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(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         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
 154 static 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
 173 static 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
 380 static 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
 390 static 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 */
 403 static const struct x86_cpu_id eps_cpu_id[] = {
 404         { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST },
 405         {}
 406 };
 407 MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
 408
 409 static 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
 418 static 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 */
 425 module_param(freq_failsafe_off, int, 0644);
 426 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
 427 module_param(voltage_failsafe_off, int, 0644);
 428 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
 429 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 430 module_param(ignore_acpi_limit, int, 0644);
 431 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
 432 #endif
 433 module_param(set_max_voltage, int, 0644);
 434 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
 435
 436 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
 437 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
 438 MODULE_LICENSE("GPL");
 439
 440 module_init(eps_init);
 441 module_exit(eps_exit);