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 = ¢aur->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, ¢aur->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); 442