RE: [EXT] Re: [PATCH 2/4] dt-bindings: arm: fsl: add imx-se-fw binding doc

From: Pankaj Gupta
Date: Tue May 21 2024 - 08:17:41 EST

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> -----Original Message-----
> From: Pankaj Gupta
> Sent: Monday, May 13, 2024 9:07 PM
> To: Rob Herring <robh@xxxxxxxxxx>
> Cc: Jonathan Corbet <corbet@xxxxxxx>; Krzysztof Kozlowski
> <krzysztof.kozlowski+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>; linux-
> doc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx
> Subject: RE: [EXT] Re: [PATCH 2/4] dt-bindings: arm: fsl: add imx-se-fw binding
> doc
>
>
>
> > -----Original Message-----
> > From: Rob Herring <robh@xxxxxxxxxx>
> > Sent: Saturday, May 11, 2024 1:39 AM
> > To: Pankaj Gupta <pankaj.gupta@xxxxxxx>
> > Cc: Jonathan Corbet <corbet@xxxxxxx>; Krzysztof Kozlowski
> > <krzysztof.kozlowski+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>; linux-
> > doc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > devicetree@xxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx; linux-arm-
> > kernel@xxxxxxxxxxxxxxxxxxx
> > Subject: [EXT] Re: [PATCH 2/4] dt-bindings: arm: fsl: add imx-se-fw
> > binding doc
> >
> > Caution: This is an external email. Please take care when clicking
> > links or opening attachments. When in doubt, report the message using
> > the 'Report this email' button
> >
> >
> > On Fri, May 10, 2024 at 06:57:28PM +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 | 186
> > +++++++++++++++++++++
> > > 1 file changed, 186 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..a858ef6965cb
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/firmware/fsl,imx-se.yaml
> > > @@ -0,0 +1,186 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
> > > +---
> > > +$id:
> > > +https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fde
> > > +vi
> > > +cetree.org%2Fschemas%2Ffirmware%2Ffsl%2Cimx-
> > se.yaml%23&data=05%7C02%7
> > >
> >
> +Cpankaj.gupta%40nxp.com%7C2c17789530e9431069b308dc712d0e47%7C
> > 686ea1d3
> > >
> >
> +bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638509685520936926%7CUnkn
> > own%7CTWF
> > >
> >
> +pbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJX
> > VCI6
> > >
> >
> +Mn0%3D%7C0%7C%7C%7C&sdata=Rwof3k3K1OWimcI5ApRMiyvD%2FPXgk
> > b%2BRWrvx76J
> > > +YBtw%3D&reserved=0
> > > +$schema:
> > > +https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fde
> > > +vi
> > > +cetree.org%2Fmeta-
> > schemas%2Fcore.yaml%23&data=05%7C02%7Cpankaj.gupta%
> > >
> >
> +40nxp.com%7C2c17789530e9431069b308dc712d0e47%7C686ea1d3bc2b4c
> > 6fa92cd9
> > >
> >
> +9c5c301635%7C0%7C0%7C638509685520944809%7CUnknown%7CTWFpb
> > GZsb3d8eyJWI
> > >
> >
> +joiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7
> > C0%7C%
> > >
> >
> +7C%7C&sdata=aile3WnYE69fuJHvAOXQARlqLV9roZDuDK63fCj2ZTE%3D&res
> > erved=0
> > > +
> > > +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 is based on the
> > > + messaging unit(s).
> > > +
> > > +properties:
> > > + '#address-cells':
> > > + const: 1
> > > +
> > > + '#size-cells':
> > > + const: 0
> > > +
> > > + compatible:
> > > + enum:
> > > + - fsl,imx8ulp-ele
> > > + - fsl,imx93-ele
> >
> > You basically have 0 properties in the parent node. What's the point of it?
> > Either just get rid of it and define the child nodes independently or
> > make the parent contain all the resources.
> >

Making the parent contains all the properties:

+ ele-if@0 {
+ compatible = "fsl,imx8ulp-ele";
+ reg = <0x0>;
+ mbox-names = "tx", "rx";
+ mboxes = <&s4muap 0 0>, <&s4muap 1 0>;
+ sram = <&sram0>;
+ };

Will this be fine? Kindly suggest.
Thanks.

