1a10760c91
The attached patch introduces runtime latency measurement for ICH[234] based chipsets instead of using CPUFREQ_ETERNAL. It includes some sanity checks in case the measured value is out of range and assigns a safe value of 500uSec that should still be enough on problematics chipsets (current testing report values ~200uSec). The measurement is currently done in speedstep_get_freqs in order to avoid further unnecessary transitions and in the hope it'll come handy for SMI also. Signed-off-by: Mattia Dongili <malattia@linux.it> Acked-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Dave Jones <davej@redhat.com> speedstep-ich.c | 4 ++-- speedstep-lib.c | 32 +++++++++++++++++++++++++++++++- speedstep-lib.h | 1 + speedstep-smi.c | 1 + 4 files changed, 35 insertions(+), 3 deletions(-)
429 lines
11 KiB
C
429 lines
11 KiB
C
/*
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* Intel SpeedStep SMI driver.
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*
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* (C) 2003 Hiroshi Miura <miura@da-cha.org>
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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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*/
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/*********************************************************************
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* SPEEDSTEP - DEFINITIONS *
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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 <linux/pci.h>
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#include <linux/slab.h>
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#include <linux/delay.h>
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#include <asm/ist.h>
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#include "speedstep-lib.h"
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/* speedstep system management interface port/command.
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*
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* These parameters are got from IST-SMI BIOS call.
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* If user gives it, these are used.
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*
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*/
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static int smi_port = 0;
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static int smi_cmd = 0;
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static unsigned int smi_sig = 0;
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/* info about the processor */
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static unsigned int speedstep_processor = 0;
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/*
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* There are only two frequency states for each processor. Values
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* are in kHz for the time being.
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*/
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static struct cpufreq_frequency_table speedstep_freqs[] = {
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{SPEEDSTEP_HIGH, 0},
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{SPEEDSTEP_LOW, 0},
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{0, CPUFREQ_TABLE_END},
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};
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#define GET_SPEEDSTEP_OWNER 0
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#define GET_SPEEDSTEP_STATE 1
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#define SET_SPEEDSTEP_STATE 2
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#define GET_SPEEDSTEP_FREQS 4
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/* how often shall the SMI call be tried if it failed, e.g. because
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* of DMA activity going on? */
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#define SMI_TRIES 5
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#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "speedstep-smi", msg)
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/**
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* speedstep_smi_ownership
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*/
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static int speedstep_smi_ownership (void)
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{
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u32 command, result, magic;
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u32 function = GET_SPEEDSTEP_OWNER;
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unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
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command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
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magic = virt_to_phys(magic_data);
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dprintk("trying to obtain ownership with command %x at port %x\n", command, smi_port);
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__asm__ __volatile__(
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"out %%al, (%%dx)\n"
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: "=D" (result)
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: "a" (command), "b" (function), "c" (0), "d" (smi_port), "D" (0), "S" (magic)
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);
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dprintk("result is %x\n", result);
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return result;
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}
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/**
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* speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
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* @low: the low frequency value is placed here
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* @high: the high frequency value is placed here
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*
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* Only available on later SpeedStep-enabled systems, returns false results or
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* even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
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* shows that the latter occurs if !(ist_info.event & 0xFFFF).
