/* * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> * * Licensed under the terms of the GNU GPL License version 2. * * Library for common functions for Intel SpeedStep v.1 and v.2 support * * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous* */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/init.h> #include <linux/cpufreq.h> #include <asm/msr.h> #include <asm/tsc.h> #include "speedstep-lib.h" #define PFX "speedstep-lib: " #ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK static int relaxed_check; #else #define relaxed_check 0 #endif /********************************************************************* * GET PROCESSOR CORE SPEED IN KHZ * *********************************************************************/ static unsigned int pentium3_get_frequency(enum speedstep_processor processor) { /* See table 14 of p3_ds.pdf and table 22 of 29834003.pdf */ struct { unsigned int ratio; /* Frequency Multiplier (x10) */ u8 bitmap; /* power on configuration bits [27, 25:22] (in MSR 0x2a) */ } msr_decode_mult[] = { { 30, 0x01 }, { 35, 0x05 }, { 40, 0x02 }, { 45, 0x06 }, { 50, 0x00 }, { 55, 0x04 }, { 60, 0x0b }, { 65, 0x0f }, { 70, 0x09 }, { 75, 0x0d }, { 80, 0x0a }, { 85, 0x26 }, { 90, 0x20 }, { 100, 0x2b }, { 0, 0xff } /* error or unknown value */ }; /* PIII(-M) FSB settings: see table b1-b of 24547206.pdf */ struct { unsigned int value; /* Front Side Bus speed in MHz */ u8 bitmap; /* power on configuration bits [18: 19] (in MSR 0x2a) */ } msr_decode_fsb[] = { { 66, 0x0 }, { 100, 0x2 }, { 133, 0x1 }, { 0, 0xff} }; u32 msr_lo, msr_tmp; int i = 0, j = 0; /* read MSR 0x2a - we only need the low 32 bits */ rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp); pr_debug("P3 - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp); msr_tmp = msr_lo; /* decode the FSB */ msr_tmp &= 0x00c0000; msr_tmp >>= 18; while (msr_tmp != msr_decode_fsb[i].bitmap) { if (msr_decode_fsb[i].bitmap == 0xff) return 0; i++; } /* decode the multiplier */ if (processor == SPEEDSTEP_CPU_PIII_C_EARLY) { pr_debug("workaround for early PIIIs\n"); msr_lo &= 0x03c00000; } else msr_lo &= 0x0bc00000; msr_lo >>= 22; while (msr_lo != msr_decode_mult[j].bitmap) { if (msr_decode_mult[j].bitmap == 0xff) return 0; j++; } pr_debug("speed is %u\n", (msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100)); return msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100; } static unsigned int pentiumM_get_frequency(void) { u32 msr_lo, msr_tmp; rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp); pr_debug("PM - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp); /* see table B-2 of 24547212.pdf */ if (msr_lo & 0x00040000) { printk(KERN_DEBUG PFX "PM - invalid FSB: 0x%x 0x%x\n", msr_lo, msr_tmp); return 0; } msr_tmp = (msr_lo >> 22) & 0x1f; pr_debug("bits 22-26 are 0x%x, speed is %u\n", msr_tmp, (msr_tmp * 100 * 1000)); return msr_tmp * 100 * 1000; } static unsigned int pentium_core_get_frequency(void) { u32 fsb = 0; u32 msr_lo, msr_tmp; int ret; rdmsr(MSR_FSB_FREQ, msr_lo, msr_tmp); /* see table B-2 of 25366920.pdf */ switch (msr_lo & 0x07) { case 5: fsb = 100000; break; case 1: fsb = 133333; break; case 3: fsb = 166667; break; case 2: fsb = 200000; break; case 0: fsb = 266667; break; case 4: fsb = 333333; break; default: printk(KERN_ERR "PCORE - MSR_FSB_FREQ undefined value"); } rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp); pr_debug("PCORE - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp); msr_tmp = (msr_lo >> 22) & 0x1f; pr_debug("bits 22-26 are 0x%x, speed is %u\n", msr_tmp, (msr_tmp * fsb)); ret = (msr_tmp * fsb); return ret; } static unsigned int pentium4_get_frequency(void) { struct