185 lines
		
	
	
		
			6.2 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			185 lines
		
	
	
		
			6.2 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
Tegra124 SOCTHERM thermal management system
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The SOCTHERM IP block contains thermal sensors, support for polled
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or interrupt-based thermal monitoring, CPU and GPU throttling based
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on temperature trip points, and handling external overcurrent
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notifications. It is also used to manage emergency shutdown in an
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overheating situation.
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Required properties :
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- compatible : For Tegra124, must contain "nvidia,tegra124-soctherm".
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  For Tegra132, must contain "nvidia,tegra132-soctherm".
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  For Tegra210, must contain "nvidia,tegra210-soctherm".
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- reg : Should contain at least 2 entries for each entry in reg-names:
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  - SOCTHERM register set
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  - Tegra CAR register set: Required for Tegra124 and Tegra210.
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  - CCROC register set: Required for Tegra132.
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- reg-names :  Should contain at least 2 entries:
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  - soctherm-reg
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  - car-reg
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  - ccroc-reg
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- interrupts : Defines the interrupt used by SOCTHERM
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- clocks : Must contain an entry for each entry in clock-names.
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  See ../clocks/clock-bindings.txt for details.
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- clock-names : Must include the following entries:
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  - tsensor
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  - soctherm
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- resets : Must contain an entry for each entry in reset-names.
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  See ../reset/reset.txt for details.
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- reset-names : Must include the following entries:
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  - soctherm
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- #thermal-sensor-cells : Should be 1. See ./thermal.txt for a description
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    of this property. See <dt-bindings/thermal/tegra124-soctherm.h> for a
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    list of valid values when referring to thermal sensors.
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- throttle-cfgs: A sub-node which is a container of configuration for each
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    hardware throttle events. These events can be set as cooling devices.
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  * throttle events: Sub-nodes must be named as "light" or "heavy".
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      Properties:
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      - nvidia,priority: Each throttles has its own throttle settings, so the
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        SW need to set priorities for various throttle, the HW arbiter can select
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        the final throttle settings.
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        Bigger value indicates higher priority, In general, higher priority
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        translates to lower target frequency. SW needs to ensure that critical
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        thermal alarms are given higher priority, and ensure that there is
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        no race if priority of two vectors is set to the same value.
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        The range of this value is 1~100.
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      - nvidia,cpu-throt-percent: This property is for Tegra124 and Tegra210.
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        It is the throttling depth of pulse skippers, it's the percentage
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        throttling.
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      - nvidia,cpu-throt-level: This property is only for Tegra132, it is the
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        level of pulse skippers, which used to throttle clock frequencies. It
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        indicates cpu clock throttling depth, and the depth can be programmed.
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        Must set as following values:
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        TEGRA_SOCTHERM_THROT_LEVEL_LOW, TEGRA_SOCTHERM_THROT_LEVEL_MED
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        TEGRA_SOCTHERM_THROT_LEVEL_HIGH, TEGRA_SOCTHERM_THROT_LEVEL_NONE
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      - #cooling-cells: Should be 1. This cooling device only support on/off state.
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        See ./thermal.txt for a description of this property.
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Note:
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- the "critical" type trip points will be set to SOC_THERM hardware as the
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shut down temperature. Once the temperature of this thermal zone is higher
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than it, the system will be shutdown or reset by hardware.
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- the "hot" type trip points will be set to SOC_THERM hardware as the throttle
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temperature. Once the the temperature of this thermal zone is higher
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than it, it will trigger the HW throttle event.
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Example :
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	soctherm@700e2000 {
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		compatible = "nvidia,tegra124-soctherm";
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		reg = <0x0 0x700e2000 0x0 0x600  /* SOC_THERM reg_base */
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			0x0 0x60006000 0x0 0x400 /* CAR reg_base */
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		reg-names = "soctherm-reg", "car-reg";
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		interrupts = <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>;
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		clocks = <&tegra_car TEGRA124_CLK_TSENSOR>,
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			<&tegra_car TEGRA124_CLK_SOC_THERM>;
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		clock-names = "tsensor", "soctherm";
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		resets = <&tegra_car 78>;
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		reset-names = "soctherm";
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		#thermal-sensor-cells = <1>;
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		throttle-cfgs {
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			/*
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			 * When the "heavy" cooling device triggered,
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			 * the HW will skip cpu clock's pulse in 85% depth
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			 */
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			throttle_heavy: heavy {
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				nvidia,priority = <100>;
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				nvidia,cpu-throt-percent = <85>;
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				#cooling-cells = <1>;
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			};
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			/*
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			 * When the "light" cooling device triggered,
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			 * the HW will skip cpu clock's pulse in 50% depth
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			 */
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			throttle_light: light {
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				nvidia,priority = <80>;
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				nvidia,cpu-throt-percent = <50>;
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				#cooling-cells = <1>;
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			};
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			/*
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			 * If these two devices are triggered in same time, the HW throttle
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			 * arbiter will select the highest priority as the final throttle
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			 * settings to skip cpu pulse.
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			 */
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		};
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	};
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Example: referring to Tegra132's "reg", "reg-names" and "throttle-cfgs" :
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	soctherm@700e2000 {
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		compatible = "nvidia,tegra132-soctherm";
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		reg = <0x0 0x700e2000 0x0 0x600  /* SOC_THERM reg_base */
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			0x0 0x70040000 0x0 0x200>; /* CCROC reg_base */;
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		reg-names = "soctherm-reg", "ccroc-reg";
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		throttle-cfgs {
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			/*
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			 * When the "heavy" cooling device triggered,
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			 * the HW will skip cpu clock's pulse in HIGH level
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			 */
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			throttle_heavy: heavy {
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				nvidia,priority = <100>;
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				nvidia,cpu-throt-level = <TEGRA_SOCTHERM_THROT_LEVEL_HIGH>;
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				#cooling-cells = <1>;
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			};
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			/*
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			 * When the "light" cooling device triggered,
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			 * the HW will skip cpu clock's pulse in MED level
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			 */
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			throttle_light: light {
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				nvidia,priority = <80>;
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				nvidia,cpu-throt-level = <TEGRA_SOCTHERM_THROT_LEVEL_MED>;
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				#cooling-cells = <1>;
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			};
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			/*
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			 * If these two devices are triggered in same time, the HW throttle
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			 * arbiter will select the highest priority as the final throttle
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			 * settings to skip cpu pulse.
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			 */
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		};
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	};
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Example: referring to thermal sensors :
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       thermal-zones {
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                cpu {
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                        polling-delay-passive = <1000>;
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                        polling-delay = <1000>;
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                        thermal-sensors =
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                                <&soctherm TEGRA124_SOCTHERM_SENSOR_CPU>;
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			trips {
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				cpu_shutdown_trip: shutdown-trip {
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					temperature = <102500>;
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					hysteresis = <1000>;
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					type = "critical";
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				};
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				cpu_throttle_trip: throttle-trip {
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					temperature = <100000>;
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					hysteresis = <1000>;
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					type = "hot";
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				};
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			};
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			cooling-maps {
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				map0 {
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					trip = <&cpu_throttle_trip>;
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					cooling-device = <&throttle_heavy 1 1>;
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				};
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			};
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                };
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	};
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