drivers/cpufreq/e_powersaver.c

   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
  34 struct 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
  42 static struct eps_cpu_data *eps_cpu[NR_CPUS];
  43
  44 /* Module parameters */
  45 static int freq_failsafe_off;
  46 static int voltage_failsafe_off;
  47 static int set_max_voltage;
  48
  49 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
  50 static int ignore_acpi_limit;
  51
  52 static struct acpi_processor_performance *eps_acpi_cpu_perf;
  53
  54 /* Minimum necessary to get acpi_processor_get_bios_limit() working */
  55 static 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
  78 static 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
  90 static 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
 106 static int eps_set_state(struct eps_cpu_data *centaur,
 107                          struct cpufreq_policy *policy,
 108                          u32 dest_state)
 109 {
 110         struct cpufreq_freqs freqs;
 111         u32 lo, hi;
 112         int err = 0;
 113         int i;
 114
 115         freqs.old = eps_get(policy->cpu);
 116         freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
 117         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 118
 119         /* Wait while CPU is busy */
 120         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 121         i = 0;
 122         while (lo & ((1 << 16) | (1 << 17))) {
 123                 udelay(16);
 124                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 125                 i++;
 126                 if (unlikely(i > 64)) {
 127                         err = -ENODEV;
 128                         goto postchange;
 129                 }
 130         }
 131         /* Set new multiplier and voltage */
 132         wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
 133         /* Wait until transition end */
 134         i = 0;
 135         do {
 136                 udelay(16);
 137                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 138                 i++;
 139                 if (unlikely(i > 64)) {
 140                         err = -ENODEV;
 141                         goto postchange;
 142                 }
 143         } while (lo & ((1 << 16) | (1 << 17)));
 144
 145         /* Return current frequency */
 146 postchange:
 147         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 148         freqs.new = centaur->fsb * ((lo >> 8) & 0xff);
 149
 150 #ifdef DEBUG
 151         {
 152         u8 current_multiplier, current_voltage;
 153
 154         /* Print voltage and multiplier */
 155         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 156         current_voltage = lo & 0xff;
 157         printk(KERN_INFO "eps: Current voltage = %dmV\n",
 158                 current_voltage * 16 + 700);
 159         current_multiplier = (lo >> 8) & 0xff;
 160         printk(KERN_INFO "eps: Current multiplier = %d\n",
 161                 current_multiplier);
 162         }
 163 #endif
 164         if (err)
 165                 freqs.new = freqs.old;
 166
 167         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 168         return err;
 169 }
 170
 171 static int eps_target(struct cpufreq_policy *policy,
 172                                unsigned int target_freq,
 173                                unsigned int relation)
 174 {
 175         struct eps_cpu_data *centaur;
 176         unsigned int newstate = 0;
 177         unsigned int cpu = policy->cpu;
 178         unsigned int dest_state;
 179         int ret;
 180
 181         if (unlikely(eps_cpu[cpu] == NULL))
 182                 return -ENODEV;
 183         centaur = eps_cpu[cpu];
 184
 185         if (unlikely(cpufreq_frequency_table_target(policy,
 186                         &eps_cpu[cpu]->freq_table[0],
 187                         target_freq,
 188                         relation,
 189                         &newstate))) {
 190                 return -EINVAL;
 191         }
 192
 193         /* Make frequency transition */
 194         dest_state = centaur->freq_table[newstate].driver_data & 0xffff;
 195         ret = eps_set_state(centaur, policy, dest_state);
 196         if (ret)
 197                 printk(KERN_ERR "eps: Timeout!\n");
 198         return ret;
 199 }
 200
 201 static int eps_verify(struct cpufreq_policy *policy)
 202 {
 203         return cpufreq_frequency_table_verify(policy,
 204                         &eps_cpu[policy->cpu]->freq_table[0]);
 205 }
 206
 207 static int eps_cpu_init(struct cpufreq_policy *policy)
 208 {
 209         unsigned int i;
 210         u32 lo, hi;
 211         u64 val;
 212         u8 current_multiplier, current_voltage;
 213         u8 max_multiplier, max_voltage;
 214         u8 min_multiplier, min_voltage;
 215         u8 brand = 0;
 216         u32 fsb;
 217         struct eps_cpu_data *centaur;
 218         struct cpuinfo_x86 *c = &cpu_data(0);
 219         struct cpufreq_frequency_table *f_table;
 220         int k, step, voltage;
 221         int ret;
 222         int states;
 223 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 224         unsigned int limit;
 225 #endif
 226
 227         if (policy->cpu != 0)
 228                 return -ENODEV;
 229
 230         /* Check brand */
