linux-kernel - [PATCH v8 5/7] cpufreq: cppc: Update MIN_PERF/MAX

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Message-ID: <20260206142658.72583-6-sumitg@nvidia.com>
Date: Fri, 6 Feb 2026 19:56:56 +0530
From: Sumit Gupta <sumitg@...dia.com>
To: <rafael@...nel.org>, <viresh.kumar@...aro.org>, <pierre.gondois@....com>,
	<zhenglifeng1@...wei.com>, <ionela.voinescu@....com>, <lenb@...nel.org>,
	<robert.moore@...el.com>, <corbet@....net>, <rdunlap@...radead.org>,
	<ray.huang@....com>, <gautham.shenoy@....com>, <mario.limonciello@....com>,
	<perry.yuan@....com>, <zhanjie9@...ilicon.com>, <yumpusamongus@...il.com>,
	<dedekind1@...il.com>, <linux-pm@...r.kernel.org>,
	<linux-acpi@...r.kernel.org>, <linux-doc@...r.kernel.org>,
	<acpica-devel@...ts.linux.dev>, <linux-kernel@...r.kernel.org>
CC: <linux-tegra@...r.kernel.org>, <treding@...dia.com>,
	<jonathanh@...dia.com>, <vsethi@...dia.com>, <ksitaraman@...dia.com>,
	<sanjayc@...dia.com>, <nhartman@...dia.com>, <mochs@...dia.com>,
	<bbasu@...dia.com>, <sumitg@...dia.com>
Subject: [PATCH v8 5/7] cpufreq: cppc: Update MIN_PERF/MAX_PERF in target callbacks

Update MIN_PERF and MAX_PERF registers from policy->min and policy->max
in the .target() and .fast_switch() callbacks. This allows controlling
performance bounds via standard scaling_min_freq and scaling_max_freq
sysfs interfaces.

Similar to intel_cpufreq which updates HWP min/max limits in .target(),
cppc_cpufreq now programs MIN_PERF/MAX_PERF along with DESIRED_PERF.
Since MIN_PERF/MAX_PERF can be updated even when auto_sel is disabled,
they are updated unconditionally.

Also program MIN_PERF/MAX_PERF in store_auto_select() when enabling
autonomous selection so the platform uses correct bounds immediately.

Suggested-by: Rafael J. Wysocki <rafael@...nel.org>
Signed-off-by: Sumit Gupta <sumitg@...dia.com>
---
 drivers/cpufreq/cppc_cpufreq.c | 41 +++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index e394cdac7f87..b277530ac420 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -287,6 +287,21 @@ static inline void cppc_freq_invariance_exit(void)
 }
 #endif /* CONFIG_ACPI_CPPC_CPUFREQ_FIE */
 
+static void cppc_cpufreq_update_perf_limits(struct cppc_cpudata *cpu_data,
+					    struct cpufreq_policy *policy)
+{
+	struct cppc_perf_caps *caps = &cpu_data->perf_caps;
+	u32 min_perf, max_perf;
+
+	min_perf = cppc_khz_to_perf(caps, policy->min);
+	max_perf = cppc_khz_to_perf(caps, policy->max);
+
+	cpu_data->perf_ctrls.min_perf =
+		clamp_t(u32, min_perf, caps->lowest_perf, caps->highest_perf);
+	cpu_data->perf_ctrls.max_perf =
+		clamp_t(u32, max_perf, caps->lowest_perf, caps->highest_perf);
+}
+
 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
 				   unsigned int target_freq,
 				   unsigned int relation)
@@ -298,6 +313,8 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
 
 	cpu_data->perf_ctrls.desired_perf =
 			cppc_khz_to_perf(&cpu_data->perf_caps, target_freq);
+	cppc_cpufreq_update_perf_limits(cpu_data, policy);
+
 	freqs.old = policy->cur;
 	freqs.new = target_freq;
 
@@ -322,8 +339,9 @@ static unsigned int cppc_cpufreq_fast_switch(struct cpufreq_policy *policy,
 
 	desired_perf = cppc_khz_to_perf(&cpu_data->perf_caps, target_freq);
 	cpu_data->perf_ctrls.desired_perf = desired_perf;
-	ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
+	cppc_cpufreq_update_perf_limits(cpu_data, policy);
 
+	ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls);
 	if (ret) {
 		pr_debug("Failed to set target on CPU:%d. ret:%d\n",
 			 cpu, ret);
@@ -869,6 +887,27 @@ static ssize_t store_auto_select(struct cpufreq_policy *policy,
 
 	cpu_data->perf_ctrls.auto_sel = val;
 
+	if (val) {
+		u32 old_min_perf = cpu_data->perf_ctrls.min_perf;
+		u32 old_max_perf = cpu_data->perf_ctrls.max_perf;
+
+		/*
+		 * When enabling autonomous selection, program MIN_PERF and
+		 * MAX_PERF from current policy limits so that the platform
+		 * uses the correct performance bounds immediately.
+		 */
+		cppc_cpufreq_update_perf_limits(cpu_data, policy);
+
+		ret = cppc_set_perf(policy->cpu, &cpu_data->perf_ctrls);
+		if (ret) {
+			cpu_data->perf_ctrls.min_perf = old_min_perf;
+			cpu_data->perf_ctrls.max_perf = old_max_perf;
+			cppc_set_auto_sel(policy->cpu, false);
+			cpu_data->perf_ctrls.auto_sel = false;
+			return ret;
+		}
+	}
+
 	return count;
 }
 
-- 
2.34.1