1 /* 2 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> 3 * 4 * Licensed under the terms of the GNU GPL License version 2. 5 * 6 * Library for common functions for Intel SpeedStep v.1 and v.2 support 7 * 8 * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous* 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/moduleparam.h> 14 #include <linux/init.h> 15 #include <linux/cpufreq.h> 16 17 #include <asm/msr.h> 18 #include <asm/tsc.h> 19 #include "speedstep-lib.h" 20 21 #define PFX "speedstep-lib: " 22 23 #ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK 24 static int relaxed_check; 25 #else 26 #define relaxed_check 0 27 #endif 28 29 /********************************************************************* 30 * GET PROCESSOR CORE SPEED IN KHZ * 31 *********************************************************************/ 32 33 static unsigned int pentium3_get_frequency(enum speedstep_processor processor) 34 { 35 /* See table 14 of p3_ds.pdf and table 22 of 29834003.pdf */ 36 struct { 37 unsigned int ratio; /* Frequency Multiplier (x10) */ 38 u8 bitmap; /* power on configuration bits 39 [27, 25:22] (in MSR 0x2a) */ 40 } msr_decode_mult[] = { 41 { 30, 0x01 }, 42 { 35, 0x05 }, 43 { 40, 0x02 }, 44 { 45, 0x06 }, 45 { 50, 0x00 }, 46 { 55, 0x04 }, 47 { 60, 0x0b }, 48 { 65, 0x0f }, 49 { 70, 0x09 }, 50 { 75, 0x0d }, 51 { 80, 0x0a }, 52 { 85, 0x26 }, 53 { 90, 0x20 }, 54 { 100, 0x2b }, 55 { 0, 0xff } /* error or unknown value */ 56 }; 57 58 /* PIII(-M) FSB settings: see table b1-b of 24547206.pdf */ 59 struct { 60 unsigned int value; /* Front Side Bus speed in MHz */ 61 u8 bitmap; /* power on configuration bits [18: 19] 62 (in MSR 0x2a) */ 63 } msr_decode_fsb[] = { 64 { 66, 0x0 }, 65 { 100, 0x2 }, 66 { 133, 0x1 }, 67 { 0, 0xff} 68 }; 69 70 u32 msr_lo, msr_tmp; 71 int i = 0, j = 0; 72 73 /* read MSR 0x2a - we only need the low 32 bits */ 74 rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp); 75 pr_debug("P3 - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp); 76 msr_tmp = msr_lo; 77 78 /* decode the FSB */ 79 msr_tmp &= 0x00c0000; 80 msr_tmp >>= 18; 81 while (msr_tmp != msr_decode_fsb[i].bitmap) { 82 if (msr_decode_fsb[i].bitmap == 0xff) 83 return 0; 84 i++; 85 } 86 87 /* decode the multiplier */ 88 if (processor == SPEEDSTEP_CPU_PIII_C_EARLY) { 89 pr_debug("workaround for early PIIIs\n"); 90 msr_lo &= 0x03c00000; 91 } else 92 msr_lo &= 0x0bc00000; 93 msr_lo >>= 22; 94 while (msr_lo != msr_decode_mult[j].bitmap) { 95 if (msr_decode_mult[j].bitmap == 0xff) 96 return 0; 97 j++; 98 } 99 100 pr_debug("speed is %u\n", 101 (msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100)); 102 103 return msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100; 104 } 105 106 107 static unsigned int pentiumM_get_frequency(void) 108 { 109 u32 msr_lo, msr_tmp; 110 111 rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp); 112 pr_debug("PM - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp); 113 114 /* see table B-2 of 24547212.pdf */ 115 if (msr_lo & 0x00040000) { 116 printk(KERN_DEBUG PFX "PM - invalid FSB: 0x%x 0x%x\n", 117 msr_lo, msr_tmp); 118 return 0; 119 } 120 121 msr_tmp = (msr_lo >> 22) & 0x1f; 122 pr_debug("bits 22-26 are 0x%x, speed