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127 lines
3.1 KiB
127 lines
3.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* SFI Performance States Driver |
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* |
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* Author: Vishwesh M Rudramuni <[email protected]> |
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* Author: Srinidhi Kasagar <[email protected]> |
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*/ |
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#include <linux/cpufreq.h> |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/sfi.h> |
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#include <linux/slab.h> |
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#include <linux/smp.h> |
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#include <asm/msr.h> |
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static struct cpufreq_frequency_table *freq_table; |
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static struct sfi_freq_table_entry *sfi_cpufreq_array; |
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static int num_freq_table_entries; |
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static int sfi_parse_freq(struct sfi_table_header *table) |
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{ |
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struct sfi_table_simple *sb; |
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struct sfi_freq_table_entry *pentry; |
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int totallen; |
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sb = (struct sfi_table_simple *)table; |
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num_freq_table_entries = SFI_GET_NUM_ENTRIES(sb, |
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struct sfi_freq_table_entry); |
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if (num_freq_table_entries <= 1) { |
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pr_err("No p-states discovered\n"); |
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return -ENODEV; |
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} |
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pentry = (struct sfi_freq_table_entry *)sb->pentry; |
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totallen = num_freq_table_entries * sizeof(*pentry); |
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sfi_cpufreq_array = kmemdup(pentry, totallen, GFP_KERNEL); |
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if (!sfi_cpufreq_array) |
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return -ENOMEM; |
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return 0; |
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} |
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static int sfi_cpufreq_target(struct cpufreq_policy *policy, unsigned int index) |
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{ |
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unsigned int next_perf_state = 0; /* Index into perf table */ |
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u32 lo, hi; |
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next_perf_state = policy->freq_table[index].driver_data; |
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rdmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, &lo, &hi); |
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lo = (lo & ~INTEL_PERF_CTL_MASK) | |
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((u32) sfi_cpufreq_array[next_perf_state].ctrl_val & |
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INTEL_PERF_CTL_MASK); |
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wrmsr_on_cpu(policy->cpu, MSR_IA32_PERF_CTL, lo, hi); |
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return 0; |
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} |
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static int sfi_cpufreq_cpu_init(struct cpufreq_policy *policy) |
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{ |
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policy->shared_type = CPUFREQ_SHARED_TYPE_HW; |
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policy->cpuinfo.transition_latency = 100000; /* 100us */ |
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policy->freq_table = freq_table; |
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return 0; |
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} |
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static struct cpufreq_driver sfi_cpufreq_driver = { |
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.flags = CPUFREQ_CONST_LOOPS, |
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.verify = cpufreq_generic_frequency_table_verify, |
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.target_index = sfi_cpufreq_target, |
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.init = sfi_cpufreq_cpu_init, |
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.name = "sfi-cpufreq", |
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.attr = cpufreq_generic_attr, |
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}; |
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static int __init sfi_cpufreq_init(void) |
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{ |
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int ret, i; |
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/* parse the freq table from SFI */ |
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ret = sfi_table_parse(SFI_SIG_FREQ, NULL, NULL, sfi_parse_freq); |
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if (ret) |
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return ret; |
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freq_table = kcalloc(num_freq_table_entries + 1, sizeof(*freq_table), |
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GFP_KERNEL); |
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if (!freq_table) { |
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ret = -ENOMEM; |
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goto err_free_array; |
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} |
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for (i = 0; i < num_freq_table_entries; i++) { |
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freq_table[i].driver_data = i; |
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freq_table[i].frequency = sfi_cpufreq_array[i].freq_mhz * 1000; |
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} |
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freq_table[i].frequency = CPUFREQ_TABLE_END; |
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ret = cpufreq_register_driver(&sfi_cpufreq_driver); |
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if (ret) |
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goto err_free_tbl; |
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return ret; |
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err_free_tbl: |
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kfree(freq_table); |
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err_free_array: |
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kfree(sfi_cpufreq_array); |
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return ret; |
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} |
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late_initcall(sfi_cpufreq_init); |
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static void __exit sfi_cpufreq_exit(void) |
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{ |
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cpufreq_unregister_driver(&sfi_cpufreq_driver); |
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kfree(freq_table); |
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kfree(sfi_cpufreq_array); |
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} |
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module_exit(sfi_cpufreq_exit); |
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MODULE_AUTHOR("Vishwesh M Rudramuni <[email protected]>"); |
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MODULE_DESCRIPTION("SFI Performance-States Driver"); |
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MODULE_LICENSE("GPL");
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