@@ -389,7 +389,8 @@ static inline int amd_pstate_cppc_enable(struct cpufreq_policy *policy)
static int msr_init_perf(struct amd_cpudata *cpudata)
{
union perf_cached perf = READ_ONCE(cpudata->perf);
- u64 cap1, numerator;
+ u64 cap1, numerator, cppc_req;
+ u8 min_perf;
int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
&cap1);
@@ -400,6 +401,22 @@ static int msr_init_perf(struct amd_cpudata *cpudata)
if (ret)
return ret;
+ ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &cppc_req);
+ if (ret)
+ return ret;
+
+ WRITE_ONCE(cpudata->cppc_req_cached, cppc_req);
+ min_perf = FIELD_GET(AMD_CPPC_MIN_PERF_MASK, cppc_req);
+
+ /*
+ * Clear out the min_perf part to check if the rest of the MSR is 0, if yes, this is an
+ * indication that the min_perf value is the one specified through the BIOS option
+ */
+ cppc_req &= ~(AMD_CPPC_MIN_PERF_MASK);
+
+ if (!cppc_req && min_perf)
+ perf.bios_min_perf = min_perf;
+
perf.highest_perf = numerator;
perf.max_limit_perf = numerator;
perf.min_limit_perf = FIELD_GET(AMD_CPPC_LOWEST_PERF_MASK, cap1);
@@ -580,20 +597,26 @@ static int amd_pstate_verify(struct cpufreq_policy_data *policy_data)
{
/*
* Initialize lower frequency limit (i.e.policy->min) with
- * lowest_nonlinear_frequency which is the most energy efficient
- * frequency. Override the initial value set by cpufreq core and
- * amd-pstate qos_requests.
+ * lowest_nonlinear_frequency or the min frequency (if) specified in BIOS,
+ * Override the initial value set by cpufreq core and amd-pstate qos_requests.
*/
if (policy_data->min == FREQ_QOS_MIN_DEFAULT_VALUE) {
struct cpufreq_policy *policy __free(put_cpufreq_policy) =
cpufreq_cpu_get(policy_data->cpu);
struct amd_cpudata *cpudata;
+ union perf_cached perf;
if (!policy)
return -EINVAL;
cpudata = policy->driver_data;
- policy_data->min = cpudata->lowest_nonlinear_freq;
+ perf = READ_ONCE(cpudata->perf);
+
+ if (perf.bios_min_perf)
+ policy_data->min = perf_to_freq(perf, cpudata->nominal_freq,
+ perf.bios_min_perf);
+ else
+ policy_data->min = cpudata->lowest_nonlinear_freq;
}
cpufreq_verify_within_cpu_limits(policy_data);
@@ -1041,6 +1064,9 @@ static void amd_pstate_cpu_exit(struct cpufreq_policy *policy)
{
struct amd_cpudata *cpudata = policy->driver_data;
+ /* Reset CPPC_REQ MSR to the BIOS value */
+ amd_pstate_update_perf(policy, cpudata->perf.bios_min_perf, 0U, 0U, 0U, false);
+
freq_qos_remove_request(&cpudata->req[1]);
freq_qos_remove_request(&cpudata->req[0]);
policy->fast_switch_possible = false;
@@ -1428,7 +1454,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
struct amd_cpudata *cpudata;
union perf_cached perf;
struct device *dev;
- u64 value;
int ret;
/*
@@ -1493,12 +1518,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
cpudata->epp_default = AMD_CPPC_EPP_BALANCE_PERFORMANCE;
}
- if (cpu_feature_enabled(X86_FEATURE_CPPC)) {
- ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value);
- if (ret)
- return ret;
- WRITE_ONCE(cpudata->cppc_req_cached, value);
- }
ret = amd_pstate_set_epp(policy, cpudata->epp_default);
if (ret)
return ret;
@@ -1518,6 +1537,9 @@ static void amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
struct amd_cpudata *cpudata = policy->driver_data;
if (cpudata) {
+ /* Reset CPPC_REQ MSR to the BIOS value */
+ amd_pstate_update_perf(policy, cpudata->perf.bios_min_perf, 0U, 0U, 0U, false);
+
kfree(cpudata);
policy->driver_data = NULL;
}
@@ -1575,13 +1597,27 @@ static int amd_pstate_cpu_online(struct cpufreq_policy *policy)
static int amd_pstate_cpu_offline(struct cpufreq_policy *policy)
{
- return 0;
+ struct amd_cpudata *cpudata = policy->driver_data;
+
+ /*
+ * Reset CPPC_REQ MSR to the BIOS value, this will allow us to retain the BIOS specified
+ * min_perf value across kexec reboots. If this CPU is just onlined normally after this, the
+ * limits, epp and desired perf will get reset to the cached values in cpudata struct
+ */
+ return amd_pstate_update_perf(policy, cpudata->perf.bios_min_perf, 0U, 0U, 0U, false);
}
static int amd_pstate_suspend(struct cpufreq_policy *policy)
{
struct amd_cpudata *cpudata = policy->driver_data;
+ /*
+ * Reset CPPC_REQ MSR to the BIOS value, this will allow us to retain the BIOS specified
+ * min_perf value across kexec reboots. If this CPU is just resumed back without kexec,
+ * the limits, epp and desired perf will get reset to the cached values in cpudata struct
+ */
+ amd_pstate_update_perf(policy, cpudata->perf.bios_min_perf, 0U, 0U, 0U, false);
+
/* invalidate to ensure it's rewritten during resume */
cpudata->cppc_req_cached = 0;
@@ -30,6 +30,7 @@
* @lowest_perf: the absolute lowest performance level of the processor
* @min_limit_perf: Cached value of the performance corresponding to policy->min
* @max_limit_perf: Cached value of the performance corresponding to policy->max
+ * @bios_min_perf: Cached perf value corresponding to the "Requested CPU Min Frequency" BIOS option
*/
union perf_cached {
struct {
@@ -39,6 +40,7 @@ union perf_cached {
u8 lowest_perf;
u8 min_limit_perf;
u8 max_limit_perf;
+ u8 bios_min_perf;
};
u64 val;
};
Initialize lower frequency limit to the "Requested CPU Min frequency" BIOS option (if it is set) value as part of the driver->init() callback. The BIOS specified value is passed by the PMFW as min_perf in CPPC_REQ MSR. To ensure that we don't mistake a stale min_perf value in CPPC_REQ value as the "Requested CPU Min frequency" during a kexec wakeup, reset the CPPC_REQ.min_perf value back to the BIOS specified one in the offline, exit and suspend callbacks. amd_pstate_target() and amd_pstate_epp_update_limit() which are invoked as part of the resume() and online() callbacks will take care of restoring the CPPC_REQ back to the latest sane values. Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com> --- drivers/cpufreq/amd-pstate.c | 62 ++++++++++++++++++++++++++++-------- drivers/cpufreq/amd-pstate.h | 2 ++ 2 files changed, 51 insertions(+), 13 deletions(-)