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424 lines
11 KiB
424 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Based on documentation provided by Dave Jones. Thanks! |
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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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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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/slab.h> |
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#include <linux/timex.h> |
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#include <linux/io.h> |
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#include <linux/delay.h> |
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#include <asm/cpu_device_id.h> |
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#include <asm/msr.h> |
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#include <asm/tsc.h> |
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#if IS_ENABLED(CONFIG_ACPI_PROCESSOR) |
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#include <linux/acpi.h> |
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#include <acpi/processor.h> |
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#endif |
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#define EPS_BRAND_C7M 0 |
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#define EPS_BRAND_C7 1 |
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#define EPS_BRAND_EDEN 2 |
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#define EPS_BRAND_C3 3 |
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#define EPS_BRAND_C7D 4 |
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struct eps_cpu_data { |
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u32 fsb; |
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#if IS_ENABLED(CONFIG_ACPI_PROCESSOR) |
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u32 bios_limit; |
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#endif |
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struct cpufreq_frequency_table freq_table[]; |
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}; |
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static struct eps_cpu_data *eps_cpu[NR_CPUS]; |
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/* Module parameters */ |
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static int freq_failsafe_off; |
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static int voltage_failsafe_off; |
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static int set_max_voltage; |
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#if IS_ENABLED(CONFIG_ACPI_PROCESSOR) |
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static int ignore_acpi_limit; |
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static struct acpi_processor_performance *eps_acpi_cpu_perf; |
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/* Minimum necessary to get acpi_processor_get_bios_limit() working */ |
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static int eps_acpi_init(void) |
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{ |
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eps_acpi_cpu_perf = kzalloc(sizeof(*eps_acpi_cpu_perf), |
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GFP_KERNEL); |
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if (!eps_acpi_cpu_perf) |
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return -ENOMEM; |
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if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map, |
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GFP_KERNEL)) { |
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kfree(eps_acpi_cpu_perf); |
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eps_acpi_cpu_perf = NULL; |
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return -ENOMEM; |
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} |
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if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) { |
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free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map); |
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kfree(eps_acpi_cpu_perf); |
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eps_acpi_cpu_perf = NULL; |
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return -EIO; |
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} |
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return 0; |
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} |
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static int eps_acpi_exit(struct cpufreq_policy *policy) |
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{ |
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if (eps_acpi_cpu_perf) { |
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acpi_processor_unregister_performance(0); |
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free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map); |
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kfree(eps_acpi_cpu_perf); |
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eps_acpi_cpu_perf = NULL; |
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} |
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return 0; |
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} |
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#endif |
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static unsigned int eps_get(unsigned int cpu) |
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{ |
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struct eps_cpu_data *centaur; |
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u32 lo, hi; |
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if (cpu) |
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return 0; |
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centaur = eps_cpu[cpu]; |
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if (centaur == NULL) |
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return 0; |
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/* Return current frequency */ |
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rdmsr(MSR_IA32_PERF_STATUS, lo, hi); |
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return centaur->fsb * ((lo >> 8) & 0xff); |
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} |
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static int eps_set_state(struct eps_cpu_data *centaur, |
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struct cpufreq_policy *policy, |
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u32 dest_state) |
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{ |
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u32 lo, hi; |
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int i; |
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/* Wait while CPU is busy */ |
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rdmsr(MSR_IA32_PERF_STATUS, lo, hi); |
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i = 0; |
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while (lo & ((1 << 16) | (1 << 17))) { |
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udelay(16); |
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rdmsr(MSR_IA32_PERF_STATUS, lo, hi); |
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i++; |
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if (unlikely(i > 64)) { |
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return -ENODEV; |
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} |
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} |
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/* Set new multiplier and voltage */ |
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wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0); |
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/* Wait until transition end */ |
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i = 0; |
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do { |
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udelay(16); |
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rdmsr(MSR_IA32_PERF_STATUS, lo, hi); |
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i++; |
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if (unlikely(i > 64)) { |
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return -ENODEV; |
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} |
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} while (lo & ((1 << 16) | (1 << 17))); |
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#ifdef DEBUG |
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{ |
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u8 current_multiplier, current_voltage; |
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/* Print voltage and multiplier */ |
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rdmsr(MSR_IA32_PERF_STATUS, lo, hi); |
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current_voltage = lo & 0xff; |
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pr_info("Current voltage = %dmV\n", current_voltage * 16 + 700); |
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current_multiplier = (lo >> 8) & 0xff; |
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pr_info("Current multiplier = %d\n", current_multiplier); |
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} |
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#endif |
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return 0; |
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} |
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static int eps_target(struct cpufreq_policy *policy, unsigned int index) |
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{ |
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struct eps_cpu_data *centaur; |
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unsigned int cpu = policy->cpu; |
