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_cpu_init(struct cpufreq_policy *policy)
 202 {
 203         unsigned int i;
 204         u32 lo, hi;
 205         u64 val;
 206         u8 current_multiplier, current_voltage;
 207         u8 max_multiplier, max_voltage;
 208         u8 min_multiplier, min_voltage;
 209         u8 brand = 0;
 210         u32 fsb;
 211         struct eps_cpu_data *centaur;
 212         struct cpuinfo_x86 *c = &cpu_data(0);
 213         struct cpufreq_frequency_table *f_table;
 214         int k, step, voltage;
 215         int ret;
 216         int states;
 217 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 218         unsigned int limit;
 219 #endif
 220
 221         if (policy->cpu != 0)
 222                 return -ENODEV;
 223
 224         /* Check brand */
 225         printk(KERN_INFO "eps: Detected VIA ");
 226
 227         switch (c->x86_model) {
 228         case 10:
 229                 rdmsr(0x1153, lo, hi);
 230                 brand = (((lo >> 2) ^ lo) >> 18) & 3;
 231                 printk(KERN_CONT "Model A ");
 232                 break;
 233         case 13:
 234                 rdmsr(0x1154, lo, hi);
 235                 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
 236                 printk(KERN_CONT "Model D ");
 237                 break;
 238         }
 239
 240         switch (brand) {
 241         case EPS_BRAND_C7M:
 242                 printk(KERN_CONT "C7-M\n");
 243                 break;
 244         case EPS_BRAND_C7:
 245                 printk(KERN_CONT "C7\n");
 246                 break;
 247         case EPS_BRAND_EDEN:
 248                 printk(KERN_CONT "Eden\n");
 249                 break;
 250         case EPS_BRAND_C7D:
 251                 printk(KERN_CONT "C7-D\n");
 252                 break;
 253         case EPS_BRAND_C3:
 254                 printk(KERN_CONT "C3\n");
 255                 return -ENODEV;
 256                 break;
 257         }
 258         /* Enable Enhanced PowerSaver */
 259         rdmsrl(MSR_IA32_MISC_ENABLE, val);
 260         if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 261                 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
 262                 wrmsrl(MSR_IA32_MISC_ENABLE, val);
 263                 /* Can be locked at 0 */
 264                 rdmsrl(MSR_IA32_MISC_ENABLE, val);
 265                 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 266                         printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
 267                         return -ENODEV;
 268                 }
 269         }
 270
 271         /* Print voltage and multiplier */
 272         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 273         current_voltage = lo & 0xff;
 274         printk(KERN_INFO "eps: Current voltage = %dmV\n",
 275                         current_voltage * 16 + 700);
 276         current_multiplier = (lo >> 8) & 0xff;
 277         printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
 278
 279         /* Print limits */
 280         max_voltage = hi & 0xff;
 281         printk(KERN_INFO "eps: Highest voltage = %dmV\n",
 282                         max_voltage * 16 + 700);
 283         max_multiplier = (hi >> 8) & 0xff;
 284         printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
 285         min_voltage = (hi >> 16) & 0xff;
 286         printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
 287                         min_voltage * 16 + 700);
 288         min_multiplier = (hi >> 24) & 0xff;
 289         printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
 290
 291         /* Sanity checks */
 292         if (current_multiplier == 0 || max_multiplier == 0
 293             || min_multiplier == 0)
 294                 return -EINVAL;
 295         if (current_multiplier > max_multiplier
 296             || max_multiplier <= min_multiplier)
 297                 return -EINVAL;
 298         if (current_voltage > 0x1f || max_voltage > 0x1f)
 299                 return -EINVAL;
 300         if (max_voltage < min_voltage
 301             || current_voltage < min_voltage
 302             || current_voltage > max_voltage)
 303                 return -EINVAL;
 304
 305         /* Check for systems using underclocked CPU */
 306         if (!freq_failsafe_off && max_multiplier != current_multiplier) {
 307                 printk(KERN_INFO "eps: Your processor is running at different "
 308                         "frequency then its maximum. Aborting.\n");
 309                 printk(KERN_INFO "eps: You can use freq_failsafe_off option "
 310                         "to disable this check.\n");
 311                 return -EINVAL;
 312         }
 313         if (!voltage_failsafe_off && max_voltage != current_voltage) {
 314                 printk(KERN_INFO "eps: Your processor is running at different "
 315                         "voltage then its maximum. Aborting.\n");
 316                 printk(KERN_INFO "eps: You can use voltage_failsafe_off "
 317                         "option to disable this check.\n");
 318                 return -EINVAL;
 319         }
 320
 321         /* Calc FSB speed */
 322         fsb = cpu_khz / current_multiplier;
 323
 324 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 325         /* Check for ACPI processor speed limit */
 326         if (!ignore_acpi_limit && !eps_acpi_init()) {
 327                 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
 328                         printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
