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cpufreq: tegra194: get consistent cpuinfo_cur_freq 

Frequency returned by 'cpuinfo_cur_freq' using counters is not fixed
and keeps changing slightly. This change returns a consistent value
from freq_table. If the reconstructed frequency has acceptable delta
from the last written value, then return the frequency corresponding
to the last written ndiv value from freq_table. Otherwise, print a
warning and return the reconstructed freq.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
This commit is contained in:
Sumit Gupta 2020-10-14 15:06:11 +05:30 committed by Viresh Kumar
parent 75118c8ef9
commit 68b9cd7270
1 changed files with 53 additions and 9 deletions
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62
drivers/cpufreq/tegra194-cpufreq.c
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@ -180,9 +180,61 @@ static unsigned int tegra194_get_speed_common(u32 cpu, u32 delay)
return (rate_mhz * KHZ); /* in KHz */
}
static void get_cpu_ndiv(void *ndiv)
{
u64 ndiv_val;
asm volatile("mrs %0, s3_0_c15_c0_4" : "=r" (ndiv_val) : );
*(u64 *)ndiv = ndiv_val;
}
static void set_cpu_ndiv(void *data)
{
struct cpufreq_frequency_table *tbl = data;
u64 ndiv_val = (u64)tbl->driver_data;
asm volatile("msr s3_0_c15_c0_4, %0" : : "r" (ndiv_val));
}
static unsigned int tegra194_get_speed(u32 cpu)
{
return tegra194_get_speed_common(cpu, US_DELAY);
struct tegra194_cpufreq_data *data = cpufreq_get_driver_data();
struct cpufreq_frequency_table *pos;
unsigned int rate;
u64 ndiv;
int ret;
u32 cl;
smp_call_function_single(cpu, get_cpu_cluster, &cl, true);
/* reconstruct actual cpu freq using counters */
rate = tegra194_get_speed_common(cpu, US_DELAY);
/* get last written ndiv value */
ret = smp_call_function_single(cpu, get_cpu_ndiv, &ndiv, true);
if (WARN_ON_ONCE(ret))
return rate;
/*
* If the reconstructed frequency has acceptable delta from
* the last written value, then return freq corresponding
* to the last written ndiv value from freq_table. This is
* done to return consistent value.
*/
cpufreq_for_each_valid_entry(pos, data->tables[cl]) {
if (pos->driver_data != ndiv)
continue;
if (abs(pos->frequency - rate) > 115200) {
pr_warn("cpufreq: cpu%d,cur:%u,set:%u,set ndiv:%llu\n",
cpu, rate, pos->frequency, ndiv);
} else {
rate = pos->frequency;
}
break;
}
return rate;
}
static int tegra194_cpufreq_init(struct cpufreq_policy *policy)
@ -209,14 +261,6 @@ static int tegra194_cpufreq_init(struct cpufreq_policy *policy)
return 0;
}
static void set_cpu_ndiv(void *data)
{
struct cpufreq_frequency_table *tbl = data;
u64 ndiv_val = (u64)tbl->driver_data;
asm volatile("msr s3_0_c15_c0_4, %0" : : "r" (ndiv_val));
}
static int tegra194_cpufreq_set_target(struct cpufreq_policy *policy,
unsigned int index)
{