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

[Conor Dooley <conor@kernel.org>]

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On Tue, Jul 23, 2024 at 09:28:31AM +0000, Pankaj Gupta wrote:
> 
> > -----Original Message-----
> > From: Conor Dooley <conor@kernel.org>
> > Sent: Monday, July 22, 2024 10:20 PM
> > To: Pankaj Gupta <pankaj.gupta@nxp.com>
> > Cc: Jonathan Corbet <corbet@lwn.net>; Rob Herring <robh@kernel.org>;
> > Krzysztof Kozlowski <krzk+dt@kernel.org>; Conor Dooley
> > <conor+dt@kernel.org>; Shawn Guo <shawnguo@kernel.org>; Sascha Hauer
> > <s.hauer@pengutronix.de>; Pengutronix Kernel Team
> > <kernel@pengutronix.de>; Fabio Estevam <festevam@gmail.com>; Rob
> > Herring <robh+dt@kernel.org>; linux-doc@vger.kernel.org; linux-
> > kernel@vger.kernel.org; devicetree@vger.kernel.org; imx@lists.linux.dev;
> > linux-arm-kernel@lists.infradead.org
> > Subject: [EXT] Re: [PATCH v6 2/5] dt-bindings: arm: fsl: add imx-se-fw binding
> > doc

Please fix this ^

> > 
> > 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@nxp.com>
> > > ---
> > >  .../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@nxp.com>
> > > +
> > > +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".

Which I came across after reading the updated series. If you ask me for
my opinion on something, just wait til I reply to you before sending
another version.

> 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 {"

Just because something got in before doesn't mean it should now.

> 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.

 I already did:
> > 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.

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