Pileus Git - ~andy/linux/blob - 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
  47 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
  48 static int ignore_acpi_limit;
  49
  50 static struct acpi_processor_performance *eps_acpi_cpu_perf;
  51
  52 /* Minimum necessary to get acpi_processor_get_bios_limit() working */
  53 static int eps_acpi_init(void)
  54 {
  55         eps_acpi_cpu_perf = kzalloc(sizeof(struct acpi_processor_performance),
  56                                       GFP_KERNEL);
  57         if (!eps_acpi_cpu_perf)
  58                 return -ENOMEM;
  59
  60         if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
  61                                                                 GFP_KERNEL)) {
  62                 kfree(eps_acpi_cpu_perf);
  63                 eps_acpi_cpu_perf = NULL;
  64                 return -ENOMEM;
  65         }
  66
  67         if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
  68                 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
  69                 kfree(eps_acpi_cpu_perf);
  70                 eps_acpi_cpu_perf = NULL;
  71                 return -EIO;
  72         }
  73         return 0;
  74 }
  75
  76 static int eps_acpi_exit(struct cpufreq_policy *policy)
  77 {
  78         if (eps_acpi_cpu_perf) {
  79                 acpi_processor_unregister_performance(eps_acpi_cpu_perf, 0);
  80                 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
  81                 kfree(eps_acpi_cpu_perf);
  82                 eps_acpi_cpu_perf = NULL;
  83         }
  84         return 0;
  85 }
  86 #endif
  87
  88 static unsigned int eps_get(unsigned int cpu)
  89 {
  90         struct eps_cpu_data *centaur;
  91         u32 lo, hi;
  92
  93         if (cpu)
  94                 return 0;
  95         centaur = eps_cpu[cpu];
  96         if (centaur == NULL)
  97                 return 0;
  98
  99         /* Return current frequency */
 100         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 101         return centaur->fsb * ((lo >> 8) & 0xff);
 102 }
 103
 104 static int eps_set_state(struct eps_cpu_data *centaur,
 105                          unsigned int cpu,
 106                          u32 dest_state)
 107 {
 108         struct cpufreq_freqs freqs;
 109         u32 lo, hi;
 110         int err = 0;
 111         int i;
 112
 113         freqs.old = eps_get(cpu);
 114         freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
 115         freqs.cpu = cpu;
 116         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 117
 118         /* Wait while CPU is busy */
 119         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 120         i = 0;
 121         while (lo & ((1 << 16) | (1 << 17))) {
 122                 udelay(16);
 123                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 124                 i++;
 125                 if (unlikely(i > 64)) {
 126                         err = -ENODEV;
 127                         goto postchange;
 128                 }
 129         }
 130         /* Set new multiplier and voltage */
 131         wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
 132         /* Wait until transition end */
 133         i = 0;
 134         do {
 135                 udelay(16);
 136                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 137                 i++;
 138                 if (unlikely(i > 64)) {
 139                         err = -ENODEV;
 140                         goto postchange;
 141                 }
 142         } while (lo & ((1 << 16) | (1 << 17)));
 143
 144         /* Return current frequency */
 145 postchange:
 146         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 147         freqs.new = centaur->fsb * ((lo >> 8) & 0xff);
 148
 149 #ifdef DEBUG
 150         {
 151         u8 current_multiplier, current_voltage;
 152
 153         /* Print voltage and multiplier */
 154         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 155         current_voltage = lo & 0xff;
 156         printk(KERN_INFO "eps: Current voltage = %dmV\n",
 157                 current_voltage * 16 + 700);
 158         current_multiplier = (lo >> 8) & 0xff;
 159         printk(KERN_INFO "eps: Current multiplier = %d\n",
 160                 current_multiplier);
 161         }
 162 #endif
 163         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 164         return err;
 165 }
 166
 167 static int eps_target(struct cpufreq_policy *policy,
 168                                unsigned int target_freq,
 169                                unsigned int relation)
 170 {
 171         struct eps_cpu_data *centaur;
 172         unsigned int newstate = 0;
 173         unsigned int cpu = policy->cpu;
 174         unsigned int dest_state;
 175         int ret;
 176
 177         if (unlikely(eps_cpu[cpu] == NULL))
 178                 return -ENODEV;
 179         centaur = eps_cpu[cpu];
 180
 181         if (unlikely(cpufreq_frequency_table_target(policy,
 182                         &eps_cpu[cpu]->freq_table[0],
 183                         target_freq,
 184                         relation,
 185                         &newstate))) {
 186                 return -EINVAL;
 187         }
 188
 189         /* Make frequency transition */
 190         dest_state = centaur->freq_table[newstate].index & 0xffff;
 191         ret = eps_set_state(centaur, cpu, dest_state);
 192         if (ret)
