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kernel/linux-imx6_3.14.28/drivers/cpufreq/cris-etraxfs-cpufreq.c 2.29 KB
6b13f685e   김민수   BSP 최초 추가
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  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/cpufreq.h>
  #include <hwregs/reg_map.h>
  #include <arch/hwregs/reg_rdwr.h>
  #include <arch/hwregs/config_defs.h>
  #include <arch/hwregs/bif_core_defs.h>
  
  static int
  cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
  			 void *data);
  
  static struct notifier_block cris_sdram_freq_notifier_block = {
  	.notifier_call = cris_sdram_freq_notifier
  };
  
  static struct cpufreq_frequency_table cris_freq_table[] = {
  	{0x01, 6000},
  	{0x02, 200000},
  	{0, CPUFREQ_TABLE_END},
  };
  
  static unsigned int cris_freq_get_cpu_frequency(unsigned int cpu)
  {
  	reg_config_rw_clk_ctrl clk_ctrl;
  	clk_ctrl = REG_RD(config, regi_config, rw_clk_ctrl);
  	return clk_ctrl.pll ? 200000 : 6000;
  }
  
  static int cris_freq_target(struct cpufreq_policy *policy, unsigned int state)
  {
  	reg_config_rw_clk_ctrl clk_ctrl;
  	clk_ctrl = REG_RD(config, regi_config, rw_clk_ctrl);
  
  	local_irq_disable();
  
  	/* Even though we may be SMP they will share the same clock
  	 * so all settings are made on CPU0. */
  	if (cris_freq_table[state].frequency == 200000)
  		clk_ctrl.pll = 1;
  	else
  		clk_ctrl.pll = 0;
  	REG_WR(config, regi_config, rw_clk_ctrl, clk_ctrl);
  
  	local_irq_enable();
  
  	return 0;
  }
  
  static int cris_freq_cpu_init(struct cpufreq_policy *policy)
  {
  	return cpufreq_generic_init(policy, cris_freq_table, 1000000);
  }
  
  static struct cpufreq_driver cris_freq_driver = {
  	.get = cris_freq_get_cpu_frequency,
  	.verify = cpufreq_generic_frequency_table_verify,
  	.target_index = cris_freq_target,
  	.init = cris_freq_cpu_init,
  	.exit = cpufreq_generic_exit,
  	.name = "cris_freq",
  	.attr = cpufreq_generic_attr,
  };
  
  static int __init cris_freq_init(void)
  {
  	int ret;
  	ret = cpufreq_register_driver(&cris_freq_driver);
  	cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
  				  CPUFREQ_TRANSITION_NOTIFIER);
  	return ret;
  }
  
  static int
  cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
  			 void *data)
  {
  	int i;
  	struct cpufreq_freqs *freqs = data;
  	if (val == CPUFREQ_PRECHANGE) {
  		reg_bif_core_rw_sdram_timing timing =
  		    REG_RD(bif_core, regi_bif_core, rw_sdram_timing);
  		timing.cpd = (freqs->new == 200000 ? 0 : 1);
  
  		if (freqs->new == 200000)
  			for (i = 0; i < 50000; i++) ;
  		REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
  	}
  	return 0;
  }
  
  module_init(cris_freq_init);