cpufreq: add support for CPU DVFS based on SCMI message protocol
On some ARM based systems, a separate Cortex-M based System Control Processor(SCP) provides the overall power, clock, reset and system control including CPU DVFS. SCMI Message Protocol is used to communicate with the SCP. This patch adds a cpufreq driver for such systems using SCMI interface to drive CPU DVFS. Cc: linux-pm@vger.kernel.org Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Sudeep Holla
Родитель
b23688aefb
Коммит
99d6bdf338
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@ -13385,7 +13385,7 @@ L: linux-arm-kernel@lists.infradead.org
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S: Maintained
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F: Documentation/devicetree/bindings/arm/arm,sc[mp]i.txt
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F: drivers/clk/clk-sc[mp]i.c
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F: drivers/cpufreq/scpi-cpufreq.c
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F: drivers/cpufreq/sc[mp]i-cpufreq.c
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F: drivers/firmware/arm_scpi.c
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F: drivers/firmware/arm_scmi/
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F: include/linux/sc[mp]i_protocol.h
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@ -238,6 +238,17 @@ config ARM_SA1100_CPUFREQ
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config ARM_SA1110_CPUFREQ
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bool
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config ARM_SCMI_CPUFREQ
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tristate "SCMI based CPUfreq driver"
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depends on ARM_SCMI_PROTOCOL || COMPILE_TEST
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select PM_OPP
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help
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This adds the CPUfreq driver support for ARM platforms using SCMI
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protocol for CPU power management.
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This driver uses SCMI Message Protocol driver to interact with the
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firmware providing the CPU DVFS functionality.
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config ARM_SPEAR_CPUFREQ
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bool "SPEAr CPUFreq support"
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depends on PLAT_SPEAR
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@ -75,6 +75,7 @@ obj-$(CONFIG_ARM_S3C24XX_CPUFREQ_DEBUGFS) += s3c24xx-cpufreq-debugfs.o
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obj-$(CONFIG_ARM_S5PV210_CPUFREQ) += s5pv210-cpufreq.o
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obj-$(CONFIG_ARM_SA1100_CPUFREQ) += sa1100-cpufreq.o
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obj-$(CONFIG_ARM_SA1110_CPUFREQ) += sa1110-cpufreq.o
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obj-$(CONFIG_ARM_SCMI_CPUFREQ) += scmi-cpufreq.o
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obj-$(CONFIG_ARM_SCPI_CPUFREQ) += scpi-cpufreq.o
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obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
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obj-$(CONFIG_ARM_STI_CPUFREQ) += sti-cpufreq.o
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@ -0,0 +1,246 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* System Control and Power Interface (SCMI) based CPUFreq Interface driver
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*
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* Copyright (C) 2018 ARM Ltd.
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* Sudeep Holla <sudeep.holla@arm.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/cpumask.h>
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#include <linux/cpu_cooling.h>
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#include <linux/export.h>
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#include <linux/module.h>
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#include <linux/pm_opp.h>
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#include <linux/slab.h>
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#include <linux/scmi_protocol.h>
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#include <linux/types.h>
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struct scmi_data {
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int domain_id;
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struct device *cpu_dev;
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struct thermal_cooling_device *cdev;
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};
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static const struct scmi_handle *handle;
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static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
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{
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struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
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struct scmi_perf_ops *perf_ops = handle->perf_ops;
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struct scmi_data *priv = policy->driver_data;
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unsigned long rate;
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int ret;
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ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false);
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if (ret)
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return 0;
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return rate / 1000;
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}
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/*
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* perf_ops->freq_set is not a synchronous, the actual OPP change will
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* happen asynchronously and can get notified if the events are
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* subscribed for by the SCMI firmware
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*/
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static int
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scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
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{
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int ret;
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struct scmi_data *priv = policy->driver_data;
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struct scmi_perf_ops *perf_ops = handle->perf_ops;
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u64 freq = policy->freq_table[index].frequency * 1000;
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ret = perf_ops->freq_set(handle, priv->domain_id, freq, false);
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if (!ret)
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arch_set_freq_scale(policy->related_cpus, freq,
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policy->cpuinfo.max_freq);
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return ret;
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}
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static int
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scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
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{
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int cpu, domain, tdomain;
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struct device *tcpu_dev;
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domain = handle->perf_ops->device_domain_id(cpu_dev);
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if (domain < 0)
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return domain;
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for_each_possible_cpu(cpu) {
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if (cpu == cpu_dev->id)
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continue;
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tcpu_dev = get_cpu_device(cpu);
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if (!tcpu_dev)
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continue;
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tdomain = handle->perf_ops->device_domain_id(tcpu_dev);
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if (tdomain == domain)
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cpumask_set_cpu(cpu, cpumask);
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}
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return 0;
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}
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static int scmi_cpufreq_init(struct cpufreq_policy *policy)
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{
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int ret;
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unsigned int latency;
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struct device *cpu_dev;
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struct scmi_data *priv;
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struct cpufreq_frequency_table *freq_table;
