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

Krzysztof Kozlowski
2023-08-28T06:55:47Z

On 28/08/2023 08:00, Varun Sethi wrote:
> Hi Greg,
>
>> -----Original Message-----
>> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Sent: Friday, August 25, 2023 12:54 AM
>> To: Krzysztof Kozlowski <krzk@kernel.org>
>> Cc: Rob Herring <robh@kernel.org>; Pankaj Gupta
>> <pankaj.gupta@nxp.com>; shawnguo@kernel.org; s.hauer@pengutronix.de;
>> kernel@pengutronix.de; clin@suse.com; conor+dt@kernel.org;
>> pierre.gondois@arm.com; Jacky Bai <ping.bai@nxp.com>; Clark Wang
>> <xiaoning.wang@nxp.com>; Wei Fang <wei.fang@nxp.com>; Peng Fan
>> <peng.fan@nxp.com>; Bough Chen <haibo.chen@nxp.com>;
>> festevam@gmail.com; dl-linux-imx <linux-imx@nxp.com>;
>> davem@davemloft.net; krzysztof.kozlowski+dt@linaro.org; linux-arm-
>> kernel@lists.infradead.org; devicetree@vger.kernel.org; linux-
>> kernel@vger.kernel.org; Gaurav Jain <gaurav.jain@nxp.com>;
>> alexander.stein@ew.tq-group.com; Sahil Malhotra
>> <sahil.malhotra@nxp.com>; Aisheng Dong <aisheng.dong@nxp.com>; Varun
>> Sethi <V.Sethi@nxp.com>
>> Subject: [EXT] Re: [PATCH v5 01/11] dt-bindings: arm: fsl: add imx-se-fw
>> binding doc
>>
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>>
>> 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://github.com/nxp-imx/imx-secure-enclave
> https://github.com/nxp-imx/imx-smw
>

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.

Best regards,
Krzysztof