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*/
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static int speedstep_smi_get_freqs (unsigned int *low, unsigned int *high)
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{
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u32 command, result = 0, edi, high_mhz, low_mhz;
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u32 state=0;
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u32 function = GET_SPEEDSTEP_FREQS;
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if (!(ist_info.event & 0xFFFF)) {
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dprintk("bug #1422 -- can't read freqs from BIOS\n");
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return -ENODEV;
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}
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command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
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dprintk("trying to determine frequencies with command %x at port %x\n", command, smi_port);
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__asm__ __volatile__("movl $0, %%edi\n"
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"out %%al, (%%dx)\n"
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: "=a" (result), "=b" (high_mhz), "=c" (low_mhz), "=d" (state), "=D" (edi)
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: "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)
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);
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dprintk("result %x, low_freq %u, high_freq %u\n", result, low_mhz, high_mhz);
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/* abort if results are obviously incorrect... */
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if ((high_mhz + low_mhz) < 600)
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return -EINVAL;
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*high = high_mhz * 1000;
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*low = low_mhz * 1000;
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return result;
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}
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/**
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* speedstep_get_state - set the SpeedStep state
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* @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
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*
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*/
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static int speedstep_get_state (void)
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{
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u32 function=GET_SPEEDSTEP_STATE;
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u32 result, state, edi, command;
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command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
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dprintk("trying to determine current setting with command %x at port %x\n", command, smi_port);
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__asm__ __volatile__("movl $0, %%edi\n"
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"out %%al, (%%dx)\n"
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: "=a" (result), "=b" (state), "=D" (edi)
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: "a" (command), "b" (function), "c" (0), "d" (smi_port), "S" (0)
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);
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dprintk("state is %x, result is %x\n", state, result);
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return (state & 1);
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}
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/**
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* speedstep_set_state - set the SpeedStep state
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* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
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*
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*/
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static void speedstep_set_state (unsigned int state)
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{
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unsigned int result = 0, command, new_state;
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unsigned long flags;
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unsigned int function=SET_SPEEDSTEP_STATE;
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unsigned int retry = 0;
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if (state > 0x1)
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return;
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/* Disable IRQs */
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local_irq_save(flags);
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command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
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dprintk("trying to set frequency to state %u with command %x at port %x\n", state, command, smi_port);
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do {
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if (retry) {
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dprintk("retry %u, previous result %u, waiting...\n", retry, result);
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mdelay(retry * 50);
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}
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retry++;
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__asm__ __volatile__(
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"movl $0, %%edi\n"
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"out %%al, (%%dx)\n"
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: "=b" (new_state), "=D" (result)
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: "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0)
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);
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} while ((new_state != state) && (retry <= SMI_TRIES));
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/* enable IRQs */
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local_irq_restore(flags);
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if (new_state == state) {
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dprintk("change to %u MHz succeeded after %u tries with result %u\n", (speedstep_freqs[new_state].frequency / 1000), retry, result);
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} else {
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printk(KERN_ERR "cpufreq: change failed with new_state %u and result %u\n", new_state, result);
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}
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return;
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}
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/**
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* speedstep_target - set a new CPUFreq policy
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* @policy: new policy
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* @target_freq: new freq
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* @relation:
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*
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* Sets a new CPUFreq policy/freq.
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*/
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static int speedstep_target (struct cpufreq_policy *policy,
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unsigned int target_freq, unsigned int relation)
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{
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unsigned int newstate = 0;
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struct cpufreq_freqs freqs;
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if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0], target_freq, relation, &newstate))
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return -EINVAL;
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freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
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freqs.new = speedstep_freqs[newstate].frequency;
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freqs.cpu = 0; /* speedstep.c is UP only driver */
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if (freqs.old == freqs.new)
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return 0;
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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speedstep_set_state(newstate);
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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return 0;
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}
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/**
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* speedstep_verify - verifies a new CPUFreq policy
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* @policy: new policy
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*
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* Limit must be within speedstep_low_freq and speedstep_high_freq, with
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* at least one border included.
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*/
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static int speedstep_verify (struct cpufreq_policy *policy)
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{
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return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
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}
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static int speedstep_cpu_init(struct cpufreq_policy *policy)
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{
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int result;
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unsigned int speed,state;
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/* capability check */
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if (policy->cpu != 0)
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return -ENODEV;
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result = speedstep_smi_ownership();
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if (result) {
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dprintk("fails in aquiring ownership of a SMI interface.\n");
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return -EINVAL;
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}
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/* detect low and high frequency */
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result = speedstep_smi_get_freqs(&speedstep_freqs[SPEEDSTEP_LOW].frequency,
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&speedstep_freqs[SPEEDSTEP_HIGH].frequency);
