diff options
author | Magnus Damm <damm@igel.co.jp> | 2009-05-25 08:10:28 +0000 |
---|---|---|
committer | Paul Mundt <lethal@linux-sh.org> | 2009-05-26 17:08:39 +0900 |
commit | c94a85746f7bdc13035acdf88c130d7b6fa41bde (patch) | |
tree | 8aff35100dcb0a62c82452357ea267f92376dc7a /arch/sh/kernel/cpu | |
parent | c9904dd15922f349b5f06839e34b1723d4a75940 (diff) |
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: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel/cpu')
-rw-r--r-- | arch/sh/kernel/cpu/clock.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpu/clock.c b/arch/sh/kernel/cpu/clock.c index 012d23476a7..59764d6c5f4 100644 --- a/arch/sh/kernel/cpu/clock.c +++ b/arch/sh/kernel/cpu/clock.c @@ -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) { |