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kernel/linux-imx6_3.14.28/drivers/cpufreq/cris-artpec3-cpufreq.c 2.25 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 <hwregs/reg_rdwr.h>
  #include <hwregs/clkgen_defs.h>
  #include <hwregs/ddr2_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_clkgen_rw_clk_ctrl clk_ctrl;
  	clk_ctrl = REG_RD(clkgen, regi_clkgen, rw_clk_ctrl);
  	return clk_ctrl.pll ? 200000 : 6000;
  }
  
  static int cris_freq_target(struct cpufreq_policy *policy, unsigned int state)
  {
  	reg_clkgen_rw_clk_ctrl clk_ctrl;
  	clk_ctrl = REG_RD(clkgen, regi_clkgen, 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(clkgen, regi_clkgen, 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_ddr2_rw_cfg cfg =
  		  REG_RD(ddr2, regi_ddr2_ctrl, rw_cfg);
  		cfg.ref_interval = (freqs->new == 200000 ? 1560 : 46);
  
  		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);