RE: [EXT] Re: [PATCH v5 01/11] dt-bindings: arm: fsl: add imx-se-fw binding doc

From: Varun Sethi
Date: Mon Aug 28 2023 - 05:15:04 EST


Hi Krzysztof,

> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> Sent: Monday, August 28, 2023 12:25 PM
> To: Varun Sethi <V.Sethi@xxxxxxx>; Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx>; Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> Cc: Rob Herring <robh@xxxxxxxxxx>; Pankaj Gupta
> <pankaj.gupta@xxxxxxx>; shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx;
> kernel@xxxxxxxxxxxxxx; clin@xxxxxxxx; conor+dt@xxxxxxxxxx;
> pierre.gondois@xxxxxxx; Jacky Bai <ping.bai@xxxxxxx>; Clark Wang
> <xiaoning.wang@xxxxxxx>; Wei Fang <wei.fang@xxxxxxx>; Peng Fan
> <peng.fan@xxxxxxx>; Bough Chen <haibo.chen@xxxxxxx>;
> festevam@xxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> davem@xxxxxxxxxxxxx; krzysztof.kozlowski+dt@xxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Gaurav Jain <gaurav.jain@xxxxxxx>;
> alexander.stein@xxxxxxxxxxxxxxx; Sahil Malhotra
> <sahil.malhotra@xxxxxxx>; Aisheng Dong <aisheng.dong@xxxxxxx>
> Subject: Re: [EXT] Re: [PATCH v5 01/11] dt-bindings: arm: fsl: add
imx-se-fw
> binding doc
>
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>
> On 28/08/2023 08:00, Varun Sethi wrote:
> > Hi Greg,
> >
> >> -----Original Message-----
> >> From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> >> Sent: Friday, August 25, 2023 12:54 AM
> >> To: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> >> Cc: Rob Herring <robh@xxxxxxxxxx>; Pankaj Gupta
> >> <pankaj.gupta@xxxxxxx>; shawnguo@xxxxxxxxxx;
> s.hauer@xxxxxxxxxxxxxx;
> >> kernel@xxxxxxxxxxxxxx; clin@xxxxxxxx; conor+dt@xxxxxxxxxx;
> >> pierre.gondois@xxxxxxx; Jacky Bai <ping.bai@xxxxxxx>; Clark Wang
> >> <xiaoning.wang@xxxxxxx>; Wei Fang <wei.fang@xxxxxxx>; Peng Fan
> >> <peng.fan@xxxxxxx>; Bough Chen <haibo.chen@xxxxxxx>;
> >> festevam@xxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>;
> >> davem@xxxxxxxxxxxxx; krzysztof.kozlowski+dt@xxxxxxxxxx; linux-arm-
> >> kernel@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> >> kernel@xxxxxxxxxxxxxxx; Gaurav Jain <gaurav.jain@xxxxxxx>;
> >> alexander.stein@xxxxxxxxxxxxxxx; Sahil Malhotra
> >> <sahil.malhotra@xxxxxxx>; Aisheng Dong <aisheng.dong@xxxxxxx>;
> Varun
> >> Sethi <V.Sethi@xxxxxxx>
> >> Subject: [EXT] Re: [PATCH v5 01/11] 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 Thu, Aug 24, 2023 at 08:45:41PM +0200, Krzysztof Kozlowski wrote:
> >>> On 23/08/2023 14:43, Rob Herring wrote:
> >>>>> + |
> >>>>> + +------------------------------------------------------ |
> >>>>> + | | | |
> >>>>> + userspace /dev/ele_muXch0 | | |
> >>>>> + /dev/ele_muXch1 | |
> >>>>> + /dev/ele_muXchY |
> >>>>> + |
> >>>>> +
> >>>>> + When a user sends a command to the firmware, it registers its
> >>>>> + device_ctx as waiter of a response from firmware.
> >>>>> +
> >>>>> + A user can be registered as receiver of command from the ELE.
> >>>>> + Create char devices in /dev as channels of the form
> >>>>> + /dev/ele_muXchY with X the id of the driver and Y for each
> >>>>> + users. It allows to send and receive messages to the NXP
> >>>>> + EdgeLock Enclave IP firmware on NXP SoC, where current possible
> >> value, i.e., supported SoC(s) are imx8ulp, imx93.
> >>>>
> >>>> Looks like a bunch of Linux details which don't belong in the
binding.
> >>>>
> >>>> Why do you need your own custom interface to userspace? No one
> else
> >>>> has a similar feature in their platforms? Something like virtio or
> >>>> rpmsg doesn't work?
> >>>
> >>> +Cc Greg,
> >>>
> >>> I doubt they care. This is some stub-driver to pass messages from
> >>> user-space to the firmware. The interface is undocumented, without
> >>> examples and no user-space user.
> >>
> >> Great, no user? Let's delete the code then :)
> >>
> > [Varun] We do have middleware applications that utilize the driver.
> > Following
> > are the links:
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith
> > ub.com%2Fnxp-imx%2Fimx-secure-
> enclave&data=05%7C01%7CV.Sethi%40nxp.com
> > %7Ceda172f10a684cc926a908dba793b776%7C686ea1d3bc2b4c6fa92cd99c5c
> 301635
> > %7C0%7C0%7C638288025110398317%7CUnknown%7CTWFpbGZsb3d8eyJW
> IjoiMC4wLjAw
> >
> MDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%
> 7C&sda
> >
> ta=jJ%2FZl1myldPaciswIps2dDuuzp%2BqXGZDnvh07yD%2BEFU%3D&reserve
> d=0
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith
> > ub.com%2Fnxp-imx%2Fimx-
> smw&data=05%7C01%7CV.Sethi%40nxp.com%7Ceda172f1
> >
> 0a684cc926a908dba793b776%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7
> C0%7C
> >
> 638288025110398317%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwM
> DAiLCJQIjo
> >
> iV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=U
> VjBwmzZ
> > myHu%2Fmy6WZiQcz2qksA67W1BtwFIJ8%2Ft7nQ%3D&reserved=0
> >
>
> Why this is not explained in the cover letter and in the patch adding the
> interfaces? You still need to document and explain the interface.
>

[Varun] Following information would be added in the next version of the
patchset:
1. Details of the users for this driver.
2. The ABI document would be enhanced to provide information about the
interfaces leveraged
by the user space middleware applications.

Please let me know if this would be sufficient.

Regards
Varun Sethi


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