Re: [RFC PATCH v5 0/3] Sysbus device generic QAPI plug support

[Peter Maydell]

On Mon, 30 May 2022 at 10:50, Damien Hedde <damien.hedde@greensocs.com> wrote:
> TYPE_SYS_BUS_DEVICE also comes with reset support.
> If a device is on not on any bus it is not reached by the root sysbus
> reset which propagates to every device (and other sub-buses).
> Even if we move all the mmio/sysbus-irq logic into TYPE_DEVICE, we will
> still miss that. The bus is needed to handle the reset.
> For devices created in machine init code, we have the option to do it in
> the machine reset handler. But for user created device, this is an issue.

Yes, the missing reset support in TYPE_DEVICE is a design
flaw that we really should try to address.

> If we end up putting in TYPE_DEVICE support for mmios, interrupts and
> some way to do the bus reset. What would be the difference between the
> current TYPE_SYS_BUS_DEVICE ?

There would be none, and the idea would be to get rid of
TYPE_SYS_BUS_DEVICE entirely...

-- PMM