Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Convert the midway driver to use busdma. Except for this conversion the
following changes have been done:

- stylify. The original code was too hard to read.
- get rid of a number of compilation options (Adaptec-only, Eni-only, no-DMA).
- more debugging features.
- locking. This is not correct yet in the absence of interface layer locking,
but is correct enough to not to cause lock order reversals.
- remove RAW mode. There are no users of this in the tree and I doubt that
there are any.
- remove NetBSD compatibility code. There was no way to keep NetBSD non-busdma
and FreeBSD busdma code together.
- if_en now buildable as a module.

This has been actively tested on sparc64 and i386 with ENI server and
client cards and an Adaptec card (thanks to kjc).

Reviewed by: mdodd, arr

newbusify the en atm driver.

also
- sync with netbsd
- fix a bug that miscalculates tx cell counts when the pointer size isn't 4

tested both ENI and Adaptec cards on both i386 and alpha.

Make LINT compile again.

update ATM driver. (base version: midway.c 1.67 --> 1.68)

several new features are added:
- support vc/vp shaping
- support pvc shadow interface

code cleanup:
- remove WMAYBE related code. ENI WMAYBE DMA doen't work.
- remove updating if_lastchange for every packet.
- BPF related code is moved to midway.c as it should be.
(bpfwrite should work if atm_pseudohdr and LLC/SNAP are
prepended.)
- BPF link type is changed to DLT_ATM_RFC1483.
BPF now understands only LLC/SNAP!! (because bpf can't
handle variable link header length.)
It is recommended to use LLC/SNAP instead of NULL
encapsulation for various reasons. (BPF, IPv6,
interoperability, etc.)

the code has been used for months in ALTQ and KAME IPv6.

OKed by phk long time ago.

This commit was generated by cvs2svn to compensate for changes in r25603,
which included commits to RCS files with non-trunk default branches.

import Chuck Cranor's ATM driver