Hi,
> > Atari SCC variants have their own quirks, so something more configurable
> > will be needed.
>
> We probably should have an SCC/ESCC core driver the way we have for
> a lot of the other common chips like 8390 ethernet or ESP SCSI. I
> know there's lots of systems with these chips that each have drivers.
Didn't seem too many of those in drivers/serial ...
> > What are the quirks the m68k mac SCC driver woukd add? From memory, I have
> > this
>
> Most of the m68k mac serial quirks are the same as the ones in the
> pmac serial driver. There is only one interrupt for both ports, but
According to my 2.2.25 source, SCC A is at interrupt number 33, SCC B is at 34.
Did that change with tha A/UX interrupt style?
What seems to be true is all interrupt types for a given channel go to the same
handler...
The platform device would need to have one interrupt number each for TX, RX,
status and special condition for each channel, plus data/control ports forr
each, plus flags. The Mac platform device would have only one interrupt per
channel (and perhaps a flag indicating that).
> the drivers do funny things to make it look mostly like each port
> has its own interrupt. There are some odd things about how Apple
> hooked up the hardware flow control. I suspect that any models with
Right you are ...
> built-in modems need enable/disable code for that on m68k macs
Are there any Macs with builtin modems in the standard configuration?
> There isn't much m68k mac specific, and I don't think the issues
> you mention for Atari are issues on macs. The AV systems have
> DMA but don't have a tx-dma channel for the second port. The one
> interrupt is hooked up to IRQ 4, which means it doesn't go through
This is on AV Macs only (because the PSC interrupts are at 32-35 there)?
> > Can the platform bus device code define architecture specific init callbacks
> > to hide this?
>
> We could probably do something along those lines, but I can't see
> tying it directly to the platform bus. I think it would be better
> to make a zilog SCC/ESCC core driver and write a driver for each
> bus interface type the way the ESP driver now works. It just seems
> simpler from a code maintenance perspective.
I don't think using callbacks would be a clean way of handling this, so your
idea may be better.
VME and Atari used to use the same driver in 2.2 so that should still be
possible now.
Michael
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