Re: [PATCH] arm: dom0less: add TEE support

[Julien Grall <julien@xxxxxxx>]

Hi Bertrand,

On 30/05/2024 14:22, Bertrand Marquis wrote:
> > On 30 May 2024, at 12:35, Julien Grall <julien@xxxxxxx> wrote:
> >
> > Hi Bertrand,
> >
> > On 30/05/2024 10:40, Bertrand Marquis wrote:
> > > > But we are making assumption that all TEE implementation will have its
> > > > node inside "/firmware/". I am not 100% sure that this is correct. For
> > > > example I saw that Google Trusty uses "/trusty" node (directly inside
> > > > the DTS root). On other hand, it is not defined in dts bindings, as far
> > > > as I know.
> > > Regarding the firmware part you can easily handle that by looking for /firmware
> > > and create it if it does not exist before creating your sub-node and this should
> > > be node in the optee node creation function not in tee.c.
> > This would work if the node /firmware doesn't exist. But how would you handle 
> > the case where it is already present?
> >
> > I looked at the libfdt API and AFAICT the DTB creation needs to be linear. IOW, 
> > you can't add a subnode to an already created node.
> >
> > There is an helper to create a placeholder, but AFAIK this is only for a 
> > property. You also need to know the size in advance.
> I thought it was possible but i definitely can be wrong.
>
> As right now we have only one need for the node, we could delay a possible 
> solution and just create it in the optee driver.
I am fine with that.

Cheers,

--
Julien Grall