is %u\n", 123 msr_tmp, (msr_tmp * 100 * 1000)); 124 125 return msr_tmp * 100 * 1000; 126 } 127 128 static unsigned int pentium_core_get_frequency(void) 129 { 130 u32 fsb = 0; 131 u32 msr_lo, msr_tmp; 132 int ret; 133 134 rdmsr(MSR_FSB_FREQ, msr_lo, msr_tmp); 135 /* see table B-2 of 25366920.pdf */ 136 switch (msr_lo & 0x07) { 137 case 5: 138 fsb = 100000; 139 break; 140 case 1: 141 fsb = 133333; 142 break; 143 case 3: 144 fsb = 166667; 145 break; 146 case 2: 147 fsb = 200000; 148 break; 149 case 0: 150 fsb = 266667; 151 break; 152 case 4: 153 fsb = 333333; 154 break; 155 default: 156 printk(KERN_ERR "PCORE - MSR_FSB_FREQ undefined value"); 157 } 158 159 rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp); 160 pr_debug("PCORE - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", 161 msr_lo, msr_tmp); 162 163 msr_tmp = (msr_lo >> 22) & 0x1f; 164 pr_debug("bits 22-26 are 0x%x, speed is %u\n", 165 msr_tmp, (msr_tmp * fsb)); 166 167 ret = (msr_tmp * fsb); 168 return ret; 169 } 170 171 172 static unsigned int pentium4_get_frequency(void) 173 { 174 struct cpuinfo_x86 *c = &boot_cpu_data; 175 u32 msr_lo, msr_hi, mult; 176 unsigned int fsb = 0; 177 unsigned int ret; 178 u8 fsb_code; 179 180 /* Pentium 4 Model 0 and 1 do not have the Core Clock Frequency 181 * to System Bus Frequency Ratio Field in the Processor Frequency 182 * Configuration Register of the MSR. Therefore the current 183 * frequency cannot be calculated and has to be measured. 184 */ 185 if (c->x86_model < 2) 186 return cpu_khz; 187 188 rdmsr(0x2c, msr_lo, msr_hi); 189 190 pr_debug("P4 - MSR_EBC_FREQUENCY_ID: 0x%x 0x%x\n", msr_lo, msr_hi); 191 192 /* decode the FSB: see IA-32 Intel (C) Architecture Software 193 * Developer's Manual, Volume 3: System Prgramming Guide, 194 * revision #12 in Table B-1: MSRs in the Pentium 4 and 195 * Intel Xeon Processors, on page B-4 and B-5. 196 */ 197 fsb_code = (msr_lo >> 16) & 0x7; 198 switch (fsb_code) { 199 case 0: 200 fsb = 100 * 1000; 201 break; 202 case 1: 203 fsb = 13333 * 10; 204 break; 205 case 2: 206 fsb = 200 * 1000; 207 break; 208 } 209 210 if (!fsb) 211 printk(KERN_DEBUG PFX "couldn't detect FSB speed. " 212 "Please send an e-mail to <linux@brodo.de>\n"); 213 214 /* Multiplier. */ 215 mult = msr_lo >> 24; 216 217 pr_debug("P4 - FSB %u kHz; Multiplier %u; Speed %u kHz\n", 218 fsb, mult, (fsb * mult)); 219 220 ret = (fsb * mult); 221 return ret; 222 } 223 224 225 /* Warning: may get called from smp_call_function_single. */ 226 unsigned int speedstep_get_frequency(enum speedstep_processor processor) 227 { 228 switch (processor) { 229 case SPEEDSTEP_CPU_PCORE: 230 return pentium_core_get_frequency(); 231 case SPEEDSTEP_CPU_PM: 232 return pentiumM_get_frequency(); 233 case SPEEDSTEP_CPU_P4D: 234 case SPEEDSTEP_CPU_P4M: 235 return pentium4_get_frequency(); 236 case SPEEDSTEP_CPU_PIII_T: 237 case SPEEDSTEP_CPU_PIII_C: 238 case SPEEDSTEP_CPU_PIII_C_EARLY: 239 return pentium3_get_frequency(processor); 240 default: 241 return 0; 242 }; 243 return 0; 244 } 245 EXPORT_SYMBOL_GPL(speedstep_get_frequency); 246 247 248 /********************************************************************* 249 * DETECT SPEEDSTEP-CAPABLE PROCESSOR * 250 *********************************************************************/ 251 252 /* Keep in sync with the x86_cpu_id tables in the different modules */ 253 unsigned int speedstep_detect_processor(void) 254 { 255 struct cpuinfo_x86 *c = &cpu_data(0); 256 u32 ebx, msr_lo, msr_hi; 257 258 pr_debug("x86: %x, model: %x\n", c->x86, c->x86_model); 259 260 if ((c->x86_vendor != X86_VENDOR_INTEL) || 261 ((c->x86 != 6) && (c->x86 != 0xF))) 262 return 0; 263 264 if (c->x86 == 0xF) { 265 /* Intel Mobile Pentium 4-M 266 * or Intel Mobile Pentium 4 with 533 MHz FSB */ 267 if (c->x86_model != 2) 268 return 0; 269 270 ebx = cpuid_ebx(0x00000001); 271 ebx &= 0x000000FF; 272 273 pr_debug("ebx value is %x, x86_mask is %x\n", ebx, c->x86_mask); 274 275 switch (c->x86_mask) { 276 case 4: 277 /* 278 * B-stepping [M-P4-M] 279 * sample has ebx = 0x0f, production has 0x0e. 280 */ 281 if ((ebx == 0x0e) || (ebx == 0x0f)) 282 return SPEEDSTEP_CPU_P4M; 283 break; 284 case 7: 285 /* 286 * C-stepping [M-P4-M] 287 * needs to have ebx=0x0e, else it's a celeron: 288 * cf. 25130917.pdf / page 7, footnote 5 even 289 * though 25072120.pdf / page 7 doesn't say 290 * samples are only of B-stepping... 291 */ 292 if (ebx == 0x0e) 293 return SPEEDSTEP_CPU_P4M; 294 break; 295 case 9: 296 /* 297 * D-stepping [M-P4-M or M-P4/533] 298 * 299 * this is totally strange: CPUID 0x0F29 is 300 * used by M-P4-M, M-P4/533 and(!) Celeron CPUs. 301 * The latter need to be sorted out as they don't 302 * support speedstep. 303 * Celerons with CPUID 0x0F29 may have either 304 * ebx=0x8 or 0xf -- 25130917.pdf doesn't say anything 305 * specific. 306 * M-P4-Ms may have either ebx=0xe or 0xf [see above] 307 * M-P4/533 have either ebx=0xe or 0xf. [25317607.pdf] 308 * also, M-P4M HTs have ebx=0x8, too 309 * For now, they are distinguished by the model_id 310 * string 311 */ 312 if ((ebx == 0x0e) || 313 (strstr(c->x86_model_id, 314 "Mobile Intel(R) Pentium(R) 4") != NULL)) 315 return SPEEDSTEP_CPU_P4M; 316 break; 317 default: 318 break; 319 } 320 return 0; 321 } 322 323 switch (c->x86_model) { 324 case 0x0B: /* Intel PIII [Tualatin] */ 325 /* cpuid_ebx(1) is 0x04 for desktop PIII, 326 * 0x06 for mobile PIII-M */ 327 ebx = cpuid_ebx(0x00000001); 328 pr_debug("ebx is %x\n", ebx); 329 330 ebx &= 0x000000FF; 331 332 if (ebx != 0x06) 333 return 0; 334 335 /* So far all PIII-M processors support SpeedStep. See 336 * Intel's 24540640.pdf of June 2003 337 */ 338 return SPEEDSTEP_CPU_PIII_T; 339 340 case 0x08: /* Intel PIII [Coppermine] */ 341 342 /* all mobile PIII Coppermines have FSB 100 MHz 343 * ==> sort out a few desktop PIIIs. */ 344 rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_hi); 345 pr_debug("Coppermine: MSR_IA32_EBL_CR_POWERON is 0x%x, 0x%x\n", 346 msr_lo, msr_hi); 347 msr_lo &= 0x00c0000; 348 if (msr_lo != 0x0080000) 349 return 0; 350 351 /* 352 * If the processor is a mobile version, 353 * platform ID has bit 50 set 354 * it has SpeedStep technology if either 355 * bit 56 or 57 is set 356 */ 357 rdmsr(MSR_IA32_PLATFORM_ID, msr_lo, msr_hi); 358 pr_debug("Coppermine: MSR_IA32_PLATFORM ID is 0x%x, 0x%x\n", 359 msr_lo, msr_hi); 360 if ((msr_hi & (1<<18)) && 361 (relaxed_check ? 