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unsigned int dest_state; |
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int ret; |
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if (unlikely(eps_cpu[cpu] == NULL)) |
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return -ENODEV; |
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centaur = eps_cpu[cpu]; |
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/* Make frequency transition */ |
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dest_state = centaur->freq_table[index].driver_data & 0xffff; |
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ret = eps_set_state(centaur, policy, dest_state); |
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if (ret) |
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pr_err("Timeout!\n"); |
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return ret; |
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} |
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static int eps_cpu_init(struct cpufreq_policy *policy) |
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{ |
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unsigned int i; |
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u32 lo, hi; |
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u64 val; |
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u8 current_multiplier, current_voltage; |
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u8 max_multiplier, max_voltage; |
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u8 min_multiplier, min_voltage; |
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u8 brand = 0; |
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u32 fsb; |
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struct eps_cpu_data *centaur; |
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struct cpuinfo_x86 *c = &cpu_data(0); |
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struct cpufreq_frequency_table *f_table; |
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int k, step, voltage; |
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int states; |
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#if IS_ENABLED(CONFIG_ACPI_PROCESSOR) |
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unsigned int limit; |
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#endif |
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if (policy->cpu != 0) |
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return -ENODEV; |
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/* Check brand */ |
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pr_info("Detected VIA "); |
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switch (c->x86_model) { |
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case 10: |
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rdmsr(0x1153, lo, hi); |
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brand = (((lo >> 2) ^ lo) >> 18) & 3; |
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pr_cont("Model A "); |
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break; |
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case 13: |
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rdmsr(0x1154, lo, hi); |
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brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff; |
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pr_cont("Model D "); |
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break; |
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} |
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switch (brand) { |
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case EPS_BRAND_C7M: |
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pr_cont("C7-M\n"); |
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break; |
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case EPS_BRAND_C7: |
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pr_cont("C7\n"); |
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break; |
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case EPS_BRAND_EDEN: |
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pr_cont("Eden\n"); |
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break; |
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case EPS_BRAND_C7D: |
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pr_cont("C7-D\n"); |
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break; |
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case EPS_BRAND_C3: |
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pr_cont("C3\n"); |
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return -ENODEV; |
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} |
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/* Enable Enhanced PowerSaver */ |
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rdmsrl(MSR_IA32_MISC_ENABLE, val); |
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if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { |
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val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP; |
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wrmsrl(MSR_IA32_MISC_ENABLE, val); |
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/* Can be locked at 0 */ |
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rdmsrl(MSR_IA32_MISC_ENABLE, val); |
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if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) { |
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pr_info("Can't enable Enhanced PowerSaver\n"); |
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return -ENODEV; |
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} |
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} |
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/* Print voltage and multiplier */ |
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rdmsr(MSR_IA32_PERF_STATUS, lo, hi); |
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current_voltage = lo & 0xff; |
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pr_info("Current voltage = %dmV\n", current_voltage * 16 + 700); |
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current_multiplier = (lo >> 8) & 0xff; |
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pr_info("Current multiplier = %d\n", current_multiplier); |
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/* Print limits */ |
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max_voltage = hi & 0xff; |
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pr_info("Highest voltage = %dmV\n", max_voltage * 16 + 700); |
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max_multiplier = (hi >> 8) & 0xff; |
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pr_info("Highest multiplier = %d\n", max_multiplier); |
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min_voltage = (hi >> 16) & 0xff; |
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pr_info("Lowest voltage = %dmV\n", min_voltage * 16 + 700); |
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min_multiplier = (hi >> 24) & 0xff; |
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pr_info("Lowest multiplier = %d\n", min_multiplier); |
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/* Sanity checks */ |
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if (current_multiplier == 0 || max_multiplier == 0 |
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|| min_multiplier == 0) |
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return -EINVAL; |
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if (current_multiplier > max_multiplier |
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|| max_multiplier <= min_multiplier) |
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return -EINVAL; |
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if (current_voltage > 0x1f || max_voltage > 0x1f) |
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return -EINVAL; |
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if (max_voltage < min_voltage |
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|| current_voltage < min_voltage |
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|| current_voltage > max_voltage) |
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return -EINVAL; |
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/* Check for systems using underclocked CPU */ |
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if (!freq_failsafe_off && max_multiplier != current_multiplier) { |
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pr_info("Your processor is running at different frequency then its maximum. Aborting.\n"); |
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pr_info("You can use freq_failsafe_off option to disable this check.\n"); |
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return -EINVAL; |
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} |
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if (!voltage_failsafe_off && max_voltage != current_voltage) { |
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pr_info("Your processor is running at different voltage then its maximum. Aborting.\n"); |
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pr_info("You can use voltage_failsafe_off option to disable this check.\n"); |
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return -EINVAL; |
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} |
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/* Calc FSB speed */ |
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fsb = cpu_khz / current_multiplier; |
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#if IS_ENABLED(CONFIG_ACPI_PROCESSOR) |
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/* Check for ACPI processor speed limit */ |
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if (!ignore_acpi_limit && !eps_acpi_init()) { |
