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

From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Varun Sethi <V.Sethi@nxp.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Krzysztof Kozlowski <krzk@kernel.org>
Cc: Rob Herring <robh@kernel.org>,
	Pankaj Gupta <pankaj.gupta@nxp.com>,
	"shawnguo@kernel.org" <shawnguo@kernel.org>,
	"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	"clin@suse.com" <clin@suse.com>,
	"conor+dt@kernel.org" <conor+dt@kernel.org>,
	"pierre.gondois@arm.com" <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" <festevam@gmail.com>,
	dl-linux-imx <linux-imx@nxp.com>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"krzysztof.kozlowski+dt@linaro.org"
	<krzysztof.kozlowski+dt@linaro.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Gaurav Jain <gaurav.jain@nxp.com>,
	"alexander.stein@ew.tq-group.com"
	<alexander.stein@ew.tq-group.com>,
	Sahil Malhotra <sahil.malhotra@nxp.com>,
	Aisheng Dong <aisheng.dong@nxp.com>
Subject: Re: [EXT] Re: [PATCH v5 01/11] dt-bindings: arm: fsl: add imx-se-fw binding doc
Date: Mon, 28 Aug 2023 08:55:05 +0200	[thread overview]
Message-ID: <9f983d06-e82b-e572-e007-18d39c15ead7@linaro.org> (raw)
In-Reply-To: <AM9PR04MB8211D170F1D484E083C8F899E8E0A@AM9PR04MB8211.eurprd04.prod.outlook.com>

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

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