/* * CPPC (Collaborative Processor Performance Control) driver for * interfacing with the CPUfreq layer and governors. See * cppc_acpi.c for CPPC specific methods. * * (C) Copyright 2014, 2015 Linaro Ltd. * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; version 2 * of the License. */ #define pr_fmt(fmt) "CPPC Cpufreq:" fmt #include <linux/kernel.h> #include <linux/module.h> #include <linux/delay.h> #include <linux/cpu.h> #include <linux/cpufreq.h> #include <linux/dmi.h> #include <linux/vmalloc.h> #include <asm/unaligned.h> #include <acpi/cppc_acpi.h> /* Minimum struct length needed for the DMI processor entry we want */ #define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48 /* Offest in the DMI processor structure for the max frequency */ #define DMI_PROCESSOR_MAX_SPEED 0x14 /* * These structs contain information parsed from per CPU * ACPI _CPC structures. * e.g. For each CPU the highest, lowest supported * performance capabilities, desired performance level * requested etc. */ static struct cppc_cpudata **all_cpu_data; /* Capture the max KHz from DMI */ static u64 cppc_dmi_max_khz; /* Callback function used to retrieve the max frequency from DMI */ static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private) { const u8 *dmi_data = (const u8 *)dm; u16 *mhz = (u16 *)private; if (dm->type == DMI_ENTRY_PROCESSOR && dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) { u16 val = (u16)get_unaligned((const u16 *) (dmi_data + DMI_PROCESSOR_MAX_SPEED)); *mhz = val > *mhz ? val : *mhz; } } /* Look up the max frequency in DMI */ static u64 cppc_get_dmi_max_khz(void) { u16 mhz = 0; dmi_walk(cppc_find_dmi_mhz, &mhz); /* * Real stupid fallback value, just in case there is no * actual value set. */ mhz = mhz ? mhz : 1; return (1000 * mhz); } static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { struct cppc_cpudata *cpu; struct cpufreq_freqs freqs; u32 desired_perf; int ret = 0; cpu = all_cpu_data[policy->cpu]; desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz; /* Return if it is exactly the same perf */ if (desired_perf == cpu->perf_ctrls.desired_perf) return ret; cpu->perf_ctrls.desired_perf = desired_perf; freqs.old = policy->cur; freqs.new = target_freq; cpufreq_freq_transition_begin(policy, &freqs); ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls); cpufreq_freq_transition_end(policy, &freqs, ret != 0); if (ret) pr_debug("Failed to set target on CPU:%d. ret:%d\n", cpu->cpu, ret); return ret; } static int cppc_verify_policy(struct cpufreq_policy *policy) { cpufreq_verify_within_cpu_limits(policy); return 0; } static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy) { int cpu_num = policy->cpu; struct cppc_cpudata *cpu = all_cpu_data[cpu_num]; int ret; cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf; ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); if (ret) pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n", cpu->perf_caps.lowest_perf, cpu_num, ret); } static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) { struct cppc_cpudata *cpu; unsigned int cpu_num = policy->cpu; int ret = 0; cpu = all_cpu_data[policy->cpu]; cpu->cpu = cpu_num; ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps); if (ret) { pr_debug("Err reading CPU%d perf capabilities. ret:%d\n", cpu_num, ret); return ret; } cppc_dmi_max_khz = cppc_get_dmi_max_khz(); /* * Set min to lowest nonlinear perf to avoid any efficiency penalty (see * Section 8.4.7.1.1.5 of ACPI 6.1 spec) */ policy->min = cpu->perf_caps.lowest_nonlinear_perf * cppc_dmi_max_khz / cpu->perf_caps.highest_perf; policy->max = cppc_dmi_max_khz; /* * Set cpuinfo.min_freq to Lowest to make the full range of performance * available if userspace wants to use any perf between lowest & lowest * nonlinear perf */ policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz / cpu->perf_caps.highest_perf; policy->cpuinfo.max_freq = cppc_dmi_max_khz; policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num); policy->shared_type = cpu->shared_type; if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) cpumask_copy(policy->cpus, cpu->shared_cpu_map); else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) { /* Support only SW_ANY for now. */ pr_debug("Unsupported CPU co-ord type\n"); return -EFAULT; } cpu->cur_policy = policy; /* Set policy->cur to max now. The governors will adjust later. */ policy->cur = cppc_dmi_max_khz; cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf; ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls); if (ret) pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n", cpu->perf_caps.highest_perf, cpu_num, ret); return ret; } static struct cpufreq_driver cppc_cpufreq_driver = { .flags = CPUFREQ_CONST_LOOPS, .verify = cppc_verify_policy, .target = cppc_cpufreq_set_target, .init = cppc_cpufreq_cpu_init, .stop_cpu = cppc_cpufreq_stop_cpu, .name = "cppc_cpufreq", }; static int __init cppc_cpufreq_init(void) { int i, ret = 0; struct cppc_cpudata *cpu; if (acpi_disabled) return -ENODEV; all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL); if (!all_cpu_data) return -ENOMEM; for_each_possible_cpu(i) { all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL); if (!all_cpu_data[i]) goto out; cpu = all_cpu_data[i]; if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL)) goto out; } ret = acpi_get_psd_map(all_cpu_data); if (ret) { pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n"); goto out; } ret = cpufreq_register_driver(&cppc_cpufreq_driver); if (ret) goto out; return ret; out: for_each_possible_cpu(i) { cpu = all_cpu_data[i]; if (!cpu) break; free_cpumask_var(cpu->shared_cpu_map); kfree(cpu); } kfree(all_cpu_data); return -ENODEV; } static void __exit cppc_cpufreq_exit(void) { struct cppc_cpudata *cpu; int i; cpufreq_unregister_driver(&cppc_cpufreq_driver); for_each_possible_cpu(i) { cpu = all_cpu_data[i]; free_cpumask_var(cpu->shared_cpu_map); kfree(cpu); } kfree(all_cpu_data); } module_exit(cppc_cpufreq_exit); MODULE_AUTHOR("Ashwin Chaugule"); MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec"); MODULE_LICENSE("GPL"); late_initcall(cppc_cpufreq_init); static const struct acpi_device_id cppc_acpi_ids[] = { {ACPI_PROCESSOR_DEVICE_HID, }, {} }; MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);