add support for console resuming, implement it for uart, use on x86

This change adds a new optional console method cn_resume and a kernel
console interface cnresume. Consoles that may need to re-in

add support for console resuming, implement it for uart, use on x86

This change adds a new optional console method cn_resume and a kernel
console interface cnresume. Consoles that may need to re-initialize
their hardware after suspend (e.g., because firmware does not care to do
it) will implement cn_resume. Note that it is called in rather early
environment not unlike early boot, so the same restrictions apply.
Platform specific code, for platforms that support hardware suspend,
should call cnresume early after resume, before any console output is
expected.

This change fixes a problem with a system of mine failing to resume when
a serial console is used. I found that the serial port was in a strange
configuration and an attempt to write to it likely resulted in an
infinite loop.

To avoid adding cn_resume method to every console driver, CONSOLE_DRIVER
macro has been extended to support optional methods.

Reviewed by: imp, mav
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D15552

show more ...

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error

sys/dev: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

show more ...

- Make the code consistent with itself style-wise and bring it closer
to style(9).
- Mark unused arguments as such.
- Make the ttystates table const.

Fix tty_drain() and, thus, TIOCDRAIN of the current tty(4) incarnation
to actually wait until the TX FIFOs of UARTs have be drained before
returning. This is done by bringing the equivalent of the TS

Fix tty_drain() and, thus, TIOCDRAIN of the current tty(4) incarnation
to actually wait until the TX FIFOs of UARTs have be drained before
returning. This is done by bringing the equivalent of the TS_BUSY flag
found in the previous implementation back in an ABI-preserving way.
Reported and tested by: Patrick Powell

Most likely, drivers for USB-serial-adapters likewise incorporating
TX FIFOs as well as other terminal devices that buffer output in some
form should also provide implementations of tsw_busy.

MFC after: 3 days

show more ...

Provide the tty-layer mutex when initializing the pps api. This allows
time_pps_fetch() to be used in blocking mode.

Also, don't init the pps api for system devices (consoles) that provide a
custom

Provide the tty-layer mutex when initializing the pps api. This allows
time_pps_fetch() to be used in blocking mode.

Also, don't init the pps api for system devices (consoles) that provide a
custom attach routine. The device may actually be a keyboard or other non-
tty device. If it wants to do pps processing (unlikely) it must handle
everything for itself. (In reality, only a sun keyboard uses a custom
attach routine, and it doesn't make a good pps device.)

show more ...

Do not prevent processes from making changes to the baudrate or the
CLOCAL and HUPCL control flags. There are legit reasons for allowing
those to be changed. When /etc/ttys has the "3wire" type (with

Do not prevent processes from making changes to the baudrate or the
CLOCAL and HUPCL control flags. There are legit reasons for allowing
those to be changed. When /etc/ttys has the "3wire" type (without a
baudrate) for the serial port that is the low-level console, then
this change has no effect.

Obtained from: Juniper Networks, Inc.

show more ...

Pass the actual baudrate to tty_init_console(). This defines the initial
baudrate of the device special file, and makes sure that on open(2) the
UART is programmed with the correct baudrate. This the

Pass the actual baudrate to tty_init_console(). This defines the initial
baudrate of the device special file, and makes sure that on open(2) the
UART is programmed with the correct baudrate. This then eliminates the
need in uart_tty_param() to override the speed setting.

show more ...

Plumb the cn_grab and cn_ungrab routines down into the uart
clients. Mask RX interrupts while grabbed on the atmel serial
driver. This UART interrupts every character. When interrupts are
enabled at

Plumb the cn_grab and cn_ungrab routines down into the uart
clients. Mask RX interrupts while grabbed on the atmel serial
driver. This UART interrupts every character. When interrupts are
enabled at the mountroot> prompt, this means the ISR eats the
characters. Rather than try to create a cooperative buffering system
for the low level kernel console, instead just mask out the ISR. For
NS8250 and decsendents this isn't needed, since interrupts only happen
after 14 or more characters (depending on the fifo settings). Plumb
such that these are optional so there's no change in behavior for all
the other UART clients. ddb worked on this platform because all
interrupts were disabled while it was running, so this problem wasn't
noticed. The mountroot> issue has been around for a very very long
time.

MFC after: 3 days

show more ...

MFC change 197721:
Fix RTS/CTS flow control, broken by the TTY overhaul. The new TTY
interface is fairly simple WRT dealing with flow control, but
needed 2 new RX buffer functions with "get-char-fro

MFC change 197721:
Fix RTS/CTS flow control, broken by the TTY overhaul. The new TTY
interface is fairly simple WRT dealing with flow control, but
needed 2 new RX buffer functions with "get-char-from-buf" separated
from "advance-buf-pointer" so that the pointer could be advanced
only when ttydisc_rint() succeeded.

Approved by: re (kib)

show more ...

kern cons: introduce infrastructure for console grabbing by kernel

At the moment grab and ungrab methods of all console drivers are no-ops.

