IRQS on 6 Slot Macs

Etsushi Kato ekato at
Wed Nov 5 22:38:28 EST 2003

On 2003.11.5, at 07:38  PM, Michael Schmitz wrote:

>>> In my queue of projects (massive and ever lengthening) is to install
>>> a 53CF96 in place of a MESH and/or vice versa and see what happens.
>>> However, I wonder if a similar test could be done with software.   I
>>> assume that Linux implements some kind of driver to support MESH.
>>> Is there a driver for the 53CF96 which could be substituted or
>>> compared as an experiment.
>> There's a driver for the 53C96 in the Quadra (mac_esp.c and
>> NCR53C9x.c).
>> The NCR53C9x.c core supports various 53C9x chips, including (53CF9x
>> and FAS*),
>> and is used on various platforms.  It's very similar to the esp.c
>> core for
>> SPARC, but Dave didn't like us to merge non-SPARC support in his
>> driver.
> The Quadra 53C96 driver is a strange beast since we don't know how to
> use
> DMA on those boxes (in case they have DMA) so it implements PIO.
> Plus we had trouble with reselection interrupt races there. Better
> look at the Amiga ESP code.

I once modified NCR53C9x.c to make it work with DMA for NuBus PowerMac.
  It works with both 53C94 (on PowerMac 6/7/8100) and 53CF94 (PowerMac
8100) behind AMIC DMA (see NCR53C9x.c and nbpmac_esp.c at

Etsushi Kato
ekato at

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