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cpu_dev = get_cpu_device(policy->cpu);
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if (!cpu_dev) {
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pr_err("failed to get cpu%d device\n", policy->cpu);
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return -ENODEV;
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}
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ret = handle->perf_ops->add_opps_to_device(handle, cpu_dev);
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if (ret) {
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dev_warn(cpu_dev, "failed to add opps to the device\n");
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return ret;
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}
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ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
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if (ret) {
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dev_warn(cpu_dev, "failed to get sharing cpumask\n");
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return ret;
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}
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ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
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if (ret) {
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dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
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__func__, ret);
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return ret;
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}
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ret = dev_pm_opp_get_opp_count(cpu_dev);
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if (ret <= 0) {
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dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
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ret = -EPROBE_DEFER;
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goto out_free_opp;
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}
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv) {
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ret = -ENOMEM;
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goto out_free_opp;
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}
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ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
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if (ret) {
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dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
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goto out_free_priv;
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}
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priv->cpu_dev = cpu_dev;
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priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev);
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policy->driver_data = priv;
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ret = cpufreq_table_validate_and_show(policy, freq_table);
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if (ret) {
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dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
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ret);
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goto out_free_cpufreq_table;
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}
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/* SCMI allows DVFS request for any domain from any CPU */
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policy->dvfs_possible_from_any_cpu = true;
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latency = handle->perf_ops->get_transition_latency(handle, cpu_dev);
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if (!latency)
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latency = CPUFREQ_ETERNAL;
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policy->cpuinfo.transition_latency = latency;
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return 0;
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out_free_cpufreq_table:
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dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
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out_free_priv:
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kfree(priv);
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out_free_opp:
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dev_pm_opp_cpumask_remove_table(policy->cpus);
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return ret;
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}
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static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
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{
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struct scmi_data *priv = policy->driver_data;
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cpufreq_cooling_unregister(priv->cdev);
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dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
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kfree(priv);
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dev_pm_opp_cpumask_remove_table(policy->related_cpus);
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return 0;
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}
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static void scmi_cpufreq_ready(struct cpufreq_policy *policy)
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{
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struct scmi_data *priv = policy->driver_data;
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priv->cdev = of_cpufreq_cooling_register(policy);
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}
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static struct cpufreq_driver scmi_cpufreq_driver = {
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.name = "scmi",
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.flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
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CPUFREQ_NEED_INITIAL_FREQ_CHECK,
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.verify = cpufreq_generic_frequency_table_verify,
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.attr = cpufreq_generic_attr,
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.target_index = scmi_cpufreq_set_target,
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.get = scmi_cpufreq_get_rate,
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.init = scmi_cpufreq_init,
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.exit = scmi_cpufreq_exit,
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.ready = scmi_cpufreq_ready,
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};
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static int scmi_cpufreq_probe(struct scmi_device *sdev)
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{
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int ret;
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handle = sdev->handle;
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if (!handle || !handle->perf_ops)
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return -ENODEV;
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ret = cpufreq_register_driver(&scmi_cpufreq_driver);
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if (ret) {
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dev_err(&sdev->dev, "%s: registering cpufreq failed, err: %d\n",
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__func__, ret);
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}
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return ret;
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}
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static void scmi_cpufreq_remove(struct scmi_device *sdev)
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{
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cpufreq_unregister_driver(&scmi_cpufreq_driver);
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}
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static const struct scmi_device_id scmi_id_table[] = {
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{ SCMI_PROTOCOL_PERF },
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{ },
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};
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MODULE_DEVICE_TABLE(scmi, scmi_id_table);
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static struct scmi_driver scmi_cpufreq_drv = {
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.name = "scmi-cpufreq",
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.probe = scmi_cpufreq_probe,
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.remove = scmi_cpufreq_remove,
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.id_table = scmi_id_table,
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};
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module_scmi_driver(scmi_cpufreq_drv);
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MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
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MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
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MODULE_LICENSE("GPL v2");
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