[PATCH v10 3/8] cpufreq: amd-pstate: Unify computation of {max,min,nominal,lowest_nonlinear}_freq

Perry Yuan
2024-03-25T03:04:19Z

Currently the amd_get_{min, max, nominal, lowest_nonlinear}_freq()
helpers computes the values of min_freq, max_freq, nominal_freq and
lowest_nominal_freq respectively afresh from
cppc_get_perf_caps(). This is not necessary as there are fields in
cpudata to cache these values.

To simplify this, add a single helper function named
amd_pstate_init_freq() which computes all these frequencies at once, and
caches it in cpudata.

Use the cached values everywhere else in the code.

Reviewed-by: Li Meng <li.meng@amd.com>
Tested-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@amd.com>
Co-developed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
drivers/cpufreq/amd-pstate.c | 126 ++++++++++++++++-------------------
1 file changed, 59 insertions(+), 67 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 2015c9fcc3c9..ba1baa6733e6 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -606,74 +606,22 @@ static void amd_pstate_adjust_perf(unsigned int cpu,

static int amd_get_min_freq(struct amd_cpudata *cpudata)
{
- struct cppc_perf_caps cppc_perf;
-
- int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
- if (ret)
- return ret;
-
- /* Switch to khz */
- return cppc_perf.lowest_freq * 1000;
+ return READ_ONCE(cpudata->min_freq);
}

static int amd_get_max_freq(struct amd_cpudata *cpudata)
{
- struct cppc_perf_caps cppc_perf;
- u32 max_perf, max_freq, nominal_freq, nominal_perf;
- u64 boost_ratio;
-
- int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
- if (ret)
- return ret;
-
- nominal_freq = cppc_perf.nominal_freq;
- nominal_perf = READ_ONCE(cpudata->nominal_perf);
- max_perf = READ_ONCE(cpudata->highest_perf);
-
- boost_ratio = div_u64(max_perf << SCHED_CAPACITY_SHIFT,
- nominal_perf);
-
- max_freq = nominal_freq * boost_ratio >> SCHED_CAPACITY_SHIFT;
-
- /* Switch to khz */
- return max_freq * 1000;
+ return READ_ONCE(cpudata->max_freq);
}

static int amd_get_nominal_freq(struct amd_cpudata *cpudata)
{
- struct cppc_perf_caps cppc_perf;
-
- int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
- if (ret)
- return ret;
-
- /* Switch to khz */
- return cppc_perf.nominal_freq * 1000;
+ return READ_ONCE(cpudata->nominal_freq);
}

static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
{
- struct cppc_perf_caps cppc_perf;
- u32 lowest_nonlinear_freq, lowest_nonlinear_perf,
- nominal_freq, nominal_perf;
- u64 lowest_nonlinear_ratio;
-
- int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
- if (ret)
- return ret;
-
- nominal_freq = cppc_perf.nominal_freq;
- nominal_perf = READ_ONCE(cpudata->nominal_perf);
-
- lowest_nonlinear_perf = cppc_perf.lowest_nonlinear_perf;
-
- lowest_nonlinear_ratio = div_u64(lowest_nonlinear_perf << SCHED_CAPACITY_SHIFT,
- nominal_perf);
-
- lowest_nonlinear_freq = nominal_freq * lowest_nonlinear_ratio >> SCHED_CAPACITY_SHIFT;
-
- /* Switch to khz */
- return lowest_nonlinear_freq * 1000;
+ return READ_ONCE(cpudata->lowest_nonlinear_freq);
}

static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
@@ -828,6 +776,53 @@ static void amd_pstate_update_limits(unsigned int cpu)
mutex_unlock(&amd_pstate_driver_lock);
}

+/**
+ * amd_pstate_init_freq: Initialize the max_freq, min_freq,
+ * nominal_freq and lowest_nonlinear_freq for
+ * the @cpudata object.
+ *
+ * Requires: highest_perf, lowest_perf, nominal_perf and
+ * lowest_nonlinear_perf members of @cpudata to be
+ * initialized.
+ *
+ * Returns 0 on success, non-zero value on failure.
+ */
+static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
+{
+ int ret;
+ u32 min_freq;
+ u32 highest_perf, max_freq;
+ u32 nominal_perf, nominal_freq;
+ u32 lowest_nonlinear_perf, lowest_nonlinear_freq;
+ u32 boost_ratio, lowest_nonlinear_ratio;
+ struct cppc_perf_caps cppc_perf;
+
+
+ ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
+ if (ret)
+ return ret;
+
+ min_freq = cppc_perf.lowest_freq * 1000;
+ nominal_freq = cppc_perf.nominal_freq * 1000;
+ nominal_perf = READ_ONCE(cpudata->nominal_perf);
+
+ highest_perf = READ_ONCE(cpudata->highest_perf);
+ boost_ratio = div_u64(highest_perf << SCHED_CAPACITY_SHIFT, nominal_perf);
+ max_freq = nominal_freq * boost_ratio >> SCHED_CAPACITY_SHIFT;
+
+ lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
+ lowest_nonlinear_ratio = div_u64(lowest_nonlinear_perf << SCHED_CAPACITY_SHIFT,
+ nominal_perf);
+ lowest_nonlinear_freq = nominal_freq * lowest_nonlinear_ratio >> SCHED_CAPACITY_SHIFT;
+
+ WRITE_ONCE(cpudata->min_freq, min_freq);
+ WRITE_ONCE(cpudata->lowest_nonlinear_freq, lowest_nonlinear_freq);
+ WRITE_ONCE(cpudata->nominal_freq, nominal_freq);
+ WRITE_ONCE(cpudata->max_freq, max_freq);
+
+ return 0;
+}
+
static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
{
int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
@@ -855,6 +850,10 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
if (ret)
goto free_cpudata1;

+ ret = amd_pstate_init_freq(cpudata);
+ if (ret)
+ goto free_cpudata1;
+
min_freq = amd_get_min_freq(cpudata);
max_freq = amd_get_max_freq(cpudata);
nominal_freq = amd_get_nominal_freq(cpudata);
@@ -896,13 +895,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
goto free_cpudata2;
}

- /* Initial processor data capability frequencies */
- cpudata->max_freq = max_freq;
- cpudata->min_freq = min_freq;
cpudata->max_limit_freq = max_freq;
cpudata->min_limit_freq = min_freq;
- cpudata->nominal_freq = nominal_freq;
- cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;

policy->driver_data = cpudata;

@@ -1317,6 +1311,10 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
if (ret)
goto free_cpudata1;

+ ret = amd_pstate_init_freq(cpudata);
+ if (ret)
+ goto free_cpudata1;
+
min_freq = amd_get_min_freq(cpudata);
max_freq = amd_get_max_freq(cpudata);
nominal_freq = amd_get_nominal_freq(cpudata);
@@ -1333,12 +1331,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
/* It will be updated by governor */
policy->cur = policy->cpuinfo.min_freq;

- /* Initial processor data capability frequencies */
- cpudata->max_freq = max_freq;
- cpudata->min_freq = min_freq;
- cpudata->nominal_freq = nominal_freq;
- cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
-
policy->driver_data = cpudata;

cpudata->epp_cached = amd_pstate_get_epp(cpudata, 0);
--
2.34.1