 329                                 limit/1000000,
 330                                 (limit%1000000)/10000);
 331                         eps_acpi_exit(policy);
 332                         /* Check if max_multiplier is in BIOS limits */
 333                         if (limit && max_multiplier * fsb > limit) {
 334                                 printk(KERN_INFO "eps: Aborting.\n");
 335                                 return -EINVAL;
 336                         }
 337                 }
 338         }
 339 #endif
 340
 341         /* Allow user to set lower maximum voltage then that reported
 342          * by processor */
 343         if (brand == EPS_BRAND_C7M && set_max_voltage) {
 344                 u32 v;
 345
 346                 /* Change mV to something hardware can use */
 347                 v = (set_max_voltage - 700) / 16;
 348                 /* Check if voltage is within limits */
 349                 if (v >= min_voltage && v <= max_voltage) {
 350                         printk(KERN_INFO "eps: Setting %dmV as maximum.\n",
 351                                 v * 16 + 700);
 352                         max_voltage = v;
 353                 }
 354         }
 355
 356         /* Calc number of p-states supported */
 357         if (brand == EPS_BRAND_C7M)
 358                 states = max_multiplier - min_multiplier + 1;
 359         else
 360                 states = 2;
 361
 362         /* Allocate private data and frequency table for current cpu */
 363         centaur = kzalloc(sizeof(*centaur)
 364                     + (states + 1) * sizeof(struct cpufreq_frequency_table),
 365                     GFP_KERNEL);
 366         if (!centaur)
 367                 return -ENOMEM;
 368         eps_cpu[0] = centaur;
 369
 370         /* Copy basic values */
 371         centaur->fsb = fsb;
 372 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 373         centaur->bios_limit = limit;
 374 #endif
 375
 376         /* Fill frequency and MSR value table */
 377         f_table = &centaur->freq_table[0];
 378         if (brand != EPS_BRAND_C7M) {
 379                 f_table[0].frequency = fsb * min_multiplier;
 380                 f_table[0].driver_data = (min_multiplier << 8) | min_voltage;
 381                 f_table[1].frequency = fsb * max_multiplier;
 382                 f_table[1].driver_data = (max_multiplier << 8) | max_voltage;
 383                 f_table[2].frequency = CPUFREQ_TABLE_END;
 384         } else {
 385                 k = 0;
 386                 step = ((max_voltage - min_voltage) * 256)
 387                         / (max_multiplier - min_multiplier);
 388                 for (i = min_multiplier; i <= max_multiplier; i++) {
 389                         voltage = (k * step) / 256 + min_voltage;
 390                         f_table[k].frequency = fsb * i;
 391                         f_table[k].driver_data = (i << 8) | voltage;
 392                         k++;
 393                 }
 394                 f_table[k].frequency = CPUFREQ_TABLE_END;
 395         }
 396
 397         policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
 398
 399         ret = cpufreq_table_validate_and_show(policy, &centaur->freq_table[0]);
 400         if (ret) {
 401                 kfree(centaur);
 402                 return ret;
 403         }
 404
 405         return 0;
 406 }
 407
 408 static int eps_cpu_exit(struct cpufreq_policy *policy)
 409 {
 410         unsigned int cpu = policy->cpu;
 411
 412         /* Bye */
 413         cpufreq_frequency_table_put_attr(policy->cpu);
 414         kfree(eps_cpu[cpu]);
 415         eps_cpu[cpu] = NULL;
 416         return 0;
 417 }
 418
 419 static struct cpufreq_driver eps_driver = {
 420         .verify         = cpufreq_generic_frequency_table_verify,
 421         .target         = eps_target,
 422         .init           = eps_cpu_init,
 423         .exit           = eps_cpu_exit,
 424         .get            = eps_get,
 425         .name           = "e_powersaver",
 426         .attr           = cpufreq_generic_attr,
 427 };
 428
 429
 430 /* This driver will work only on Centaur C7 processors with
 431  * Enhanced SpeedStep/PowerSaver registers */
 432 static const struct x86_cpu_id eps_cpu_id[] = {
 433         { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST },
 434         {}
 435 };
 436 MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
 437
 438 static int __init eps_init(void)
 439 {
 440         if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
 441                 return -ENODEV;
 442         if (cpufreq_register_driver(&eps_driver))
 443                 return -EINVAL;
 444         return 0;
 445 }
 446
 447 static void __exit eps_exit(void)
 448 {
 449         cpufreq_unregister_driver(&eps_driver);
 450 }
 451
 452 /* Allow user to overclock his machine or to change frequency to higher after
 453  * unloading module */
 454 module_param(freq_failsafe_off, int, 0644);
 455 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
 456 module_param(voltage_failsafe_off, int, 0644);
 457 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
 458 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 459 module_param(ignore_acpi_limit, int, 0644);
 460 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
 461 #endif
 462 module_param(set_max_voltage, int, 0644);
 463 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
 464
 465 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
 466 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
 467 MODULE_LICENSE("GPL");
 468
 469 module_init(eps_init);
 470 module_exit(eps_exit);