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/msr.h>
  20 #include <asm/tsc.h>
  21
  22 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
  23 #include <linux/acpi.h>
  24 #include <acpi/processor.h>
  25 #endif
  26
  27 #define EPS_BRAND_C7M   0
  28 #define EPS_BRAND_C7    1
  29 #define EPS_BRAND_EDEN  2
  30 #define EPS_BRAND_C3    3
  31 #define EPS_BRAND_C7D   4
  32
  33 struct eps_cpu_data {
  34         u32 fsb;
  35 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
  36         u32 bios_limit;
  37 #endif
  38         struct cpufreq_frequency_table freq_table[];
  39 };
  40
  41 static struct eps_cpu_data *eps_cpu[NR_CPUS];
  42
  43 /* Module parameters */
  44 static int freq_failsafe_off;
  45 static int voltage_failsafe_off;
  46 static int set_max_voltage;
  47
  48 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
  49 static int ignore_acpi_limit;
  50
  51 static struct acpi_processor_performance *eps_acpi_cpu_perf;
  52
  53 /* Minimum necessary to get acpi_processor_get_bios_limit() working */
  54 static int eps_acpi_init(void)
  55 {
  56         eps_acpi_cpu_perf = kzalloc(sizeof(struct acpi_processor_performance),
  57                                       GFP_KERNEL);
  58         if (!eps_acpi_cpu_perf)
  59                 return -ENOMEM;
  60
  61         if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
  62                                                                 GFP_KERNEL)) {
  63                 kfree(eps_acpi_cpu_perf);
  64                 eps_acpi_cpu_perf = NULL;
  65                 return -ENOMEM;
  66         }
  67
  68         if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
  69                 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
  70                 kfree(eps_acpi_cpu_perf);
  71                 eps_acpi_cpu_perf = NULL;
  72                 return -EIO;
  73         }
  74         return 0;
  75 }
  76
  77 static int eps_acpi_exit(struct cpufreq_policy *policy)
  78 {
  79         if (eps_acpi_cpu_perf) {
  80                 acpi_processor_unregister_performance(eps_acpi_cpu_perf, 0);
  81                 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
  82                 kfree(eps_acpi_cpu_perf);
  83                 eps_acpi_cpu_perf = NULL;
  84         }
  85         return 0;
  86 }
  87 #endif
  88
  89 static unsigned int eps_get(unsigned int cpu)
  90 {
  91         struct eps_cpu_data *centaur;
  92         u32 lo, hi;
  93
  94         if (cpu)
  95                 return 0;
  96         centaur = eps_cpu[cpu];
  97         if (centaur == NULL)
  98                 return 0;
  99
 100         /* Return current frequency */
 101         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 102         return centaur->fsb * ((lo >> 8) & 0xff);
 103 }
 104
 105 static int eps_set_state(struct eps_cpu_data *centaur,
 106                          unsigned int cpu,
 107                          u32 dest_state)
 108 {
 109         struct cpufreq_freqs freqs;
 110         u32 lo, hi;
 111         int err = 0;
 112         int i;
 113
 114         freqs.old = eps_get(cpu);
 115         freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
 116         freqs.cpu = cpu;
 117         cpufreq_notify_transition(&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         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 165         return err;
 166 }
 167
 168 static int eps_target(struct cpufreq_policy *policy,
 169                                unsigned int target_freq,
 170                                unsigned int relation)
 171 {
 172         struct eps_cpu_data *centaur;
 173         unsigned int newstate = 0;
 174         unsigned int cpu = policy->cpu;
 175         unsigned int dest_state;
 176         int ret;
 177
 178         if (unlikely(eps_cpu[cpu] == NULL))
 179                 return -ENODEV;
 180         centaur = eps_cpu[cpu];
 181
 182         if (unlikely(cpufreq_frequency_table_target(policy,
 183                         &eps_cpu[cpu]->freq_table[0],
 184                         target_freq,
 185                         relation,
 186                         &newstate))) {
 187                 return -EINVAL;
 188         }
 189
 190         /* Make frequency transition */
 191         dest_state = centaur->freq_table[newstate].index & 0xffff;
 192         ret = eps_set_state(centaur, cpu, dest_state);
 193         if (ret)
 194                 printk(KERN_ERR "eps: Timeout!\n");
 195         return ret;
 196 }
 197
 198 static int eps_verify(struct cpufreq_policy *policy)
 199 {
 200         return cpufreq_frequency_table_verify(policy,
 201                         &eps_cpu[policy->cpu]->freq_table[0]);
 202 }
 203
 204 static int eps_cpu_init(struct cpufreq_policy *policy)
 205 {
 206         unsigned int i;
 207         u32 lo, hi;
 208         u64 val;
 209         u8 current_multiplier, current_voltage;
 210         u8 max_multiplier, max_voltage;
 211         u8 min_multiplier, min_voltage;
 212         u8 brand = 0;
 213         u32 fsb;
 214         struct eps_cpu_data *centaur;
 215         struct cpuinfo_x86 *c = &cpu_data(0);
 216         struct cpufreq_frequency_table *f_table;
 217         int k, step, voltage;
 218         int ret;
 219         int states;
 220 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 221         unsigned int limit;
