Axi Watchdog

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Last updated: Nov 14, 2024 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

  • 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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