[PATCH v2 0/3] arm64: dts: qcom: x1e80100: Enable APSS watchdog in EL2

[PATCH v2 0/3] arm64: dts: qcom: x1e80100: Enable APSS watchdog in EL2

[Abel Vesa]

On X1E80100 platforms, in EL2, the APSS watchdog is accessible.
The APSS WDT HW is compatible with the one from SC8280XP, SM8250 and the
like. So describe it in the SoC dtsi, mark it as reserved and enable it
the EL2 overlay. Also document its compatible.

Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
---
Changes in v2:
- Moved the node in the SoC dtsi and marked it as reserved.
  This allowed dropping the interrupt-parent property.
  As suggested by Stephan.
- Added separate patch to enable the node in EL2 overlay.
- Picked up Rob's R-b patch for bindings patch..
- Link to v1: https://patch.msgid.link/20251214-arm64-dts-qcom-x1e80100-el2-add-apss-wdt-v1-0-94ee80b8cbe7@oss.qualcomm.com

---
Abel Vesa (3):
      dt-bindings: watchdog: Document X1E80100 compatible
      arm64: dts: qcom: hamoa: Add the APSS watchdog
      arm64: dts: qcom: x1-el2: Enable the APSS watchdog

 Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml | 1 +
 arch/arm64/boot/dts/qcom/hamoa.dtsi                      | 8 ++++++++
 arch/arm64/boot/dts/qcom/x1-el2.dtso                     | 4 ++++
 3 files changed, 13 insertions(+)
---
base-commit: d9771d0dbe18dd643760431870a6abf9b0866bb0
change-id: 20251214-arm64-dts-qcom-x1e80100-el2-add-apss-wdt-e04ca6c99f0f

Best regards,
--  
Abel Vesa <abel.vesa@oss.qualcomm.com>

[PATCH v2 1/3] dt-bindings: watchdog: Document X1E80100 compatible

[Abel Vesa]

Document the compatible for the X1E80100 platform to the Qualcomm watchdog
binding. The HW implementation is compatible with the KPSS WDT.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
---
 Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml
index 54f5311ed016..f2c4bc900e5f 100644
--- a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml
+++ b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml
@@ -43,6 +43,7 @@ properties:
               - qcom,apss-wdt-sm6350
               - qcom,apss-wdt-sm8150
               - qcom,apss-wdt-sm8250
+              - qcom,apss-wdt-x1e80100
           - const: qcom,kpss-wdt
       - const: qcom,kpss-wdt
         deprecated: true

-- 
2.48.1

[PATCH v2 2/3] arm64: dts: qcom: hamoa: Add the APSS watchdog

[Abel Vesa]

The watchdog support in EL1 is SBSA compliant, handled by Gunyah
hypervisor, but in EL2. the watchdog is an instance of the APSS WDT HW
block, same as older platforms. So describe the APSS WDT node and mark
it as reserved, as it will only be enabled in EL2 overlay.

Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
---
 arch/arm64/boot/dts/qcom/hamoa.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/hamoa.dtsi b/arch/arm64/boot/dts/qcom/hamoa.dtsi
index a17900eacb20..b65dfad71c2f 100644
--- a/arch/arm64/boot/dts/qcom/hamoa.dtsi
+++ b/arch/arm64/boot/dts/qcom/hamoa.dtsi
@@ -8302,6 +8302,14 @@ gic_its: msi-controller@17040000 {
 			};
 		};
 
+		apss_watchdog: watchdog@17410000 {
+			compatible = "qcom,apss-wdt-x1e80100", "qcom,kpss-wdt";
+			reg = <0x0 0x17410000 0x0 0x1000>;
+			clocks = <&sleep_clk>;
+			interrupts = <GIC_SPI 0 IRQ_TYPE_EDGE_RISING>;
+			status = "reserved"; /* Accessible in EL2 only */
+		};
+
 		cpucp_mbox: mailbox@17430000 {
 			compatible = "qcom,x1e80100-cpucp-mbox";
 			reg = <0 0x17430000 0 0x10000>, <0 0x18830000 0 0x10000>;

-- 
2.48.1

[PATCH v2 3/3] arm64: dts: qcom: x1-el2: Enable the APSS watchdog

[Abel Vesa]

In EL2, the APSS watchdog is available. So enable it in the overlay.

Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
---
 arch/arm64/boot/dts/qcom/x1-el2.dtso | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/x1-el2.dtso b/arch/arm64/boot/dts/qcom/x1-el2.dtso
index 2d1c9151cf1b..175679be01eb 100644
--- a/arch/arm64/boot/dts/qcom/x1-el2.dtso
+++ b/arch/arm64/boot/dts/qcom/x1-el2.dtso
@@ -7,6 +7,10 @@
 /dts-v1/;
 /plugin/;
 
+&apss_watchdog {
+	status = "okay";
+};
+
 /* We can't and don't need to use zap shader in EL2 as linux can zap the gpu on it's own. */
 &gpu_zap_shader {
 	status = "disabled";

-- 
2.48.1

Re: [PATCH v2 2/3] arm64: dts: qcom: hamoa: Add the APSS watchdog

[Konrad Dybcio]

On 12/19/25 11:00 AM, Abel Vesa wrote:
> The watchdog support in EL1 is SBSA compliant, handled by Gunyah
> hypervisor, but in EL2. the watchdog is an instance of the APSS WDT HW
> block, same as older platforms. So describe the APSS WDT node and mark
> it as reserved, as it will only be enabled in EL2 overlay.
> 
> Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
> ---
>  arch/arm64/boot/dts/qcom/hamoa.dtsi | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/hamoa.dtsi b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> index a17900eacb20..b65dfad71c2f 100644
> --- a/arch/arm64/boot/dts/qcom/hamoa.dtsi
> +++ b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> @@ -8302,6 +8302,14 @@ gic_its: msi-controller@17040000 {
>  			};
>  		};
>  
> +		apss_watchdog: watchdog@17410000 {
> +			compatible = "qcom,apss-wdt-x1e80100", "qcom,kpss-wdt";
> +			reg = <0x0 0x17410000 0x0 0x1000>;
> +			clocks = <&sleep_clk>;
> +			interrupts = <GIC_SPI 0 IRQ_TYPE_EDGE_RISING>;
> +			status = "reserved"; /* Accessible in EL2 only */

This is technically incorrect - it's not accessible if Gunyah is
present, which is only somewhat related - if you run a different
hypervisor which doesn't explicitly block access to this region, you
can still access it even though Linux may be running at EL1

Konrad

Re: [PATCH v2 3/3] arm64: dts: qcom: x1-el2: Enable the APSS watchdog

[Dmitry Baryshkov]

On Fri, Dec 19, 2025 at 12:00:30PM +0200, Abel Vesa wrote:
> In EL2, the APSS watchdog is available. So enable it in the overlay.
> 
> Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
> ---
>  arch/arm64/boot/dts/qcom/x1-el2.dtso | 4 ++++
>  1 file changed, 4 insertions(+)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>


-- 
With best wishes
Dmitry

Re: [PATCH v2 1/3] dt-bindings: watchdog: Document X1E80100 compatible

[Guenter Roeck]

On 12/19/25 02:00, Abel Vesa wrote:
> Document the compatible for the X1E80100 platform to the Qualcomm watchdog
> binding. The HW implementation is compatible with the KPSS WDT.
> 
> Acked-by: Rob Herring (Arm) <robh@kernel.org>
> Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>   Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml
> index 54f5311ed016..f2c4bc900e5f 100644
> --- a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml
> +++ b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml
> @@ -43,6 +43,7 @@ properties:
>                 - qcom,apss-wdt-sm6350
>                 - qcom,apss-wdt-sm8150
>                 - qcom,apss-wdt-sm8250
> +              - qcom,apss-wdt-x1e80100
>             - const: qcom,kpss-wdt
>         - const: qcom,kpss-wdt
>           deprecated: true
> 

Re: [PATCH v2 2/3] arm64: dts: qcom: hamoa: Add the APSS watchdog

[Abel Vesa]

On 25-12-19 13:15:00, Konrad Dybcio wrote:
> On 12/19/25 11:00 AM, Abel Vesa wrote:
> > The watchdog support in EL1 is SBSA compliant, handled by Gunyah
> > hypervisor, but in EL2. the watchdog is an instance of the APSS WDT HW
> > block, same as older platforms. So describe the APSS WDT node and mark
> > it as reserved, as it will only be enabled in EL2 overlay.
> > 
> > Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
> > ---
> >  arch/arm64/boot/dts/qcom/hamoa.dtsi | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/qcom/hamoa.dtsi b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> > index a17900eacb20..b65dfad71c2f 100644
> > --- a/arch/arm64/boot/dts/qcom/hamoa.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> > @@ -8302,6 +8302,14 @@ gic_its: msi-controller@17040000 {
> >  			};
> >  		};
> >  
> > +		apss_watchdog: watchdog@17410000 {
> > +			compatible = "qcom,apss-wdt-x1e80100", "qcom,kpss-wdt";
> > +			reg = <0x0 0x17410000 0x0 0x1000>;
> > +			clocks = <&sleep_clk>;
> > +			interrupts = <GIC_SPI 0 IRQ_TYPE_EDGE_RISING>;
> > +			status = "reserved"; /* Accessible in EL2 only */
> 
> This is technically incorrect - it's not accessible if Gunyah is
> present, which is only somewhat related - if you run a different
> hypervisor which doesn't explicitly block access to this region, you
> can still access it even though Linux may be running at EL1

Fair enough. But in the case where you have a different hypervisor,
I guess the EL2 dtso should be used.

So, since AFAIK all devices come with Gunyah by default, it makes sense
to mark it as reserved (or disable it otherwise) and then enable it in EL2
dtso.

