Messages in this thread | | | Subject | Re: [Patch 1/2] cpufreq: tegra194: get consistent cpuinfo_cur_freq | From | Sumit Gupta <> | Date | Tue, 6 Oct 2020 00:10:15 +0530 |
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>> 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> >> --- >> drivers/cpufreq/tegra194-cpufreq.c | 66 ++++++++++++++++++++++++++++++++------ >> 1 file changed, 57 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/cpufreq/tegra194-cpufreq.c b/drivers/cpufreq/tegra194-cpufreq.c >> index e1d931c..d5b608d 100644 >> --- a/drivers/cpufreq/tegra194-cpufreq.c >> +++ b/drivers/cpufreq/tegra194-cpufreq.c >> @@ -180,9 +180,65 @@ 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 cpufreq_frequency_table *table, *pos; >> + struct cpufreq_policy policy; >> + unsigned int rate; >> + u64 ndiv; >> + int err; >> + >> + cpufreq_get_policy(&policy, cpu); >> + table = policy.freq_table; > > Maybe getting freq-table from cluster specific data would be better/faster. > will do the change in next patch version.
>> + >> + /* reconstruct actual cpu freq using counters*/ >> + rate = tegra194_get_speed_common(cpu, US_DELAY); >> + >> + /* get last written ndiv value*/ >> + err = smp_call_function_single(cpu, get_cpu_ndiv, &ndiv, true); >> + if (err) { >> + pr_err("cpufreq: Failed to get ndiv for CPU%d, ret:%d\n", >> + cpu, err); >> + return rate; >> + } >> + >> + /* if the reconstructed frequency has acceptable delta from > > Both have got the multi-line comments wrong. Format is wrong and every sentence > needs to start with a capital letter. > will correct.
>> + * 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, table) { >> + if (pos->driver_data != ndiv) >> + continue; >> + >> + if (abs(pos->frequency - rate) > 115200) { >> + pr_warn("cpufreq: high delta (%d) on CPU%d\n", >> + abs(pos->frequency - rate), cpu); >> + pr_warn("cpufreq: cur:%u, set:%u, set ndiv:%llu\n", >> + rate, pos->frequency, ndiv); > > Both of these can be merged in a single line I think. There is no need to print > delta as you already print both the frequencies. > Will do this also in next patch version.
>> + } else { >> + rate = pos->frequency; >> + } >> + break; >> + } >> + return rate; >> } >> >> static int tegra194_cpufreq_init(struct cpufreq_policy *policy) >> @@ -209,14 +265,6 @@ 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) >> { >> -- >> 2.7.4 > > -- > viresh >
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