Re: [PATCH v8 08/11] hw/core: deprecate old reset functions and introduce new ones

[Markus Armbruster <armbru@redhat.com>]

Peter Maydell <peter.maydell@linaro.org> writes:

> On Wed, 28 Apr 2021 at 06:03, Markus Armbruster <armbru@redhat.com> wrote:
>> For what it's worth, Damien further explained the two helpers in
>> docs/devel/reset.rst:
>>
>>     For Devices and Buses, the following helper functions exist:
>>
>>     - ``device_cold_reset()``
>>     - ``bus_cold_reset()``
>>
>>     These are simple wrappers around resettable_reset() function; they only cast the
>>     Device or Bus into an Object and pass the cold reset type. When possible
>>     prefer to use these functions instead of ``resettable_reset()``.
>>
>> I figure what's missing is guidance on how to transition code from
>> legacy reset to multi-phase reset.  Ideally with a working example
>> people can study.  Damien, can you help us out?
>
> These are two separate things:
>  1) callsites which want to reset some other device, and currently
>     mostly use eg device_legacy_reset() -- the transition to be done
>     is to move them to use device_cold_reset(). Similarly, callsites
>     which currently reset a bus with qbus_reset_all() and should move
>     to bus_cold_reset().
>  2) devices which implement reset and currently do so with a
>     single reset method -- the transition to be done is to have
>     them implement however many phases of 3-phase reset they need
>
> (1) is easier than (2) because there are many fewer callsites
> trying to manually reset devices or buses than there are
> devices that implement reset.

My ignorance on "these are two separate things" is further evidence that
working examples are needed.  Damien?  Peter?  Pretty-please?