[PATCH v3 04/13] cpufreq: amd-pstate: prefetch cppc_req_cached value in amd_pstate_cpu_init()

From: Perry Yuan
Date: Tue Jul 12 2022 - 11:40:50 EST


This cppc_req_cached valued should be prefetched during
amd_pstate_cpu_init call period, then the amd_pstate_update() will get
correct cached value before updating the perf to change the cpu perf
level.

Signed-off-by: Perry Yuan <Perry.Yuan@xxxxxxx>
---
drivers/cpufreq/amd-pstate.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 43e6df9f67f6..e4904da54541 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -547,12 +547,17 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;

policy->driver_data = cpudata;
+ if (!shared_mem) {
+ ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL, &value);
+ if (ret)
+ return ret;
+ WRITE_ONCE(cpudata->cppc_hw_conf_cached, value);

- ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_HW_CTL, &value);
- if (ret)
- return ret;
- WRITE_ONCE(cpudata->cppc_hw_conf_cached, value);
-
+ ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value);
+ if (ret)
+ return ret;
+ WRITE_ONCE(cpudata->cppc_req_cached, value);
+ }
amd_pstate_boost_init(cpudata);

return 0;
--
2.25.1