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kernel/linux-rt-4.4.41/drivers/cpufreq/scpi-cpufreq.c 3.05 KB
5113f6f70   김현기   kernel add
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  /*
   * System Control and Power Interface (SCPI) based CPUFreq Interface driver
   *
   * It provides necessary ops to arm_big_little cpufreq driver.
   *
   * Copyright (C) 2015 ARM Ltd.
   * Sudeep Holla <sudeep.holla@arm.com>
   *
   * 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 <linux/cpufreq.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/pm_opp.h>
  #include <linux/scpi_protocol.h>
  #include <linux/types.h>
  
  #include "arm_big_little.h"
  
  static struct scpi_ops *scpi_ops;
  
  static struct scpi_dvfs_info *scpi_get_dvfs_info(struct device *cpu_dev)
  {
  	int domain = topology_physical_package_id(cpu_dev->id);
  
  	if (domain < 0)
  		return ERR_PTR(-EINVAL);
  	return scpi_ops->dvfs_get_info(domain);
  }
  
  static int scpi_opp_table_ops(struct device *cpu_dev, bool remove)
  {
  	int idx, ret = 0;
  	struct scpi_opp *opp;
  	struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev);
  
  	if (IS_ERR(info))
  		return PTR_ERR(info);
  
  	if (!info->opps)
  		return -EIO;
  
  	for (opp = info->opps, idx = 0; idx < info->count; idx++, opp++) {
  		if (remove)
  			dev_pm_opp_remove(cpu_dev, opp->freq);
  		else
  			ret = dev_pm_opp_add(cpu_dev, opp->freq,
  					     opp->m_volt * 1000);
  		if (ret) {
  			dev_warn(cpu_dev, "failed to add opp %uHz %umV
  ",
  				 opp->freq, opp->m_volt);
  			while (idx-- > 0)
  				dev_pm_opp_remove(cpu_dev, (--opp)->freq);
  			return ret;
  		}
  	}
  	return ret;
  }
  
  static int scpi_get_transition_latency(struct device *cpu_dev)
  {
  	struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev);
  
  	if (IS_ERR(info))
  		return PTR_ERR(info);
  	return info->latency;
  }
  
  static int scpi_init_opp_table(struct device *cpu_dev)
  {
  	return scpi_opp_table_ops(cpu_dev, false);
  }
  
  static void scpi_free_opp_table(struct device *cpu_dev)
  {
  	scpi_opp_table_ops(cpu_dev, true);
  }
  
  static struct cpufreq_arm_bL_ops scpi_cpufreq_ops = {
  	.name	= "scpi",
  	.get_transition_latency = scpi_get_transition_latency,
  	.init_opp_table = scpi_init_opp_table,
  	.free_opp_table = scpi_free_opp_table,
  };
  
  static int scpi_cpufreq_probe(struct platform_device *pdev)
  {
  	scpi_ops = get_scpi_ops();
  	if (!scpi_ops)
  		return -EIO;
  
  	return bL_cpufreq_register(&scpi_cpufreq_ops);
  }
  
  static int scpi_cpufreq_remove(struct platform_device *pdev)
  {
  	bL_cpufreq_unregister(&scpi_cpufreq_ops);
  	scpi_ops = NULL;
  	return 0;
  }
  
  static struct platform_driver scpi_cpufreq_platdrv = {
  	.driver = {
  		.name	= "scpi-cpufreq",
  		.owner	= THIS_MODULE,
  	},
  	.probe		= scpi_cpufreq_probe,
  	.remove		= scpi_cpufreq_remove,
  };
  module_platform_driver(scpi_cpufreq_platdrv);
  
  MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
  MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
  MODULE_LICENSE("GPL v2");