Re: [Qemu-devel] [PATCH v1 13/16] qdev: gpio: Define qdev_pass_gpios()

[Alexander Graf]

On 15.08.14 07:11, Peter Crosthwaite wrote:
> On Tue, Aug 12, 2014 at 8:55 PM, Alexander Graf <address@hidden> wrote:
> > On 12.08.14 12:48, Peter Crosthwaite wrote:
> > > On Tue, Aug 12, 2014 at 7:24 PM, Alexander Graf <address@hidden> wrote:
> > > > On 04.08.14 03:58, Peter Crosthwaite wrote:
> > > > > Allows a container to take ownership of GPIOs in a contained
> > > > > device and automatically connect them as GPIOs to the container.
> > > > >
> > > > > This prepares for deprecation of the SYSBUS IRQ functionality, which
> > > > > has this feature. We push it up to the device level instead of sysbus
> > > > > level. There's nothing sysbus specific about passing GPIOs to
> > > > > containers so its a legitimate device-level generic feature.
> > > > >
> > > > > Signed-off-by: Peter Crosthwaite <address@hidden>
> > > > > ---
> > > > >
> > > > >     hw/core/qdev.c         | 28 ++++++++++++++++++++++++++++
> > > > >     include/hw/qdev-core.h |  3 +++
> > > > >     2 files changed, 31 insertions(+)
> > > > >
> > > > > diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> > > > > index bf2c227..708363f 100644
> > > > > --- a/hw/core/qdev.c
> > > > > +++ b/hw/core/qdev.c
> > > > > @@ -440,6 +440,34 @@ void qdev_connect_gpio_out(DeviceState * dev, int
> > > > > n,
> > > > > qemu_irq pin)
> > > > >         qdev_connect_gpio_out_named(dev, NULL, n, pin);
> > > > >     }
> > > > >     +void qdev_pass_gpios(DeviceState *dev, DeviceState *container,
> > > > > +                     const char *name)
> > > > > +{
> > > > > +    int i;
> > > > > +    NamedGPIOList *ngl = qdev_get_named_gpio_list(dev, name);
> > > > > +
> > > > > +    for (i = 0; i < ngl->num_in; i++) {
> > > > > +        char *propname = g_strdup_printf("%s[%d]",
> > > > > +                                         ngl->name ? ngl->name :
> > > > > +                                                   "unnamed-gpio-in",
> > > >
> > > > Really just a minor nit, but I think the code flow would look a lot nicer
> > > > if
> > > > you did the name check in a separate variable.
> > > >
> > > >     const char *name = ngl->name ? ngl->name : "unnamed-gpio-in";
> Just done it this way. Although have used "nm" instead of "name"
> instead as "name" is already used.
>
> > > I think I may even go an extra step and get it macroified. How about:
> > >
> > > #define QDEV_GPIO_IN_NAME(a) ((a) ? (a) : "unnamed-gpio-io")
> > >
> > > and then you can continue to use it inline without extra variables or
> > > nasty "?:"?
> >
> > The variable will get optimized out, so for the sake of readability I would
> > still vote to have it around. Whether you declare it via a macro or with an
> > a ? a : b macro I don't really care much about :).
> >
> > In fact, it might make more sense to literally have the typical
> >
> >    (a ? a : b)
> >
> > flow macroified in a generic place somewhere.
> Hmm not sure what this wins though? inline "? :" is concise and self
> documenting IMO. You just need to not stuff-up the "()"s (which is
> admittedly quite easy to do.
>
> Anyways, it's a patch for another day.

Yeah, probably not a big win really :).


Alex