RE: [EXT] Re: [PATCH v6 2/5] dt-bindings: arm: fsl: add imx-se-fw binding doc

[Pankaj Gupta]

> -----Original Message-----
> From: Conor Dooley <conor@xxxxxxxxxx>
> Sent: Monday, July 22, 2024 10:20 PM
> To: Pankaj Gupta <pankaj.gupta@xxxxxxx>
> Cc: Jonathan Corbet <corbet@xxxxxxx>; Rob Herring <robh@xxxxxxxxxx>;
> Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx>; Conor Dooley
> <conor+dt@xxxxxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>; Sascha Hauer
> <s.hauer@xxxxxxxxxxxxxx>; Pengutronix Kernel Team
> <kernel@xxxxxxxxxxxxxx>; Fabio Estevam <festevam@xxxxxxxxx>; Rob
> Herring <robh+dt@xxxxxxxxxx>; linux-doc@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Subject: [EXT] Re: [PATCH v6 2/5] dt-bindings: arm: fsl: add imx-se-fw binding
> doc
> 
> On Mon, Jul 22, 2024 at 10:21:37AM +0530, Pankaj Gupta wrote:
> > The NXP security hardware IP(s) like: i.MX EdgeLock Enclave, V2X etc.,
> > creates an embedded secure enclave within the SoC boundary to enable
> > features like:
> > - HSM
> > - SHE
> > - V2X
> >
> > Secure-Enclave(s) communication interface are typically via message
> > unit, i.e., based on mailbox linux kernel driver. This driver enables
> > communication ensuring well defined message sequence protocol between
> > Application Core and enclave's firmware.
> >
> > Driver configures multiple misc-device on the MU, for multiple
> > user-space applications, to be able to communicate over single MU.
> >
> > It exists on some i.MX processors. e.g. i.MX8ULP, i.MX93 etc.
> >
> > Signed-off-by: Pankaj Gupta <pankaj.gupta@xxxxxxx>
> > ---
> >  .../devicetree/bindings/firmware/fsl,imx-se.yaml   | 91
> ++++++++++++++++++++++
> >  1 file changed, 91 insertions(+)
> >
> > diff --git
> > a/Documentation/devicetree/bindings/firmware/fsl,imx-se.yaml
> > b/Documentation/devicetree/bindings/firmware/fsl,imx-se.yaml
> > new file mode 100644
> > index 000000000000..7511d0e9cf98
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/firmware/fsl,imx-se.yaml
> > @@ -0,0 +1,91 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/firmware/fsl,imx-se.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: NXP i.MX HW Secure Enclave(s) EdgeLock Enclave
> > +
> > +maintainers:
> > +  - Pankaj Gupta <pankaj.gupta@xxxxxxx>
> > +
> > +description: |
> > +  NXP's SoC may contain one or multiple embedded secure-enclave HW
> > +  IP(s) like i.MX EdgeLock Enclave, V2X etc. These NXP's HW IP(s)
> > +  enables features like
> > +    - Hardware Security Module (HSM),
> > +    - Security Hardware Extension (SHE), and
> > +    - Vehicular to Anything (V2X)
> > +
> > +  Communication interface to the secure-enclaves(se) is based on the
> > + messaging unit(s).
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - fsl,imx8ulp-se
> > +      - fsl,imx93-se
> > +      - fsl,imx95-se
> > +
> > +  mboxes:
> > +    items:
> > +      - description: mailbox phandle to send message to se firmware
> > +      - description: mailbox phandle to receive message from se
> > + firmware
> > +
> > +  mbox-names:
> > +    items:
> > +      - const: tx
> > +      - const: rx
> > +
> > +  memory-region:
> > +    maxItems: 1
> > +
> > +  sram:
> > +    maxItems: 1
> > +
> > +required:
> > +  - compatible
> > +  - mboxes
> > +  - mbox-names
> > +
> > +allOf:
> > +  # memory-region
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - fsl,imx8ulp-se
> > +              - fsl,imx93-se
> > +    then:
> > +      required:
> > +        - memory-region
> > +    else:
> > +      properties:
> > +        memory-region: false
> > +
> > +  # sram
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - fsl,imx8ulp-se
> > +    then:
> > +      required:
> > +        - sram
> > +
> > +    else:
> > +      properties:
> > +        sram: false
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    senclave-firmware {
> 
> Last revision this was "firmware", but now you've got something that appears
> non-generic. Why did you change it? 

In case you missed, there was a previous email requesting your view on this change.
Having node as "firmware {", is very generic that has wide interpretation.
Hence, replaced firmware with "senclave-firmware".

Why "senclave"?
Like sram, for secure RAM, I proposed senclave for secure enclave.


Moreover, there are plenty of examples of YAML(s), that were already committed; that are using this:
linux_bkp$:> find Documentation/ -name "*.yaml" | xargs grep -r "\-firmware {"

Documentation/devicetree/bindings/crypto/xlnx,zynqmp-aes.yaml:      zynqmp_firmware: zynqmp-firmware {
Documentation/devicetree/bindings/fpga/xlnx,zynqmp-pcap-fpga.yaml:      zynqmp_firmware: zynqmp-firmware {
Documentation/devicetree/bindings/gpio/xlnx,zynqmp-gpio-modepin.yaml:    zynqmp-firmware {
 And more...

If you any other suggested word to pre-fix , that narrows down this broad referenced word "firmware". Please suggest.
	
> The normal differentiator for multiple
> nodes is -[0-9]*, why can't you use that, if you're worried about multiple
> nodes?
Thanks Conor, for the suggestion this. Will use this. Thanks.

> 
> > +      compatible = "fsl,imx95-se";
> > +      mboxes = <&ele_mu0 0 0>, <&ele_mu0 1 0>;
> > +      mbox-names = "tx", "rx";
> > +    };
> > +...
> >
> > --
> > 2.34.1
> >