Single host/multiple hwifs vs. multiple hosts?

Single host/multiple hwifs vs. multiple hosts?

[Geert Uytterhoeven]

Hi all,

I'm wondering what are the differences between adding a single IDE host with
multiple hwifs vs. adding a separate IDE host for each hwif?
Do both ways work?

I'm asking because I want to convert the Amiga Buddha IDE driver to the new
driver model, using Multi Function Devices (many Zorro expansion cards contain
multiple devices):
  - A Catweasel expansion card would have:
      * 2 Buddha IDE MFD cells,
      * 1 Catweasel floppy MFD cell.
  - A Buddha expansion card would have:
      * 3 Buddha IDE MFD cells.
  - An X-Surf expansion card would have:
      * 2 Buddha IDE MFD cells,
      * 1 8390 Ethernet cell.
Registering a separate IDE host/hwif for each IDE MFD cell would be easier to
handle than a single IDE host with multiple IDE hwifs.

Thanks in advance!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: Single host/multiple hwifs vs. multiple hosts?

[Geert Uytterhoeven]

On Sun, Mar 4, 2012 at 13:15, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> I'm wondering what are the differences between adding a single IDE host with
> multiple hwifs vs. adding a separate IDE host for each hwif?
> Do both ways work?

Does no one know?

Thx again!

> I'm asking because I want to convert the Amiga Buddha IDE driver to the new
> driver model, using Multi Function Devices (many Zorro expansion cards contain
> multiple devices):
>  - A Catweasel expansion card would have:
>      * 2 Buddha IDE MFD cells,
>      * 1 Catweasel floppy MFD cell.
>  - A Buddha expansion card would have:
>      * 3 Buddha IDE MFD cells.
>  - An X-Surf expansion card would have:
>      * 2 Buddha IDE MFD cells,
>      * 1 8390 Ethernet cell.
> Registering a separate IDE host/hwif for each IDE MFD cell would be easier to
> handle than a single IDE host with multiple IDE hwifs.
>
> Thanks in advance!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: Single host/multiple hwifs vs. multiple hosts?

[Mark Lord]

On 12-04-08 05:12 AM, Geert Uytterhoeven wrote:
> On Sun, Mar 4, 2012 at 13:15, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>> I'm wondering what are the differences between adding a single IDE host with
>> multiple hwifs vs. adding a separate IDE host for each hwif?
>> Do both ways work?
> 
> Does no one know?

When I first wrote that code, the idea was that if a given chip
had multiple IDE ports (hardware interfaces, or hwifs for short),
then that's how it would be done.  One controller, multiple hwifs.

This was before IDE had anything to do with the SCSI subsystem,
and allowed for things like controller chips which could operate
only a single hwif at any point in time (aka. "serialized").

Nowadays, the code's be hacked beyond recognition from its original form
and intent, so who knows!  :)