Make some UART consoles to not spin wait for data to be sent.

At least with Tx FIFO enabled it shows me ~10% reduction of verbose boot
time with serial console at 115200 baud.

Most affect comments, very few have user-visible effects.

separate driver. Add support for activating clock and hwreset resources
for these devices when the EXT_RESOURCES option is present.

Reviewed by:		andrew, mmel, Emmanuel Vadot <manu@bidouilliste.com>
Approved by:		adrian (mentor)
Differential Revision:	https://reviews.freebsd.org/D5749

Obtained from:         Semihalf
Submitted by:          Michal Stanek <mst@semihalf.com>
Sponsored by:          Annapurna Labs
Approved by:           cognet (mentor)
Reviewed by:           imp, wma
Differential revision: https://reviews.freebsd.org/D5404

 - don't enable transmitter empty interrupt before filling TX FIFO.
 - add missing uart_barrier() call in interrupt service routine

uart_dev_ns8250 now relies on compatible property instead of additional
'busy-detect' cell. All drivers with compatible = "snps,dw-apb-uart" have
busy detection turned on. DTS files of devices affected by the change
were modified and 'busy-detect' property was removed.

Reviewed by:    andrew, ian, imp
Obtained from:  Semihalf
Sponsored by:   Stormshield
Submitted by:   Bartosz Szczepanek <bsz@semihalf.com>
Differential revision:  https://reviews.freebsd.org/D4218

This compatibility string is used in .dts file of Armada38x
and isrequired for driver attachment.

Reviewed by:    andrew, ian, imp
Obtained from:  Semihalf
Sponsored by:   Stormshield
Submitted by:   Michal Stanek <mst@semihalf.com>
Differential revision:  https://reviews.freebsd.org/D4216

option to invert the polarity in software. Also add an option to capture
very narrow pulses by using the hardware's MSR delta-bit capability of
latching line state changes.

This effectively reverts the mistake I made in r286595 which was based on
empirical measurements made on hardware using TTL-level signaling, in which
the logic levels are inverted from RS-232. Thus, this re-syncs the polarity
with the requirements of RFC 2783, which is writen in terms of RS-232
signaling.

Narrow-pulse mode uses the ability of most ns8250 and similar chips to
provide a delta indication in the modem status register. The hardware is
able to notice and latch the change when the pulse width is shorter than
interrupt latency, which results in the signal no longer being asserted by
time the interrupt service code runs. When running in this mode we get
notified only that "a pulse happened" so the driver synthesizes both an
ASSERT and a CLEAR event (with the same timestamp for each). When the pulse
width is about equal to the interrupt latency the driver may intermittantly
see both edges of the pulse. To prevent generating spurious events, the
driver implements a half-second lockout period after generating an event
before it will generate another.

Differential Revision:	https://reviews.freebsd.org/D4477

It turns out on a 16550 w/ a 25MHz SoC reference clock you get a little
over 3% error at 115200 baud, which causes this to fail.

Just .. cope. Things cope these days.

Default to 30 (3.0%) as before, but allow UART_DEV_TOLERANCE_PCT to be
set at build time to change that.

Without this fix, you cannot disable the quirks by setting it to 0, just
the presence of the FDT node was enough to enable it.