LXR linux/drivers/cpufreq/e

   1/*
   2 *  Based on documentation provided by Dave Jones. Thanks!
   3 *
   4 *  Licensed under the terms of the GNU GPL License version 2.
   5 *
   6 *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/module.h>
  11#include <linux/init.h>
  12#include <linux/cpufreq.h>
  13#include <linux/ioport.h>
  14#include <linux/slab.h>
  15#include <linux/timex.h>
  16#include <linux/io.h>
  17#include <linux/delay.h>
  18
  19#include <asm/cpu_device_id.h>
  20#include <asm/msr.h>
  21#include <asm/tsc.h>
  22
  23#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
  24#include <linux/acpi.h>
  25#include <acpi/processor.h>
  26#endif
  27
  28#define EPS_BRAND_C7M   0
  29#define EPS_BRAND_C7    1
  30#define EPS_BRAND_EDEN  2
  31#define EPS_BRAND_C3    3
  32#define EPS_BRAND_C7D   4
  33
  34struct eps_cpu_data {
  35        u32 fsb;
  36#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
  37        u32 bios_limit;
  38#endif
  39        struct cpufreq_frequency_table freq_table[];
  40};
  41
  42static struct eps_cpu_data *eps_cpu[NR_CPUS];
  43
  44/* Module parameters */
  45static int freq_failsafe_off;
  46static int voltage_failsafe_off;
  47static int set_max_voltage;
  48
  49#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
  50static int ignore_acpi_limit;
  51
  52static struct acpi_processor_performance *eps_acpi_cpu_perf;
  53
  54/* Minimum necessary to get acpi_processor_get_bios_limit() working */
  55static int eps_acpi_init(void)
  56{
  57        eps_acpi_cpu_perf = kzalloc(sizeof(*eps_acpi_cpu_perf),
  58                                      GFP_KERNEL);
  59        if (!eps_acpi_cpu_perf)
  60                return -ENOMEM;
  61
  62        if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
  63                                                                GFP_KERNEL)) {
  64                kfree(eps_acpi_cpu_perf);
  65                eps_acpi_cpu_perf = NULL;
  66                return -ENOMEM;
  67        }
  68
  69        if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
  70                free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
  71                kfree(eps_acpi_cpu_perf);
  72                eps_acpi_cpu_perf = NULL;
  73                return -EIO;
  74        }
  75        return 0;
  76}
  77
  78static int eps_acpi_exit(struct cpufreq_policy *policy)
  79{
  80        if (eps_acpi_cpu_perf) {
  81                acpi_processor_unregister_performance(eps_acpi_cpu_perf, 0);
  82                free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
  83                kfree(eps_acpi_cpu_perf);
  84                eps_acpi_cpu_perf = NULL;
  85        }
  86        return 0;
  87}
  88#endif
  89
  90static unsigned int eps_get(unsigned int cpu)
  91{
  92        struct eps_cpu_data *centaur;
  93        u32 lo, hi;
  94
  95        if (cpu)
  96                return 0;
  97        centaur = eps_cpu[cpu];
  98        if (centaur == NULL)
  99                return 0;
 100
 101        /* Return current frequency */
 102        rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 103        return centaur->fsb * ((lo >> 8) & 0xff);
 104}
 105
 106static int eps_set_state(struct eps_cpu_data *centaur,
 107                         struct cpufreq_policy *policy,
 108                         u32 dest_state)
 109{
 110        u32 lo, hi;
 111        int i;
 112
 113        /* Wait while CPU is busy */
 114        rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 115        i = 0;
 116        while (lo & ((1 << 16) | (1 << 17))) {
 117                udelay(16);
 118                rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 119                i++;
 120                if (unlikely(i > 64)) {
 121                        return -ENODEV;
 122                }
 123        }
 124        /* Set new multiplier and voltage */
 125        wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
 126        /* Wait until transition end */
 127        i = 0;
 128        do {
 129                udelay(16);
 130                rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 131                i++;
 132                if (unlikely(i > 64)) {
 133                        return -ENODEV;
 134                }
 135        } while (lo & ((1 << 16) | (1 << 17)));
 136
 137#ifdef DEBUG
 138        {
 139        u8 current_multiplier, current_voltage;
 140
 141        /* Print voltage and multiplier */
 142        rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 143        current_voltage = lo & 0xff;
 144        printk(KERN_INFO "eps: Current voltage = %dmV\n",
 145                current_voltage * 16 + 700);
 146        current_multiplier = (lo >> 8) & 0xff;
 147        printk(KERN_INFO "eps: Current multiplier = %d\n",
 148                current_multiplier);
 149        }
 150#endif
 151        return 0;
 152}
 153
 154static int eps_target(struct cpufreq_policy *policy, unsigned int index)
 155{
 156        struct eps_cpu_data *centaur;
 157        unsigned int cpu = policy->cpu;
 158        unsigned int dest_state;
 159        int ret;
 160
 161        if (unlikely(eps_cpu[cpu] == NULL))
 162                return -ENODEV;
 163        centaur = eps_cpu[cpu];
 164
 165        /* Make frequency transition */
 166        dest_state = centaur->freq_table[index].driver_data & 0xffff;
 167        ret = eps_set_state(centaur, policy, dest_state);
 168        if (ret)
