336 lines
8.5 KiB
C
336 lines
8.5 KiB
C
/*
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* Pentium 4/Xeon CPU on demand clock modulation/speed scaling
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* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
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* (C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
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* (C) 2002 Arjan van de Ven <arjanv@redhat.com>
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* (C) 2002 Tora T. Engstad
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* The author(s) of this software shall not be held liable for damages
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* of any nature resulting due to the use of this software. This
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* software is provided AS-IS with no warranties.
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*
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* Date Errata Description
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* 20020525 N44, O17 12.5% or 25% DC causes lockup
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*
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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/init.h>
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#include <linux/smp.h>
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#include <linux/cpufreq.h>
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#include <linux/slab.h>
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#include <linux/cpumask.h>
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#include <linux/sched.h> /* current / set_cpus_allowed() */
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#include <asm/processor.h>
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#include <asm/msr.h>
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#include <asm/timex.h>
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#include "speedstep-lib.h"
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#define PFX "p4-clockmod: "
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#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "p4-clockmod", msg)
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/*
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* Duty Cycle (3bits), note DC_DISABLE is not specified in
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* intel docs i just use it to mean disable
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*/
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enum {
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DC_RESV, DC_DFLT, DC_25PT, DC_38PT, DC_50PT,
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DC_64PT, DC_75PT, DC_88PT, DC_DISABLE
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};
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#define DC_ENTRIES 8
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static int has_N44_O17_errata[NR_CPUS];
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static unsigned int stock_freq;
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static struct cpufreq_driver p4clockmod_driver;
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static unsigned int cpufreq_p4_get(unsigned int cpu);
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static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
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{
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u32 l, h;
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if (!cpu_online(cpu) || (newstate > DC_DISABLE) || (newstate == DC_RESV))
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return -EINVAL;
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rdmsr(MSR_IA32_THERM_STATUS, l, h);
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if (l & 0x01)
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dprintk("CPU#%d currently thermal throttled\n", cpu);
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if (has_N44_O17_errata[cpu] && (newstate == DC_25PT || newstate == DC_DFLT))
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newstate = DC_38PT;
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rdmsr(MSR_IA32_THERM_CONTROL, l, h);
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if (newstate == DC_DISABLE) {
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dprintk("CPU#%d disabling modulation\n", cpu);
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wrmsr(MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
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} else {
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dprintk("CPU#%d setting duty cycle to %d%%\n",
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cpu, ((125 * newstate) / 10));
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/* bits 63 - 5 : reserved
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* bit 4 : enable/disable
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* bits 3-1 : duty cycle
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* bit 0 : reserved
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*/
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l = (l & ~14);
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l = l | (1<<4) | ((newstate & 0x7)<<1);
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wrmsr(MSR_IA32_THERM_CONTROL, l, h);
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}
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return 0;
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}
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static struct cpufreq_frequency_table p4clockmod_table[] = {
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{DC_RESV, CPUFREQ_ENTRY_INVALID},
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{DC_DFLT, 0},
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{DC_25PT, 0},
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{DC_38PT, 0},
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{DC_50PT, 0},
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{DC_64PT, 0},
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{DC_75PT, 0},
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{DC_88PT, 0},
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{DC_DISABLE, 0},
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{DC_RESV, CPUFREQ_TABLE_END},
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};
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static int cpufreq_p4_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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unsigned int newstate = DC_RESV;
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struct cpufreq_freqs freqs;
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cpumask_t cpus_allowed;
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int i;
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if (cpufreq_frequency_table_target(policy, &p4clockmod_table[0], target_freq, relation, &newstate))
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return -EINVAL;
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freqs.old = cpufreq_p4_get(policy->cpu);
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freqs.new = stock_freq * p4clockmod_table[newstate].index / 8;
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if (freqs.new == freqs.old)
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return 0;
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/* notifiers */
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for_each_cpu_mask(i, policy->cpus) {
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freqs.cpu = i;
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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}
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/* run on each logical CPU, see section 13.15.3 of IA32 Intel Architecture Software
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* Developer's Manual, Volume 3
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*/
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cpus_allowed = current->cpus_allowed;
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for_each_cpu_mask(i, policy->cpus) {
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cpumask_t this_cpu = cpumask_of_cpu(i);
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set_cpus_allowed(current, this_cpu);
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BUG_ON(smp_processor_id() != i);
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cpufreq_p4_setdc(i, p4clockmod_table[newstate].index);
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}
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set_cpus_allowed(current, cpus_allowed);
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/* notifiers */
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for_each_cpu_mask(i, policy->cpus) {
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freqs.cpu = i;
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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}
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return 0;
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}
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static int cpufreq_p4_verify(struct cpufreq_policy *policy)
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{
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return cpufreq_frequency_table_verify(policy, &p4clockmod_table[0]);
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}
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static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
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{
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if (c->x86 == 0x06) {
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if (cpu_has(c, X86_FEATURE_EST))
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printk(KERN_WARNING PFX "Warning: EST-capable CPU detected. "
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"The acpi-cpufreq module offers voltage scaling"
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" in addition of frequency scaling. You should use "
