Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932101AbdI1NO6 (ORCPT ); Thu, 28 Sep 2017 09:14:58 -0400 Received: from foss.arm.com ([217.140.101.70]:57306 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932082AbdI1NO4 (ORCPT ); Thu, 28 Sep 2017 09:14:56 -0400 From: Sudeep Holla To: ALKML , LKML , DTML Cc: Sudeep Holla , Roy Franz , Harb Abdulhamid , Nishanth Menon , Arnd Bergmann , Loc Ho , Alexey Klimov , Ryan Harkin , Jassi Brar , "Rafael J. Wysocki" , Viresh Kumar , linux-pm@vger.kernel.org Subject: [PATCH v3 21/22] cpufreq: add support for CPU DVFS based on SCMI message protocol Date: Thu, 28 Sep 2017 14:11:45 +0100 Message-Id: <1506604306-20739-22-git-send-email-sudeep.holla@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1506604306-20739-1-git-send-email-sudeep.holla@arm.com> References: <1506604306-20739-1-git-send-email-sudeep.holla@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9829 Lines: 346 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: "Rafael J. Wysocki" Cc: Viresh Kumar Cc: linux-pm@vger.kernel.org Signed-off-by: Sudeep Holla --- MAINTAINERS | 2 +- drivers/cpufreq/Kconfig.arm | 11 ++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/scmi-cpufreq.c | 271 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 284 insertions(+), 1 deletion(-) create mode 100644 drivers/cpufreq/scmi-cpufreq.c diff --git a/MAINTAINERS b/MAINTAINERS index 32c184391aee..1733813c52d9 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12942,7 +12942,7 @@ L: linux-arm-kernel@lists.infradead.org S: Maintained F: Documentation/devicetree/bindings/arm/arm,sc[mp]i.txt F: drivers/clk/clk-sc[mp]i.c -F: drivers/cpufreq/scpi-cpufreq.c +F: drivers/cpufreq/sc[mp]i-cpufreq.c F: drivers/firmware/arm_scpi.c F: drivers/firmware/arm_scmi/ F: include/linux/sc[mp]i_protocol.h diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index bdce4488ded1..e21f84cbd9b4 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -205,6 +205,17 @@ config ARM_SA1100_CPUFREQ config ARM_SA1110_CPUFREQ bool +config ARM_SCMI_CPUFREQ + tristate "SCMI based CPUfreq driver" + depends on ARM_SCMI_PROTOCOL || COMPILE_TEST + select PM_OPP + help + This adds the CPUfreq driver support for ARM platforms using SCMI + protocol for CPU power management. + + This driver uses SCMI Message Protocol driver to interact with the + firmware providing the CPU DVFS functionality. + config ARM_SCPI_CPUFREQ tristate "SCPI based CPUfreq driver" depends on ARM_BIG_LITTLE_CPUFREQ && ARM_SCPI_PROTOCOL && COMMON_CLK_SCPI diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index c7af9b2a255e..1206207f9b62 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -71,6 +71,7 @@ obj-$(CONFIG_ARM_S3C64XX_CPUFREQ) += s3c64xx-cpufreq.o obj-$(CONFIG_ARM_S5PV210_CPUFREQ) += s5pv210-cpufreq.o obj-$(CONFIG_ARM_SA1100_CPUFREQ) += sa1100-cpufreq.o obj-$(CONFIG_ARM_SA1110_CPUFREQ) += sa1110-cpufreq.o +obj-$(CONFIG_ARM_SCMI_CPUFREQ) += scmi-cpufreq.o obj-$(CONFIG_ARM_SCPI_CPUFREQ) += scpi-cpufreq.o obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o obj-$(CONFIG_ARM_STI_CPUFREQ) += sti-cpufreq.o diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c new file mode 100644 index 000000000000..bc5385638eb4 --- /dev/null +++ b/drivers/cpufreq/scmi-cpufreq.c @@ -0,0 +1,271 @@ +/* + * System Control and Power Interface (SCMI) based CPUFreq Interface driver + * + * Copyright (C) 2017 ARM Ltd. + * Sudeep Holla + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct scmi_data { + int domain_id; + struct device *cpu_dev; + struct thermal_cooling_device *cdev; +}; + +static const struct scmi_handle *handle; + +unsigned int scmi_cpufreq_get_rate(unsigned int cpu) +{ + struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); + struct scmi_perf_ops *perf_ops = handle->perf_ops; + struct scmi_data *priv = policy->driver_data; + unsigned long rate; + int ret; + + ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false); + if (ret) + return 0; + return rate / 1000; +} + +/* + * perf_ops->freq_set is not a synchronous, the actual OPP change will + * happen asynchronously and can get notified if the events are + * subscribed for by the SCMI firmware + */ +static int +scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) +{ + struct scmi_data *priv = policy->driver_data; + struct scmi_perf_ops *perf_ops = handle->perf_ops; + u64 freq = policy->freq_table[index].frequency * 1000; + + return perf_ops->freq_set(handle, priv->domain_id, freq, false); +} + +static int +scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) +{ + int cpu, domain, tdomain; + struct device *tcpu_dev; + + domain = handle->perf_ops->device_domain_id(cpu_dev); + if (domain < 0) + return domain; + + for_each_possible_cpu(cpu) { + if (cpu == cpu_dev->id) + continue; + + tcpu_dev = get_cpu_device(cpu); + if (!tcpu_dev) + continue; + + tdomain = handle->perf_ops->device_domain_id(tcpu_dev); + if (tdomain == domain) + cpumask_set_cpu(cpu, cpumask); + } + + return 0; +} + +static int scmi_cpufreq_init(struct cpufreq_policy *policy) +{ + int ret; + unsigned int latency; + struct device *cpu_dev; + struct scmi_data *priv; + struct cpufreq_frequency_table *freq_table; + + cpu_dev = get_cpu_device(policy->cpu); + if (!cpu_dev) { + pr_err("failed to get cpu%d device\n", policy->cpu); + return -ENODEV; + } + + ret = handle->perf_ops->add_opps_to_device(cpu_dev); + if (ret) { + dev_warn(cpu_dev, "failed to add opps to the device\n"); + return ret; + } + + ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus); + if (ret) { + dev_warn(cpu_dev, "failed to get sharing cpumask\n"); + return ret; + } + + ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); + if (ret) { + dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", + __func__, ret); + return ret; + } + + /* + * We need OPP table to function and since OPPs are added by the + * platform, let's wait for the same. + */ + ret = dev_pm_opp_get_opp_count(cpu_dev); + if (ret <= 0) { + dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); + ret = -EPROBE_DEFER; + goto out_free_opp; + } + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) { + ret = -ENOMEM; + goto out_free_opp; + } + + ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); + if (ret) { + dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); + goto out_free_priv; + } + + priv->cpu_dev = cpu_dev; + priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev); + + policy->driver_data = priv; + + ret = cpufreq_table_validate_and_show(policy, freq_table); + if (ret) { + dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__, + ret); + goto out_free_cpufreq_table; + } + + /* SCMI allows DVFS request for any domain from any CPU */ + policy->dvfs_possible_from_any_cpu = true; + + latency = handle->perf_ops->get_transition_latency(cpu_dev); + if (!latency) + latency = CPUFREQ_ETERNAL; + + policy->cpuinfo.transition_latency = latency; + + return 0; + +out_free_cpufreq_table: + dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); +out_free_priv: + kfree(priv); +out_free_opp: + dev_pm_opp_cpumask_remove_table(policy->cpus); + + return ret; +} + +static int scmi_cpufreq_exit(struct cpufreq_policy *policy) +{ + struct scmi_data *priv = policy->driver_data; + + cpufreq_cooling_unregister(priv->cdev); + dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); + kfree(priv); + dev_pm_opp_cpumask_remove_table(policy->related_cpus); + + return 0; +} + +static void scmi_cpufreq_ready(struct cpufreq_policy *policy) +{ + struct scmi_data *priv = policy->driver_data; + struct device_node *np = of_node_get(priv->cpu_dev->of_node); + + if (WARN_ON(!np)) + return; + + if (of_find_property(np, "#cooling-cells", NULL)) { + u32 pcoeff = 0; + + of_property_read_u32(np, "dynamic-power-coefficient", + &pcoeff); + + priv->cdev = of_cpufreq_power_cooling_register(np, policy, + pcoeff, NULL); + if (IS_ERR(priv->cdev)) { + dev_err(priv->cpu_dev, + "running cpufreq without cooling device: %ld\n", + PTR_ERR(priv->cdev)); + + priv->cdev = NULL; + } + } + + of_node_put(np); +} + +static struct cpufreq_driver scmi_cpufreq_driver = { + .name = "scmi", + .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY | + CPUFREQ_NEED_INITIAL_FREQ_CHECK, + .verify = cpufreq_generic_frequency_table_verify, + .attr = cpufreq_generic_attr, + .target_index = scmi_cpufreq_set_target, + .get = scmi_cpufreq_get_rate, + .init = scmi_cpufreq_init, + .exit = scmi_cpufreq_exit, + .ready = scmi_cpufreq_ready, +}; + +static int scmi_cpufreq_probe(struct platform_device *pdev) +{ + int ret; + + handle = devm_scmi_handle_get(&pdev->dev); + + if (IS_ERR_OR_NULL(handle) || !handle->perf_ops) + return -EPROBE_DEFER; + + ret = cpufreq_register_driver(&scmi_cpufreq_driver); + if (ret) { + dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n", + __func__, ret); + } + + return ret; +} + +static int scmi_cpufreq_remove(struct platform_device *pdev) +{ + cpufreq_unregister_driver(&scmi_cpufreq_driver); + return 0; +} + +static struct platform_driver scmi_cpufreq_platdrv = { + .driver = { + .name = "scmi-cpufreq", + }, + .probe = scmi_cpufreq_probe, + .remove = scmi_cpufreq_remove, +}; +module_platform_driver(scmi_cpufreq_platdrv); + +MODULE_AUTHOR("Sudeep Holla "); +MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver"); +MODULE_LICENSE("GPL v2"); -- 2.7.4