[PATCH v4 10/11] arm64: dts: exynos: gs101: Add thermal management unit

Tudor Ambarus tudor.ambarus at linaro.org
Thu Apr 23 08:22:58 PDT 2026


Add the Thermal Management Unit (TMU) support for the Google GS101 SoC.

Describe the TMU using a consolidated SoC node that includes memory
resources for interrupt identification and a phandle to the ACPM IPC
interface for functional control.

Define thermal zones for the little, mid, and big CPU clusters, including
associated trip points and cooling-device maps to enable thermal
mitigation.

Signed-off-by: Tudor Ambarus <tudor.ambarus at linaro.org>
---
 arch/arm64/boot/dts/exynos/google/gs101-tmu.dtsi | 136 +++++++++++++++++++++++
 arch/arm64/boot/dts/exynos/google/gs101.dtsi     |  18 +++
 2 files changed, 154 insertions(+)

diff --git a/arch/arm64/boot/dts/exynos/google/gs101-tmu.dtsi b/arch/arm64/boot/dts/exynos/google/gs101-tmu.dtsi
new file mode 100644
index 000000000000..b27d1a539ec2
--- /dev/null
+++ b/arch/arm64/boot/dts/exynos/google/gs101-tmu.dtsi
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Google GS101 TMU configurations device tree source
+ *
+ * Copyright 2020 Samsung Electronics Co., Ltd.
+ * Copyright 2020 Google LLC.
+ * Copyright 2026 Linaro Ltd.
+ */
+
+#include <dt-bindings/thermal/thermal.h>
+
+/ {
+	thermal-zones {
+		cpucl2-thermal {
+			polling-delay-passive = <0>;
+			polling-delay = <0>;
+			thermal-sensors = <&tmu_top 0>;
+
+			trips {
+				big_switch_on: big-switch-on {
+					temperature = <80000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+
+				big_mitigate: big-mitigate {
+					temperature = <90000>;
+					hysteresis = <5000>;
+					type = "passive";
+				};
+
+				big_hot: big-hot {
+					temperature = <100000>;
+					hysteresis = <5000>;
+					type = "hot";
+				};
+
+				big_critical: big-critical {
+					temperature = <105000>;
+					hysteresis = <2000>;
+					type = "critical";
+				};
+			};
+
+			cooling-maps {
+				map0 {
+					trip = <&big_mitigate>;
+					cooling-device = <&cpu6 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu7 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+				};
+			};
+		};
+
+		cpucl1-thermal {
+			polling-delay-passive = <0>;
+			polling-delay = <0>;
+			thermal-sensors = <&tmu_top 1>;
+
+			trips {
+				mid_switch_on: mid-switch-on {
+					temperature = <80000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+
+				mid_mitigate: mid-mitigate {
+					temperature = <90000>;
+					hysteresis = <5000>;
+					type = "passive";
+				};
+
+				mid_hot: mid-hot {
+					temperature = <100000>;
+					hysteresis = <5000>;
+					type = "hot";
+				};
+
+				mid_critical: mid-critical {
+					temperature = <105000>;
+					hysteresis = <2000>;
+					type = "critical";
+				};
+			};
+
+			cooling-maps {
+				map0 {
+				     trip = <&mid_mitigate>;
+					cooling-device = <&cpu4 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu5 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+			       };
+			};
+		};
+
+		cpucl0-thermal {
+			polling-delay-passive = <0>;
+			polling-delay = <0>;
+			thermal-sensors = <&tmu_top 2>;
+
+			trips {
+				little_switch_on: little-switch-on {
+					temperature = <80000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+
+				little_mitigate: little-mitigate {
+					temperature = <90000>;
+					hysteresis = <5000>;
+					type = "passive";
+				};
+
+				little_hot: little-hot {
+					temperature = <100000>;
+					hysteresis = <5000>;
+					type = "hot";
+				};
+
