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sh: add shared clock framework frequency table code

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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: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Magnus Damm 2009-05-25 08:10:28 +00:00 committed by Paul Mundt
parent c9904dd159
commit c94a85746f
2 changed files with 93 additions and 0 deletions
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18
arch/sh/include/asm/clock.h
View file

@ -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 */

75
arch/sh/kernel/cpu/clock.c
View file

@ -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)
{