Re: [Q] zynqmp-ipi-mailbox and SGI interrupts

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2026-10-16 11:10:29 [-0500], Shah, Tanmay wrote:
> Hello,
Hello,

> Thank you for your email, please find my response below:

Thank you for your email, too.

> > So is this SGI-IPI a thing or not?
> > 
> 
> Yes it is. Ideally, TF-A and Linux can share the IPI. If the IPI
> interrupt is used by the TF-A and the expectation is that Linux mailbox
> work on the same IPI (because all other IPIs are busy) then the work
> around is, TF-A will generate SGI for the linux mbox driver, and the
> mbox driver will use that SGI via device-tree.
> 
> It is a vendor specific use case. So the dt-node for this use case, may
> not be available in the usptream kernel, but can be enabled if correct
> SGI is configured via the device-tree.

And it has to be a per-CPU interrupt? It can't become a regular
interrupt which is not per-CPU? Does the driver at some point access
per-CPU registers?

> Thank you,
> Tanmay
> 
Sebastian