1 : (msr_hi & (3<<24)))) { 362 if (c->x86_mask == 0x01) { 363 pr_debug("early PIII version\n"); 364 return SPEEDSTEP_CPU_PIII_C_EARLY; 365 } else 366 return SPEEDSTEP_CPU_PIII_C; 367 } 368 369 default: 370 return 0; 371 } 372 } 373 EXPORT_SYMBOL_GPL(speedstep_detect_processor); 374 375 376 /********************************************************************* 377 * DETECT SPEEDSTEP SPEEDS * 378 *********************************************************************/ 379 380 unsigned int speedstep_get_freqs(enum speedstep_processor processor, 381 unsigned int *low_speed, 382 unsigned int *high_speed, 383 unsigned int *transition_latency, 384 void (*set_state) (unsigned int state)) 385 { 386 unsigned int prev_speed; 387 unsigned int ret = 0; 388 unsigned long flags; 389 ktime_t tv1, tv2; 390 391 if ((!processor) || (!low_speed) || (!high_speed) || (!set_state)) 392 return -EINVAL; 393 394 pr_debug("trying to determine both speeds\n"); 395 396 /* get current speed */ 397 prev_speed = speedstep_get_frequency(processor); 398 if (!prev_speed) 399 return -EIO; 400 401 pr_debug("previous speed is %u\n", prev_speed); 402 403 preempt_disable(); 404 local_irq_save(flags); 405 406 /* switch to low state */ 407 set_state(SPEEDSTEP_LOW); 408 *low_speed = speedstep_get_frequency(processor); 409 if (!*low_speed) { 410 ret = -EIO; 411 goto out; 412 } 413 414 pr_debug("low speed is %u\n", *low_speed); 415 416 /* start latency measurement */ 417 if (transition_latency) 418 tv1 = ktime_get(); 419 420 /* switch to high state */ 421 set_state(SPEEDSTEP_HIGH); 422 423 /* end latency measurement */ 424 if (transition_latency) 425 tv2 = ktime_get(); 426 427 *high_speed = speedstep_get_frequency(processor); 428 if (!*high_speed) { 429 ret = -EIO; 430 goto out; 431 } 432 433 pr_debug("high speed is %u\n", *high_speed); 434 435 if (*low_speed == *high_speed) { 436 ret = -ENODEV; 437 goto out; 438 } 439 440 /* switch to previous state, if necessary */ 441 if (*high_speed != prev_speed) 442 set_state(SPEEDSTEP_LOW); 443 444 if (transition_latency) { 445 *transition_latency = ktime_to_us(ktime_sub(tv2, tv1)); 446 pr_debug("transition latency is %u uSec\n", *transition_latency); 447 448 /* convert uSec to nSec and add 20% for safety reasons */ 449 *transition_latency *= 1200; 450 451 /* check if the latency measurement is too high or too low 452 * and set it to a safe value (500uSec) in that case 453 */ 454 if (*transition_latency > 10000000 || 455 *transition_latency < 50000) { 456 printk(KERN_WARNING PFX "frequency transition " 457 "measured seems out of range (%u " 458 "nSec), falling back to a safe one of" 459 "%u nSec.\n", 460 *transition_latency, 500000); 461 *transition_latency = 500000; 462 } 463 } 464 465 out: 466 local_irq_restore(flags); 467 preempt_enable(); 468 469 return ret; 470 } 471 EXPORT_SYMBOL_GPL(speedstep_get_freqs); 472 473 #ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK 474 module_param(relaxed_check, int, 0444); 475 MODULE_PARM_DESC(relaxed_check, 476 "Don't do all checks for speedstep capability."); 477 #endif 478 479 MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>"); 480 MODULE_DESCRIPTION("Library for Intel SpeedStep 1 or 2 cpufreq drivers."); 481 MODULE_LICENSE("GPL"); 482