[PATCH v8 07/13] cpufreq: amd-pstate: implement amd pstate cpu online and offline callback

[Perry Yuan]

From: Perry Yuan <Perry.Yuan@xxxxxxx>

Adds online and offline driver callback support to allow cpu cores go
offline and help to restore the previous working states when core goes
back online later for EPP driver mode.

Reviewed-by: Mario Limonciello <Mario.Limonciello@xxxxxxx>
Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
---
 drivers/cpufreq/amd-pstate.c | 82 ++++++++++++++++++++++++++++++++++++
 include/linux/amd-pstate.h   |  1 +
 2 files changed, 83 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 66b39457a312..cb647f55a169 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1020,6 +1020,86 @@ static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
 	return 0;
 }
 
+static void amd_pstate_epp_reenable(struct amd_cpudata *cpudata)
+{
+	struct cppc_perf_ctrls perf_ctrls;
+	u64 value, max_perf;
+	int ret;
+
+	ret = amd_pstate_enable(true);
+	if (ret)
+		pr_err("failed to enable amd pstate during resume, return %d\n", ret);
+
+	value = READ_ONCE(cpudata->cppc_req_cached);
+	max_perf = READ_ONCE(cpudata->highest_perf);
+
+	if (boot_cpu_has(X86_FEATURE_CPPC)) {
+		wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+	} else {
+		perf_ctrls.max_perf = max_perf;
+		perf_ctrls.energy_perf = AMD_CPPC_ENERGY_PERF_PREF(cpudata->epp_cached);
+		cppc_set_perf(cpudata->cpu, &perf_ctrls);
+	}
+}
+
+static int amd_pstate_epp_cpu_online(struct cpufreq_policy *policy)
+{
+	struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
+
+	pr_debug("AMD CPU Core %d going online\n", cpudata->cpu);
+
+	if (cppc_state == AMD_PSTATE_ACTIVE) {
+		amd_pstate_epp_reenable(cpudata);
+		cpudata->suspended = false;
+	}
+
+	return 0;
+}
+
+static void amd_pstate_epp_offline(struct cpufreq_policy *policy)
+{
+	struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
+	struct cppc_perf_ctrls perf_ctrls;
+	int min_perf;
+	u64 value;
+
+	min_perf = READ_ONCE(cpudata->lowest_perf);
+	value = READ_ONCE(cpudata->cppc_req_cached);
+
+	mutex_lock(&amd_pstate_limits_lock);
+	if (boot_cpu_has(X86_FEATURE_CPPC)) {
+		cpudata->epp_policy = CPUFREQ_POLICY_UNKNOWN;
+
+		/* Set max perf same as min perf */
+		value &= ~AMD_CPPC_MAX_PERF(~0L);
+		value |= AMD_CPPC_MAX_PERF(min_perf);
+		value &= ~AMD_CPPC_MIN_PERF(~0L);
+		value |= AMD_CPPC_MIN_PERF(min_perf);
+		wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+	} else {
+		perf_ctrls.desired_perf = 0;
+		perf_ctrls.max_perf = min_perf;
+		perf_ctrls.energy_perf = AMD_CPPC_ENERGY_PERF_PREF(HWP_EPP_BALANCE_POWERSAVE);
+		cppc_set_perf(cpudata->cpu, &perf_ctrls);
+	}
+	mutex_unlock(&amd_pstate_limits_lock);
+}
+
+static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy)
+{
+	struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
+
+	pr_debug("AMD CPU Core %d going offline\n", cpudata->cpu);
+
+	if (cpudata->suspended)
+		return 0;
+
+	if (cppc_state == AMD_PSTATE_ACTIVE)
+		amd_pstate_epp_offline(policy);
+
+	return 0;
+}
+
 static int amd_pstate_epp_verify_policy(struct cpufreq_policy_data *policy)
 {
 	cpufreq_verify_within_cpu_limits(policy);
@@ -1047,6 +1127,8 @@ static struct cpufreq_driver amd_pstate_epp_driver = {
 	.init		= amd_pstate_epp_cpu_init,
 	.exit		= amd_pstate_epp_cpu_exit,
 	.update_limits	= amd_pstate_epp_update_limits,
+	.offline	= amd_pstate_epp_cpu_offline,
+	.online		= amd_pstate_epp_cpu_online,
 	.name		= "amd_pstate_epp",
 	.attr		= amd_pstate_epp_attr,
 };
diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
index fe1aef743c09..1424b09ef543 100644
--- a/include/linux/amd-pstate.h
+++ b/include/linux/amd-pstate.h
@@ -82,6 +82,7 @@ struct amd_cpudata {
 	s16	epp_cached;
 	u32	policy;
 	u64	cppc_cap1_cached;
+	bool	suspended;
 };
 
 /**
-- 
2.34.1