Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Restore binary compatibility for GIO_KEYMAP and PIO_KEYMAP.

Back in 2009 I changed the ABI of the GIO_KEYMAP and PIO_KEYMAP ioctls
to support wide characters. I created a patch to add ABI compatibility
for the old calls, but I didn't get any feedback to that.

It seems now people are upgrading from 8 to 9 they experience this
issue, so add it anyway.

Fix bugs in the Sun -> AT keycode translation table which caused the
Props key to act as Again and the Paste and Copy keys to be inverted.

Don't expose the uart_ops structure directly, but instead have
it obtained through the uart_class structure. This allows us
to declare the uart_class structure as weak and as such allows
us to reference it even when it's not compiled-in.
It also allows is to get the uart_ops structure by name, which
makes it possible to implement the dt tag handling in uart_getenv().
The side-effect of all this is that we're using the uart_class
structure more consistently which means that we now also have
access to the size of the bus space block needed by the hardware
when we map the bus space, eliminating any hardcoding.

- Add a uart_rxready() and corresponding device-specific implementations
that can be used to check whether receive data is ready, i.e. whether
the subsequent call of uart_poll() should return a char, and unlike
uart_poll() doesn't actually receive data.
- Remove the device-specific implementations of uart_poll() and implement
uart_poll() in terms of uart_getc() and the newly added uart_rxready()
in order to minimize code duplication.
- In sunkbd(4) take advantage of uart_rxready() and use it to implement
the polled mode part of sunkbd_check() so we don't need to buffer a
potentially read char in the softc.
- Fix some mis-indentation in sunkbd_read_char().

Discussed with: marcel

- In sunkbd_probe_keyboard() don't bother to determine the keyboard layout
as we have no use for that info. Instead let this function return the
keyboard ID and verify at its invocation in sunkbd_configure() that we're
talking to a Sun type 4/5/6 keyboard, i.e. a keyboard supported by this
driver.
- Add an option SUNKBD_EMULATE_ATKBD whose code is based on the respective
code in ukbd(4) and like UKBD_EMULATE_ATSCANCODE causes this driver to
emit AT keyboard/KB_101 compatible scan codes in K_RAW mode as assumed by
kbdmux(4). Unlike UKBD_EMULATE_ATSCANCODE, SUNKBD_EMULATE_ATKBD also
triggers the use of AT keyboard maps and thus allows to use the map files
in share/syscons/keymaps with this driver at the cost of an additional
translation (in ukbd(4) this just is the way of operation).
- Implement an option SUNKBD_DFLT_KEYMAP, which like the equivalent options
of the other keyboard drivers allows to specify the default in-kernel
keyboard map. For obvious reasons this made to only work when also using
SUNKBD_EMULATE_ATKBD.
- Implement sunkbd_check(), sunkbd_check_char() and sunkbd_clear_state(),
which are also required for interoperability with kbdmux(4).
- Implement K_CODE mode and FreeBSD keypad compose.
- As a minor hack define KBD_DFLT_KEYMAP also in the !SUNKBD_EMULATE_ATKBD
case so we can obtain fkey_tab from <dev/kbd/kbdtables.h> rather than
having to duplicate it and #ifdef some more code.
- Don't use the TX-buffer for writing the two command bytes for setting the
keyboard LEDs as this consequently requires a hardware FIFO that is at
least two bytes in depth, which the NMOS-variant of the Zilog SCCs doesn't
have. Thus use an inlined version of uart_putc() to consecutively write
the command bytes (a cleaner approach would be to do this via the soft
interrupt handler but that variant wouldn't work while in ddb(4)). [1]
- Fix some minor style(9) bugs.

PR: 90316 [1]
Reviewed by: marcel [1]

Fix our ioctl(2) implementation when the argument is "int". New
ioctls passing integer arguments should use the _IOWINT() macro.
This fixes a lot of ioctl's not working on sparc64, most notable
being keyboard/syscons ioctls.

Full ABI compatibility is provided, with the bonus of fixing the
handling of old ioctls on sparc64.

Reviewed by: bde (with contributions)
Tested by: emax, marius
MFC after: 1 week

Do not try to call keyboard callback unless keyboard is active and busy.
This should fix 'kbdcontrol -K < /dev/console' panic on sparc64 with sunkbd(4).

PR: sparc64/96798
MFC after: 1 week

MFp4:
Stop using our local UART_IPEND_* and instead use the global SER_INT_*
as defined in <sys/serial.h>.

