Re: [PATCH v8 2/2] watchdog: Add driver for Gunyah Watchdog

From: Mukesh Ojha

Date: Thu Dec 11 2025 - 08:20:49 EST


On Tue, Nov 18, 2025 at 10:40:57AM +0000, Hrishabh Rajput wrote:
> On Qualcomm SoCs running under the Gunyah hypervisor, access to watchdog
> through MMIO is not available on all platforms. Depending on the
> hypervisor configuration, the watchdog is either fully emulated or
> exposed via ARM's SMC Calling Conventions (SMCCC) through the Vendor
> Specific Hypervisor Service Calls space.
>
> Add driver to support the SMC-based watchdog provided by the Gunyah
> Hypervisor. Device registration is done in the QCOM SCM driver after
> checks to restrict the watchdog initialization to Qualcomm devices
> running under Gunyah.
>
> Gunyah watchdog is not a hardware but an SMC-based vendor-specific
> hypervisor interface provided by the Gunyah hypervisor. The design
> involving QCOM SCM driver for registering the platform device has been
> devised to avoid adding non-hardware nodes to devicetree.
>
> Tested-by: Shivendra Pratap <shivendra.pratap@xxxxxxxxxxxxxxxx>
> Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> Signed-off-by: Hrishabh Rajput <hrishabh.rajput@xxxxxxxxxxxxxxxx>

I wanted to test the latest mem-inspect (Minidump) patches, but due to a
firmware bug, my last log after crash messages were not being captured. This
forced me to get another device. I had an SM8750, but it does not
support dump collection because of the missing Gunyah watchdog support
in the upstream. Luckily, this series came to the rescue, and now I am
able to capture the last crash messages.

Feel free to add

Tested-by: Mukesh Ojha <mukesh.ojha@xxxxxxxxxxxxxxxx>

to the series.

--
-Mukesh Ojha