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kernel/linux-rt-4.4.41/drivers/cpufreq/s3c2410-cpufreq.c 3.64 KB
5113f6f70   김현기   kernel add
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  /*
   * Copyright (c) 2006-2008 Simtec Electronics
   *	http://armlinux.simtec.co.uk/
   *	Ben Dooks <ben@simtec.co.uk>
   *
   * S3C2410 CPU Frequency scaling
   *
   * 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/init.h>
  #include <linux/module.h>
  #include <linux/interrupt.h>
  #include <linux/ioport.h>
  #include <linux/cpufreq.h>
  #include <linux/device.h>
  #include <linux/clk.h>
  #include <linux/err.h>
  #include <linux/io.h>
  
  #include <asm/mach/arch.h>
  #include <asm/mach/map.h>
  
  #include <mach/regs-clock.h>
  
  #include <plat/cpu.h>
  #include <plat/cpu-freq-core.h>
  
  /* Note, 2410A has an extra mode for 1:4:4 ratio, bit 2 of CLKDIV */
  
  static void s3c2410_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
  {
  	u32 clkdiv = 0;
  
  	if (cfg->divs.h_divisor == 2)
  		clkdiv |= S3C2410_CLKDIVN_HDIVN;
  
  	if (cfg->divs.p_divisor != cfg->divs.h_divisor)
  		clkdiv |= S3C2410_CLKDIVN_PDIVN;
  
  	__raw_writel(clkdiv, S3C2410_CLKDIVN);
  }
  
  static int s3c2410_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
  {
  	unsigned long hclk, fclk, pclk;
  	unsigned int hdiv, pdiv;
  	unsigned long hclk_max;
  
  	fclk = cfg->freq.fclk;
  	hclk_max = cfg->max.hclk;
  
  	cfg->freq.armclk = fclk;
  
  	s3c_freq_dbg("%s: fclk is %lu, max hclk %lu
  ",
  		      __func__, fclk, hclk_max);
  
  	hdiv = (fclk > cfg->max.hclk) ? 2 : 1;
  	hclk = fclk / hdiv;
  
  	if (hclk > cfg->max.hclk) {
  		s3c_freq_dbg("%s: hclk too big
  ", __func__);
  		return -EINVAL;
  	}
  
  	pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
  	pclk = hclk / pdiv;
  
  	if (pclk > cfg->max.pclk) {
  		s3c_freq_dbg("%s: pclk too big
  ", __func__);
  		return -EINVAL;
  	}
  
  	pdiv *= hdiv;
  
  	/* record the result */
  	cfg->divs.p_divisor = pdiv;
  	cfg->divs.h_divisor = hdiv;
  
  	return 0;
  }
  
  static struct s3c_cpufreq_info s3c2410_cpufreq_info = {
  	.max		= {
  		.fclk	= 200000000,
  		.hclk	= 100000000,
  		.pclk	=  50000000,
  	},
  
  	/* transition latency is about 5ms worst-case, so
  	 * set 10ms to be sure */
  	.latency	= 10000000,
  
  	.locktime_m	= 150,
  	.locktime_u	= 150,
  	.locktime_bits	= 12,
  
  	.need_pll	= 1,
  
  	.name		= "s3c2410",
  	.calc_iotiming	= s3c2410_iotiming_calc,
  	.set_iotiming	= s3c2410_iotiming_set,
  	.get_iotiming	= s3c2410_iotiming_get,
  
  	.set_fvco	= s3c2410_set_fvco,
  	.set_refresh	= s3c2410_cpufreq_setrefresh,
  	.set_divs	= s3c2410_cpufreq_setdivs,
  	.calc_divs	= s3c2410_cpufreq_calcdivs,
  
  	.debug_io_show	= s3c_cpufreq_debugfs_call(s3c2410_iotiming_debugfs),
  };
  
  static int s3c2410_cpufreq_add(struct device *dev,
  			       struct subsys_interface *sif)
  {
  	return s3c_cpufreq_register(&s3c2410_cpufreq_info);
  }
  
  static struct subsys_interface s3c2410_cpufreq_interface = {
  	.name		= "s3c2410_cpufreq",
  	.subsys		= &s3c2410_subsys,
  	.add_dev	= s3c2410_cpufreq_add,
  };
  
  static int __init s3c2410_cpufreq_init(void)
  {
  	return subsys_interface_register(&s3c2410_cpufreq_interface);
  }
  arch_initcall(s3c2410_cpufreq_init);
  
  static int s3c2410a_cpufreq_add(struct device *dev,
  				struct subsys_interface *sif)
  {
  	/* alter the maximum freq settings for S3C2410A. If a board knows
  	 * it only has a maximum of 200, then it should register its own
  	 * limits. */
  
  	s3c2410_cpufreq_info.max.fclk = 266000000;
  	s3c2410_cpufreq_info.max.hclk = 133000000;
  	s3c2410_cpufreq_info.max.pclk =  66500000;
  	s3c2410_cpufreq_info.name = "s3c2410a";
  
  	return s3c2410_cpufreq_add(dev, sif);
  }
  
  static struct subsys_interface s3c2410a_cpufreq_interface = {
  	.name		= "s3c2410a_cpufreq",
  	.subsys		= &s3c2410a_subsys,
  	.add_dev	= s3c2410a_cpufreq_add,
  };
  
  static int __init s3c2410a_cpufreq_init(void)
  {
  	return subsys_interface_register(&s3c2410a_cpufreq_interface);
  }
  arch_initcall(s3c2410a_cpufreq_init);