| Message ID | 20250610-wdt_reset_reason-v5-3-2d2835160ab5@oss.qualcomm.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add support to read the watchdog bootstatus from IMEM | expand |
On Tue, 10 Jun 2025 19:15:19 +0530, Kathiravan Thirumoorthy wrote: > Document the "sram" property for the watchdog device on Qualcomm > IPQ platforms. Use this property to extract the restart reason from > IMEM, which is updated by XBL. Populate the watchdog's bootstatus sysFS > entry with this information, when the system reboots due to a watchdog > timeout. > > Describe this property for the IPQ5424 watchdog device and extend support > to other targets subsequently. > > Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com> > --- > Changes in v5: > - Rename the property 'qcom,imem' to 'sram' > Changes in v4: > - New patch > --- > .../devicetree/bindings/watchdog/qcom-wdt.yaml | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > My bot found errors running 'make dt_binding_check' on your patch: yamllint warnings/errors: dtschema/dtc warnings/errors: /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/dma/stericsson,dma40.example.dtb: dma-controller@801c0000 (stericsson,db8500-dma40): sram:0: [4294967295, 4294967295] is too long from schema $id: http://devicetree.org/schemas/dma/stericsson,dma40.yaml# doc reference errors (make refcheckdocs): See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20250610-wdt_reset_reason-v5-3-2d2835160ab5@oss.qualcomm.com The base for the series is generally the latest rc1. A different dependency should be noted in *this* patch. If you already ran 'make dt_binding_check' and didn't see the above error(s), then make sure 'yamllint' is installed and dt-schema is up to date: pip3 install dtschema --upgrade Please check and re-submit after running the above command yourself. Note that DT_SCHEMA_FILES can be set to your schema file to speed up checking your schema. However, it must be unset to test all examples with your schema.
On Tue, Jun 10, 2025 at 07:15:19PM +0530, Kathiravan Thirumoorthy wrote: > Document the "sram" property for the watchdog device on Qualcomm > IPQ platforms. Use this property to extract the restart reason from > IMEM, which is updated by XBL. Populate the watchdog's bootstatus sysFS > entry with this information, when the system reboots due to a watchdog > timeout. > > Describe this property for the IPQ5424 watchdog device and extend support > to other targets subsequently. > > Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com> > --- > Changes in v5: > - Rename the property 'qcom,imem' to 'sram' > Changes in v4: > - New patch > --- > .../devicetree/bindings/watchdog/qcom-wdt.yaml | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml > index 49e2b807db0bc9d3edfc93ec41ad0df0b74ed032..74a09c391fd8e2befeac07f254ea16d0ca362248 100644 > --- a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml > +++ b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml > @@ -81,6 +81,16 @@ properties: > minItems: 1 > maxItems: 5 > > + sram: > + $ref: /schemas/types.yaml#/definitions/phandle-array > + description: > + phandle to the IMEM syscon node that exposes the system restart reason > + items: > + - items: > + - description: phandle of IMEM syscon > + - description: offset of restart reason region > + - description: value indicate that the watchdog timeout has occurred A 'sram' property points to an SRAM region (see mmio-sram binding), not a syscon and offset. The 'value' should be a separate property or implied by the compatible. Rob
Thanks Rob for the review comments! On 6/10/2025 11:33 PM, Rob Herring wrote: > On Tue, Jun 10, 2025 at 07:15:19PM +0530, Kathiravan Thirumoorthy wrote: >> Document the "sram" property for the watchdog device on Qualcomm >> IPQ platforms. Use this property to extract the restart reason from >> IMEM, which is updated by XBL. Populate the watchdog's bootstatus sysFS >> entry with this information, when the system reboots due to a watchdog >> timeout. >> >> Describe this property for the IPQ5424 watchdog device and extend support >> to other targets subsequently. >> >> Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com> >> --- >> Changes in v5: >> - Rename the property 'qcom,imem' to 'sram' >> Changes in v4: >> - New patch >> --- >> .../devicetree/bindings/watchdog/qcom-wdt.yaml | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml >> index 49e2b807db0bc9d3edfc93ec41ad0df0b74ed032..74a09c391fd8e2befeac07f254ea16d0ca362248 100644 >> --- a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml >> +++ b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml >> @@ -81,6 +81,16 @@ properties: >> minItems: 1 >> maxItems: 5 >> >> + sram: >> + $ref: /schemas/types.yaml#/definitions/phandle-array >> + description: >> + phandle to the IMEM syscon node that exposes the system restart reason >> + items: >> + - items: >> + - description: phandle of IMEM syscon >> + - description: offset of restart reason region >> + - description: value indicate that the watchdog timeout has occurred > A 'sram' property points to an SRAM region (see mmio-sram binding), not > a syscon and offset. > > The 'value' should be a separate property or implied by the compatible. Sorry for the delay. It was a long weekend here! Let me start with the requirement (Please feel free to skip it). When the system goes for reboot, Xtensible Boot loader (XBL) find the cause and update the particular offset (in this case it is 0x7b0) in the IMEM region with the known values. On the next boot, if the system is rebooted due to watchdog timeout, watchdog's bootstatus is updated accordingly, which this series tries to address it. Based on the previous review comments / discussions [1], it is decided to go with the above approach, i.e., name the property to 'sram' and let it points to the syscon region (IMEM) along with the offset to read and what value to expect. So that we don't have to touch the driver if either of the offset or the value changes across the platforms. Currently, IMEM region (which is a on-chip SRAM) in the most of the QCOM platforms are modeled as 'syscon' [2]. So I have followed the same approach here as well. Should I describe the IMEM region as "sram" (mmio-sram) instead of the "syscon" (existing approach) and retrieve the offset and desired value from the compatible? or stick with existing approach and name the property to something else? Could you guide me here to proceed further? [1] https://lore.kernel.org/linux-arm-msm/20250519-wdt_reset_reason-v4-3-d59d21275c75@oss.qualcomm.com/#t [2] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/Documentation/devicetree/bindings/sram/qcom,imem.yaml Thanks, Kathiravan T. > > Rob
diff --git a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml index 49e2b807db0bc9d3edfc93ec41ad0df0b74ed032..74a09c391fd8e2befeac07f254ea16d0ca362248 100644 --- a/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml +++ b/Documentation/devicetree/bindings/watchdog/qcom-wdt.yaml @@ -81,6 +81,16 @@ properties: minItems: 1 maxItems: 5 + sram: + $ref: /schemas/types.yaml#/definitions/phandle-array + description: + phandle to the IMEM syscon node that exposes the system restart reason + items: + - items: + - description: phandle of IMEM syscon + - description: offset of restart reason region + - description: value indicate that the watchdog timeout has occurred + required: - compatible - reg @@ -117,6 +127,16 @@ allOf: required: - clock-frequency + - if: + properties: + compatible: + contains: + enum: + - qcom,apss-wdt-ipq5424 + then: + required: + - sram + unevaluatedProperties: false examples:
Document the "sram" property for the watchdog device on Qualcomm IPQ platforms. Use this property to extract the restart reason from IMEM, which is updated by XBL. Populate the watchdog's bootstatus sysFS entry with this information, when the system reboots due to a watchdog timeout. Describe this property for the IPQ5424 watchdog device and extend support to other targets subsequently. Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com> --- Changes in v5: - Rename the property 'qcom,imem' to 'sram' Changes in v4: - New patch --- .../devicetree/bindings/watchdog/qcom-wdt.yaml | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)