> ## Documentation Index
> Fetch the complete documentation index at: https://dragonwingdocs-staging.qualcomm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Thermal architecture

The thermal architecture shows how the Qualcomm Linux thermal framework interacts with temperature sensors (Tsens) hardware, cooling map interfaces, and user space clients.

<img src="https://mintcdn.com/qualcomm-staging/WZioBEQiRyWH3u4c/System/Power/media/k2c-perf/Thermal-architecture.svg?fit=max&auto=format&n=WZioBEQiRyWH3u4c&q=85&s=34b8c62cd1993ef1b0587b55cbb0e237" alt="Thermal Architecture Diagram" width="941" height="320" data-path="System/Power/media/k2c-perf/Thermal-architecture.svg" />

**Figure: Thermal architecture**

**Table: Description of the components of thermal architecture**

| Components of Thermal Architecture | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| ---------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Thermal device tree                | <ul><li>A thermal device tree consists of various thermal zones.</li><li>A thermal zone is configured for every Tsens.</li><li>Each thermal zone consists of sensor hardware information, different levels of thermal thresholds, and their respective cooling actions.</li><li>All rules for a thermal zone are defined in the device tree.</li></ul>                                                                                                      |
| Thermal framework                  | The thermal framework parses the thermal zone rules from the device tree and configures Tsens hardware to generate interrupts when temperature crosses the threshold.                                                                                                                                                                                                                                                                                       |
| Thermal governor                   | <ul><li>The thermal governor is a temperature monitor algorithm that controls the temperature of a thermal zone.</li><li>It mitigates the cooling devices associated with the zone and keeps the temperature within the limit.</li><li>On receiving an interrupt notification from Tsens hardware, the thermal framework uses a stepwise thermal governor to communicate the cooling actions to the cooling map interface (CPU frequency driver).</li></ul> |
| Cooling map interface              | <ul><li>A cooling map interface is a collection of devices that can be throttled to reduce the temperature of Qualcomm Linux.</li><li>Every trip instance of the thermal zone is associated with a cooling device.</li><li>The thermal core framework aggregates all the cooling device instance requests and places the aggregated requests to the cooling device.</li></ul>                                                                               |
| User space clients                 | User space clients use the following interfaces to communicate with the thermal framework:<br /><br /><ul><li>The `sysfs` interface is used to read the temperature of Tsens and kernel trip information.</li><li>The `Netlink` interface gets information on Tsens temperature notifications.</li></ul>                                                                                                                                                    |

## Next steps

* [Thermal mitigation policies](thermal-mitigation-policies)