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