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

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

Toss bogus mergeinfo.

MFC r235634

Fix and update battery status bits according to linux driver

MFC r228631: kern cons: introduce infrastructure for console grabbing by
kernel

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

Approved by: re (implicit)

Follow up to r225203 refining break-to-debugger run-time configuration
improvements:

(1) Implement new model in previously missed at91 UART driver
(2) Move BREAK_TO_DEBUGGER and ALT_BREAK_TO_DEBUGGER from opt_comconsole.h
to opt_kdb.h (spotted by np)
(3) Garbage collect now-unused opt_comconsole.h

MFC after: 3 weeks
Approved by: re (bz)

Attempt to make break-to-debugger and alternative break-to-debugger more
accessible:

(1) Always compile in support for breaking into the debugger if options
KDB is present in the kernel.

(2) Disable both by default, but allow them to be enabled via tunables
and sysctls debug.kdb.break_to_debugger and
debug.kdb.alt_break_to_debugger.

(3) options BREAK_TO_DEBUGGER and options ALT_BREAK_TO_DEBUGGER continue
to behave as before -- only now instead of compiling in
break-to-debugger support, they change the default values of the
above sysctls to enable those features by default. Current kernel
configurations should, therefore, continue to behave as expected.

(4) Migrate alternative break-to-debugger state machine logic out of
individual device drivers into centralised KDB code. This has a
number of upsides, but also one downside: it's now tricky to release
sio spin locks when entering the debugger, so we don't. However,
similar logic does not exist in other device drivers, including uart.

(5) dcons requires some special handling; unlike other console types, it
allows overriding KDB's own debugger selection, so we need a new
interface to KDB to allow that to work.

GENERIC kernels in -CURRENT will now support break-to-debugger as long as
appropriate boot/run-time options are set, which should improve the
debuggability of BETA kernels significantly.

MFC after: 3 weeks
Reviewed by: kib, nwhitehorn
Approved by: re (bz)

Start using the 'init_static_kenv()' API provided by r198561 to initialize
CFE environment variables.

Create the "cfecons" tty directly using tty_makedev(). It is not clear what
the intention of having two ttys pointing to the same cfe console device was.

Also we were not initializing the output[] array passed in as input to
tty_makedev() so one name of the ttys was garbage.

Fix the code that calls cfe_write() to deal with the case where only a partial
buffer is written out.

cfe_cngetc() needs to return if there is no character available as input.
If we don't do this then the cfe_timeout() function will spin forever
because cfe_cngetc() will only ever return if there is valid input.

Approved by: imp (mentor)

Using svn cp rather than cp to copy these files over had the benefit
of preserving their history. It had the problem that it also copied
over mergeinfo data. Since we're retiring the projects/mips branch,
I'm removing the svn:mergeinfo property from them all.

Submitted by: jhb

Fix bug in cfe_enumenv(). The CFE API to invoke is CFE_CMD_ENV_ENUM
and not CFE_CMD_ENV_SET.

Submitted by: neel@

Merge from projects/mips to head by hand:

copy over cfe_env.c...

Last minute TTY API change: remove mutex argument from tty_alloc().

I don't want people to override the mutex when allocating a TTY. It has
to be there, to keep drivers like syscons happy. So I'm creating a
tty_alloc_mutex() which can be used in those cases. tty_alloc_mutex()
should eventually be removed.

The advantage of this approach, is that we can just remove a function,
without breaking the regular API in the future.

Remove an unused variable to make the SENTRY5 mips kernel compile
(though with some asm warning).

Remove unused consdev structure fields.

The cn_unit and cn_tp fields don't seem to be used anywhere. Some
drivers set them, while others don't. Just remove them, in an attempt to
make our consdev code a little easier to understand.

Change while (cond)\n\t\t; to while (cond)\n\t\tcontinue; since the
former more explicitly tells the compiler that you want an empty loop.
There are some lint programs that use this hint to avoid generating
warnings.

No functional change...

Catch up to latest tty, kdb and SYSINIT changes. Modeled after the
dev/ofw changes, since this driver appears to have used that as a
start years ago...

The Ultra2 never had a CFE console or CFE boot loader. Kill obvious
cut-n-paste leftover.

Support for CFE boot loaders. Initially the support is for MIPS, but
other processors will work too.

Submitted by: bms@
Obtained from: p4 mips2 branch