 169                printk(KERN_ERR "eps: Timeout!\n");
 170        return ret;
 171}
 172
 173static int eps_cpu_init(struct cpufreq_policy *policy)
 174{
 175        unsigned int i;
 176        u32 lo, hi;
 177        u64 val;
 178        u8 current_multiplier, current_voltage;
 179        u8 max_multiplier, max_voltage;
 180        u8 min_multiplier, min_voltage;
 181        u8 brand = 0;
 182        u32 fsb;
 183        struct eps_cpu_data *centaur;
 184        struct cpuinfo_x86 *c = &cpu_data(0);
 185        struct cpufreq_frequency_table *f_table;
 186        int k, step, voltage;
 187        int ret;
 188        int states;
 189#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 190        unsigned int limit;
 191#endif
 192
 193        if (policy->cpu != 0)
 194                return -ENODEV;
 195
 196        /* Check brand */
 197        printk(KERN_INFO "eps: Detected VIA ");
 198
 199        switch (c->x86_model) {
 200        case 10:
 201                rdmsr(0x1153, lo, hi);
 202                brand = (((lo >> 2) ^ lo) >> 18) & 3;
 203                printk(KERN_CONT "Model A ");
 204                break;
 205        case 13:
 206                rdmsr(0x1154, lo, hi);
 207                brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
 208                printk(KERN_CONT "Model D ");
 209                break;
 210        }
 211
 212        switch (brand) {
 213        case EPS_BRAND_C7M:
 214                printk(KERN_CONT "C7-M\n");
 215                break;
 216        case EPS_BRAND_C7:
 217                printk(KERN_CONT "C7\n");
 218                break;
 219        case EPS_BRAND_EDEN:
 220                printk(KERN_CONT "Eden\n");
 221                break;
 222        case EPS_BRAND_C7D:
 223                printk(KERN_CONT "C7-D\n");
 224                break;
 225        case EPS_BRAND_C3:
 226                printk(KERN_CONT "C3\n");
 227                return -ENODEV;
 228                break;
 229        }
 230        /* Enable Enhanced PowerSaver */
 231        rdmsrl(MSR_IA32_MISC_ENABLE, val);
 232        if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 233                val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
 234                wrmsrl(MSR_IA32_MISC_ENABLE, val);
 235                /* Can be locked at 0 */
 236                rdmsrl(MSR_IA32_MISC_ENABLE, val);
 237                if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 238                        printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
 239                        return -ENODEV;
 240                }
 241        }
 242
 243        /* Print voltage and multiplier */
 244        rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 245        current_voltage = lo & 0xff;
 246        printk(KERN_INFO "eps: Current voltage = %dmV\n",
 247                        current_voltage * 16 + 700);
 248        current_multiplier = (lo >> 8) & 0xff;
 249        printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
 250
 251        /* Print limits */
 252        max_voltage = hi & 0xff;
 253        printk(KERN_INFO "eps: Highest voltage = %dmV\n",
 254                        max_voltage * 16 + 700);
 255        max_multiplier = (hi >> 8) & 0xff;
 256        printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
 257        min_voltage = (hi >> 16) & 0xff;
 258        printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
 259                        min_voltage * 16 + 700);
 260        min_multiplier = (hi >> 24) & 0xff;
 261        printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
 262
 263        /* Sanity checks */
 264        if (current_multiplier == 0 || max_multiplier == 0
 265            || min_multiplier == 0)
 266                return -EINVAL;
 267        if (current_multiplier > max_multiplier
 268            || max_multiplier <= min_multiplier)
 269                return -EINVAL;
 270        if (current_voltage > 0x1f || max_voltage > 0x1f)
 271                return -EINVAL;
 272        if (max_voltage < min_voltage
 273            || current_voltage < min_voltage
 274            || current_voltage > max_voltage)
 275                return -EINVAL;
 276
 277        /* Check for systems using underclocked CPU */
 278        if (!freq_failsafe_off && max_multiplier != current_multiplier) {
 279                printk(KERN_INFO "eps: Your processor is running at different "
 280                        "frequency then its maximum. Aborting.\n");
 281                printk(KERN_INFO "eps: You can use freq_failsafe_off option "
 282                        "to disable this check.\n");
 283                return -EINVAL;
 284        }
 285        if (!voltage_failsafe_off && max_voltage != current_voltage) {
 286                printk(KERN_INFO "eps: Your processor is running at different "
 287                        "voltage then its maximum. Aborting.\n");
 288                printk(KERN_INFO "eps: You can use voltage_failsafe_off "
 289                        "option to disable this check.\n");
 290                return -EINVAL;
 291        }
 292
 293        /* Calc FSB speed */
 294        fsb = cpu_khz / current_multiplier;
 295
 296#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 297        /* Check for ACPI processor speed limit */
 298        if (!ignore_acpi_limit && !eps_acpi_init()) {
 299                if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
 300                        printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