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if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) { |
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pr_info("ACPI limit %u.%uGHz\n", |
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limit/1000000, |
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(limit%1000000)/10000); |
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eps_acpi_exit(policy); |
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/* Check if max_multiplier is in BIOS limits */ |
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if (limit && max_multiplier * fsb > limit) { |
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pr_info("Aborting\n"); |
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return -EINVAL; |
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} |
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} |
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} |
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#endif |
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/* Allow user to set lower maximum voltage then that reported |
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* by processor */ |
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if (brand == EPS_BRAND_C7M && set_max_voltage) { |
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u32 v; |
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/* Change mV to something hardware can use */ |
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v = (set_max_voltage - 700) / 16; |
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/* Check if voltage is within limits */ |
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if (v >= min_voltage && v <= max_voltage) { |
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pr_info("Setting %dmV as maximum\n", v * 16 + 700); |
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max_voltage = v; |
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} |
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} |
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/* Calc number of p-states supported */ |
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if (brand == EPS_BRAND_C7M) |
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states = max_multiplier - min_multiplier + 1; |
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else |
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states = 2; |
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/* Allocate private data and frequency table for current cpu */ |
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centaur = kzalloc(struct_size(centaur, freq_table, states + 1), |
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GFP_KERNEL); |
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if (!centaur) |
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return -ENOMEM; |
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eps_cpu[0] = centaur; |
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/* Copy basic values */ |
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centaur->fsb = fsb; |
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#if IS_ENABLED(CONFIG_ACPI_PROCESSOR) |
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centaur->bios_limit = limit; |
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#endif |
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/* Fill frequency and MSR value table */ |
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f_table = ¢aur->freq_table[0]; |
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if (brand != EPS_BRAND_C7M) { |
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f_table[0].frequency = fsb * min_multiplier; |
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f_table[0].driver_data = (min_multiplier << 8) | min_voltage; |
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f_table[1].frequency = fsb * max_multiplier; |
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f_table[1].driver_data = (max_multiplier << 8) | max_voltage; |
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f_table[2].frequency = CPUFREQ_TABLE_END; |
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} else { |
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k = 0; |
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step = ((max_voltage - min_voltage) * 256) |
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/ (max_multiplier - min_multiplier); |
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for (i = min_multiplier; i <= max_multiplier; i++) { |
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voltage = (k * step) / 256 + min_voltage; |
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f_table[k].frequency = fsb * i; |
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f_table[k].driver_data = (i << 8) | voltage; |
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k++; |
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} |
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f_table[k].frequency = CPUFREQ_TABLE_END; |
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} |
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policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */ |
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policy->freq_table = ¢aur->freq_table[0]; |
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return 0; |
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} |
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static int eps_cpu_exit(struct cpufreq_policy *policy) |
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{ |
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unsigned int cpu = policy->cpu; |
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/* Bye */ |
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kfree(eps_cpu[cpu]); |
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eps_cpu[cpu] = NULL; |
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return 0; |
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} |
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static struct cpufreq_driver eps_driver = { |
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.verify = cpufreq_generic_frequency_table_verify, |
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.target_index = eps_target, |
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.init = eps_cpu_init, |
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.exit = eps_cpu_exit, |
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.get = eps_get, |
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.name = "e_powersaver", |
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.attr = cpufreq_generic_attr, |
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}; |
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/* This driver will work only on Centaur C7 processors with |
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* Enhanced SpeedStep/PowerSaver registers */ |
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static const struct x86_cpu_id eps_cpu_id[] = { |
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X86_MATCH_VENDOR_FAM_FEATURE(CENTAUR, 6, X86_FEATURE_EST, NULL), |
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{} |
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}; |
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MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id); |
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static int __init eps_init(void) |
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{ |
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if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10) |
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return -ENODEV; |
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if (cpufreq_register_driver(&eps_driver)) |
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return -EINVAL; |
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return 0; |
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} |
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static void __exit eps_exit(void) |
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{ |
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cpufreq_unregister_driver(&eps_driver); |
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} |
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/* Allow user to overclock his machine or to change frequency to higher after |
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* unloading module */ |
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module_param(freq_failsafe_off, int, 0644); |
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MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check"); |
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module_param(voltage_failsafe_off, int, 0644); |
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MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check"); |
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#if IS_ENABLED(CONFIG_ACPI_PROCESSOR) |
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module_param(ignore_acpi_limit, int, 0644); |
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MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit"); |
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#endif |
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module_param(set_max_voltage, int, 0644); |
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MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only"); |
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MODULE_AUTHOR("Rafal Bilski <[email protected]>"); |
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MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's."); |
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MODULE_LICENSE("GPL"); |
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module_init(eps_init); |
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module_exit(eps_exit);
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