+				little_critical: little-critical {
+					temperature = <105000>;
+					hysteresis = <2000>;
+					type = "critical";
+				};
+			};
+
+			cooling-maps {
+				map0 {
+					trip = <&little_mitigate>;
+					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu2 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu3 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+				};
+			};
+		};
+	};
+};
diff --git a/arch/arm64/boot/dts/exynos/google/gs101.dtsi b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
index d085f9fb0f62..4b8c7edaddb6 100644
--- a/arch/arm64/boot/dts/exynos/google/gs101.dtsi
+++ b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
@@ -74,6 +74,7 @@ cpu0: cpu at 0 {
 			compatible = "arm,cortex-a55";
 			reg = <0x0000>;
 			clocks = <&acpm_ipc GS101_CLK_ACPM_DVFS_CPUCL0>;
+			#cooling-cells = <2>;
 			enable-method = "psci";
 			cpu-idle-states = <&ananke_cpu_sleep>;
 			capacity-dmips-mhz = <250>;
@@ -86,6 +87,7 @@ cpu1: cpu at 100 {
 			compatible = "arm,cortex-a55";
 			reg = <0x0100>;
 			clocks = <&acpm_ipc GS101_CLK_ACPM_DVFS_CPUCL0>;
+			#cooling-cells = <2>;
 			enable-method = "psci";
 			cpu-idle-states = <&ananke_cpu_sleep>;
 			capacity-dmips-mhz = <250>;
@@ -98,6 +100,7 @@ cpu2: cpu at 200 {
 			compatible = "arm,cortex-a55";
 			reg = <0x0200>;
 			clocks = <&acpm_ipc GS101_CLK_ACPM_DVFS_CPUCL0>;
+			#cooling-cells = <2>;
 			enable-method = "psci";
 			cpu-idle-states = <&ananke_cpu_sleep>;
 			capacity-dmips-mhz = <250>;
@@ -110,6 +113,7 @@ cpu3: cpu at 300 {
 			compatible = "arm,cortex-a55";
 			reg = <0x0300>;
 			clocks = <&acpm_ipc GS101_CLK_ACPM_DVFS_CPUCL0>;
+			#cooling-cells = <2>;
 			enable-method = "psci";
 			cpu-idle-states = <&ananke_cpu_sleep>;
 			capacity-dmips-mhz = <250>;
@@ -122,6 +126,7 @@ cpu4: cpu at 400 {
 			compatible = "arm,cortex-a76";
 			reg = <0x0400>;
 			clocks = <&acpm_ipc GS101_CLK_ACPM_DVFS_CPUCL1>;
+			#cooling-cells = <2>;
 			enable-method = "psci";
 			cpu-idle-states = <&enyo_cpu_sleep>;
 			capacity-dmips-mhz = <620>;
@@ -134,6 +139,7 @@ cpu5: cpu at 500 {
 			compatible = "arm,cortex-a76";
 			reg = <0x0500>;
 			clocks = <&acpm_ipc GS101_CLK_ACPM_DVFS_CPUCL1>;
+			#cooling-cells = <2>;
 			enable-method = "psci";
 			cpu-idle-states = <&enyo_cpu_sleep>;
 			capacity-dmips-mhz = <620>;
@@ -146,6 +152,7 @@ cpu6: cpu at 600 {
 			compatible = "arm,cortex-x1";
 			reg = <0x0600>;
 			clocks = <&acpm_ipc GS101_CLK_ACPM_DVFS_CPUCL2>;
+			#cooling-cells = <2>;
 			enable-method = "psci";
 			cpu-idle-states = <&hera_cpu_sleep>;
 			capacity-dmips-mhz = <1024>;
@@ -158,6 +165,7 @@ cpu7: cpu at 700 {
 			compatible = "arm,cortex-x1";
 			reg = <0x0700>;
 			clocks = <&acpm_ipc GS101_CLK_ACPM_DVFS_CPUCL2>;
+			#cooling-cells = <2>;
 			enable-method = "psci";
 			cpu-idle-states = <&hera_cpu_sleep>;
 			capacity-dmips-mhz = <1024>;
@@ -639,6 +647,15 @@ watchdog_cl1: watchdog at 10070000 {
 			status = "disabled";
 		};
 
+		tmu_top: thermal-sensor at 100a0000 {
+			compatible = "google,gs101-tmu-top";
+			reg = <0x100a0000 0x800>;
+			clocks = <&cmu_misc CLK_GOUT_MISC_TMU_TOP_PCLK>;
+			interrupts = <GIC_SPI 769 IRQ_TYPE_LEVEL_HIGH 0>;
+			samsung,acpm-ipc = <&acpm_ipc>;
+			#thermal-sensor-cells = <1>;
+		};
+
 		trng: rng at 10141400 {
 			compatible = "google,gs101-trng",
 				     "samsung,exynos850-trng";
@@ -1861,3 +1878,4 @@ timer {
 };
 
 #include "gs101-pinctrl.dtsi"
+#include "gs101-tmu.dtsi"

-- 
2.54.0.545.g6539524ca2-goog




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