Re: [Qemu-devel] [PATCH v3 08/33] Add function to control reset with gpio inputs

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Aug 09, 2019 at 10:45:43AM +0200, Damien Hedde wrote:
> 
> 
> On 8/9/19 7:51 AM, David Gibson wrote:
> > On Wed, Aug 07, 2019 at 11:37:51AM +0100, Peter Maydell wrote:
> >> On Wed, 31 Jul 2019 at 07:33, David Gibson <david@gibson.dropbear.id.au> wrote:
> >>>
> >>> On Mon, Jul 29, 2019 at 04:56:29PM +0200, Damien Hedde wrote:
> >>>> It adds the possibility to add 2 gpios to control the warm and cold reset.
> >>>> With theses ios, the reset can be maintained during some time.
> >>>> Each io is associated with a state to detect level changes.
> >>>>
> >>>> Vmstate subsections are also added to the existsing device_reset
> >>>> subsection.
> >>>
> >>> This doesn't seem like a thing that should be present on every single
> >>> DeviceState.
> >>
> >> It's a facility that's going to be useful to multiple different
> >> subclasses of DeviceState, so it seems to me cleaner to
> >> have base class support for the common feature rather than
> >> to reimplement it entirely from scratch in every subclass
> >> that wants it.
> > 
> > Hm, I suppose so.  Would it really have to be from scratch, though?
> > Couldn't some suitable helper functions make adding such GPIOs to a
> > device pretty straightforward?
> > 
> 
> This patch does that. A device does have to use the helper to add the
> gpio. Either qdev_init_warm_reset_gpio(...) or
> qdev_init_cold_reset_gpio(...) , like any another gpio.

Ah, sorry, I misunderstood.

That seems ok then.

> 
> The mechanics to control the reset with gpio change is done in the base
> class and there is some state pre-allocated (and associated vmstate
> description) to it.
> 
> If that's a problem I can only provide helpers and let devices handle
> state allocation and vmstate addition.
> 
> Damien
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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