Current intended meaning of the calls is that the kernel

kern cons: introduce infrastructure for console grabbing by kernel

At the moment grab and ungrab methods of all console drivers are no-ops.

Current intended meaning of the calls is that the kernel takes control of
console input. In the future the semantics may be extended to mean that
the calling thread takes full ownership of the console (e.g. console
output from other threads could be suspended).

Inspired by: bde
MFC after: 2 months

show more ...

In uart_tty_outwakeup(), check CTS/RTS flow control settings and
prevent sending data when CTS is de-asserted.
In uart_tty_intr(), call uart_tty_outwakeup() when the CTS signal
changed, knowing that

In uart_tty_outwakeup(), check CTS/RTS flow control settings and
prevent sending data when CTS is de-asserted.
In uart_tty_intr(), call uart_tty_outwakeup() when the CTS signal
changed, knowing that uart_tty_outwakeup() will do the right
thing for flow control. This avoids redundant conditionals.

PR: kern/148644
Submitted by: John Wehle <[email protected]>
MFC after: 3 days

show more ...

Remove unneeded includes of <sys/termios.h>.

Fix RTS/CTS flow control, broken by the TTY overhaul. The new TTY
interface is fairly simple WRT dealing with flow control, but
needed 2 new RX buffer functions with "get-char-from-buf" separated
fro

Fix RTS/CTS flow control, broken by the TTY overhaul. The new TTY
interface is fairly simple WRT dealing with flow control, but
needed 2 new RX buffer functions with "get-char-from-buf" separated
from "advance-buf-pointer" so that the pointer could be advanced
only when ttydisc_rint() succeeded.

MFC after: 1 week

show more ...

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 cr

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.

show more ...

Minor style(9) compliance change.

Fix detaching of uart(4) devices.

With our new TTY layer we use a two step device destruction procedure.
The TTY first gets abandoned by the device driver. When the TTY layer
notices all threads hav

Fix detaching of uart(4) devices.

With our new TTY layer we use a two step device destruction procedure.
The TTY first gets abandoned by the device driver. When the TTY layer
notices all threads have left the TTY layer, it deallocates the TTY.

This means that the device unit number should not be reused before a
callback from the TTY layer to the device driver has been made. newbus
doesn't seem to support this concept (yet), so right now just add a
destructor with a big comment in it. It's not ideal, but at least it's
better than panicing.

Reported by: rnoland

show more ...

Integrate the new MPSAFE TTY layer to the FreeBSD operating system.

The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve

Integrate the new MPSAFE TTY layer to the FreeBSD operating system.

The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:

- Improved driver model:

The old TTY layer has a driver model that is not abstract enough to
make it friendly to use. A good example is the output path, where the
device drivers directly access the output buffers. This means that an
in-kernel PPP implementation must always convert network buffers into
TTY buffers.

If a PPP implementation would be built on top of the new TTY layer
(still needs a hooks layer, though), it would allow the PPP
implementation to directly hand the data to the TTY driver.

- Improved hotplugging:

With the old TTY layer, it isn't entirely safe to destroy TTY's from
the system. This implementation has a two-step destructing design,
where the driver first abandons the TTY. After all threads have left
the TTY, the TTY layer calls a routine in the driver, which can be
used to free resources (unit numbers, etc).

The pts(4) driver also implements this feature, which means
posix_openpt() will now return PTY's that are created on the fly.

- Improved performance:

One of the major improvements is the per-TTY mutex, which is expected
to improve scalability when compared to the old Giant locking.
Another change is the unbuffered copying to userspace, which is both
used on TTY device nodes and PTY masters.

Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.

Obtained from: //depot/projects/mpsafetty/...
Approved by: philip (ex-mentor)
Discussed: on the lists, at BSDCan, at the DevSummit
Sponsored by: Snow B.V., the Netherlands
dcons(4) fixed by: kan

show more ...

Properly propagate overrun conditions to the TTY layer.

MFC after: 3 days

Convert to new console api

Don't open if we're going away.

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

- Use swi_remove() to teardown swi handlers rather than
intr_event_remove_handler().
- Remove tty: prefix from a couple of swi handler names.

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 pie

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)

show more ...

Eliminate two unused arguments to ttycreate().

In uart_cnprobe(), fill in the cn_name field of the consdev structure.
The core console code checks this field when a console is added and
emits a warning if it's empty. In practice the warning is ha

In uart_cnprobe(), fill in the cn_name field of the consdev structure.
The core console code checks this field when a console is added and
emits a warning if it's empty. In practice the warning is harmless for
uart(4), because the cn_name is filled in as soon as the device name is
known; which is when the device is enumerated.
To avoid the warning, to avoid possible complications caused by emitting
the warning without there (possibly) being a console selected yet and to
avoid complications when the UART isn't found during bus enumeration, we
just preset the cn_name field here to the name of the driver.

show more ...