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if (result) {
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/* fall back to speedstep_lib.c dection mechanism: try both states out */
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dprintk("could not detect low and high frequencies by SMI call.\n");
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result = speedstep_get_freqs(speedstep_processor,
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&speedstep_freqs[SPEEDSTEP_LOW].frequency,
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&speedstep_freqs[SPEEDSTEP_HIGH].frequency,
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NULL,
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&speedstep_set_state);
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if (result) {
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dprintk("could not detect two different speeds -- aborting.\n");
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return result;
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} else
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dprintk("workaround worked.\n");
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}
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/* get current speed setting */
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state = speedstep_get_state();
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speed = speedstep_freqs[state].frequency;
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dprintk("currently at %s speed setting - %i MHz\n",
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(speed == speedstep_freqs[SPEEDSTEP_LOW].frequency) ? "low" : "high",
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(speed / 1000));
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/* cpuinfo and default policy values */
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policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
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policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
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policy->cur = speed;
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result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
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if (result)
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return (result);
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cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
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return 0;
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}
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static int speedstep_cpu_exit(struct cpufreq_policy *policy)
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{
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cpufreq_frequency_table_put_attr(policy->cpu);
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return 0;
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}
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static unsigned int speedstep_get(unsigned int cpu)
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{
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if (cpu)
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return -ENODEV;
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return speedstep_get_processor_frequency(speedstep_processor);
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}
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static int speedstep_resume(struct cpufreq_policy *policy)
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{
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int result = speedstep_smi_ownership();
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if (result)
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dprintk("fails in re-aquiring ownership of a SMI interface.\n");
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return result;
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}
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static struct freq_attr* speedstep_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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NULL,
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};
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static struct cpufreq_driver speedstep_driver = {
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.name = "speedstep-smi",
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.verify = speedstep_verify,
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.target = speedstep_target,
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.init = speedstep_cpu_init,
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.exit = speedstep_cpu_exit,
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.get = speedstep_get,
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.resume = speedstep_resume,
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.owner = THIS_MODULE,
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.attr = speedstep_attr,
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};
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/**
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* speedstep_init - initializes the SpeedStep CPUFreq driver
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*
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* Initializes the SpeedStep support. Returns -ENODEV on unsupported
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* BIOS, -EINVAL on problems during initiatization, and zero on
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* success.
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*/
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static int __init speedstep_init(void)
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{
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speedstep_processor = speedstep_detect_processor();
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switch (speedstep_processor) {
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case SPEEDSTEP_PROCESSOR_PIII_T:
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case SPEEDSTEP_PROCESSOR_PIII_C:
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case SPEEDSTEP_PROCESSOR_PIII_C_EARLY:
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break;
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case SPEEDSTEP_PROCESSOR_P4M:
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printk(KERN_INFO "speedstep-smi: you're trying to use this cpufreq driver on a Pentium 4-based CPU. Most likely it will not work.\n");
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break;
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default:
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speedstep_processor = 0;
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}
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if (!speedstep_processor) {
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dprintk ("No supported Intel CPU detected.\n");
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return -ENODEV;
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}
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dprintk("signature:0x%.8lx, command:0x%.8lx, event:0x%.8lx, perf_level:0x%.8lx.\n",
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ist_info.signature, ist_info.command, ist_info.event, ist_info.perf_level);
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/* Error if no IST-SMI BIOS or no PARM
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sig= 'ISGE' aka 'Intel Speedstep Gate E' */
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if ((ist_info.signature != 0x47534943) && (
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(smi_port == 0) || (smi_cmd == 0)))
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return -ENODEV;
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if (smi_sig == 1)
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smi_sig = 0x47534943;
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else
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smi_sig = ist_info.signature;
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/* setup smi_port from MODLULE_PARM or BIOS */
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if ((smi_port > 0xff) || (smi_port < 0)) {
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return -EINVAL;
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} else if (smi_port == 0) {
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smi_port = ist_info.command & 0xff;
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}
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if ((smi_cmd > 0xff) || (smi_cmd < 0)) {
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return -EINVAL;
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} else if (smi_cmd == 0) {
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smi_cmd = (ist_info.command >> 16) & 0xff;
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}
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return cpufreq_register_driver(&speedstep_driver);
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}
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/**
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* speedstep_exit - unregisters SpeedStep support
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*
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* Unregisters SpeedStep support.
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*/
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static void __exit speedstep_exit(void)
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{
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cpufreq_unregister_driver(&speedstep_driver);
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}
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module_param(smi_port, int, 0444);
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module_param(smi_cmd, int, 0444);
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module_param(smi_sig, uint, 0444);
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MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value -- Intel's default setting is 0xb2");
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MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value -- Intel's default setting is 0x82");
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MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the SMI interface.");
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MODULE_AUTHOR ("Hiroshi Miura");
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MODULE_DESCRIPTION ("Speedstep driver for IST applet SMI interface.");
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MODULE_LICENSE ("GPL");
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module_init(speedstep_init);
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module_exit(speedstep_exit);
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