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| author |   Pierre Gondois <Pierre.Gondois@arm.com> | 2022-05-18 11:09:00 +0200 |
|---|---|---|
| committer |   Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-05-19 19:45:34 +0200 |
| commit | 3cc30dd00a580ca0c9c0b01639841cfd72d10129 (patch) | |
| tree | ee1594495bd71716abe6d4dc3cc9091b137c2375 /drivers/cpufreq | |
| parent | ACPI: CPPC: Assume no transition latency if no PCCT (diff) | |
| download | linux-dev-3cc30dd00a580ca0c9c0b01639841cfd72d10129.tar.xz linux-dev-3cc30dd00a580ca0c9c0b01639841cfd72d10129.zip | |
cpufreq: CPPC: Enable fast_switch
The communication mean of the _CPC desired performance can be
PCC, System Memory, System IO, or Functional Fixed Hardware.
commit b7898fda5bc7 ("cpufreq: Support for fast frequency switching")
fast_switching is 'for switching CPU frequencies from interrupt
context'.
Writes to SystemMemory and SystemIo are fast and suitable this.
This is not the case for PCC and might not be the case for FFH.
Enable fast_switching for the cppc_cpufreq driver in above cases.
Add cppc_allow_fast_switch() to check the desired performance
register address space and set fast_switching accordingly.
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/cppc_cpufreq.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index 3eaa23d1aaf5..bb4118cea2a0 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -389,6 +389,27 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy, return ret; } +static unsigned int cppc_cpufreq_fast_switch(struct cpufreq_policy *policy, + unsigned int target_freq) +{ + struct cppc_cpudata *cpu_data = policy->driver_data; + unsigned int cpu = policy->cpu; + u32 desired_perf; + int ret; + + desired_perf = cppc_cpufreq_khz_to_perf(cpu_data, target_freq); + cpu_data->perf_ctrls.desired_perf = desired_perf; + ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls); + + if (ret) { + pr_debug("Failed to set target on CPU:%d. ret:%d\n", + cpu, ret); + return 0; + } + + return target_freq; +} + static int cppc_verify_policy(struct cpufreq_policy_data *policy) { cpufreq_verify_within_cpu_limits(policy); @@ -721,6 +742,8 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) goto out; } + policy->fast_switch_possible = cppc_allow_fast_switch(); + /* * If 'highest_perf' is greater than 'nominal_perf', we assume CPU Boost * is supported. @@ -866,6 +889,7 @@ static struct cpufreq_driver cppc_cpufreq_driver = { .verify = cppc_verify_policy, .target = cppc_cpufreq_set_target, .get = cppc_cpufreq_get_rate, + .fast_switch = cppc_cpufreq_fast_switch, .init = cppc_cpufreq_cpu_init, .exit = cppc_cpufreq_cpu_exit, .set_boost = cppc_cpufreq_set_boost, |