'RELENG_5_3_0_RELEASE'.

This commit was manufactured to restore the state of the 5.3-RELEASE image.

of mine introduced in revision 1.10.

Approved by:	marcel
Prodded by:	marcel

  and that can be used as an identify function for all kinds of busses on a
  certain platform. Expect for sparc64 these are only stubs right now. [1]
- For sparc64, add code to its uart_cpu_identify() for registering the on-
  board ISA UARTs and their resources based on information obtained from
  Open Firmware.
  It would be better if this would be done in the OFW ISA code. However, due
  to the common FreeBSD ISA code and PNP-IDs not always being present in the
  properties of the ISA nodes there seems to be no good way to implement that.
  Therefore special casing UARTs as the sole really relevant ISA devices on
  sparc64 seemed reasonable. [2]

Approved by:	marcel
Discussed with:	marcel [1], tmm [2]
Tested by:	make universe

"... uart_cpu_sparc64.c currently only looks at /options if ttyX is
the selected console. However, there's one case where it should
additionally look at /chosen. If "keyboard" is the selected input-
device and "screen" the output-device (both via /options) but the
keyboard is unplugged, OF automatically switches to ttya for the
console. It even prints a line telling so on "screen". Solaris
respects this behaviour and uses ttya as the console in this case
and people probably expect FreeBSD to do the same (it's also very
handy to temporarily switch consoles)..."

Submitted by: Marius Strobl <marius@alchemy.franken.de>
Has no doubt the change is correct: marcel

other architectures (like ia64), the variable has to be set to
an OpenFirmware device name.

to select a serial console and debug port (resp). On ia64 these replace
the use of hints completely and take precedence over hints on alpha,
amd64 and i386. On sparc64 these variables are not yet recognised.

The reasons for introducing these variables are:
1.  Hints have side-effects. They reserve the unit number for use by
    isa or acpi devices and therefore cannot be used to select a pci
    device. Also, the use of a unit number to select a device prior
    to bus enumeration is nonsense. The new variables have no side-
    effects and are not based on unit numbers.
2.  Hints don't have the expression power to allow the sysadmin to
    select UARTs that are not legacy PC devices and need the support
    of compile-time constants to give the sysadmin some level of
    flexibility.

The hw.uart.console and hw.uart.dbgport variables specify a list of
attributes. An attribute is a tag-value pair, seperated by a colon.
Attributes are seperated by a comma. Where possible, tags are the
same as those in /etc/remote (only br and pa in practice). Details
can be found in the manpage (not part of this commit).

Not tested on: amd64, pc98

stdin, such as when using a serial console.  We must recognize these
devices here so that we can override the tty attach routine.

and the Z8530 drivers used the I/O address as a quick and dirty way to
determine which channel they operated on, but formalizing this by
introducing iobase is not a solution. How for example would a driver
know which channel it controls for a multi-channel UART that only has a
single I/O range?

Instead, add an explicit field, called chan, to struct uart_bas that
holds the channel within a device, or 0 otherwise. The chan field is
initialized both by the system device probing (i.e. a system console)
or it is passed down to uart_bus_probe() by any of the bus front-ends.
As such, it impacts all platforms and bus drivers and makes it a rather
large commit.

Remove the use of iobase in uart_cpu_eqres() for pc98. It is expected
that platforms have the capability to compare tag and handle pairs for
equality; as to determine whether two pairs access the same device or
not. The use of iobase for pc98 makes it impossible to formalize this
and turn it into a real newbus function later. This commit reverts
uart_cpu_eqres() for pc98 to an unimplemented function. It has to be
reimplemented using only the tag and handle fields in struct uart_bas.

Rewrite the SAB82532 and Z8530 drivers to use the chan field in struct
uart_bas. Remove the IS_CHANNEL_A and IS_CHANNEL_B macros. We don't
need to abstract anything anymore.

Discussed with: nyan
Tested on: i386, ia64, sparc64

- Remove buggy uart_cpu_busaddr() function.