/*
   * Blackfin core clock scaling
   *
   * Copyright 2008-2011 Analog Devices Inc.
   *
   * Licensed under the GPL-2 or later.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/init.h>
  #include <linux/clk.h>
  #include <linux/cpufreq.h>
  #include <linux/fs.h>
  #include <linux/delay.h>
  #include <asm/blackfin.h>
  #include <asm/time.h>
  #include <asm/dpmc.h>
  
  
  /* this is the table of CCLK frequencies, in Hz */
  /* .driver_data is the entry in the auxiliary dpm_state_table[] */
  static struct cpufreq_frequency_table bfin_freq_table[] = {
  	{
  		.frequency = CPUFREQ_TABLE_END,
  		.driver_data = 0,
  	},
  	{
  		.frequency = CPUFREQ_TABLE_END,
  		.driver_data = 1,
  	},
  	{
  		.frequency = CPUFREQ_TABLE_END,
  		.driver_data = 2,
  	},
  	{
  		.frequency = CPUFREQ_TABLE_END,
  		.driver_data = 0,
  	},
  };
  
  static struct bfin_dpm_state {
  	unsigned int csel; /* system clock divider */
  	unsigned int tscale; /* change the divider on the core timer interrupt */
  } dpm_state_table[3];
  
  #if defined(CONFIG_CYCLES_CLOCKSOURCE)
  /*
   * normalized to maximum frequency offset for CYCLES,
   * used in time-ts cycles clock source, but could be used
   * somewhere also.
   */
  unsigned long long __bfin_cycles_off;
  unsigned int __bfin_cycles_mod;
  #endif
  
  /**************************************************************************/
  static void __init bfin_init_tables(unsigned long cclk, unsigned long sclk)
  {
  
  	unsigned long csel, min_cclk;
  	int index;
  
  	/* Anomaly 273 seems to still exist on non-BF54x w/dcache turned on */
  #if ANOMALY_05000273 || ANOMALY_05000274 || \
  	(!(defined(CONFIG_BF54x) || defined(CONFIG_BF60x)) \
  	&& defined(CONFIG_BFIN_EXTMEM_DCACHEABLE))
  	min_cclk = sclk * 2;
  #else
  	min_cclk = sclk;
  #endif
  
  #ifndef CONFIG_BF60x
  	csel = ((bfin_read_PLL_DIV() & CSEL) >> 4);
  #else
  	csel = bfin_read32(CGU0_DIV) & 0x1F;
  #endif
  
  	for (index = 0;  (cclk >> index) >= min_cclk && csel <= 3 && index < 3; index++, csel++) {
  		bfin_freq_table[index].frequency = cclk >> index;
  #ifndef CONFIG_BF60x
  		dpm_state_table[index].csel = csel << 4; /* Shift now into PLL_DIV bitpos */
  #else
  		dpm_state_table[index].csel = csel;
  #endif
  		dpm_state_table[index].tscale =  (TIME_SCALE >> index) - 1;
  
  		pr_debug("cpufreq: freq:%d csel:0x%x tscale:%d
  ",
  						 bfin_freq_table[index].frequency,
  						 dpm_state_table[index].csel,
  						 dpm_state_table[index].tscale);
  	}
  	return;
  }
  
  static void bfin_adjust_core_timer(void *info)
  {
  	unsigned int tscale;
  	unsigned int index = *(unsigned int *)info;
  
  	/* we have to adjust the core timer, because it is using cclk */
  	tscale = dpm_state_table[index].tscale;
  	bfin_write_TSCALE(tscale);
  	return;
  }
  
  static unsigned int bfin_getfreq_khz(unsigned int cpu)
  {
  	/* Both CoreA/B have the same core clock */
  	return get_cclk() / 1000;
  }
  
  #ifdef CONFIG_BF60x
  unsigned long cpu_set_cclk(int cpu, unsigned long new)
  {
  	struct clk *clk;
  	int ret;
  
  	clk = clk_get(NULL, "CCLK");
  	if (IS_ERR(clk))
  		return -ENODEV;
  
  	ret = clk_set_rate(clk, new);
  	clk_put(clk);
  	return ret;
  }
  #endif
  
  static int bfin_target(struct cpufreq_policy *policy, unsigned int index)
  {
  #ifndef CONFIG_BF60x
  	unsigned int plldiv;
  #endif
  	static unsigned long lpj_ref;
  	static unsigned int  lpj_ref_freq;
  	unsigned int old_freq, new_freq;
  	int ret = 0;
  
  #if defined(CONFIG_CYCLES_CLOCKSOURCE)
  	cycles_t cycles;
  #endif
  
  	old_freq = bfin_getfreq_khz(0);
  	new_freq = bfin_freq_table[index].frequency;
  
  #ifndef CONFIG_BF60x
  	plldiv = (bfin_read_PLL_DIV() & SSEL) | dpm_state_table[index].csel;
  	bfin_write_PLL_DIV(plldiv);
  #else
  	ret = cpu_set_cclk(policy->cpu, new_freq * 1000);
  	if (ret != 0) {
  		WARN_ONCE(ret, "cpufreq set freq failed %d
  ", ret);
  		return ret;
  	}
  #endif
  	on_each_cpu(bfin_adjust_core_timer, &index, 1);
  #if defined(CONFIG_CYCLES_CLOCKSOURCE)
  	cycles = get_cycles();
  	SSYNC();
  	cycles += 10; /* ~10 cycles we lose after get_cycles() */
  	__bfin_cycles_off += (cycles << __bfin_cycles_mod) - (cycles << index);
  	__bfin_cycles_mod = index;
  #endif
  	if (!lpj_ref_freq) {
  		lpj_ref = loops_per_jiffy;
  		lpj_ref_freq = old_freq;
  	}
  	if (new_freq != old_freq) {
  		loops_per_jiffy = cpufreq_scale(lpj_ref,
  				lpj_ref_freq, new_freq);
  	}
  
  	return ret;
  }
  
  static int __bfin_cpu_init(struct cpufreq_policy *policy)
  {
  
  	unsigned long cclk, sclk;
  
  	cclk = get_cclk() / 1000;
  	sclk = get_sclk() / 1000;
  
  	if (policy->cpu == CPUFREQ_CPU)
  		bfin_init_tables(cclk, sclk);
  
  	policy->cpuinfo.transition_latency = 50000; /* 50us assumed */
  
  	return cpufreq_table_validate_and_show(policy, bfin_freq_table);
  }
  
  static struct cpufreq_driver bfin_driver = {
  	.verify = cpufreq_generic_frequency_table_verify,
  	.target_index = bfin_target,
  	.get = bfin_getfreq_khz,
  	.init = __bfin_cpu_init,
  	.name = "bfin cpufreq",
  	.attr = cpufreq_generic_attr,
  };
  
  static int __init bfin_cpu_init(void)
  {
  	return cpufreq_register_driver(&bfin_driver);
  }
  
  static void __exit bfin_cpu_exit(void)
  {
  	cpufreq_unregister_driver(&bfin_driver);
  }
  
  MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
  MODULE_DESCRIPTION("cpufreq driver for Blackfin");
  MODULE_LICENSE("GPL");
  
  module_init(bfin_cpu_init);
  module_exit(bfin_cpu_exit);