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