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Axi Watchdog

Axi Watchdog

Owned by Confluence Wiki Admin (Unlicensed)
Last updated: May 28, 2025 by T, Harini

Introduction

This page describes the AXI WDT/Window watchdog driver which is available in mainline and Xilinx Linux distribution as
drivers/watchdog/of_xilinx_wdt.c

HW IP Features

  • Connects as a 32-bit slave on a AXI4-Lite interface

  • Watchdog timer with selectable timeout period and interrupt

  • Configurable WDT enable: enable-once or enable-repeatedly

  • One 32-bit free-running timebase counter with rollover interrupt-dual control register

  • Generic watchdog timer feature implemented.



Known Issues and Limitations

  • The current driver does not support the Axi Window watchdog feature.

Kernel Configuration

The following config options should be enabled in order to build the xilinx watchdog driver:
CONFIG_XILINX_WATCHDOG
CONFIG_WATCHDOG

¦ Symbol: XILINX_WATCHDOG [=y] ¦ ¦ Type : tristate ¦ ¦ Prompt: Xilinx Watchdog timer ¦ ¦ Location: ¦ ¦ -> Device Drivers ¦ ¦ (4) -> Watchdog Timer Support (WATCHDOG [=y]) ¦ ¦ Defined at drivers/watchdog/Kconfig:171 ¦ ¦ Depends on: WATCHDOG [=y] && HAS_IOMEM [=y] ¦ ¦ Selects: WATCHDOG_CORE [=y]



Devicetree

For more details, please refer
Documentation/devicetree/bindings/watchdog/of-xilinx-wdt.txt
Example:

watchdog { compatible = "xlnx,xps-timebase-wdt-1.0.a"; reg = <0x42600000 0x1000>; xlnx-wdt-enable-once = <0>; xlnx-wdt-interval = <0x1b>; };

Test procedure

Change the parameters using IOCTLs and see if reported values is correct.

# /bin/wdt_app /dev/watchdog1

Last boot is caused by : Power-On-Reset
The timeout was is 42 seconds
root@uart:~#


Mainline Status

  • This driver is currently in sync with the mainline kernel.


Change Log

  • 2025.1

    • None

  • 2024.2

    • None

  •  2024.1

    • Summary

      • watchdog: of_xilinx_wdt: Remove unnecessary clock disable call in the remove path

    • Commits

  •  2023.2

    • Summary

      • watchdog: of_xilinx_wdt: Revert Versal WWDT support

      • watchdog: of_xilinx_wdt: Use devm_clk_get_enabled() helper

      • watchdog: of_xilinx_wdt: Remove unnecessary clock disable call in the remove path

    • Commits

  •  2023.1

    • Summary

      • watchdog: of_xilinx_wdt: Update maximum timeout value based on ref clock 

    • Commits

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