/*

   * clock scaling for the UniCore-II

   *
   * Code specific to PKUnity SoC and UniCore ISA
   *
   *	Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
   *	Copyright (C) 2001-2010 Guan Xuetao
   *
   * 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.
   */

  #include <linux/err.h>

  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/init.h>
  #include <linux/clk.h>
  #include <linux/cpufreq.h>
  
  #include <mach/hardware.h>
  
  static struct cpufreq_driver ucv2_driver;
  
  /* make sure that only the "userspace" governor is run
   * -- anything else wouldn't make sense on this platform, anyway.
   */

  static int ucv2_verify_speed(struct cpufreq_policy *policy)

  {
  	if (policy->cpu)
  		return -EINVAL;

  	cpufreq_verify_within_cpu_limits(policy);

  	return 0;
  }

  static int ucv2_target(struct cpufreq_policy *policy,
  			 unsigned int target_freq,
  			 unsigned int relation)
  {

  	struct cpufreq_freqs freqs;

  	int ret;

  	freqs.old = policy->cur;
  	freqs.new = target_freq;

  	cpufreq_freq_transition_begin(policy, &freqs);

  	ret = clk_set_rate(policy->clk, target_freq * 1000);

  	cpufreq_freq_transition_end(policy, &freqs, ret);

  	return ret;

  }
  
  static int __init ucv2_cpu_init(struct cpufreq_policy *policy)
  {
  	if (policy->cpu != 0)
  		return -EINVAL;

  	policy->min = policy->cpuinfo.min_freq = 250000;
  	policy->max = policy->cpuinfo.max_freq = 1000000;
  	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;

  	policy->clk = clk_get(NULL, "MAIN_CLK");

  	return PTR_ERR_OR_ZERO(policy->clk);

  }
  
  static struct cpufreq_driver ucv2_driver = {
  	.flags		= CPUFREQ_STICKY,
  	.verify		= ucv2_verify_speed,
  	.target		= ucv2_target,

  	.get		= cpufreq_generic_get,

  	.init		= ucv2_cpu_init,
  	.name		= "UniCore-II",
  };
  
  static int __init ucv2_cpufreq_init(void)
  {
  	return cpufreq_register_driver(&ucv2_driver);
  }
  
  arch_initcall(ucv2_cpufreq_init);