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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