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cpufreq: arm_big_little: add SCPI interface driver
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. SCPI Message Protocol is used to communicate with the SCPI. This patch adds a interface driver for adding OPPs and registering the arm_big_little cpufreq driver for such systems. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linux-pm@vger.kernel.org
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4 changed files with 136 additions and 0 deletions
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@ -9155,6 +9155,7 @@ L: linux-arm-kernel@lists.infradead.org
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S: Maintained
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F: Documentation/devicetree/bindings/arm/arm,scpi.txt
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F: drivers/clk/clk-scpi.c
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F: drivers/cpufreq/scpi-cpufreq.c
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F: drivers/firmware/arm_scpi.c
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F: include/linux/scpi_protocol.h
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@ -199,6 +199,16 @@ config ARM_SA1100_CPUFREQ
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config ARM_SA1110_CPUFREQ
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bool
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config ARM_SCPI_CPUFREQ
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tristate "SCPI based CPUfreq driver"
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depends on ARM_BIG_LITTLE_CPUFREQ && ARM_SCPI_PROTOCOL
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help
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This adds the CPUfreq driver support for ARM big.LITTLE platforms
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using SCPI protocol for CPU power management.
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This driver uses SCPI 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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@ -72,6 +72,7 @@ obj-$(CONFIG_ARM_S3C64XX_CPUFREQ) += s3c64xx-cpufreq.o
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obj-$(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-$(CONFIG_ARM_SCPI_CPUFREQ) += scpi-cpufreq.o
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obj-$(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_TEGRA124_CPUFREQ) += tegra124-cpufreq.o
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124
drivers/cpufreq/scpi-cpufreq.c
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124
drivers/cpufreq/scpi-cpufreq.c
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@ -0,0 +1,124 @@
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/*
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* System Control and Power Interface (SCPI) based CPUFreq Interface driver
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*
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* It provides necessary ops to arm_big_little cpufreq driver.
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*
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* Copyright (C) 2015 ARM Ltd.
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* Sudeep Holla <sudeep.holla@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/cpufreq.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/pm_opp.h>
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#include <linux/scpi_protocol.h>
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#include <linux/types.h>
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#include "arm_big_little.h"
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static struct scpi_ops *scpi_ops;
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static struct scpi_dvfs_info *scpi_get_dvfs_info(struct device *cpu_dev)
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{
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u8 domain = topology_physical_package_id(cpu_dev->id);
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if (domain < 0)
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return ERR_PTR(-EINVAL);
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return scpi_ops->dvfs_get_info(domain);
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}
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static int scpi_opp_table_ops(struct device *cpu_dev, bool remove)
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{
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int idx, ret = 0;
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struct scpi_opp *opp;
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struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev);
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if (IS_ERR(info))
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return PTR_ERR(info);
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if (!info->opps)
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return -EIO;
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for (opp = info->opps, idx = 0; idx < info->count; idx++, opp++) {
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if (remove)
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dev_pm_opp_remove(cpu_dev, opp->freq);
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else
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ret = dev_pm_opp_add(cpu_dev, opp->freq,
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opp->m_volt * 1000);
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if (ret) {
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dev_warn(cpu_dev, "failed to add opp %uHz %umV\n",
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opp->freq, opp->m_volt);
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while (idx-- > 0)
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dev_pm_opp_remove(cpu_dev, (--opp)->freq);
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return ret;
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}
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}
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return ret;
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}
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static int scpi_get_transition_latency(struct device *cpu_dev)
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{
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struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev);
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if (IS_ERR(info))
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return PTR_ERR(info);
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return info->latency;
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}
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static int scpi_init_opp_table(struct device *cpu_dev)
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{
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return scpi_opp_table_ops(cpu_dev, false);
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}
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static void scpi_free_opp_table(struct device *cpu_dev)
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{
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scpi_opp_table_ops(cpu_dev, true);
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}
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static struct cpufreq_arm_bL_ops scpi_cpufreq_ops = {
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.name = "scpi",
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.get_transition_latency = scpi_get_transition_latency,
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.init_opp_table = scpi_init_opp_table,
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.free_opp_table = scpi_free_opp_table,
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};
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static int scpi_cpufreq_probe(struct platform_device *pdev)
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{
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scpi_ops = get_scpi_ops();
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if (!scpi_ops)
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return -EIO;
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return bL_cpufreq_register(&scpi_cpufreq_ops);
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}
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static int scpi_cpufreq_remove(struct platform_device *pdev)
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{
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bL_cpufreq_unregister(&scpi_cpufreq_ops);
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scpi_ops = NULL;
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return 0;
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}
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static struct platform_driver scpi_cpufreq_platdrv = {
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.driver = {
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.name = "scpi-cpufreq",
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.owner = THIS_MODULE,
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},
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.probe = scpi_cpufreq_probe,
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.remove = scpi_cpufreq_remove,
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};
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module_platform_driver(scpi_cpufreq_platdrv);
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MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
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MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
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MODULE_LICENSE("GPL v2");
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