| /* |
| * 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; |
| int ret = 0; |
| |
| cpu = all_cpu_data[policy->cpu]; |
| |
| cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz; |
| 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(); |
| |
| policy->min = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz / cpu->perf_caps.highest_perf; |
| policy->max = cppc_dmi_max_khz; |
| policy->cpuinfo.min_freq = policy->min; |
| policy->cpuinfo.max_freq = policy->max; |
| 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; |
| } |
| |
| cpumask_set_cpu(policy->cpu, policy->cpus); |
| 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) |
| kfree(all_cpu_data[i]); |
| |
| 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); |