 301                                limit/1000000,
 302                                (limit%1000000)/10000);
 303                        eps_acpi_exit(policy);
 304                        /* Check if max_multiplier is in BIOS limits */
 305                        if (limit && max_multiplier * fsb > limit) {
 306                                printk(KERN_INFO "eps: Aborting.\n");
 307                                return -EINVAL;
 308                        }
 309                }
 310        }
 311#endif
 312
 313        /* Allow user to set lower maximum voltage then that reported
 314         * by processor */
 315        if (brand == EPS_BRAND_C7M && set_max_voltage) {
 316                u32 v;
 317
 318                /* Change mV to something hardware can use */
 319                v = (set_max_voltage - 700) / 16;
 320                /* Check if voltage is within limits */
 321                if (v >= min_voltage && v <= max_voltage) {
 322                        printk(KERN_INFO "eps: Setting %dmV as maximum.\n",
 323                                v * 16 + 700);
 324                        max_voltage = v;
 325                }
 326        }
 327
 328        /* Calc number of p-states supported */
 329        if (brand == EPS_BRAND_C7M)
 330                states = max_multiplier - min_multiplier + 1;
 331        else
 332                states = 2;
 333
 334        /* Allocate private data and frequency table for current cpu */
 335        centaur = kzalloc(sizeof(*centaur)
 336                    + (states + 1) * sizeof(struct cpufreq_frequency_table),
 337                    GFP_KERNEL);
 338        if (!centaur)
 339                return -ENOMEM;
 340        eps_cpu[0] = centaur;
 341
 342        /* Copy basic values */
 343        centaur->fsb = fsb;
 344#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 345        centaur->bios_limit = limit;
 346#endif
 347
 348        /* Fill frequency and MSR value table */
 349        f_table = &centaur->freq_table[0];
 350        if (brand != EPS_BRAND_C7M) {
 351                f_table[0].frequency = fsb * min_multiplier;
 352                f_table[0].driver_data = (min_multiplier << 8) | min_voltage;
 353                f_table[1].frequency = fsb * max_multiplier;
 354                f_table[1].driver_data = (max_multiplier << 8) | max_voltage;
 355                f_table[2].frequency = CPUFREQ_TABLE_END;
 356        } else {
 357                k = 0;
 358                step = ((max_voltage - min_voltage) * 256)
 359                        / (max_multiplier - min_multiplier);
 360                for (i = min_multiplier; i <= max_multiplier; i++) {
 361                        voltage = (k * step) / 256 + min_voltage;
 362                        f_table[k].frequency = fsb * i;
 363                        f_table[k].driver_data = (i << 8) | voltage;
 364                        k++;
 365                }
 366                f_table[k].frequency = CPUFREQ_TABLE_END;
 367        }
 368
 369        policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
 370
 371        ret = cpufreq_table_validate_and_show(policy, &centaur->freq_table[0]);
 372        if (ret) {
 373                kfree(centaur);
 374                return ret;
 375        }
 376
 377        return 0;
 378}
 379
 380static int eps_cpu_exit(struct cpufreq_policy *policy)
 381{
 382        unsigned int cpu = policy->cpu;
 383
 384        /* Bye */
 385        kfree(eps_cpu[cpu]);
 386        eps_cpu[cpu] = NULL;
 387        return 0;
 388}
 389
 390static struct cpufreq_driver eps_driver = {
 391        .verify         = cpufreq_generic_frequency_table_verify,
 392        .target_index   = eps_target,
 393        .init           = eps_cpu_init,
 394        .exit           = eps_cpu_exit,
 395        .get            = eps_get,
 396        .name           = "e_powersaver",
 397        .attr           = cpufreq_generic_attr,
 398};
 399
 400
 401/* This driver will work only on Centaur C7 processors with
 402 * Enhanced SpeedStep/PowerSaver registers */
 403static const struct x86_cpu_id eps_cpu_id[] = {
 404        { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST },
 405        {}
 406};
 407MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
 408
 409static int __init eps_init(void)
 410{
 411        if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
 412                return -ENODEV;
 413        if (cpufreq_register_driver(&eps_driver))
 414                return -EINVAL;
 415        return 0;
 416}
 417
 418static void __exit eps_exit(void)
 419{
 420        cpufreq_unregister_driver(&eps_driver);
 421}
 422
 423/* Allow user to overclock his machine or to change frequency to higher after
 424 * unloading module */
 425module_param(freq_failsafe_off, int, 0644);
 426MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
 427module_param(voltage_failsafe_off, int, 0644);
 428MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
 429#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 430module_param(ignore_acpi_limit, int, 0644);
 431MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
 432#endif
 433module_param(set_max_voltage, int, 0644);
 434MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
 435
 436MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
 437MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
 438MODULE_LICENSE("GPL");
 439
 440module_init(eps_init);
 441module_exit(eps_exit);
 442