 193                 printk(KERN_ERR "eps: Timeout!\n");
 194         return ret;
 195 }
 196
 197 static int eps_verify(struct cpufreq_policy *policy)
 198 {
 199         return cpufreq_frequency_table_verify(policy,
 200                         &eps_cpu[policy->cpu]->freq_table[0]);
 201 }
 202
 203 static int eps_cpu_init(struct cpufreq_policy *policy)
 204 {
 205         unsigned int i;
 206         u32 lo, hi;
 207         u64 val;
 208         u8 current_multiplier, current_voltage;
 209         u8 max_multiplier, max_voltage;
 210         u8 min_multiplier, min_voltage;
 211         u8 brand = 0;
 212         u32 fsb;
 213         struct eps_cpu_data *centaur;
 214         struct cpuinfo_x86 *c = &cpu_data(0);
 215         struct cpufreq_frequency_table *f_table;
 216         int k, step, voltage;
 217         int ret;
 218         int states;
 219 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 220         unsigned int limit;
 221 #endif
 222
 223         if (policy->cpu != 0)
 224                 return -ENODEV;
 225
 226         /* Check brand */
 227         printk(KERN_INFO "eps: Detected VIA ");
 228
 229         switch (c->x86_model) {
 230         case 10:
 231                 rdmsr(0x1153, lo, hi);
 232                 brand = (((lo >> 2) ^ lo) >> 18) & 3;
 233                 printk(KERN_CONT "Model A ");
 234                 break;
 235         case 13:
 236                 rdmsr(0x1154, lo, hi);
 237                 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
 238                 printk(KERN_CONT "Model D ");
 239                 break;
 240         }
 241
 242         switch (brand) {
 243         case EPS_BRAND_C7M:
 244                 printk(KERN_CONT "C7-M\n");
 245                 break;
 246         case EPS_BRAND_C7:
 247                 printk(KERN_CONT "C7\n");
 248                 break;
 249         case EPS_BRAND_EDEN:
 250                 printk(KERN_CONT "Eden\n");
 251                 break;
 252         case EPS_BRAND_C7D:
 253                 printk(KERN_CONT "C7-D\n");
 254                 break;
 255         case EPS_BRAND_C3:
 256                 printk(KERN_CONT "C3\n");
 257                 return -ENODEV;
 258                 break;
 259         }
 260         /* Enable Enhanced PowerSaver */
 261         rdmsrl(MSR_IA32_MISC_ENABLE, val);
 262         if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 263                 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
 264                 wrmsrl(MSR_IA32_MISC_ENABLE, val);
 265                 /* Can be locked at 0 */
 266                 rdmsrl(MSR_IA32_MISC_ENABLE, val);
 267                 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
 268                         printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
 269                         return -ENODEV;
 270                 }
 271         }
 272
 273         /* Print voltage and multiplier */
 274         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
 275         current_voltage = lo & 0xff;
 276         printk(KERN_INFO "eps: Current voltage = %dmV\n",
 277                         current_voltage * 16 + 700);
 278         current_multiplier = (lo >> 8) & 0xff;
 279         printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
 280
 281         /* Print limits */
 282         max_voltage = hi & 0xff;
 283         printk(KERN_INFO "eps: Highest voltage = %dmV\n",
 284                         max_voltage * 16 + 700);
 285         max_multiplier = (hi >> 8) & 0xff;
 286         printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
 287         min_voltage = (hi >> 16) & 0xff;
 288         printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
 289                         min_voltage * 16 + 700);
 290         min_multiplier = (hi >> 24) & 0xff;
 291         printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
 292
 293         /* Sanity checks */
 294         if (current_multiplier == 0 || max_multiplier == 0
 295             || min_multiplier == 0)
 296                 return -EINVAL;
 297         if (current_multiplier > max_multiplier
 298             || max_multiplier <= min_multiplier)
 299                 return -EINVAL;
 300         if (current_voltage > 0x1f || max_voltage > 0x1f)
 301                 return -EINVAL;
 302         if (max_voltage < min_voltage
 303             || current_voltage < min_voltage
 304             || current_voltage > max_voltage)
 305                 return -EINVAL;
 306
 307         /* Check for systems using underclocked CPU */
 308         if (!freq_failsafe_off && max_multiplier != current_multiplier) {
 309                 printk(KERN_INFO "eps: Your processor is running at different "
 310                         "frequency then its maximum. Aborting.\n");
 311                 printk(KERN_INFO "eps: You can use freq_failsafe_off option "
 312                         "to disable this check.\n");
 313                 return -EINVAL;
 314         }
 315         if (!voltage_failsafe_off && max_voltage != current_voltage) {
 316                 printk(KERN_INFO "eps: Your processor is running at different "
 317                         "voltage then its maximum. Aborting.\n");
 318                 printk(KERN_INFO "eps: You can use voltage_failsafe_off "
 319                         "option to disable this check.\n");
 320                 return -EINVAL;
 321         }
 322
 323         /* Calc FSB speed */
