Re: [PATCH 02/20] nubus-device: expose separate super slot memory region

[Mark Cave-Ayland]

On 12/09/2021 16:50, Philippe Mathieu-Daudé wrote:

> On 9/12/21 9:48 AM, Mark Cave-Ayland wrote:
> > According to "Designing Cards and Drivers for the Macintosh Family" each 
> > physical
> > nubus slot can access 2 separate address ranges: a super slot memory region 
> > which
> > is 256MB and a standard slot memory region which is 16MB.
> >
> > Currently a Nubus device uses the physical slot number to determine whether it 
> > is
> > using a standard slot memory region or a super slot memory region rather than
> > exposing both memory regions for use as required.
> >
> > Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> > ---
> >   hw/nubus/nubus-device.c  | 36 ++++++++++++++++++------------------
> >   include/hw/nubus/nubus.h |  1 +
> >   2 files changed, 19 insertions(+), 18 deletions(-)
> >
> > diff --git a/hw/nubus/nubus-device.c b/hw/nubus/nubus-device.c
> > index be01269563..36203848e5 100644
> > --- a/hw/nubus/nubus-device.c
> > +++ b/hw/nubus/nubus-device.c
> > @@ -168,26 +168,26 @@ static void nubus_device_realize(DeviceState *dev, Error 
> > **errp)
> >       }
> >   
> >       nd->slot = nubus->current_slot++;
> > -    name = g_strdup_printf("nubus-slot-%d", nd->slot);
> > -
> > -    if (nd->slot < NUBUS_FIRST_SLOT) {
> > -        /* Super */
> > -        slot_offset = (nd->slot - 6) * NUBUS_SUPER_SLOT_SIZE;
> > -
> > -        memory_region_init(&nd->slot_mem, OBJECT(dev), name,
> > -                           NUBUS_SUPER_SLOT_SIZE);
> > -        memory_region_add_subregion(&nubus->super_slot_io, slot_offset,
> > -                                    &nd->slot_mem);
> > -    } else {
> > -        /* Normal */
> > -        slot_offset = nd->slot * NUBUS_SLOT_SIZE;
> > -
> > -        memory_region_init(&nd->slot_mem, OBJECT(dev), name, NUBUS_SLOT_SIZE);
> > -        memory_region_add_subregion(&nubus->slot_io, slot_offset,
> > -                                    &nd->slot_mem);
> > -    }
> >   
> > +    /* Super */
> > +    slot_offset = (nd->slot - 6) * NUBUS_SUPER_SLOT_SIZE;
> > +
> > +    name = g_strdup_printf("nubus-super-slot-%x", nd->slot);
> > +    memory_region_init(&nd->super_slot_mem, OBJECT(dev), name,
> > +                        NUBUS_SUPER_SLOT_SIZE);
> > +    memory_region_add_subregion(&nubus->super_slot_io, slot_offset,
> > +                                &nd->super_slot_mem);
> > +    g_free(name);
> > +
> > +    /* Normal */
> > +    slot_offset = nd->slot * NUBUS_SLOT_SIZE;
> > +
> > +    name = g_strdup_printf("nubus-slot-%x", nd->slot);
>
> I'd rather use "nubus-standard-slot-%x" or "nubus-normal-slot-%x"
> to differentiate from super-bus. (This also applies to variable
> names and trace events in this series).

I can see how this may seem ambiguous, however in "Designing Cards and Drivers for 
the Macintosh Family" the documentation always refers to "slot" as a standard slot so 
there shouldn't be any confusion for developers here.

> Anyway,
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>


ATB,

Mark.