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path: root/drivers/cpufreq/at32ap-cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/at32ap-cpufreq.c')
-rw-r--r--drivers/cpufreq/at32ap-cpufreq.c106
1 files changed, 59 insertions, 47 deletions
diff --git a/drivers/cpufreq/at32ap-cpufreq.c b/drivers/cpufreq/at32ap-cpufreq.c
index e0c38d9..856ad80 100644
--- a/drivers/cpufreq/at32ap-cpufreq.c
+++ b/drivers/cpufreq/at32ap-cpufreq.c
@@ -19,18 +19,10 @@
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/export.h>
+#include <linux/slab.h>
static struct clk *cpuclk;
-
-static int at32_verify_speed(struct cpufreq_policy *policy)
-{
- if (policy->cpu != 0)
- return -EINVAL;
-
- cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
- policy->cpuinfo.max_freq);
- return 0;
-}
+static struct cpufreq_frequency_table *freq_table;
static unsigned int at32_get_speed(unsigned int cpu)
{
@@ -43,74 +35,94 @@ static unsigned int at32_get_speed(unsigned int cpu)
static unsigned int ref_freq;
static unsigned long loops_per_jiffy_ref;
-static int at32_set_target(struct cpufreq_policy *policy,
- unsigned int target_freq,
- unsigned int relation)
+static int at32_set_target(struct cpufreq_policy *policy, unsigned int index)
{
- struct cpufreq_freqs freqs;
- long freq;
-
- /* Convert target_freq from kHz to Hz */
- freq = clk_round_rate(cpuclk, target_freq * 1000);
-
- /* Check if policy->min <= new_freq <= policy->max */
- if(freq < (policy->min * 1000) || freq > (policy->max * 1000))
- return -EINVAL;
-
- pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
+ unsigned int old_freq, new_freq;
- freqs.old = at32_get_speed(0);
- freqs.new = (freq + 500) / 1000;
- freqs.flags = 0;
+ old_freq = at32_get_speed(0);
+ new_freq = freq_table[index].frequency;
if (!ref_freq) {
- ref_freq = freqs.old;
+ ref_freq = old_freq;
loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
}
- cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
- if (freqs.old < freqs.new)
+ if (old_freq < new_freq)
boot_cpu_data.loops_per_jiffy = cpufreq_scale(
- loops_per_jiffy_ref, ref_freq, freqs.new);
- clk_set_rate(cpuclk, freq);
- if (freqs.new < freqs.old)
+ loops_per_jiffy_ref, ref_freq, new_freq);
+ clk_set_rate(cpuclk, new_freq * 1000);
+ if (new_freq < old_freq)
boot_cpu_data.loops_per_jiffy = cpufreq_scale(
- loops_per_jiffy_ref, ref_freq, freqs.new);
- cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
-
- pr_debug("cpufreq: set frequency %lu Hz\n", freq);
+ loops_per_jiffy_ref, ref_freq, new_freq);
return 0;
}
static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
{
+ unsigned int frequency, rate, min_freq;
+ int retval, steps, i;
+
if (policy->cpu != 0)
return -EINVAL;
cpuclk = clk_get(NULL, "cpu");
if (IS_ERR(cpuclk)) {
pr_debug("cpufreq: could not get CPU clk\n");
- return PTR_ERR(cpuclk);
+ retval = PTR_ERR(cpuclk);
+ goto out_err;
}
- policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
- policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
+ min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
+ frequency = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
policy->cpuinfo.transition_latency = 0;
- policy->cur = at32_get_speed(0);
- policy->min = policy->cpuinfo.min_freq;
- policy->max = policy->cpuinfo.max_freq;
- printk("cpufreq: AT32AP CPU frequency driver\n");
+ /*
+ * AVR32 CPU frequency rate scales in power of two between maximum and
+ * minimum, also add space for the table end marker.
+ *
+ * Further validate that the frequency is usable, and append it to the
+ * frequency table.
+ */
+ steps = fls(frequency / min_freq) + 1;
+ freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
+ GFP_KERNEL);
+ if (!freq_table) {
+ retval = -ENOMEM;
+ goto out_err_put_clk;
+ }
- return 0;
+ for (i = 0; i < (steps - 1); i++) {
+ rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
+
+ if (rate != frequency)
+ freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
+ else
+ freq_table[i].frequency = frequency;
+
+ frequency /= 2;
+ }
+
+ freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;
+
+ retval = cpufreq_table_validate_and_show(policy, freq_table);
+ if (!retval) {
+ printk("cpufreq: AT32AP CPU frequency driver\n");
+ return 0;
+ }
+
+ kfree(freq_table);
+out_err_put_clk:
+ clk_put(cpuclk);
+out_err:
+ return retval;
}
static struct cpufreq_driver at32_driver = {
.name = "at32ap",
.init = at32_cpufreq_driver_init,
- .verify = at32_verify_speed,
- .target = at32_set_target,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = at32_set_target,
.get = at32_get_speed,
.flags = CPUFREQ_STICKY,
};
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