @policy: new policy
 250  * @target_freq: the target frequency
 251  * @relation: how that frequency relates to achieved frequency
 252  *      (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 253  *
 254  * Sets a new CPUFreq policy.
 255  */
 256 static int speedstep_target(struct cpufreq_policy *policy,
 257                              unsigned int target_freq,
 258                              unsigned int relation)
 259 {
 260         unsigned int newstate = 0;
 261         struct cpufreq_freqs freqs;
 262         cpumask_t cpus_allowed;
 263         int i;
 264
 265         if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
 266                                 target_freq, relation, &newstate))
 267                 return -EINVAL;
 268
 269         freqs.old = _speedstep_get(policy->cpus);
 270         freqs.new = speedstep_freqs[newstate].frequency;
 271         freqs.cpu = policy->cpu;
 272
 273         dprintk("transiting from %u to %u kHz\n", freqs.old, freqs.new);
 274
 275         /* no transition necessary */
 276         if (freqs.old == freqs.new)
 277                 return 0;
 278
 279         cpus_allowed = current->cpus_allowed;
 280
 281         for_each_cpu(i, policy->cpus) {
 282                 freqs.cpu = i;
 283                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 284         }
 285
 286         /* switch to physical CPU where state is to be changed */
 287         set_cpus_allowed_ptr(current, policy->cpus);
 288
 289         speedstep_set_state(newstate);
 290
 291         /* allow to be run on all CPUs */
 292         set_cpus_allowed_ptr(current, &cpus_allowed);
 293
 294         for_each_cpu(i, policy->cpus) {
 295                 freqs.cpu = i;
 296                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 297         }
 298
 299         return 0;
 300 }
 301
 302
 303 /**
 304  * speedstep_verify - verifies a new CPUFreq policy
 305  * @policy: new policy
 306  *
 307  * Limit must be within speedstep_low_freq and speedstep_high_freq, with
 308  * at least one border included.
 309  */
 310 static int speedstep_verify(struct cpufreq_policy *policy)
 311 {
 312         return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
 313 }
 314
 315
 316 static int speedstep_cpu_init(struct cpufreq_policy *policy)
 317 {
 318         int result = 0;
 319         unsigned int speed;
 320         cpumask_t cpus_allowed;
 321
 322         /* only run on CPU to be set, or on its sibling */
 323 #ifdef CONFIG_SMP
 324         cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
 325 #endif
 326
 327         cpus_allowed = current->cpus_allowed;
 328         set_cpus_allowed_ptr(current, policy->cpus);
 329
 330         /* detect low and high frequency and transition latency */
 331         result = speedstep_get_freqs(speedstep_processor,
 332                                      &speedstep_freqs[SPEEDSTEP_LOW].frequency,
 333                                      &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
 334                                      &policy->cpuinfo.transition_latency,
 335                                      &speedstep_set_state);
 336         set_cpus_allowed_ptr(current, &cpus_allowed);
 337         if (result)
 338                 return result;
 339
 340         /* get current speed setting */
 341         speed = _speedstep_get(policy->cpus);
 342         if (!speed)
 343                 return -EIO;
 344
 345         dprintk("currently at %s speed setting - %i MHz\n",
 346                 (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
 347                 ? "low" : "high",
 348                 (speed / 1000));
 349
 350         /* cpuinfo and default policy values */
 351         policy->cur = speed;
 352
 353         result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
 354         if (result)
 355                 return result;
 356
 357         cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
 358
 359         return 0;
 360 }
 361
 362
 363 static int speedstep_cpu_exit(struct cpufreq_policy *policy)
 364 {
 365         cpufreq_frequency_table_put_attr(policy->cpu);
 366         return 0;
 367 }
 368
 369 static struct freq_attr *speedstep_attr[] = {
 370         &cpufreq_freq_attr_scaling_available_freqs,
 371         NULL,
 372 };
 373
 374
 375 static struct cpufreq_driver speedstep_driver = {
 376         .name   = "speedstep-ich",
 377         .verify = speedstep_verify,
 378         .target = speedstep_target,
 379         .init   = speedstep_cpu_init,
 380         .exit   = speedstep_cpu_exit,
 381         .get    = speedstep_get,
 382         .owner  = THIS_MODULE,
 383         .attr   = speedstep_attr,
 384 };
 385
 386
 387 /**
 388  * speedstep_init - initializes the SpeedStep CPUFreq driver
 389  *
 390  *   Initializes the SpeedStep support. Returns -ENODEV on unsupported
 391  * devices, -EINVAL on problems during initiatization, and zero on
 392  * success.
 393  */
 394 static int __init speedstep_init(void)
 395 {
 396         /* detect processor */
 397         speedstep_processor = speedstep_detect_processor();
 398         if (!speedstep_processor) {
 399                 dprintk("Intel(R) SpeedStep(TM) capable processor "
 400                                 "not found\n");
 401                 return -ENODEV;
 402         }
 403
 404         /* detect chipset */
 405         if (!speedstep_detect_chipset()) {
 406                 dprintk("Intel(R) SpeedStep(TM) for this chipset not "
 407                                 "(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@redhat.com>, "
 437                 "Dominik Brodowski <linux@brodo.de>");
 438 MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
 439                 "with ICH-M southbridges.");
 440 MODULE_LICENSE("GPL");
 441
 442 module_init(speedstep_init);
 443 module_exit(speedstep_exit);