Reorganize the interrupt handling code a bit to make a few things cleaner
and increase flexibility to allow various different approaches to be tried
in the future.
- Split struct ithd up into two pieces. struct intr_event holds the list
of interrupt handlers associated with interrupt sources.
struct intr_thread contains the data relative to an interrupt thread.
Currently we still provide a 1:1 relationship of events to threads
with the exception that events only have an associated thread if there
is at least one threaded interrupt handler attached to the event. This
means that on x86 we no longer have 4 bazillion interrupt threads with
no handlers. It also means that interrupt events with only INTR_FAST
handlers no longer have an associated thread either.
- Renamed struct intrhand to struct intr_handler to follow the struct
intr_foo naming convention. This did require renaming the powerpc
MD struct intr_handler to struct ppc_intr_handler.
- INTR_FAST no longer implies INTR_EXCL on all architectures except for
powerpc. This means that multiple INTR_FAST handlers can attach to the
same interrupt and that INTR_FAST and non-INTR_FAST handlers can attach
to the same interrupt. Sharing INTR_FAST handlers may not always be
desirable, but having sio(4) and uhci(4) fight over an IRQ isn't fun
either. Drivers can always still use INTR_EXCL to ask for an interrupt
exclusively. The way this sharing works is that when an interrupt
comes in, all the INTR_FAST handlers are executed first, and if any
threaded handlers exist, the interrupt thread is scheduled afterwards.
This type of layout also makes it possible to investigate using interrupt
filters ala OS X where the filter determines whether or not its companion
threaded handler should run.
- Aside from the INTR_FAST changes above, the impact on MD interrupt code
is mostly just 's/ithread/intr_event/'.
- A new MI ddb command 'show intrs' walks the list of interrupt events
dumping their state. It also has a '/v' verbose switch which dumps
info about all of the handlers attached to each event.
- We currently don't destroy an interrupt thread when the last threaded
handler is removed because it would suck for things like ppbus(8)'s
braindead behavior. The code is present, though, it is just under
#if 0 for now.
- Move the code to actually execute the threaded handlers for an interrrupt
event into a separate function so that ithread_loop() becomes more
readable. Previously this code was all in the middle of ithread_loop()
and indented halfway across the screen.
- Made struct intr_thread private to kern_intr.c and replaced td_ithd
with a thread private flag TDP_ITHREAD.
- In statclock, check curthread against idlethread directly rather than
curthread's proc against idlethread's proc. (Not really related to intr
changes)

Tested on: alpha, amd64, i386, sparc64
Tested on: arm, ia64 (older version of patch by cognet and marcel)

Replace the band-aid for allowing to call sunkbd_configure() multiple
times which was added in the last revision with what should be a proper
solution as long as keyboards that were pluggged in after the kernel
has fully booted aren't supported. I.e. when sunkbd_configure() is
called for the high-level console probe make sure that the keyboard is
both successfully configured (i.e. also probed) and attached. The band-
aid left the possibility to attach the keyboard device to the high-level
console without attaching the keyboard device itself when the keyboard
is plugged in after uart(4) attached but before syscons(4) does.

- Sprinkle some KBD_IS_* and KBD_*_DONE macros in sunkbd_configure() as
a band-aid allowing to call this function savely multiple times, e.g.
during sckbdprobe() and sc_probe_unit(). Otherwise calling it a second
time results in a non-working keyboard. This needs a lot of more work
to actually do the right thing and work like expected.
- Let sunkbd_configure() return the number of the found keyboards, i.e.
1 in case probing succeeds, as it's expected. The return values of the
keyboard configure functions however currently aren't checked so this
doesn't make a difference at the moment.
- Use FBSDID.

Add the keyboard system device before we probe for the keyboard.
The presence or absence of a keyboard does not change whether an
UART is designed as a keyboard port or not and thus whether we
can use the port as a TTY or not.
We now call sunkbd_attach() even when we didn't previously find
a keyboard. Emit a useful message stating that no keyboard was
found, but don't do anything else.

MFC after: 5 days

Call kbd_attach() only when KBD_INSTALL_CDEV is enabled as the function
is only defined in that case.

Add a uart attachment/syscons keyboard driver for sun keyboards. In theory
this will work with any uart backend, currently supported hardware uses
either ns8250 or z8530.