cpuinfo_x86 *c = &boot_cpu_data; u32 msr_lo, msr_hi, mult; unsigned int fsb = 0; unsigned int ret; u8 fsb_code; /* Pentium 4 Model 0 and 1 do not have the Core Clock Frequency * to System Bus Frequency Ratio Field in the Processor Frequency * Configuration Register of the MSR. Therefore the current * frequency cannot be calculated and has to be measured. */ if (c->x86_model < 2) return cpu_khz; rdmsr(0x2c, msr_lo, msr_hi); pr_debug("P4 - MSR_EBC_FREQUENCY_ID: 0x%x 0x%x\n", msr_lo, msr_hi); /* decode the FSB: see IA-32 Intel (C) Architecture Software * Developer's Manual, Volume 3: System Prgramming Guide, * revision #12 in Table B-1: MSRs in the Pentium 4 and * Intel Xeon Processors, on page B-4 and B-5. */ fsb_code = (msr_lo >> 16) & 0x7; switch (fsb_code) { case 0: fsb = 100 * 1000; break; case 1: fsb = 13333 * 10; break; case 2: fsb = 200 * 1000; break; } if (!fsb) printk(KERN_DEBUG PFX "couldn't detect FSB speed. " "Please send an e-mail to <linux@brodo.de>\n"); /* Multiplier. */ mult = msr_lo >> 24; pr_debug("P4 - FSB %u kHz; Multiplier %u; Speed %u kHz\n", fsb, mult, (fsb * mult)); ret = (fsb * mult); return ret; } /* Warning: may get called from smp_call_function_single. */ unsigned int speedstep_get_frequency(enum speedstep_processor processor) { switch (processor) { case SPEEDSTEP_CPU_PCORE: return pentium_core_get_frequency(); case SPEEDSTEP_CPU_PM: return pentiumM_get_frequency(); case SPEEDSTEP_CPU_P4D: case SPEEDSTEP_CPU_P4M: return pentium4_get_frequency(); case SPEEDSTEP_CPU_PIII_T: case SPEEDSTEP_CPU_PIII_C: case SPEEDSTEP_CPU_PIII_C_EARLY: return pentium3_get_frequency(processor); default: return 0; }; return 0; } EXPORT_SYMBOL_GPL(speedstep_get_frequency); /********************************************************************* * DETECT SPEEDSTEP-CAPABLE PROCESSOR * *********************************************************************/ /* Keep in sync with the x86_cpu_id tables in the different modules */ unsigned int speedstep_detect_processor(void) { struct cpuinfo_x86 *c = &cpu_data(0); u32 ebx, msr_lo, msr_hi; pr_debug("x86: %x, model: %x\n", c->x86, c->x86_model); if ((c->x86_vendor != X86_VENDOR_INTEL) || ((c->x86 != 6) && (c->x86 != 0xF))) return 0; if (c->x86 == 0xF) { /* Intel Mobile Pentium 4-M * or Intel Mobile Pentium 4 with 533 MHz FSB */ if (c->x86_model != 2) return 0; ebx = cpuid_ebx(0x00000001); ebx &= 0x000000FF; pr_debug("ebx value is %x, x86_mask is %x\n", ebx, c->x86_mask); switch (c->x86_mask) { case 4: /* * B-stepping [M-P4-M] * sample has ebx = 0x0f, production has 0x0e. */ if ((ebx == 0x0e) || (ebx == 0x0f)) return SPEEDSTEP_CPU_P4M; break; case 7: /* * C-stepping [M-P4-M] * needs to have ebx=0x0e, else it's a celeron: * cf. 25130917.pdf / page 7, footnote 5 even * though 25072120.pdf / page 7 doesn't say * samples are only of B-stepping... */ if (ebx == 0x0e) return SPEEDSTEP_CPU_P4M; break; case 9: /* * D-stepping [M-P4-M or M-P4/533] * * this is totally strange: CPUID 0x0F29 is * used by M-P4-M, M-P4/533 and(!) Celeron CPUs. * The latter need to be sorted out as they don't * support speedstep. * Celerons with CPUID 0x0F29 may have either * ebx=0x8 or 0xf -- 25130917.pdf doesn't say anything * specific. * M-P4-Ms may have either ebx=0xe or 0xf [see above] * M-P4/533 have either ebx=0xe or 0xf. [25317607.pdf] * also, M-P4M HTs have ebx=0x8, too * For now, they are distinguished by the model_id * string */ if ((ebx == 0x0e) || (strstr(c->x86_model_id, "Mobile Intel(R) Pentium(R) 4") != NULL)) return SPEEDSTEP_CPU_P4M; break; default: break; } return 0; } switch (c->x86_model) { case 0x0B: /* Intel PIII [Tualatin] */ /* cpuid_ebx(1) is 0x04 for desktop