262 lines
6.5 KiB
C
262 lines
6.5 KiB
C
/*
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* This file was based upon code in Powertweak Linux (http://powertweak.sf.net)
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* (C) 2000-2003 Dave Jones, Arjan van de Ven, Janne Pänkälä,
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* Dominik Brodowski.
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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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* 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/init.h>
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#include <linux/cpufreq.h>
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#include <linux/ioport.h>
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#include <linux/timex.h>
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#include <linux/io.h>
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#include <asm/msr.h>
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#define POWERNOW_IOPORT 0xfff0 /* it doesn't matter where, as long
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as it is unused */
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#define PFX "powernow-k6: "
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static unsigned int busfreq; /* FSB, in 10 kHz */
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static unsigned int max_multiplier;
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/* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
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static struct cpufreq_frequency_table clock_ratio[] = {
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{45, /* 000 -> 4.5x */ 0},
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{50, /* 001 -> 5.0x */ 0},
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{40, /* 010 -> 4.0x */ 0},
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{55, /* 011 -> 5.5x */ 0},
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{20, /* 100 -> 2.0x */ 0},
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{30, /* 101 -> 3.0x */ 0},
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{60, /* 110 -> 6.0x */ 0},
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{35, /* 111 -> 3.5x */ 0},
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{0, CPUFREQ_TABLE_END}
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};
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/**
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* powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
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*
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* Returns the current setting of the frequency multiplier. Core clock
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* speed is frequency of the Front-Side Bus multiplied with this value.
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*/
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static int powernow_k6_get_cpu_multiplier(void)
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{
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u64 invalue = 0;
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u32 msrval;
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msrval = POWERNOW_IOPORT + 0x1;
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wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
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invalue = inl(POWERNOW_IOPORT + 0x8);
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msrval = POWERNOW_IOPORT + 0x0;
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wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
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return clock_ratio[(invalue >> 5)&7].index;
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}
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/**
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* powernow_k6_set_state - set the PowerNow! multiplier
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* @best_i: clock_ratio[best_i] is the target multiplier
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*
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* Tries to change the PowerNow! multiplier
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*/
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static void powernow_k6_set_state(unsigned int best_i)
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{
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unsigned long outvalue = 0, invalue = 0;
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unsigned long msrval;
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struct cpufreq_freqs freqs;
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if (clock_ratio[best_i].index > max_multiplier) {
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printk(KERN_ERR PFX "invalid target frequency\n");
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return;
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}
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freqs.old = busfreq * powernow_k6_get_cpu_multiplier();
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freqs.new = busfreq * clock_ratio[best_i].index;
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freqs.cpu = 0; /* powernow-k6.c is UP only driver */
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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/* we now need to transform best_i to the BVC format, see AMD#23446 */
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outvalue = (1<<12) | (1<<10) | (1<<9) | (best_i<<5);
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msrval = POWERNOW_IOPORT + 0x1;
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wrmsr(MSR_K6_EPMR, msrval, 0); /* enable the PowerNow port */
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invalue = inl(POWERNOW_IOPORT + 0x8);
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invalue = invalue & 0xf;
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outvalue = outvalue | invalue;
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outl(outvalue , (POWERNOW_IOPORT + 0x8));
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msrval = POWERNOW_IOPORT + 0x0;
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wrmsr(MSR_K6_EPMR, msrval, 0); /* disable it again */
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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return;
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}
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/**
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* powernow_k6_verify - verifies a new CPUfreq policy
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* @policy: new policy
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*
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* Policy must be within lowest and highest possible CPU Frequency,
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* and at least one possible state must be within min and max.
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*/
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static int powernow_k6_verify(struct cpufreq_policy *policy)
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{
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return cpufreq_frequency_table_verify(policy, &clock_ratio[0]);
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}
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/**
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* powernow_k6_setpolicy - sets a new CPUFreq policy
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* @policy: new policy
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* @target_freq: the target frequency
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* @relation: how that frequency relates to achieved frequency
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* (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
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*
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* sets a new CPUFreq policy
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*/
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static int powernow_k6_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 = 0;
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if (cpufreq_frequency_table_target(policy, &clock_ratio[0],
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target_freq, relation, &newstate))
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return -EINVAL;
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powernow_k6_set_state(newstate);
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return 0;
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}
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static int powernow_k6_cpu_init(struct cpufreq_policy *policy)
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{
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unsigned int i, f;
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int result;
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if (policy->cpu != 0)
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return -ENODEV;
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/* get frequencies */
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max_multiplier = powernow_k6_get_cpu_multiplier();
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busfreq = cpu_khz / max_multiplier;
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/* table init */
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for (i = 0; (clock_ratio[i].frequency != CPUFREQ_TABLE_END); i++) {
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f = clock_ratio[i].index;
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if (f > max_multiplier)
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clock_ratio[i].frequency = CPUFREQ_ENTRY_INVALID;
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else
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clock_ratio[i].frequency = busfreq * f;
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}
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/* cpuinfo and default policy values */
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policy->cpuinfo.transition_latency = 200000;
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policy->cur = busfreq * max_multiplier;
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result = cpufreq_frequency_table_cpuinfo(policy, clock_ratio);
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if (result)
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return result;
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cpufreq_frequency_table_get_attr(clock_ratio, policy->cpu);
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return 0;
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}
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static int powernow_k6_cpu_exit(struct cpufreq_policy *policy)
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{
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unsigned int i;
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for (i = 0; i < 8; i++) {
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if (i == max_multiplier)
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powernow_k6_set_state(i);
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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 powernow_k6_get(unsigned int cpu)
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{
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unsigned int ret;
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ret = (busfreq * powernow_k6_get_cpu_multiplier());
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return ret;
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}
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static struct freq_attr *powernow_k6_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 powernow_k6_driver = {
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.verify = powernow_k6_verify,
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.target = powernow_k6_target,
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.init = powernow_k6_cpu_init,
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.exit = powernow_k6_cpu_exit,
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.get = powernow_k6_get,
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.name = "powernow-k6",
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.owner = THIS_MODULE,
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.attr = powernow_k6_attr,
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};
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/**
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* powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
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*
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* Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
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* devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
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* on success.
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*/
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static int __init powernow_k6_init(void)
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{
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struct cpuinfo_x86 *c = &cpu_data(0);
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if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 != 5) ||
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((c->x86_model != 12) && (c->x86_model != 13)))
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return -ENODEV;
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if (!request_region(POWERNOW_IOPORT, 16, "PowerNow!")) {
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printk(KERN_INFO PFX "PowerNow IOPORT region already used.\n");
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return -EIO;
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}
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if (cpufreq_register_driver(&powernow_k6_driver)) {
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release_region(POWERNOW_IOPORT, 16);
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return -EINVAL;
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}
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return 0;
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}
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/**
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* powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
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*
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* Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
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*/
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static void __exit powernow_k6_exit(void)
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{
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cpufreq_unregister_driver(&powernow_k6_driver);
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release_region(POWERNOW_IOPORT, 16);
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}
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MODULE_AUTHOR("Arjan van de Ven, Dave Jones <davej@redhat.com>, "
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"Dominik Brodowski <linux@brodo.de>");
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MODULE_DESCRIPTION("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
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MODULE_LICENSE("GPL");
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module_init(powernow_k6_init);
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module_exit(powernow_k6_exit);
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