 231         printk(KERN_INFO "eps: Detected VIA ");
 232
 233         switch (c->x86_model) {
 234         case 10:
 235                 rdmsr(0x1153, lo, hi);
 236                 brand = (((lo >> 2) ^ lo) >> 18) & 3;
 237                 printk(KERN_CONT "Model A ");
 238                 break;
 239         case 13:
 240                 rdmsr(0x1154, lo, hi);
 241                 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
 242                 printk(KERN_CONT "Model D ");
 243                 break;
 244         }
 245
 246         switch (brand) {
 247         case EPS_BRAND_C7M:
 248                 printk(KERN_CONT "C7-M\n");
 249                 break;
 250         case EPS_BRAND_C7:
 251                 printk(KERN_CONT "C7\n");
 252                 break;
 253         case EPS_BRAND_EDEN:
 254                 printk(KERN_CONT "Eden\n");
 255                 break;
 256         case EPS_BRAND_C7D:
 257                 printk(KERN_CONT "C7-D\n");
 258                 break;
 259         case EPS_BRAND_C3:
 260                 printk(KERN_CONT "C3\n");
 261                 return -ENODEV;
 262                 break;
 263         }
 264         /* Enable Enhanced PowerSaver */
 265         rdmsrl(MSR_IA32_MISC_ENABLE, val);
 266         if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 267                 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
 268                 wrmsrl(MSR_IA32_MISC_ENABLE, val);
 269                 /* Can be locked at 0 */
 270                 rdmsrl(MSR_IA32_MISC_ENABLE, val);
 271                 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 272                         printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
 273                         return -ENODEV;
 274                 }
 275         }
 276
 277         /* Print voltage and multiplier */
 278         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 279         current_voltage = lo & 0xff;
 280         printk(KERN_INFO "eps: Current voltage = %dmV\n",
 281                         current_voltage * 16 + 700);
 282         current_multiplier = (lo >> 8) & 0xff;
 283         printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
 284
 285         /* Print limits */
 286         max_voltage = hi & 0xff;
 287         printk(KERN_INFO "eps: Highest voltage = %dmV\n",
 288                         max_voltage * 16 + 700);
 289         max_multiplier = (hi >> 8) & 0xff;
 290         printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
 291         min_voltage = (hi >> 16) & 0xff;
 292         printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
 293                         min_voltage * 16 + 700);
 294         min_multiplier = (hi >> 24) & 0xff;
 295         printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
 296
 297         /* Sanity checks */
 298         if (current_multiplier == 0 || max_multiplier == 0
 299             || min_multiplier == 0)
 300                 return -EINVAL;
 301         if (current_multiplier > max_multiplier
 302             || max_multiplier <= min_multiplier)
 303                 return -EINVAL;
 304         if (current_voltage > 0x1f || max_voltage > 0x1f)
 305                 return -EINVAL;
 306         if (max_voltage < min_voltage
 307             || current_voltage < min_voltage
 308             || current_voltage > max_voltage)
 309                 return -EINVAL;
 310
 311         /* Check for systems using underclocked CPU */
 312         if (!freq_failsafe_off && max_multiplier != current_multiplier) {
 313                 printk(KERN_INFO "eps: Your processor is running at different "
 314                         "frequency then its maximum. Aborting.\n");
 315                 printk(KERN_INFO "eps: You can use freq_failsafe_off option "
 316                         "to disable this check.\n");
 317                 return -EINVAL;
 318         }
 319         if (!voltage_failsafe_off && max_voltage != current_voltage) {
 320                 printk(KERN_INFO "eps: Your processor is running at different "
 321                         "voltage then its maximum. Aborting.\n");
 322                 printk(KERN_INFO "eps: You can use voltage_failsafe_off "
 323                         "option to disable this check.\n");
 324                 return -EINVAL;
 325         }
 326
 327         /* Calc FSB speed */
 328         fsb = cpu_khz / current_multiplier;
 329
 330 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 331         /* Check for ACPI processor speed limit */
 332         if (!ignore_acpi_limit && !eps_acpi_init()) {
 333                 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
 334                         printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
 335                                 limit/1000000,
 336                                 (limit%1000000)/10000);
 337                         eps_acpi_exit(policy);
 338                         /* Check if max_multiplier is in BIOS limits */
 339                         if (limit && max_multiplier * fsb > limit) {
 340                                 printk(KERN_INFO "eps: Aborting.\n");
 341                                 return -EINVAL;
 342                         }
 343                 }
 344         }
 345 #endif
 346
