linux/drivers/cpufreq/speedstep-ich.c
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   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 */
  38static struct pci_dev *speedstep_chipset_dev;
  39
  40
  41/* speedstep_processor
  42 */
  43static enum speedstep_processor speedstep_processor;
  44
  45static u32 pmbase;
  46
  47/*
  48 *   There are only two frequency states for each processor. Values
  49 * are in kHz for the time being.
  50 */
  51static 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 */
  63static 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 */
  92static 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. */
 145static 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 */
 156static 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 */
 182static 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
 232static void get_freq_data(void *_speed)
 233{
 234        unsigned int *speed = _speed;
 235
 236        *speed = speedstep_get_frequency(speedstep_processor);
 237}
 238
 239static 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 */
 260static 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
 267        if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
 268                                target_freq, relation, &newstate))
 269                return -EINVAL;
 270
 271        policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
 272        freqs.old = speedstep_get(policy_cpu);
 273        freqs.new = speedstep_freqs[newstate].frequency;
 274
 275        pr_debug("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        cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 282
 283        smp_call_function_single(policy_cpu, _speedstep_set_state, &newstate,
 284                                 true);
 285
 286        cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 287
 288        return 0;
 289}
 290
 291
 292/**
 293 * speedstep_verify - verifies a new CPUFreq policy
 294 * @policy: new policy
 295 *
 296 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
 297 * at least one border included.
 298 */
 299static int speedstep_verify(struct cpufreq_policy *policy)
 300{
 301        return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
 302}
 303
 304struct get_freqs {
 305        struct cpufreq_policy *policy;
 306        int ret;
 307};
 308
 309static void get_freqs_on_cpu(void *_get_freqs)
 310{
 311        struct get_freqs *get_freqs = _get_freqs;
 312
 313        get_freqs->ret =
 314                speedstep_get_freqs(speedstep_processor,
 315                            &speedstep_freqs[SPEEDSTEP_LOW].frequency,
 316                            &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
 317                            &get_freqs->policy->cpuinfo.transition_latency,
 318                            &speedstep_set_state);
 319}
 320
 321static int speedstep_cpu_init(struct cpufreq_policy *policy)
 322{
 323        int result;
 324        unsigned int policy_cpu, speed;
 325        struct get_freqs gf;
 326
 327        /* only run on CPU to be set, or on its sibling */
 328#ifdef CONFIG_SMP
 329        cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
 330#endif
 331        policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
 332
 333        /* detect low and high frequency and transition latency */
 334        gf.policy = policy;
 335        smp_call_function_single(policy_cpu, get_freqs_on_cpu, &gf, 1);
 336        if (gf.ret)
 337                return gf.ret;
 338
 339        /* get current speed setting */
 340        speed = speedstep_get(policy_cpu);
 341        if (!speed)
 342                return -EIO;
 343
 344        pr_debug("currently at %s speed setting - %i MHz\n",
 345                (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
 346                ? "low" : "high",
 347                (speed / 1000));
 348
 349        /* cpuinfo and default policy values */
 350        policy->cur = speed;
 351
 352        result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
 353        if (result)
 354                return result;
 355
 356        cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
 357
 358        return 0;
 359}
 360
 361
 362static int speedstep_cpu_exit(struct cpufreq_policy *policy)
 363{
 364        cpufreq_frequency_table_put_attr(policy->cpu);
 365        return 0;
 366}
 367
 368static struct freq_attr *speedstep_attr[] = {
 369        &cpufreq_freq_attr_scaling_available_freqs,
 370        NULL,
 371};
 372
 373
 374static struct cpufreq_driver speedstep_driver = {
 375        .name   = "speedstep-ich",
 376        .verify = speedstep_verify,
 377        .target = speedstep_target,
 378        .init   = speedstep_cpu_init,
 379        .exit   = speedstep_cpu_exit,
 380        .get    = speedstep_get,
 381        .owner  = THIS_MODULE,
 382        .attr   = speedstep_attr,
 383};
 384
 385static const struct x86_cpu_id ss_smi_ids[] = {
 386        { X86_VENDOR_INTEL, 6, 0xb, },
 387        { X86_VENDOR_INTEL, 6, 0x8, },
 388        { X86_VENDOR_INTEL, 15, 2 },
 389        {}
 390};
 391#if 0
 392/* Autoload or not? Do not for now. */
 393MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
 394#endif
 395
 396/**
 397 * speedstep_init - initializes the SpeedStep CPUFreq driver
 398 *
 399 *   Initializes the SpeedStep support. Returns -ENODEV on unsupported
 400 * devices, -EINVAL on problems during initiatization, and zero on
 401 * success.
 402 */
 403static int __init speedstep_init(void)
 404{
 405        if (!x86_match_cpu(ss_smi_ids))
 406                return -ENODEV;
 407
 408        /* detect processor */
 409        speedstep_processor = speedstep_detect_processor();
 410        if (!speedstep_processor) {
 411                pr_debug("Intel(R) SpeedStep(TM) capable processor "
 412                                "not found\n");
 413                return -ENODEV;
 414        }
 415
 416        /* detect chipset */
 417        if (!speedstep_detect_chipset()) {
 418                pr_debug("Intel(R) SpeedStep(TM) for this chipset not "
 419                                "(yet) available.\n");
 420                return -ENODEV;
 421        }
 422
 423        /* activate speedstep support */
 424        if (speedstep_activate()) {
 425                pci_dev_put(speedstep_chipset_dev);
 426                return -EINVAL;
 427        }
 428
 429        if (speedstep_find_register())
 430                return -ENODEV;
 431
 432        return cpufreq_register_driver(&speedstep_driver);
 433}
 434
 435
 436/**
 437 * speedstep_exit - unregisters SpeedStep support
 438 *
 439 *   Unregisters SpeedStep support.
 440 */
 441static void __exit speedstep_exit(void)
 442{
 443        pci_dev_put(speedstep_chipset_dev);
 444        cpufreq_unregister_driver(&speedstep_driver);
 445}
 446
 447
 448MODULE_AUTHOR("Dave Jones <davej@redhat.com>, "
 449                "Dominik Brodowski <linux@brodo.de>");
 450MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
 451                "with ICH-M southbridges.");
 452MODULE_LICENSE("GPL");
 453
 454module_init(speedstep_init);
 455module_exit(speedstep_exit);
 456
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