PIII, * 0x06 for mobile PIII-M */ ebx = cpuid_ebx(0x00000001); pr_debug("ebx is %x\n", ebx); ebx &= 0x000000FF; if (ebx != 0x06) return 0; /* So far all PIII-M processors support SpeedStep. See * Intel's 24540640.pdf of June 2003 */ return SPEEDSTEP_CPU_PIII_T; case 0x08: /* Intel PIII [Coppermine] */ /* all mobile PIII Coppermines have FSB 100 MHz * ==> sort out a few desktop PIIIs. */ rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_hi); pr_debug("Coppermine: MSR_IA32_EBL_CR_POWERON is 0x%x, 0x%x\n", msr_lo, msr_hi); msr_lo &= 0x00c0000; if (msr_lo != 0x0080000) return 0; /* * If the processor is a mobile version, * platform ID has bit 50 set * it has SpeedStep technology if either * bit 56 or 57 is set */ rdmsr(MSR_IA32_PLATFORM_ID, msr_lo, msr_hi); pr_debug("Coppermine: MSR_IA32_PLATFORM ID is 0x%x, 0x%x\n", msr_lo, msr_hi); if ((msr_hi & (1<<18)) && (relaxed_check ? 1 : (msr_hi & (3<<24)))) { if (c->x86_mask == 0x01) { pr_debug("early PIII version\n"); return SPEEDSTEP_CPU_PIII_C_EARLY; } else return SPEEDSTEP_CPU_PIII_C; } default: return 0; } } EXPORT_SYMBOL_GPL(speedstep_detect_processor); /********************************************************************* * DETECT SPEEDSTEP SPEEDS * *********************************************************************/ unsigned int speedstep_get_freqs(enum speedstep_processor processor, unsigned int *low_speed, unsigned int *high_speed, unsigned int *transition_latency, void (*set_state) (unsigned int state)) { unsigned int prev_speed; unsigned int ret = 0; unsigned long flags; struct timeval tv1, tv2; if ((!processor) || (!low_speed) || (!high_speed) || (!set_state)) return -EINVAL; pr_debug("trying to determine both speeds\n"); /* get current speed */ prev_speed = speedstep_get_frequency(processor); if (!prev_speed) return -EIO; pr_debug("previous speed is %u\n", prev_speed); local_irq_save(flags); /* switch to low state */ set_state(SPEEDSTEP_LOW); *low_speed = speedstep_get_frequency(processor); if (!*low_speed) { ret = -EIO; goto out; } pr_debug("low speed is %u\n", *low_speed); /* start latency measurement */ if (transition_latency) do_gettimeofday(&tv1); /* switch to high state */ set_state(SPEEDSTEP_HIGH); /* end latency measurement */ if (transition_latency) do_gettimeofday(&tv2); *high_speed = speedstep_get_frequency(processor); if (!*high_speed) { ret = -EIO; goto out; } pr_debug("high speed is %u\n", *high_speed); if (*low_speed == *high_speed) { ret = -ENODEV; goto out; } /* switch to previous state, if necessary */ if (*high_speed != prev_speed) set_state(SPEEDSTEP_LOW); if (transition_latency) { *transition_latency = (tv2.tv_sec - tv1.tv_sec) * USEC_PER_SEC + tv2.tv_usec - tv1.tv_usec; pr_debug("transition latency is %u uSec\n", *transition_latency); /* convert uSec to nSec and add 20% for safety reasons */ *transition_latency *= 1200; /* check if the latency measurement is too high or too low * and set it to a safe value (500uSec) in that case */ if (*transition_latency > 10000000 || *transition_latency < 50000) { printk(KERN_WARNING PFX "frequency transition " "measured seems out of range (%u " "nSec), falling back to a safe one of" "%u nSec.\n", *transition_latency, 500000); *transition_latency = 500000; } } out: local_irq_restore(flags); return ret; } EXPORT_SYMBOL_GPL(speedstep_get_freqs); #ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK module_param(relaxed_check, int, 0444); MODULE_PARM_DESC(relaxed_check, "Don't do all checks for speedstep capability."); #endif MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>"); MODULE_DESCRIPTION("Library for Intel SpeedStep 1 or 2 cpufreq drivers."); MODULE_LICENSE("GPL");