[PATCH v4 15/19] cpufreq/amd-pstate: Update cppc_req_cached for shared mem EPP writes

[Mario Limonciello <superm1@kernel.org>]

From: Mario Limonciello <mario.limonciello@amd.com>

On EPP only writes update the cached variable so that the min/max
performance controls don't need to be updated again.

Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index da6c39564c9ea..3c87e7cde2a4d 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -336,6 +336,7 @@ static int shmem_set_epp(struct cpufreq_policy *policy, u8 epp)
 {
 	struct amd_cpudata *cpudata = policy->driver_data;
 	struct cppc_perf_ctrls perf_ctrls;
+	u64 value;
 	int ret;
 
 	if (trace_amd_pstate_epp_perf_enabled()) {
@@ -362,6 +363,11 @@ static int shmem_set_epp(struct cpufreq_policy *policy, u8 epp)
 	}
 	WRITE_ONCE(cpudata->epp_cached, epp);
 
+	value = READ_ONCE(cpudata->cppc_req_cached);
+	value &= ~AMD_CPPC_EPP_PERF_MASK;
+	value |= FIELD_PREP(AMD_CPPC_EPP_PERF_MASK, epp);
+	WRITE_ONCE(cpudata->cppc_req_cached, value);
+
 	return ret;
 }
 
-- 
2.43.0