 324         fsb = cpu_khz / current_multiplier;
 325
 326 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 327         /* Check for ACPI processor speed limit */
 328         if (!ignore_acpi_limit && !eps_acpi_init()) {
 329                 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
 330                         printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
 331                                 limit/1000000,
 332                                 (limit%1000000)/10000);
 333                         eps_acpi_exit(policy);
 334                         /* Check if max_multiplier is in BIOS limits */
 335                         if (limit && max_multiplier * fsb > limit) {
 336                                 printk(KERN_INFO "eps: Aborting.\n");
 337                                 return -EINVAL;
 338                         }
 339                 }
 340         }
 341 #endif
 342
 343         /* Calc number of p-states supported */
 344         if (brand == EPS_BRAND_C7M)
 345                 states = max_multiplier - min_multiplier + 1;
 346         else
 347                 states = 2;
 348
 349         /* Allocate private data and frequency table for current cpu */
 350         centaur = kzalloc(sizeof(struct eps_cpu_data)
 351                     + (states + 1) * sizeof(struct cpufreq_frequency_table),
 352                     GFP_KERNEL);
 353         if (!centaur)
 354                 return -ENOMEM;
 355         eps_cpu[0] = centaur;
 356
 357         /* Copy basic values */
 358         centaur->fsb = fsb;
 359 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 360         centaur->bios_limit = limit;
 361 #endif
 362
 363         /* Fill frequency and MSR value table */
 364         f_table = &centaur->freq_table[0];
 365         if (brand != EPS_BRAND_C7M) {
 366                 f_table[0].frequency = fsb * min_multiplier;
 367                 f_table[0].index = (min_multiplier << 8) | min_voltage;
 368                 f_table[1].frequency = fsb * max_multiplier;
 369                 f_table[1].index = (max_multiplier << 8) | max_voltage;
 370                 f_table[2].frequency = CPUFREQ_TABLE_END;
 371         } else {
 372                 k = 0;
 373                 step = ((max_voltage - min_voltage) * 256)
 374                         / (max_multiplier - min_multiplier);
 375                 for (i = min_multiplier; i <= max_multiplier; i++) {
 376                         voltage = (k * step) / 256 + min_voltage;
 377                         f_table[k].frequency = fsb * i;
 378                         f_table[k].index = (i << 8) | voltage;
 379                         k++;
 380                 }
 381                 f_table[k].frequency = CPUFREQ_TABLE_END;
 382         }
 383
 384         policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
 385         policy->cur = fsb * current_multiplier;
 386
 387         ret = cpufreq_frequency_table_cpuinfo(policy, &centaur->freq_table[0]);
 388         if (ret) {
 389                 kfree(centaur);
 390                 return ret;
 391         }
 392
 393         cpufreq_frequency_table_get_attr(&centaur->freq_table[0], policy->cpu);
 394         return 0;
 395 }
 396
 397 static int eps_cpu_exit(struct cpufreq_policy *policy)
 398 {
 399         unsigned int cpu = policy->cpu;
 400
 401         /* Bye */
 402         cpufreq_frequency_table_put_attr(policy->cpu);
 403         kfree(eps_cpu[cpu]);
 404         eps_cpu[cpu] = NULL;
 405         return 0;
 406 }
 407
 408 static struct freq_attr *eps_attr[] = {
 409         &cpufreq_freq_attr_scaling_available_freqs,
 410         NULL,
 411 };
 412
 413 static struct cpufreq_driver eps_driver = {
 414         .verify         = eps_verify,
 415         .target         = eps_target,
 416         .init           = eps_cpu_init,
 417         .exit           = eps_cpu_exit,
 418         .get            = eps_get,
 419         .name           = "e_powersaver",
 420         .owner          = THIS_MODULE,
 421         .attr           = eps_attr,
 422 };
 423
 424 static int __init eps_init(void)
 425 {
 426         struct cpuinfo_x86 *c = &cpu_data(0);
 427
 428         /* This driver will work only on Centaur C7 processors with
 429          * Enhanced SpeedStep/PowerSaver registers */
 430         if (c->x86_vendor != X86_VENDOR_CENTAUR
 431             || c->x86 != 6 || c->x86_model < 10)
 432                 return -ENODEV;
 433         if (!cpu_has(c, X86_FEATURE_EST))
 434                 return -ENODEV;
 435
 436         if (cpufreq_register_driver(&eps_driver))
 437                 return -EINVAL;
 438         return 0;
 439 }
 440
 441 static void __exit eps_exit(void)
 442 {
 443         cpufreq_unregister_driver(&eps_driver);
 444 }
 445
 446 /* Allow user to overclock his machine or to change frequency to higher after
 447  * unloading module */
 448 module_param(freq_failsafe_off, int, 0644);
 449 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
 450 module_param(voltage_failsafe_off, int, 0644);
 451 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
 452 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
 453 module_param(ignore_acpi_limit, int, 0644);
 454 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
 455 #endif
 456
 457 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
 458 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
 459 MODULE_LICENSE("GPL");
 460
 461 module_init(eps_init);
 462 module_exit(eps_exit);