Re: [PATCH v2 2/3] arm64: dts: qcom: hamoa: Add the APSS watchdog

[Konrad Dybcio]

On 12/23/25 5:00 PM, Abel Vesa wrote:
> On 25-12-19 13:15:00, Konrad Dybcio wrote:
>> On 12/19/25 11:00 AM, Abel Vesa wrote:
>>> The watchdog support in EL1 is SBSA compliant, handled by Gunyah
>>> hypervisor, but in EL2. the watchdog is an instance of the APSS WDT HW
>>> block, same as older platforms. So describe the APSS WDT node and mark
>>> it as reserved, as it will only be enabled in EL2 overlay.
>>>
>>> Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
>>> ---
>>>  arch/arm64/boot/dts/qcom/hamoa.dtsi | 8 ++++++++
>>>  1 file changed, 8 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/qcom/hamoa.dtsi b/arch/arm64/boot/dts/qcom/hamoa.dtsi
>>> index a17900eacb20..b65dfad71c2f 100644
>>> --- a/arch/arm64/boot/dts/qcom/hamoa.dtsi
>>> +++ b/arch/arm64/boot/dts/qcom/hamoa.dtsi
>>> @@ -8302,6 +8302,14 @@ gic_its: msi-controller@17040000 {
>>>  			};
>>>  		};
>>>  
>>> +		apss_watchdog: watchdog@17410000 {
>>> +			compatible = "qcom,apss-wdt-x1e80100", "qcom,kpss-wdt";
>>> +			reg = <0x0 0x17410000 0x0 0x1000>;
>>> +			clocks = <&sleep_clk>;
>>> +			interrupts = <GIC_SPI 0 IRQ_TYPE_EDGE_RISING>;
>>> +			status = "reserved"; /* Accessible in EL2 only */
>>
>> This is technically incorrect - it's not accessible if Gunyah is
>> present, which is only somewhat related - if you run a different
>> hypervisor which doesn't explicitly block access to this region, you
>> can still access it even though Linux may be running at EL1
> 
> Fair enough. But in the case where you have a different hypervisor,
> I guess the EL2 dtso should be used.
> 
> So, since AFAIK all devices come with Gunyah by default, it makes sense
> to mark it as reserved (or disable it otherwise) and then enable it in EL2
> dtso.

I'm just stingy about the wording. Perhaps:

status = "reserved"; /* Reserved by Gunyah */

?

The patch looks good otherwise

Konrad

Re: [PATCH v2 2/3] arm64: dts: qcom: hamoa: Add the APSS watchdog

[Abel Vesa]

On 25-12-23 18:19:50, Konrad Dybcio wrote:
> On 12/23/25 5:00 PM, Abel Vesa wrote:
> > On 25-12-19 13:15:00, Konrad Dybcio wrote:
> >> On 12/19/25 11:00 AM, Abel Vesa wrote:
> >>> The watchdog support in EL1 is SBSA compliant, handled by Gunyah
> >>> hypervisor, but in EL2. the watchdog is an instance of the APSS WDT HW
> >>> block, same as older platforms. So describe the APSS WDT node and mark
> >>> it as reserved, as it will only be enabled in EL2 overlay.
> >>>
> >>> Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
> >>> ---
> >>>  arch/arm64/boot/dts/qcom/hamoa.dtsi | 8 ++++++++
> >>>  1 file changed, 8 insertions(+)
> >>>
> >>> diff --git a/arch/arm64/boot/dts/qcom/hamoa.dtsi b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> >>> index a17900eacb20..b65dfad71c2f 100644
> >>> --- a/arch/arm64/boot/dts/qcom/hamoa.dtsi
> >>> +++ b/arch/arm64/boot/dts/qcom/hamoa.dtsi
> >>> @@ -8302,6 +8302,14 @@ gic_its: msi-controller@17040000 {
> >>>  			};
> >>>  		};
> >>>  
> >>> +		apss_watchdog: watchdog@17410000 {
> >>> +			compatible = "qcom,apss-wdt-x1e80100", "qcom,kpss-wdt";
> >>> +			reg = <0x0 0x17410000 0x0 0x1000>;
> >>> +			clocks = <&sleep_clk>;
> >>> +			interrupts = <GIC_SPI 0 IRQ_TYPE_EDGE_RISING>;
> >>> +			status = "reserved"; /* Accessible in EL2 only */
> >>
> >> This is technically incorrect - it's not accessible if Gunyah is
> >> present, which is only somewhat related - if you run a different
> >> hypervisor which doesn't explicitly block access to this region, you
> >> can still access it even though Linux may be running at EL1
> > 
> > Fair enough. But in the case where you have a different hypervisor,
> > I guess the EL2 dtso should be used.
> > 
> > So, since AFAIK all devices come with Gunyah by default, it makes sense
> > to mark it as reserved (or disable it otherwise) and then enable it in EL2
> > dtso.
> 
> I'm just stingy about the wording. Perhaps:
> 
> status = "reserved"; /* Reserved by Gunyah */
> 
> ?

Sure, will do.

> 
> The patch looks good otherwise
> 
> Konrad

Thanks for reviewing,
Abel