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)

Various whitespace and style fixes.

Several cleanups to remove the need for explicit unit numbers and a few
other fixes:
- Add pointers back to device_t objects in softc structures instead
of storing the unit and using devclass_get_device().
- Add 'lpbb', 'pcf', 'pps', and 'vpo' child devices to every 'ppbus' device
instead of just the first one.
- Store softc pointers in si_drv1 of character devices instead of
pulling the unit number from the minor number and using
devclass_get_softc() and devclass_get_device().
- Store the LP_BYPASS flag in si_drv2 instead of encoding it in the minor
number.
- Destroy character devices for lpt(4) when detaching the device.
- Use bus_print_child_footer() instead of duplicating it in
ppbus_print_child() and fix ppbus_print_child()'s return value.
- Remove unused AVM ivar from ppbus.
- Don't store the 'mode' ivar in the ppbus ivars since we always fetch it
from the parent anyway.
- Try to detach all the child devices before deleting them in
ppbus_detach().
- Use pause() instead of a tsleep() on a dummy address when polling the
ppbus.
- Use if_printf() and device_printf() instead of explicit names with unit
numbers.

Silence on: current@

Cleanup and improve mode detection. Now, you should get what you actually
want according to the modes set with the ppc(4) flags. Especially, it
should fix some problems with mode detection of parallel chipsets
configured to EPP but which have timing troubles with the drives. In such
a case, the driver should now fall back to slower modes (PS2, NIBBLE).

Port of ppbus standalone framework to the newbus system.

Note1: the correct interrupt level is invoked correctly for each driver.
For this purpose, drivers request the bus before being able to
call BUS_SETUP_INTR and BUS_TEARDOWN_INTR call is forced by the ppbus
core when drivers release it. Thus, when BUS_SETUP_INTR is called
at ppbus driver level, ppbus checks that the caller owns the
bus and stores the interrupt handler cookie (in order to unregister
it later).

Printing is impossible while plip link is up is still TRUE.
vpo (ZIP driver) and lpt are make in such a way that
using the ZIP and printing concurrently is permitted is also TRUE.

Note2: specific chipset detection is not done by default. PPC_PROBE_CHIPSET
is now needed to force chipset detection. If set, the flags 0x40
still avoid detection at boot.

Port of the pcf(4) driver to the newbus system (was previously directly
connected to the rootbus and attached by a bogus pcf_isa_probe function).

$Id$ -> $FreeBSD$

ppbus enhanced to support ZIP+ : 1284 code added, microseq improved +
some bugs corrected in vpoio.

Major ppbus updates from the author.

- ppbus now supports PLIP via the if_plip driver
- ieee1284 infrastructure added, including parallel-port PnP
- port microsequencer added, for scripting the sort of port I/O
that is common with parallel devices without endless calls up and down
through the driver structure.
- improved bus ownership behaviour among the ppbus-using drivers.
- improved I/O chipset feature detection

The vpo driver is now implemented using the microsequencer, leading to
some performance improvements as well as providing an extensive example
of its use.

Reviewed by: msmith
Submitted by: Nicolas Souchu <Nicolas.Souchu@prism.uvsq.fr>