linux-kernel - [PATCH 2/7] cpufreq: apple-soc: Drop setting the PS2 field on M2+

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Message-ID: <20241211112244.18393-3-towinchenmi@gmail.com>
Date: Wed, 11 Dec 2024 19:19:29 +0800
From: Nick Chan <towinchenmi@...il.com>
To: Hector Martin <marcan@...can.st>,
	Sven Peter <sven@...npeter.dev>,
	Alyssa Rosenzweig <alyssa@...enzweig.io>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	asahi@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-pm@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Nick Chan <towinchenmi@...il.com>
Subject: [PATCH 2/7] cpufreq: apple-soc: Drop setting the PS2 field on M2+

From: Hector Martin <marcan@...can.st>

Newer device do not use this. It is not known what this field does,
but change the behavior to be same as macOS to be safe.

Signed-off-by: Hector Martin <marcan@...can.st>
Signed-off-by: Nick Chan <towinchenmi@...il.com>
---
 drivers/cpufreq/apple-soc-cpufreq.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/cpufreq/apple-soc-cpufreq.c b/drivers/cpufreq/apple-soc-cpufreq.c
index 4dcacab9b4bf..ad6c7b8f290c 100644
--- a/drivers/cpufreq/apple-soc-cpufreq.c
+++ b/drivers/cpufreq/apple-soc-cpufreq.c
@@ -25,7 +25,7 @@
 #define APPLE_DVFS_CMD			0x20
 #define APPLE_DVFS_CMD_BUSY		BIT(31)
 #define APPLE_DVFS_CMD_SET		BIT(25)
-#define APPLE_DVFS_CMD_PS2		GENMASK(16, 12)
+#define APPLE_DVFS_CMD_PS2		GENMASK(15, 12)
 #define APPLE_DVFS_CMD_PS1		GENMASK(4, 0)
 
 /* Same timebase as CPU counter (24MHz) */
@@ -55,6 +55,7 @@
 #define APPLE_DVFS_TRANSITION_TIMEOUT 100
 
 struct apple_soc_cpufreq_info {
+	bool has_ps2;
 	u64 max_pstate;
 	u64 cur_pstate_mask;
 	u64 cur_pstate_shift;
@@ -69,18 +70,21 @@ struct apple_cpu_priv {
 static struct cpufreq_driver apple_soc_cpufreq_driver;
 
 static const struct apple_soc_cpufreq_info soc_t8103_info = {
+	.has_ps2 = true,
 	.max_pstate = 15,
 	.cur_pstate_mask = APPLE_DVFS_STATUS_CUR_PS_T8103,
 	.cur_pstate_shift = APPLE_DVFS_STATUS_CUR_PS_SHIFT_T8103,
 };
 
 static const struct apple_soc_cpufreq_info soc_t8112_info = {
+	.has_ps2 = false,
 	.max_pstate = 31,
 	.cur_pstate_mask = APPLE_DVFS_STATUS_CUR_PS_T8112,
 	.cur_pstate_shift = APPLE_DVFS_STATUS_CUR_PS_SHIFT_T8112,
 };
 
 static const struct apple_soc_cpufreq_info soc_default_info = {
+	.has_ps2 = false,
 	.max_pstate = 15,
 	.cur_pstate_mask = 0, /* fallback */
 };
@@ -148,9 +152,12 @@ static int apple_soc_cpufreq_set_target(struct cpufreq_policy *policy,
 		return -EIO;
 	}
 
-	reg &= ~(APPLE_DVFS_CMD_PS1 | APPLE_DVFS_CMD_PS2);
+	reg &= ~APPLE_DVFS_CMD_PS1;
 	reg |= FIELD_PREP(APPLE_DVFS_CMD_PS1, pstate);
-	reg |= FIELD_PREP(APPLE_DVFS_CMD_PS2, pstate);
+	if (priv->info->has_ps2) {
+		reg &= ~APPLE_DVFS_CMD_PS2;
+		reg |= FIELD_PREP(APPLE_DVFS_CMD_PS2, pstate);
+	}
 	reg |= APPLE_DVFS_CMD_SET;
 
 	writeq_relaxed(reg, priv->reg_base + APPLE_DVFS_CMD);
-- 
2.47.1