[PATCH v2 07/21] cpufreq: amd: add acpi cppc function as the backend for legacy processors

[Huang Rui]

In some old Zen based processors, they are using the shared memory that
exposed from ACPI SBIOS.

Signed-off-by: Jinzhou Su <Jinzhou.Su@xxxxxxx>
Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
---
 drivers/cpufreq/amd-pstate.c | 58 ++++++++++++++++++++++++++++++++----
 1 file changed, 53 insertions(+), 5 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index aa4610ad186e..c9bee7b1698a 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -75,6 +75,19 @@ static inline int pstate_enable(bool enable)
 	return wrmsrl_safe(MSR_AMD_CPPC_ENABLE, enable ? 1 : 0);
 }
 
+static int cppc_enable(bool enable)
+{
+	int cpu, ret = 0;
+
+	for_each_online_cpu(cpu) {
+		ret = cppc_set_enable(cpu, enable ? 1 : 0);
+		if (ret)
+			return ret;
+	}
+
+	return ret;
+}
+
 DEFINE_STATIC_CALL(amd_pstate_enable, pstate_enable);
 
 static inline int amd_pstate_enable(bool enable)
@@ -105,6 +118,24 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
 	return 0;
 }
 
+static int cppc_init_perf(struct amd_cpudata *cpudata)
+{
+	struct cppc_perf_caps cppc_perf;
+
+	int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
+	if (ret)
+		return ret;
+
+	WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());
+
+	WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
+	WRITE_ONCE(cpudata->lowest_nonlinear_perf,
+		   cppc_perf.lowest_nonlinear_perf);
+	WRITE_ONCE(cpudata->lowest_perf, cppc_perf.lowest_perf);
+
+	return 0;
+}
+
 DEFINE_STATIC_CALL(amd_pstate_init_perf, pstate_init_perf);
 
 static inline int amd_pstate_init_perf(struct amd_cpudata *cpudata)
@@ -123,6 +154,19 @@ static void pstate_update_perf(struct amd_cpudata *cpudata, u32 min_perf,
 			      READ_ONCE(cpudata->cppc_req_cached));
 }
 
+static void cppc_update_perf(struct amd_cpudata *cpudata,
+			     u32 min_perf, u32 des_perf,
+			     u32 max_perf, bool fast_switch)
+{
+	struct cppc_perf_ctrls perf_ctrls;
+
+	perf_ctrls.max_perf = max_perf;
+	perf_ctrls.min_perf = min_perf;
+	perf_ctrls.desired_perf = des_perf;
+
+	cppc_set_perf(cpudata->cpu, &perf_ctrls);
+}
+
 DEFINE_STATIC_CALL(amd_pstate_update_perf, pstate_update_perf);
 
 static inline void
@@ -368,7 +412,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 	/* It will be updated by governor */
 	policy->cur = policy->cpuinfo.min_freq;
 
-	policy->fast_switch_possible = true;
+	if (boot_cpu_has(X86_FEATURE_AMD_CPPC))
+		policy->fast_switch_possible = true;
 
 	ret = freq_qos_add_request(&policy->constraints, &cpudata->req[0],
 				   FREQ_QOS_MIN, policy->cpuinfo.min_freq);
@@ -422,7 +467,6 @@ static struct cpufreq_driver amd_pstate_driver = {
 	.flags		= CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS,
 	.verify		= amd_pstate_verify,
 	.target		= amd_pstate_target,
-	.adjust_perf    = amd_pstate_adjust_perf,
 	.init		= amd_pstate_cpu_init,
 	.exit		= amd_pstate_cpu_exit,
 	.name		= "amd-pstate",
@@ -446,10 +490,14 @@ static int __init amd_pstate_init(void)
 		return -EEXIST;
 
 	/* capability check */
-	if (!boot_cpu_has(X86_FEATURE_AMD_CPPC)) {
-		pr_debug("%s, AMD CPPC MSR based functionality is not supported\n",
+	if (boot_cpu_has(X86_FEATURE_AMD_CPPC)) {
+		pr_debug("%s, AMD CPPC MSR based functionality is supported\n",
 			 __func__);
-		return -ENODEV;
+		amd_pstate_driver.adjust_perf = amd_pstate_adjust_perf;
+	} else {
+		static_call_update(amd_pstate_enable, cppc_enable);
+		static_call_update(amd_pstate_init_perf, cppc_init_perf);
+		static_call_update(amd_pstate_update_perf, cppc_update_perf);
 	}
 
 	/* enable amd pstate feature */
-- 
2.25.1