 222 #endif
 223
 224         if (policy->cpu != 0)
 225                 return -ENODEV;
 226
 227         /* Check brand */
 228         printk(KERN_INFO "eps: Detected VIA ");
 229
 230         switch (c->x86_model) {
 231         case 10:
 232                 rdmsr(0x1153, lo, hi);
 233                 brand = (((lo >> 2) ^ lo) >> 18) & 3;
 234                 printk(KERN_CONT "Model A ");
 235                 break;
 236         case 13:
 237                 rdmsr(0x1154, lo, hi);
 238                 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
 239                 printk(KERN_CONT "Model D ");
 240                 break;
 241         }
 242
 243         switch (brand) {
 244         case EPS_BRAND_C7M:
 245                 printk(KERN_CONT "C7-M\n");
 246                 break;
 247         case EPS_BRAND_C7:
 248                 printk(KERN_CONT "C7\n");
 249                 break;
 250         case EPS_BRAND_EDEN:
 251                 printk(KERN_CONT "Eden\n");
 252                 break;
 253         case EPS_BRAND_C7D:
 254                 printk(KERN_CONT "C7-D\n");
 255                 break;
 256         case EPS_BRAND_C3:
 257                 printk(KERN_CONT "C3\n");
 258                 return -ENODEV;
 259                 break;
 260         }
 261         /* Enable Enhanced PowerSaver */
 262         rdmsrl(MSR_IA32_MISC_ENABLE, val);
 263         if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 264                 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
 265                 wrmsrl(MSR_IA32_MISC_ENABLE, val);
 266                 /* Can be locked at 0 */
 267                 rdmsrl(MSR_IA32_MISC_ENABLE, val);
 268                 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 269                         printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
 270                         return -ENODEV;
 271                 }
 272         }
 273
 274         /* Print voltage and multiplier */
 275         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 276         current_voltage = lo & 0xff;
 277         printk(KERN_INFO "eps: Current voltage = %dmV\n",
 278                         current_voltage * 16 + 700);
 279         current_multiplier = (lo >> 8) & 0xff;
 280         printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
 281
 282         /* Print limits */
 283         max_voltage = hi & 0xff;
 284         printk(KERN_INFO "eps: Highest voltage = %dmV\n",
 285                         max_voltage * 16 + 700);
 286         max_multiplier = (hi >> 8) & 0xff;
 287         printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
 288         min_voltage = (hi >> 16) & 0xff;
 289         printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
 290                         min_voltage * 16 + 700);
 291         min_multiplier = (hi >> 24) & 0xff;
 292         printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
 293
 294         /* Sanity checks */
 295         if (current_multiplier == 0 || max_multiplier == 0
 296             || min_multiplier == 0)
 297                 return -EINVAL;
 298         if (current_multiplier > max_multiplier
 299             || max_multiplier <= min_multiplier)
 300                 return -EINVAL;
 301         if (current_voltage > 0x1f || max_voltage > 0x1f)
 302                 return -EINVAL;
 303         if (max_voltage < min_voltage
 304             || current_voltage < min_voltage
 305             || current_voltage > max_voltage)
 306                 return -EINVAL;
 307
 308         /* Check for systems using underclocked CPU */
 309         if (!freq_failsafe_off && max_multiplier != current_multiplier) {
 310                 printk(KERN_INFO "eps: Your processor is running at different "
 311                         "frequency then its maximum. Aborting.\n");
 312                 printk(KERN_INFO "eps: You can use freq_failsafe_off option "
 313                         "to disable this check.\n");
 314                 return -EINVAL;
 315         }
 316         if (!voltage_failsafe_off && max_voltage != current_voltage) {
 317                 printk(KERN_INFO "eps: Your processor is running at different "
 318                         "voltage then its maximum. Aborting.\n");
 319                 printk(KERN_INFO "eps: You can use voltage_failsafe_off "
 320                         "option to disable this check.\n");
 321                 return -EINVAL;
 322         }
 323
 324         /* Calc FSB speed */
 325         fsb = cpu_khz / current_multiplier;
 326
 327 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 328         /* Check for ACPI processor speed limit */
 329         if (!ignore_acpi_limit && !eps_acpi_init()) {
 330                 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
 331                         printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
 332                                 limit/1000000,
 333                                 (limit%1000000)/10000);
 334                         eps_acpi_exit(policy);
 335                         /* Check if max_multiplier is in BIOS limits */
 336                         if (limit && max_multiplier * fsb > limit) {
 337                                 printk(KERN_INFO "eps: Aborting.\n");
 338                                 return -EINVAL;
 339                         }
