MFC r317463:

Add information about device nodes to man pages for USB serial drivers.

MFC r318016:

Fix mistake introduced to uart(4) man page in r317463.

MFC r318017:

Fix device paths for USB serial adapters: the formatting strings
contain "%u", differently from eg uart(4) which uses "%r".

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Fix minor problems caught by mandoc -Tlint.

ioctl(8) -> ioctl(2)

MFC after: 1 month
Sponsored by: The FreeBSD Foundation

Restore uart PPS signal capture polarity to its historical norm, and add an
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

Allow the choice of PPS signal captured by uart(4) to be runtime-configured,
eliminating the need to build a custom kernel to use the CTS signal.

The historical UART_PPS_ON_CTS kernel option is still honored, but now it
can be overridden at runtime using a tunable to configure all uart devices
(hw.uart.pps_mode) or specific devices (dev.uart.#.pps_mode). The per-
device config is both a tunable and a writable sysctl.

This syncs the PPS capabilities of uart(4) with the enhancements recently
recently added to ucom(4) for capturing from USB serial devices.

Relnotes: yes

use .Mt to mark up email addresses consistently (final part)

PR: 191174
Submitted by: Franco Fichtner <franco at lastsummer.de>

Fix several typos in macros or macro misusage.

Found by: make manlint
Reviewed by: ru
Approved by: philip (mentor)

Fix formatting.

MFC after: 2 weeks

document device hints including new ones to control rx fifo trigger

MFC after: 2 weeks

Markup fixes.

o Add scc(4) to the build.
o Add the scc(4) manpage to the build.
o Update the uart(4) manpage to account for scc(4).
o Update the uart(4) module build to include support for scc(4).

document the tty files that uart(4) provides like sio(4) and pty(4) both
do.. This copies only part of the FILES section from sio(4)....

We might want to make tty(4) document the files provided, and have each of
these document the characters that it uses...

Pointed out by: Yasholomew Yashinski
MFC after: 3 days

s/asynchronuous/asynchronous/

".Pp before .Sh is redundant, the latter asserts for a vertical space
already."
-- ru@

Add a HARDWARE section, required for autogeneration of the release
notes.

MFC after: 3 days

Spelling fixes.

o Properly spell my last name. Bad Hiten, no cookie :-)
o Use the email address I put in my signature.

Change an `is' to a `was' in the AUTHORS section.

Recommended by: jmallett

Mdoc Review:

* Remove extraneous .Pp in SYNOPSIS

* Remove hard sentence break

* Add the AUTHORS section

The uart(4) driver is an universal driver for various UART hardware.
It improves on sio(4) in the following areas:
o Fully newbusified to allow for memory mapped I/O. This is a must
for ia64 and sparc64,
o Machine dependent code to take full advantage of machine and firm-
ware specific ways to define serial consoles and/or debug ports.
o Hardware abstraction layer to allow the driver to be used with
various UARTs, such as the well-known ns8250 family of UARTs, the
Siemens sab82532 or the Zilog Z8530. This is especially important
for pc98 and sparc64 where it's common to have different UARTs,
o The notion of system devices to unkludge low-level consoles and
remote gdb ports and provides the mechanics necessary to support
the keyboard on sparc64 (which is UART based).
o The notion of a kernel interface so that a UART can be tied to
something other than the well-known TTY interface. This is needed
on sparc64 to present the user with a device and ioctl handling
suitable for a keyboard, but also allows us to cleanly hide an
UART when used as a debug port.

Following is a list of features and bugs/flaws specific to the ns8250
family of UARTs as compared to their support in sio(4):
o The uart(4) driver determines the FIFO size and automaticly takes
advantages of larger FIFOs and/or additional features. Note that
since I don't have sufficient access to 16[679]5x UARTs, hardware
flow control has not been enabled. This is almost trivial to do,
provided one can test. The downside of this is that broken UARTs
are more likely to not work correctly with uart(4). The need for
tunables or knobs may be large enough to warrant their creation.
o The uart(4) driver does not share the same bumpy history as sio(4)
and will therefore not provide the necessary hooks, tweaks, quirks
or work-arounds to deal with once common hardware. To that extend,
uart(4) supports a subset of the UARTs that sio(4) supports. The
question before us is whether the subset is sufficient for current
hardware.
o There is no support for multiport UARTs in uart(4). The decision
behind this is that uart(4) deals with one EIA RS232-C interface.
Packaging of multiple interfaces in a single chip or on a single
expansion board is beyond the scope of uart(4) and is now mostly
left for puc(4) to deal with. Lack of hardware made it impossible
to actually implement such a dependency other than is present for
the dual channel SAB82532 and Z8350 SCCs.

The current list of missing features is:
o No configuration capabilities. A set of tunables and sysctls is
being worked out. There are likely not going to be any or much
compile-time knobs. Such configuration does not fit well with
current hardware.
o No support for the PPS API. This is partly dependent on the
ability to configure uart(4) and partly dependent on having
sufficient information to implement it properly.

As usual, the manpage is present but lacks the attention the
software has gotten.