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)

Implement more of __ibsta: END and SRQI status bits (taken out of the
uPD7210 IRQ status).

MFC after: 1 week

Fix __retval vs. retval confusion: retval is meant to store the (userland)
pointer where data is to be returned by ibask() (currently unimplemented),
while __retval holds the value returned by the libgpib ibfoo() functions.

The confusion resulted in the ibfoo() functions returning an uninitialized
value except in situations where the GPIB activity has been terminated
abnormally.

MFC after: 3 days

GPIB overhaul, part #2: make the tnt4882 driver work with the newer
TNT5004 IC. This involved a major rewrite of a number of things, as
this chip no longer supports the NAT7210 legacy mode but requires the
host to use the (more modern) FIFO mode.

In theory, this also ought to work on the older TNT4882C chip. I'll
probably add this as optional support (perhaps by a device.hints flag)
later on. By now, FIFO mode is *only* activates iff a TNT5004 chip
has been detected (where the old code didn't work at all), while
everything else is supposed to use the old code.

MFC after: 2 weeks

Make isa_dma functions MPSAFE by introducing its own private lock. These
functions are selfcontained (ie. they touch only isa_dma.c static variables
and hardware) so a private lock is sufficient to prevent races. This changes
only i386/amd64 while there are also isa_dma functions for ia64/sparc64.
Sparc64 are ones empty stubs and ia64 ones are unused as ia64 does not
have isa (says marcel).

This patch removes explicit locking of Giant from a few drivers (there
are some that requires this but lack ones - this patch fixes this) and
also removes the need for implicit locking of Giant from attach routines
where it's provided by newbus.

Approved by: ed (mentor, implicit)
Reviewed by: jhb, attilio (glanced by)
Tested by: Giovanni Trematerra <giovanni.trematerra gmail com>
IA64 clue: marcel

Replace callout_init(..., 1) with callout_init(..., CALLOUT_MPSAFE) for
better grep-compliance and to standardize with the rest of the kernel.

Reviewed by: jhb
MFC after: 1 week

Add placeholder mutex argument to new_unrhdr().

Always go to standby efter each call.

Check handle types.
Implement more device functions.
Make DMA optional.

Add ibcntl as alias for ibcnt
Add ibsta and start to use it.
Rename the argument structure more sensibly.
Improve timeout and error handling

Split the ibfoo API into its own file.
Implement ibdma() (only affects ibrd() mode)
Implement ibeot()