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ACPI / CPPC: Add a CPUFreq driver for use with CPPC
This driver utilizes the methods introduced in a previous patch titled - "ACPI: Introduce CPU performance controls using CPPC" and enables usage with existing CPUFreq governors. Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> Reviewed-by: Al Stone <al.stone@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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3 changed files with 195 additions and 0 deletions
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@ -227,3 +227,20 @@ config ARM_PXA2xx_CPUFREQ
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This add the CPUFreq driver support for Intel PXA2xx SOCs.
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This add the CPUFreq driver support for Intel PXA2xx SOCs.
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If in doubt, say N.
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If in doubt, say N.
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config ACPI_CPPC_CPUFREQ
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tristate "CPUFreq driver based on the ACPI CPPC spec"
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depends on ACPI
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select ACPI_CPPC_LIB
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default n
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help
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This adds a CPUFreq driver which uses CPPC methods
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as described in the ACPIv5.1 spec. CPPC stands for
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Collaborative Processor Performance Controls. It
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is based on an abstract continuous scale of CPU
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performance values which allows the remote power
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processor to flexibly optimize for power and
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performance. CPPC relies on power management firmware
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support for its operation.
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If in doubt, say N.
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@ -76,6 +76,8 @@ obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
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obj-$(CONFIG_ARM_TEGRA20_CPUFREQ) += tegra20-cpufreq.o
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obj-$(CONFIG_ARM_TEGRA20_CPUFREQ) += tegra20-cpufreq.o
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obj-$(CONFIG_ARM_TEGRA124_CPUFREQ) += tegra124-cpufreq.o
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obj-$(CONFIG_ARM_TEGRA124_CPUFREQ) += tegra124-cpufreq.o
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obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
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obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
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obj-$(CONFIG_ACPI_CPPC_CPUFREQ) += cppc_cpufreq.o
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##################################################################################
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##################################################################################
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# PowerPC platform drivers
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# PowerPC platform drivers
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176
drivers/cpufreq/cppc_cpufreq.c
Normal file
176
drivers/cpufreq/cppc_cpufreq.c
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@ -0,0 +1,176 @@
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/*
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* CPPC (Collaborative Processor Performance Control) driver for
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* interfacing with the CPUfreq layer and governors. See
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* cppc_acpi.c for CPPC specific methods.
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*
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* (C) Copyright 2014, 2015 Linaro Ltd.
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* Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*/
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#define pr_fmt(fmt) "CPPC Cpufreq:" fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/vmalloc.h>
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#include <acpi/cppc_acpi.h>
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/*
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* These structs contain information parsed from per CPU
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* ACPI _CPC structures.
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* e.g. For each CPU the highest, lowest supported
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* performance capabilities, desired performance level
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* requested etc.
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*/
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static struct cpudata **all_cpu_data;
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static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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struct cpudata *cpu;
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struct cpufreq_freqs freqs;
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int ret = 0;
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cpu = all_cpu_data[policy->cpu];
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cpu->perf_ctrls.desired_perf = target_freq;
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freqs.old = policy->cur;
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freqs.new = target_freq;
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cpufreq_freq_transition_begin(policy, &freqs);
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ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
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cpufreq_freq_transition_end(policy, &freqs, ret != 0);
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if (ret)
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pr_debug("Failed to set target on CPU:%d. ret:%d\n",
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cpu->cpu, ret);
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return ret;
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}
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static int cppc_verify_policy(struct cpufreq_policy *policy)
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{
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cpufreq_verify_within_cpu_limits(policy);
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return 0;
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}
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static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
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{
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int cpu_num = policy->cpu;
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struct cpudata *cpu = all_cpu_data[cpu_num];
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int ret;
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cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
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ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
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if (ret)
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pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
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cpu->perf_caps.lowest_perf, cpu_num, ret);
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}
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static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
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{
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struct cpudata *cpu;
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unsigned int cpu_num = policy->cpu;
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int ret = 0;
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cpu = all_cpu_data[policy->cpu];
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cpu->cpu = cpu_num;
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ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
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if (ret) {
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pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
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cpu_num, ret);
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return ret;
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}
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policy->min = cpu->perf_caps.lowest_perf;
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policy->max = cpu->perf_caps.highest_perf;
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policy->cpuinfo.min_freq = policy->min;
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policy->cpuinfo.max_freq = policy->max;
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if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
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cpumask_copy(policy->cpus, cpu->shared_cpu_map);
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else {
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/* Support only SW_ANY for now. */
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pr_debug("Unsupported CPU co-ord type\n");
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return -EFAULT;
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}
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cpumask_set_cpu(policy->cpu, policy->cpus);
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cpu->cur_policy = policy;
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/* Set policy->cur to max now. The governors will adjust later. */
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policy->cur = cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
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ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
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if (ret)
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pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
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cpu->perf_caps.highest_perf, cpu_num, ret);
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return ret;
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}
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static struct cpufreq_driver cppc_cpufreq_driver = {
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.flags = CPUFREQ_CONST_LOOPS,
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.verify = cppc_verify_policy,
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.target = cppc_cpufreq_set_target,
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.init = cppc_cpufreq_cpu_init,
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.stop_cpu = cppc_cpufreq_stop_cpu,
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.name = "cppc_cpufreq",
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};
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static int __init cppc_cpufreq_init(void)
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{
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int i, ret = 0;
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struct cpudata *cpu;
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if (acpi_disabled)
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return -ENODEV;
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all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
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if (!all_cpu_data)
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return -ENOMEM;
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for_each_possible_cpu(i) {
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all_cpu_data[i] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
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if (!all_cpu_data[i])
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goto out;
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cpu = all_cpu_data[i];
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if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
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goto out;
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}
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ret = acpi_get_psd_map(all_cpu_data);
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if (ret) {
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pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
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goto out;
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}
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ret = cpufreq_register_driver(&cppc_cpufreq_driver);
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if (ret)
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goto out;
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return ret;
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out:
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for_each_possible_cpu(i)
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if (all_cpu_data[i])
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kfree(all_cpu_data[i]);
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kfree(all_cpu_data);
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return -ENODEV;
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}
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late_initcall(cppc_cpufreq_init);
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