On 2.02.2023 23:00, Douglas Anderson wrote:
> On a sc7180-based Chromebook, when I go to
> /sys/devices/system/cpu/cpu0/cpufreq I can see:
>
> cpuinfo_cur_freq:2995200
> cpuinfo_max_freq:1804800
> scaling_available_frequencies:300000 576000 ... 1708800 1804800
> scaling_cur_freq:1804800
> scaling_max_freq:1804800
>
> As you can see the `cpuinfo_cur_freq` is bogus. It turns out that this
> bogus info started showing up as of commit 205f5e984d30 ("cpufreq:
> qcom-hw: Fix the frequency returned by cpufreq_driver->get()"). That
> commit seems to assume that everyone is on the LMH bandwagon, but
> sc7180 isn't.
>
> Let's go back to the old code in the case where LMH isn't used.
>
> Fixes: 205f5e984d30 ("cpufreq: qcom-hw: Fix the frequency returned by cpufreq_driver->get()")
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---
Actually I hit the exact same issue when working on CPRh-aware
cpufreq with manual OSM programming.. LMh gets enabled by the firmware
on most recent platforms, but it's not the case for some old-timers.
I figured that adding a bool broken_lmh_freq in driver data would be
a good middleground between reverting that patch and ignoring the
issue, because it *does* matter what this function reports on LMh-
enabled platforms (yes, the subsystems are bluepilled between each
other and OSM/EPSS does not know the *real* throttled frequency),
but obviously we don't want to report 2.99Ghz otherwise..
I think 7280 had an issue where a SoC-specific compatible was not
introduced when the DT part was first merged, same goes for 6115.
6115 does have firmware-enabled LMh, not sure about 7280. In case
you wanted to go that route, I think it would be suitable to add
a blacklist of retroactively-broken platforms (match-by-machine-
compatible; don't scream at me bindings folks, I guess that's the
least messy solution) in addition to either matching the SoC-specific
compatible to epss_broken_lmh_driver_data.
Or we can forget about old DTs and just bind qcom,sc7180-cpufreq-hw
(and 7280, maybe? please check.) to this new driver data without
checking the machine compatible.
Konrad
>
> drivers/cpufreq/qcom-cpufreq-hw.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index 9505a812d6a1..957cf6bb8c05 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -143,40 +143,42 @@ static unsigned long qcom_lmh_get_throttle_freq(struct qcom_cpufreq_data *data)
> return lval * xo_rate;
> }
>
> -/* Get the current frequency of the CPU (after throttling) */
> -static unsigned int qcom_cpufreq_hw_get(unsigned int cpu)
> +/* Get the frequency requested by the cpufreq core for the CPU */
> +static unsigned int qcom_cpufreq_get_freq(unsigned int cpu)
> {
> struct qcom_cpufreq_data *data;
> + const struct qcom_cpufreq_soc_data *soc_data;
> struct cpufreq_policy *policy;
> + unsigned int index;
>
> policy = cpufreq_cpu_get_raw(cpu);
> if (!policy)
> return 0;
>
> data = policy->driver_data;
> + soc_data = qcom_cpufreq.soc_data;
>
> - return qcom_lmh_get_throttle_freq(data) / HZ_PER_KHZ;
> + index = readl_relaxed(data->base + soc_data->reg_perf_state);
> + index = min(index, LUT_MAX_ENTRIES - 1);
> +
> + return policy->freq_table[index].frequency;
> }
>
> -/* Get the frequency requested by the cpufreq core for the CPU */
> -static unsigned int qcom_cpufreq_get_freq(unsigned int cpu)
> +static unsigned int qcom_cpufreq_hw_get(unsigned int cpu)
> {
> struct qcom_cpufreq_data *data;
> - const struct qcom_cpufreq_soc_data *soc_data;
> struct cpufreq_policy *policy;
> - unsigned int index;
>
> policy = cpufreq_cpu_get_raw(cpu);
> if (!policy)
> return 0;
>
> data = policy->driver_data;
> - soc_data = qcom_cpufreq.soc_data;
>
> - index = readl_relaxed(data->base + soc_data->reg_perf_state);
> - index = min(index, LUT_MAX_ENTRIES - 1);
> + if (data->throttle_irq >= 0)
> + return qcom_lmh_get_throttle_freq(data) / HZ_PER_KHZ;
>
> - return policy->freq_table[index].frequency;
> + return qcom_cpufreq_get_freq(cpu);
> }
>
> static unsigned int qcom_cpufreq_hw_fast_switch(struct cpufreq_policy *policy,
