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Commit c94a8574 authored by Magnus Damm's avatar Magnus Damm Committed by Paul Mundt
Browse files

sh: add shared clock framework frequency table code 



Add SuperH-specific clock framework helper functions:
- clk_rate_table_build() - build cpufreq table from divisors/multipliers
- clk_rate_table_round() - use cpufreq table to find matching frequency

Signed-off-by: default avatarMagnus Damm <damm@igel.co.jp>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent c9904dd1

arch/sh/include/asm/clock.h

+18 −0
Original line number Diff line number Diff line
@@ -100,4 +100,22 @@ enum clk_sh_algo_id { 
	IP_N1,

};



struct clk_div_mult_table {

	unsigned int *divisors;

	unsigned int nr_divisors;

	unsigned int *multipliers;

	unsigned int nr_multipliers;

};



struct cpufreq_frequency_table;

void clk_rate_table_build(struct clk *clk,

			  struct cpufreq_frequency_table *freq_table,

			  int nr_freqs,

			  struct clk_div_mult_table *src_table,

			  unsigned long *bitmap);



long clk_rate_table_round(struct clk *clk,

			  struct cpufreq_frequency_table *freq_table,

			  unsigned long rate);



#endif /* __ASM_SH_CLOCK_H */

arch/sh/kernel/cpu/clock.c

+75 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/err.h>

#include <linux/platform_device.h>

#include <linux/debugfs.h>

#include <linux/cpufreq.h>

#include <asm/clock.h>

#include <asm/machvec.h>
@@ -36,6 +37,80 @@ static LIST_HEAD(clock_list); 
static DEFINE_SPINLOCK(clock_lock);

static DEFINE_MUTEX(clock_list_sem);



void clk_rate_table_build(struct clk *clk,

			  struct cpufreq_frequency_table *freq_table,

			  int nr_freqs,

			  struct clk_div_mult_table *src_table,

			  unsigned long *bitmap)

{

	unsigned long mult, div;

	unsigned long freq;

	int i;



	for (i = 0; i < nr_freqs; i++) {

		div = 1;

		mult = 1;



		if (src_table->divisors && i < src_table->nr_divisors)

			div = src_table->divisors[i];



		if (src_table->multipliers && i < src_table->nr_multipliers)

			mult = src_table->multipliers[i];



		if (!div || !mult || (bitmap && !test_bit(i, bitmap)))

			freq = CPUFREQ_ENTRY_INVALID;

		else

			freq = clk->parent->rate * mult / div;



		freq_table[i].index = i;

		freq_table[i].frequency = freq;

	}



	/* Termination entry */

	freq_table[i].index = i;

	freq_table[i].frequency = CPUFREQ_TABLE_END;

}



long clk_rate_table_round(struct clk *clk,

			  struct cpufreq_frequency_table *freq_table,

			  unsigned long rate)

{

	unsigned long rate_error, rate_error_prev = ~0UL;

	unsigned long rate_best_fit = rate;

	unsigned long highest, lowest;

	int i;



	highest = lowest = 0;



	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {

		unsigned long freq = freq_table[i].frequency;



		if (freq == CPUFREQ_ENTRY_INVALID)

			continue;



		if (freq > highest)

			highest = freq;

		if (freq < lowest)

			lowest = freq;



		rate_error = abs(freq - rate);

		if (rate_error < rate_error_prev) {

			rate_best_fit = freq;

			rate_error_prev = rate_error;

		}



		if (rate_error == 0)

			break;

	}



	if (rate >= highest)

		rate_best_fit = highest;

	if (rate <= lowest)

		rate_best_fit = lowest;



	return rate_best_fit;

}



/* Used for clocks that always have same value as the parent clock */

unsigned long followparent_recalc(struct clk *clk)

{