> > > +
> > > +patternProperties:
> > > + "^[0-9a-z]*-if@[0-9]+$":
> >
> > unit-addresses are hex.
> Accepted

>
> >
> > > + type: object
> > > + description:
> > > + Communication interface to secure-enclave node, that defines
> > hardware
> > > + properties to required to establish the communication. There can be
> > > + multiple interfaces to the same secure-enclave. Each interface is
> > > + enumerated with reg property. It optionally defines properties
> > > + depending on the compatible string and interface enum identifier.
> > > +
> > > + properties:
> > > + reg:
> > > + maxItems: 1
> > > + description: Identifier of the communication interface to
> > > + secure-
> > enclave.
> >
> > What are the identifiers based on?
> Identifier is used to identify a particular secure enclave interface, within the
> multiple secure enclave interfaces under same compatible string.
>
> Secure enclave interface is the combination of:
> - messaging unit (hardware), and
> - memory constraint applicable to a particular interface.
>
> > Is the value significant to s/w? Kind of looks like you just made up indices.
>
> For the below example:
> v2x {
> compatible = "fsl,imx95-v2x";
> #address-cells = <1>;
> #size-cells = <0>;
>
> v2x-if@0 { // if it is not @0, then what identifier to be used to identify a
> particular node.
> reg = <0x0>;
> mboxes = <&v2x_mu 0 0>, <&v2x_mu 1 0>;
> mbox-names = "tx", "rx";
> };
> v2x-if@1 {
> reg = <0x1>;
> mboxes = <&v2x_mu6 0 0>, <&v2x_mu6 1 0>;
> mbox-names = "txdb", "rxdb";
> };
> v2x-if@2 {
> reg = <0x2>;
> mboxes = <&v2x_mu7 0 0>, <&v2x_mu7 1 0>;
> mbox-names = "tx", "rx";
> };
> };
> s/w needs to differentiate one node from another node, for the same
> compatible string for the SoC.
>
> >
> > How many child nodes do you have? Is it fixed per SoC?
> It is fixed for a particular SoC.
> While number of child nodes varies from one SoC to another SoC.
>
> >
> > > +
> > > + mboxes:
> > > + description: contain a list of phandles to mailboxes.
> > > + items:
> > > + - description: Specify the mailbox used to send message
> > > + to se
> > firmware
> > > + - description: Specify the mailbox used to receive
> > > + message from se firmware
> > > +
> > > + mbox-names:
> > > + items:
> > > + - const: tx
> > > + - const: rx
> > > + - const: txdb
> > > + - const: rxdb
> > > + minItems: 2
> > > +
> > > + memory-region:
> > > + description: contains a list of phandles to reserved external memory.
> > > + items:
> > > + - description: It is used by secure-enclave firmware. It is an optional
> > > + property based on compatible and identifier to
> > > + communication
> > interface.
> > > + (see bindings/reserved-memory/reserved-memory.txt)
> > > +
> > > + sram:
> > > + description: contains a list of phandles to sram.
> > > + $ref: /schemas/types.yaml#/definitions/phandle-array
> > > + items:
> > > + - description: Phandle to the device SRAM. It is an optional property
> > > + based on compatible and identifier to communication interface.
> > > +
> > > + required:
> > > + - reg
> > > + - mboxes
> > > + - mbox-names
> > > +
> > > +allOf:
> > > + # memory-region
> > > + - if:
> > > + properties:
> > > + compatible:
> > > + contains:
> > > + enum:
> > > + - fsl,imx8ulp-ele
> > > + - fsl,imx93-ele
> >
> > What else would they contain? Those are the only compatibles defined here.
>
> It will have multiple child nodes, but fixed number of child node for a
> particular SoC.
>
> >
> > > + then:
> > > + patternProperties:
> > > + "^[0-9a-z]*-if@[0-9]+$":
> > > + allOf:
> > > + - if:
> >
> > These conditionals are hard to follow. Probably a sign some of this
> > needs to be separate or simplified.
> I am ready to separate and simplify.
> Please help by sharing an example on how to go about this change.
> Probably an example that helps me understand your point and then will start
> to work on this comment.
> It is highly appreciated. Thanks.
>
> >
> > > + properties:
> > > + reg:
> > > + items:
> > > + - enum:
> > > + - 0
> > > + then:
> > > + required:
> > > + - memory-region
> > > + else:
> > > + not:
> > > + required:
> > > + - memory-region # sram
> > > + - if:
> > > + properties:
> > > + compatible:
> > > + contains:
> > > + enum:
> > > + - fsl,imx8ulp-ele
> > > + then:
> > > + patternProperties:
> > > + "^[0-9a-z]*-if@[0-9]+$":
> > > + allOf:
> > > + - if:
> > > + properties:
> > > + reg:
> > > + items:
> > > + - enum:
> > > + - 0
> > > + then:
> > > + required:
> > > + - sram
> > > + else:
> > > + not:
> > > + required:
> > > + - sram
> > > +
> > > +additionalProperties: false

Next message: Arnaud POULIQUEN: "Re: [PATCH v5 2/7] dt-bindings: remoteproc: Add compatibility for TEE support"
Previous message: Niklas Schnelle: "[PATCH 3/3] vfio/pci: Enable VFIO_PCI_MMAP for s390"
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