 347         /* Allow user to set lower maximum voltage then that reported
 348          * by processor */
 349         if (brand == EPS_BRAND_C7M && set_max_voltage) {
 350                 u32 v;
 351
 352                 /* Change mV to something hardware can use */
 353                 v = (set_max_voltage - 700) / 16;
 354                 /* Check if voltage is within limits */
 355                 if (v >= min_voltage && v <= max_voltage) {
 356                         printk(KERN_INFO "eps: Setting %dmV as maximum.\n",
 357                                 v * 16 + 700);
 358                         max_voltage = v;
 359                 }
 360         }
 361
 362         /* Calc number of p-states supported */
 363         if (brand == EPS_BRAND_C7M)
 364                 states = max_multiplier - min_multiplier + 1;
 365         else
 366                 states = 2;
 367
 368         /* Allocate private data and frequency table for current cpu */
 369         centaur = kzalloc(sizeof(*centaur)
 370                     + (states + 1) * sizeof(struct cpufreq_frequency_table),
 371                     GFP_KERNEL);
 372         if (!centaur)
 373                 return -ENOMEM;
 374         eps_cpu[0] = centaur;
 375
 376         /* Copy basic values */
 377         centaur->fsb = fsb;
 378 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 379         centaur->bios_limit = limit;
 380 #endif
 381
 382         /* Fill frequency and MSR value table */
 383         f_table = &centaur->freq_table[0];
 384         if (brand != EPS_BRAND_C7M) {
 385                 f_table[0].frequency = fsb * min_multiplier;
 386                 f_table[0].driver_data = (min_multiplier << 8) | min_voltage;
 387                 f_table[1].frequency = fsb * max_multiplier;
 388                 f_table[1].driver_data = (max_multiplier << 8) | max_voltage;
 389                 f_table[2].frequency = CPUFREQ_TABLE_END;
 390         } else {
 391                 k = 0;
 392                 step = ((max_voltage - min_voltage) * 256)
 393                         / (max_multiplier - min_multiplier);
 394                 for (i = min_multiplier; i <= max_multiplier; i++) {
 395                         voltage = (k * step) / 256 + min_voltage;
 396                         f_table[k].frequency = fsb * i;
 397                         f_table[k].driver_data = (i << 8) | voltage;
 398                         k++;
 399                 }
 400                 f_table[k].frequency = CPUFREQ_TABLE_END;
 401         }
 402
 403         policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
 404         policy->cur = fsb * current_multiplier;
 405
 406         ret = cpufreq_frequency_table_cpuinfo(policy, &centaur->freq_table[0]);
 407         if (ret) {
 408                 kfree(centaur);
 409                 return ret;
 410         }
 411
 412         cpufreq_frequency_table_get_attr(&centaur->freq_table[0], policy->cpu);
 413         return 0;
 414 }
 415
 416 static int eps_cpu_exit(struct cpufreq_policy *policy)
 417 {
 418         unsigned int cpu = policy->cpu;
 419
 420         /* Bye */
 421         cpufreq_frequency_table_put_attr(policy->cpu);
 422         kfree(eps_cpu[cpu]);
 423         eps_cpu[cpu] = NULL;
 424         return 0;
 425 }
 426
 427 static struct freq_attr *eps_attr[] = {
 428         &cpufreq_freq_attr_scaling_available_freqs,
 429         NULL,
 430 };
 431
 432 static struct cpufreq_driver eps_driver = {
 433         .verify         = eps_verify,
 434         .target         = eps_target,
 435         .init           = eps_cpu_init,
 436         .exit           = eps_cpu_exit,
 437         .get            = eps_get,
 438         .name           = "e_powersaver",
 439         .attr           = eps_attr,
 440 };
 441
 442
 443 /* This driver will work only on Centaur C7 processors with
 444  * Enhanced SpeedStep/PowerSaver registers */
 445 static const struct x86_cpu_id eps_cpu_id[] = {
 446         { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST },
 447         {}
 448 };
 449 MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
 450
 451 static int __init eps_init(void)
 452 {
 453         if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
 454                 return -ENODEV;
 455         if (cpufreq_register_driver(&eps_driver))
 456                 return -EINVAL;
 457         return 0;
 458 }
 459
 460 static void __exit eps_exit(void)
 461 {
 462         cpufreq_unregister_driver(&eps_driver);
 463 }
 464
 465 /* Allow user to overclock his machine or to change frequency to higher after
 466  * unloading module */
 467 module_param(freq_failsafe_off, int, 0644);
 468 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
 469 module_param(voltage_failsafe_off, int, 0644);
 470 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
 471 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 472 module_param(ignore_acpi_limit, int, 0644);
 473 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
 474 #endif
 475 module_param(set_max_voltage, int, 0644);
 476 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
 477
 478 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
 479 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
 480 MODULE_LICENSE("GPL");
 481
 482 module_init(eps_init);
 483 module_exit(eps_exit);