linux-kernel - [PATCH] cpufreq/amd-pstate: fix setting policy current frequency value

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Message-ID: <20240227071133.3405003-1-li.meng@amd.com>
Date: Tue, 27 Feb 2024 15:11:33 +0800
From: Meng Li <li.meng@....com>
To: "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>, Huang Rui
	<ray.huang@....com>
CC: <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<x86@...nel.org>, <linux-acpi@...r.kernel.org>, Shuah Khan
	<skhan@...uxfoundation.org>, <linux-kselftest@...r.kernel.org>, "Nathan
 Fontenot" <nathan.fontenot@....com>, Deepak Sharma <deepak.sharma@....com>,
	Alex Deucher <alexander.deucher@....com>, Mario Limonciello
	<mario.limonciello@....com>, Shimmer Huang <shimmer.huang@....com>, "Perry
 Yuan" <Perry.Yuan@....com>, Xiaojian Du <Xiaojian.Du@....com>, Viresh Kumar
	<viresh.kumar@...aro.org>, Borislav Petkov <bp@...en8.de>, Meng Li
	<li.meng@....com>
Subject: [PATCH] cpufreq/amd-pstate: fix setting policy current frequency value

When scaling min/max freq values were being setted,
the value of policy->cur need to update.

Signed-off-by: Meng Li <li.meng@....com>
---
 drivers/cpufreq/amd-pstate.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index aa5e57e27d2b..a1062bc06a60 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -437,6 +437,8 @@ static inline bool amd_pstate_sample(struct amd_cpudata *cpudata)
 static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
 			      u32 des_perf, u32 max_perf, bool fast_switch, int gov_flags)
 {
+	unsigned long max_freq;
+	struct cpufreq_policy *policy = cpufreq_cpu_get(cpudata->cpu);
 	u64 prev = READ_ONCE(cpudata->cppc_req_cached);
 	u64 value = prev;
 
@@ -446,6 +448,9 @@ static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
 			cpudata->max_limit_perf);
 	des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
 
+	max_freq = READ_ONCE(cpudata->max_limit_freq);
+	policy->cur = div_u64(des_perf * max_freq, max_perf);
+
 	if ((cppc_state == AMD_PSTATE_GUIDED) && (gov_flags & CPUFREQ_GOV_DYNAMIC_SWITCHING)) {
 		min_perf = des_perf;
 		des_perf = 0;
@@ -560,10 +565,9 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
 				   unsigned long capacity)
 {
 	unsigned long max_perf, min_perf, des_perf,
-		      cap_perf, lowest_nonlinear_perf, max_freq;
+		      cap_perf, lowest_nonlinear_perf;
 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 	struct amd_cpudata *cpudata = policy->driver_data;
-	unsigned int target_freq;
 
 	if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
 		amd_pstate_update_min_max_limit(policy);
@@ -571,7 +575,6 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
 
 	cap_perf = READ_ONCE(cpudata->highest_perf);
 	lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
-	max_freq = READ_ONCE(cpudata->max_freq);
 
 	des_perf = cap_perf;
 	if (target_perf < capacity)
@@ -589,8 +592,6 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
 		max_perf = min_perf;
 
 	des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
-	target_freq = div_u64(des_perf * max_freq, max_perf);
-	policy->cur = target_freq;
 
 	amd_pstate_update(cpudata, min_perf, des_perf, max_perf, true,
 			policy->governor->flags);
@@ -1449,6 +1450,12 @@ static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
 
 	amd_pstate_epp_update_limit(policy);
 
+	/*
+	 * policy->cur is never updated with the amd_pstate_epp driver, but it
+	 * is used as a stale frequency value. So, keep it within limits.
+	 */
+	policy->cur = policy->min;
+
 	return 0;
 }
 
-- 
2.34.1