117 lines
3.0 KiB
C
117 lines
3.0 KiB
C
/*
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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/cpu.h>
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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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int 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_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(const struct cpumask *cpumask)
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{
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int idx, ret;
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struct scpi_opp *opp;
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struct device *cpu_dev = get_cpu_device(cpumask_first(cpumask));
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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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ret = dev_pm_opp_add(cpu_dev, opp->freq, 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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ret = dev_pm_opp_set_sharing_cpus(cpu_dev, cpumask);
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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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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 = dev_pm_opp_cpumask_remove_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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},
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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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