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"that instead of p4-clockmod, if possible.\n");
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switch (c->x86_model) {
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case 0x0E: /* Core */
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case 0x0F: /* Core Duo */
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p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
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return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_PCORE);
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case 0x0D: /* Pentium M (Dothan) */
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p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
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/* fall through */
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case 0x09: /* Pentium M (Banias) */
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return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_PM);
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}
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}
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if (c->x86 != 0xF) {
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printk(KERN_WARNING PFX "Unknown p4-clockmod-capable CPU. Please send an e-mail to <cpufreq@lists.linux.org.uk>\n");
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return 0;
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}
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/* on P-4s, the TSC runs with constant frequency independent whether
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* throttling is active or not. */
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p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
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if (speedstep_detect_processor() == SPEEDSTEP_PROCESSOR_P4M) {
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printk(KERN_WARNING PFX "Warning: Pentium 4-M detected. "
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"The speedstep-ich or acpi cpufreq modules offer "
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"voltage scaling in addition of frequency scaling. "
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"You should use either one instead of p4-clockmod, "
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"if possible.\n");
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return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_P4M);
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}
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return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_P4D);
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}
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static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
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{
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struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
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int cpuid = 0;
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unsigned int i;
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#ifdef CONFIG_SMP
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policy->cpus = cpu_sibling_map[policy->cpu];
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#endif
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/* Errata workaround */
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cpuid = (c->x86 << 8) | (c->x86_model << 4) | c->x86_mask;
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switch (cpuid) {
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case 0x0f07:
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case 0x0f0a:
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case 0x0f11:
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case 0x0f12:
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has_N44_O17_errata[policy->cpu] = 1;
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dprintk("has errata -- disabling low frequencies\n");
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}
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/* get max frequency */
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stock_freq = cpufreq_p4_get_frequency(c);
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if (!stock_freq)
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return -EINVAL;
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/* table init */
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for (i=1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {
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if ((i<2) && (has_N44_O17_errata[policy->cpu]))
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p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
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else
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p4clockmod_table[i].frequency = (stock_freq * i)/8;
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}
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cpufreq_frequency_table_get_attr(p4clockmod_table, policy->cpu);
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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 = 1000000; /* assumed */
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policy->cur = stock_freq;
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return cpufreq_frequency_table_cpuinfo(policy, &p4clockmod_table[0]);
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}
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static int cpufreq_p4_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 cpufreq_p4_get(unsigned int cpu)
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{
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cpumask_t cpus_allowed;
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u32 l, h;
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cpus_allowed = current->cpus_allowed;
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set_cpus_allowed(current, cpumask_of_cpu(cpu));
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BUG_ON(smp_processor_id() != cpu);
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rdmsr(MSR_IA32_THERM_CONTROL, l, h);
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set_cpus_allowed(current, cpus_allowed);
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if (l & 0x10) {
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l = l >> 1;
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l &= 0x7;
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} else
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l = DC_DISABLE;
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if (l != DC_DISABLE)
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return (stock_freq * l / 8);
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return stock_freq;
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}
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static struct freq_attr* p4clockmod_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 p4clockmod_driver = {
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.verify = cpufreq_p4_verify,
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.target = cpufreq_p4_target,
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.init = cpufreq_p4_cpu_init,
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.exit = cpufreq_p4_cpu_exit,
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.get = cpufreq_p4_get,
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.name = "p4-clockmod",
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.owner = THIS_MODULE,
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.attr = p4clockmod_attr,
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};
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static int __init cpufreq_p4_init(void)
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{
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struct cpuinfo_x86 *c = cpu_data;
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int ret;
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/*
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* THERM_CONTROL is architectural for IA32 now, so
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* we can rely on the capability checks
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*/
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if (c->x86_vendor != X86_VENDOR_INTEL)
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return -ENODEV;
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if (!test_bit(X86_FEATURE_ACPI, c->x86_capability) ||
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!test_bit(X86_FEATURE_ACC, c->x86_capability))
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return -ENODEV;
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ret = cpufreq_register_driver(&p4clockmod_driver);
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if (!ret)
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printk(KERN_INFO PFX "P4/Xeon(TM) CPU On-Demand Clock Modulation available\n");
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return (ret);
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}
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static void __exit cpufreq_p4_exit(void)
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{
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cpufreq_unregister_driver(&p4clockmod_driver);
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}
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MODULE_AUTHOR ("Zwane Mwaikambo <zwane@commfireservices.com>");
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MODULE_DESCRIPTION ("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
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MODULE_LICENSE ("GPL");
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late_initcall(cpufreq_p4_init);
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module_exit(cpufreq_p4_exit);
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