RE: [EXT] Re: [PATCH v7 4/5] firmware: imx: add driver for NXP EdgeLock Enclave

[Pankaj Gupta]

-----Original Message-----
From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> 
Sent: Thursday, September 26, 2024 3:22 PM
To: Pankaj Gupta <pankaj.gupta@xxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>; Rob Herring <robh@xxxxxxxxxx>;
Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx>; Conor Dooley
<conor+dt@xxxxxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>; Pengutronix Kernel
Team <kernel@xxxxxxxxxxxxxx>; Fabio Estevam <festevam@xxxxxxxxx>; Rob
Herring <robh+dt@xxxxxxxxxx>; linux-doc@xxxxxxxxxxxxxxx;
linux-kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
imx@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [EXT] Re: [PATCH v7 4/5] firmware: imx: add driver for NXP
EdgeLock Enclave

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Hi Pankaj,

On Wed, Sep 25, 2024 at 12:00:28PM +0000, Pankaj Gupta wrote:
> >> Yes.
> >
> > > Don't do this.
> >
> >> Shall the retry counter to be removed, to make it predictable?
> >>Or am I missing something.
>
>> >Either compile the firmware into the kernel or the ELE driver as module.
>>
>> Cannot compile as part of Firmware.
>> There are OTA scenarios where the latest FW, that is downloaded to 
>> replace the image in RFS, and FW needs to be re-init with this new 
>> image, by putting the Linux to power-down state.
>
>> ELE driver is compiled as module only, by default. But if someone like 
>> to make it as in-line to kernel image, still it should work.

> I am also not very happy with the situation that we can't compile drivers
into the kernel and just get the firmware later once it is available.

Driver is enabling the ROM API supports at probe time. 
And, once the rootfs is available, and the Firmware image is loaded, then it
will enable the complete set of FW API(s), along with ROM API(s).

Hence, Driver can be compiled into the kernel to enable ELE-ROM API(s).

> That's the situation we are in though and if you want to change it you
have to discuss this with the firmware maintainers.
> What you've done in the ELE driver is a hack and I doubt that you get this
through.

> Sascha

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