forked from luck/tmp_suning_uos_patched
e20e1d0ac0
I found out that a system with k6-3+ processor is unstable during network server load. The system locks up or the network card stops receiving. The reason for the instability is the CPU frequency scaling. During frequency transition the processor is in "EPM Stop Grant" state. The documentation says that the processor doesn't respond to inquiry requests in this state. Consequently, coherency of processor caches and bus master devices is not maintained, causing the system instability. This patch flushes the cache during frequency transition. It fixes the instability. Other minor changes: * u64 invalue changed to unsigned long because the variable is 32-bit * move the logic to set the multiplier to a separate function powernow_k6_set_cpu_multiplier * preserve lower 5 bits of the powernow port instead of 4 (the voltage field has 5 bits) * mask interrupts when reading the multiplier, so that the port is not open during other activity (running other kernel code with the port open shouldn't cause any misbehavior, but we should better be safe and keep the port closed) This patch should be backported to all stable kernels. If it doesn't apply cleanly, change it, or ask me to change it. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
236 lines
5.9 KiB
C
236 lines
5.9 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/cpu_device_id.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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unsigned long invalue = 0;
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u32 msrval;
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local_irq_disable();
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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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local_irq_enable();
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return clock_ratio[(invalue >> 5)&7].driver_data;
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}
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static void powernow_k6_set_cpu_multiplier(unsigned int best_i)
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{
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unsigned long outvalue, invalue;
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unsigned long msrval;
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unsigned long cr0;
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/* we now need to transform best_i to the BVC format, see AMD#23446 */
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/*
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* The processor doesn't respond to inquiry cycles while changing the
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* frequency, so we must disable cache.
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*/
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local_irq_disable();
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cr0 = read_cr0();
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write_cr0(cr0 | X86_CR0_CD);
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wbinvd();
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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 & 0x1f;
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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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write_cr0(cr0);
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local_irq_enable();
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}
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/**
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* powernow_k6_target - 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 int powernow_k6_target(struct cpufreq_policy *policy,
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unsigned int best_i)
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{
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struct cpufreq_freqs freqs;
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if (clock_ratio[best_i].driver_data > max_multiplier) {
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printk(KERN_ERR PFX "invalid target frequency\n");
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return -EINVAL;
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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].driver_data;
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
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powernow_k6_set_cpu_multiplier(best_i);
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
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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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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].driver_data;
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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 = 500000;
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return cpufreq_table_validate_and_show(policy, clock_ratio);
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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_target(policy, 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 cpufreq_driver powernow_k6_driver = {
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.verify = cpufreq_generic_frequency_table_verify,
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.target_index = 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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.attr = cpufreq_generic_attr,
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};
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static const struct x86_cpu_id powernow_k6_ids[] = {
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{ X86_VENDOR_AMD, 5, 12 },
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{ X86_VENDOR_AMD, 5, 13 },
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{}
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};
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MODULE_DEVICE_TABLE(x86cpu, powernow_k6_ids);
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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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if (!x86_match_cpu(powernow_k6_ids))
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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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