Re: [PATCH 0/6] introduce Arm FF-A support

Sudeep Holla
2022-04-13T17:29:56Z

On Wed, Apr 13, 2022 at 12:46:07PM -0400, Tom Rini wrote:
> On Wed, Apr 13, 2022 at 03:20:23PM +0100, Abdellatif El Khlifi wrote:

[...]

> > Since we can not add an FFA node in the device tree, we will make FFA a discoverable bus.
> > So, we will manually create the udevice, binding it to the driver and probing it.
> > Manually means directly calling device_bind and device_probe APIs.
> >
> > Any thoughts about this approach ?
>
> How is it both discoverable and doesn't have a device tree node, in the
> kernel?
>

I don't clearly understand your query here fully. Generally if some h/w
is discoverable, then we don't need to have device node in the DT as it
may result in conflicts.

In this we can query f/w to check if a particular feature is implemented
or not before we initialise the FF-A bus. One we discover the partitions
we add devices for each and the individual device and associated driver
gets probed based on UUID.

I have neither seen the u-boot implementation nor fully understand how
device/driver model differs from the kernel one to comment on details.
I am happy to provide any more details if required.

--
Regards,
Sudeep