hardware is interrupt-driven to a fault and sending a BREAK requires
mode switching. Always running in the BREAK-capable mode as in PR 8318
would double the overhead for sending \0's.
Reminded by: PR 8318
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
- use pseudo-dma
- provide the same features and interface as sio
- support multiple boards
- fix bugs.
Some compile-time configuration constants are set to support higher
speeds and Cyclom-16Y's at a 30% relative cost in efficiency.
Cyclom-16Y support is untested.
adapted to FreeBSD by Heikki Suonsivu <hsu@cs.hut.fi>.
Submitted by: Andrew Werple <andrew@werple.apana.org.au> and
Heikki Suonsivu <hsu@cs.hut.fi>
Obtained from: NetBSD
