Re: [PATCH v23 06/13] dt-bindings: arm: Document reboot mode magic

[Rob Herring <robh@kernel.org>]

On Tue, Jul 14, 2026 at 10:46:34PM +0530, Shivendra Pratap wrote:
> Add bindings to describe vendor-specific reboot modes. Values here
> correspond to valid parameters to vendor-specific reset types in PSCI
> SYSTEM_RESET2 call.
> 
> Signed-off-by: Shivendra Pratap <shivendra.pratap@oss.qualcomm.com>
> ---
>  Documentation/devicetree/bindings/arm/psci.yaml | 54 +++++++++++++++++++++++++
>  1 file changed, 54 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/arm/psci.yaml b/Documentation/devicetree/bindings/arm/psci.yaml
> index 6e2e0c551841..11b90e8affb3 100644
> --- a/Documentation/devicetree/bindings/arm/psci.yaml
> +++ b/Documentation/devicetree/bindings/arm/psci.yaml
> @@ -98,6 +98,37 @@ properties:
>        [1] Kernel documentation - ARM idle states bindings
>          Documentation/devicetree/bindings/cpu/idle-states.yaml
>  
> +  reboot-mode:
> +    type: object
> +    $ref: /schemas/power/reset/reboot-mode.yaml#
> +    additionalProperties: false
> +    properties:
> +      # "mode-normal" is just SYSTEM_RESET
> +      mode-normal: false
> +    patternProperties:
> +      "^mode-.*$":

Since your example violates naming rules:

"^mode-[a-z0-9]+$"

> +        minItems: 1
> +        maxItems: 3
> +        items:
> +          - description: arg1 (vendor-specific SYSTEM_RESET2 reset_type)
> +            minimum: 0x80000000
> +          - description: arg2 (cookie_lo in 2-cell form, cookie_hi in 3-cell form)
> +          - description: arg3 (cookie_lo in 3-cell form)
> +        description: |
> +          Describes a PSCI SYSTEM_RESET2 vendor-specific reset type. The string
> +          after "mode-" maps a reboot mode to a vendor-specific reset.
> +          A vendor-specific reset takes two arguments, a 32-bit reset_type and a
> +          64-bit cookie. The arguments are encoded as up to three 32-bit cells.
> +          Each mode property is encoded as mode-xxx = <arg1[, arg2[, arg3]]>,
> +          where:
> +          - arg1 is reset_type and must be >= 0x80000000.
> +          - In 2-cell form, arg2 is lower 32 bits of cookie.
> +          - In 3-cell form, arg2 is high 32 bits of cookie
> +            and arg3 is low 32 bits of cookie.
> +
> +          All values should be provided as per the PSCI SYSTEM_RESET2
> +          specification.
> +
>  patternProperties:
>    "^power-domain-":
>      $ref: /schemas/power/power-domain.yaml#
> @@ -137,6 +168,15 @@ allOf:
>        required:
>          - cpu_off
>          - cpu_on
> +  - if:
> +      not:
> +        properties:
> +          compatible:
> +            contains:
> +              const: arm,psci-1.0
> +    then:
> +      properties:
> +        reboot-mode: false
>  
>  additionalProperties: false
>  
> @@ -260,4 +300,18 @@ examples:
>          domain-idle-states = <&cluster_ret>, <&cluster_pwrdn>;
>        };
>      };
> +
> +  - |+
> +
> +    // Case 5: SYSTEM_RESET2 vendor resets
> +    psci {
> +      compatible = "arm,psci-1.0";
> +      method = "smc";
> +
> +      reboot-mode {
> +        mode-edl = <0x80000000 0x00000001>;
> +        mode-bootloader = <0x80010001 0x00000002>;
> +        mode-needscookie_64 = <0x80000000 0x00000001 0x00000002>;

Don't use '_' in property names. This is a W=2 warning.

Rob