 340                 }
 341         }
 342 #endif
 343
 344         /* Allow user to set lower maximum voltage then that reported
 345          * by processor */
 346         if (brand == EPS_BRAND_C7M && set_max_voltage) {
 347                 u32 v;
 348
 349                 /* Change mV to something hardware can use */
 350                 v = (set_max_voltage - 700) / 16;
 351                 /* Check if voltage is within limits */
 352                 if (v >= min_voltage && v <= max_voltage) {
 353                         printk(KERN_INFO "eps: Setting %dmV as maximum.\n",
 354                                 v * 16 + 700);
 355                         max_voltage = v;
 356                 }
 357         }
 358
 359         /* Calc number of p-states supported */
 360         if (brand == EPS_BRAND_C7M)
 361                 states = max_multiplier - min_multiplier + 1;
 362         else
 363                 states = 2;
 364
 365         /* Allocate private data and frequency table for current cpu */
 366         centaur = kzalloc(sizeof(struct eps_cpu_data)
 367                     + (states + 1) * sizeof(struct cpufreq_frequency_table),
 368                     GFP_KERNEL);
 369         if (!centaur)
 370                 return -ENOMEM;
 371         eps_cpu[0] = centaur;
 372
 373         /* Copy basic values */
 374         centaur->fsb = fsb;
 375 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 376         centaur->bios_limit = limit;
 377 #endif
 378
 379         /* Fill frequency and MSR value table */
 380         f_table = &centaur->freq_table[0];
 381         if (brand != EPS_BRAND_C7M) {
 382                 f_table[0].frequency = fsb * min_multiplier;
 383                 f_table[0].index = (min_multiplier << 8) | min_voltage;
 384                 f_table[1].frequency = fsb * max_multiplier;
 385                 f_table[1].index = (max_multiplier << 8) | max_voltage;
 386                 f_table[2].frequency = CPUFREQ_TABLE_END;
 387         } else {
 388                 k = 0;
 389                 step = ((max_voltage - min_voltage) * 256)
 390                         / (max_multiplier - min_multiplier);
 391                 for (i = min_multiplier; i <= max_multiplier; i++) {
 392                         voltage = (k * step) / 256 + min_voltage;
 393                         f_table[k].frequency = fsb * i;
 394                         f_table[k].index = (i << 8) | voltage;
 395                         k++;
 396                 }
 397                 f_table[k].frequency = CPUFREQ_TABLE_END;
 398         }
 399
 400         policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
 401         policy->cur = fsb * current_multiplier;
 402
 403         ret = cpufreq_frequency_table_cpuinfo(policy, &centaur->freq_table[0]);
 404         if (ret) {
 405                 kfree(centaur);
 406                 return ret;
 407         }
 408
 409         cpufreq_frequency_table_get_attr(&centaur->freq_table[0], policy->cpu);
 410         return 0;
 411 }
 412
 413 static int eps_cpu_exit(struct cpufreq_policy *policy)
 414 {
 415         unsigned int cpu = policy->cpu;
 416
 417         /* Bye */
 418         cpufreq_frequency_table_put_attr(policy->cpu);
 419         kfree(eps_cpu[cpu]);
 420         eps_cpu[cpu] = NULL;
 421         return 0;
 422 }
 423
 424 static struct freq_attr *eps_attr[] = {
 425         &cpufreq_freq_attr_scaling_available_freqs,
 426         NULL,
 427 };
 428
 429 static struct cpufreq_driver eps_driver = {
 430         .verify         = eps_verify,
 431         .target         = eps_target,
 432         .init           = eps_cpu_init,
 433         .exit           = eps_cpu_exit,
 434         .get            = eps_get,
 435         .name           = "e_powersaver",
 436         .owner          = THIS_MODULE,
 437         .attr           = eps_attr,
 438 };
 439
 440 static int __init eps_init(void)
 441 {
 442         struct cpuinfo_x86 *c = &cpu_data(0);
 443
 444         /* This driver will work only on Centaur C7 processors with
 445          * Enhanced SpeedStep/PowerSaver registers */
 446         if (c->x86_vendor != X86_VENDOR_CENTAUR
 447             || c->x86 != 6 || c->x86_model < 10)
 448                 return -ENODEV;
 449         if (!cpu_has(c, X86_FEATURE_EST))
 450                 return -ENODEV;
 451
 452         if (cpufreq_register_driver(&eps_driver))
 453                 return -EINVAL;
 454         return 0;
 455 }
 456
 457 static void __exit eps_exit(void)
 458 {
 459         cpufreq_unregister_driver(&eps_driver);
 460 }
 461
 462 /* Allow user to overclock his machine or to change frequency to higher after
 463  * unloading module */
 464 module_param(freq_failsafe_off, int, 0644);
 465 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
 466 module_param(voltage_failsafe_off, int, 0644);
 467 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
 468 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 469 module_param(ignore_acpi_limit, int, 0644);
 470 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
 471 #endif
 472 module_param(set_max_voltage, int, 0644);
 473 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
 474
 475 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
 476 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
 477 MODULE_LICENSE("GPL");
 478
 479 module_init(eps_init);
 480 module_exit(eps_exit);