If the circular buffer is empty, it just means we fit all characters to
send into the HW fifo, but not that the hardware finished transmitting
them.

So if we immediately call stop_tx() after that, this may abort any
pending characters in the HW fifo, and cause dropped characters on the
console.

Fix this by only stopping tx when the tx HW fifo is actually empty.

Fixes: 8275b48b ("tty: serial: introduce transmit helpers")
Cc: stable@vger.kernel.org
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Link: https://lore.kernel.org/r/20240303150807.68117-1-jonas.gorski@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-19-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The struct eg20t_port has a spinlock_t which is used for locking while
access I/O of the device. Then there is the uart_portlock which is
sometimes and nests within eg20t_port's lock.

The uart_port lock is not used while using the struct in
pch_uart_hal_read() which might be okay. Then both locks are used in
pch_console_write() which looks odd especially the double try_lock part.

All in all it looks like the uart_port's lock could replace eg20t_port's
lock and simplify the code.

Remove eg20t_port::lock and use uart_port's lock for the lock scope.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-18-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need to directly initialize the spinlock_t in struct
uart_port. The structure is later passed to uart_add_one_port() which
initialize the complete struct including the lock member.

Remove spin_lock_init() on uart_port's internal lock.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-17-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The interrupt service routine is always invoked with disabled
interrupts.

Remove the _irqsave() from the locking functions in the interrupts
service routine/ pch_uart_interrupt().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-16-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

push_rx() returns always 0.

Make push_rx() return void.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-15-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

handle_rx() is only a wrapper around handle_rx_to() without any
additional functionality.

Invoke handle_rx_to() directly and remove handle_rx().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-14-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Handle sysrq requests sysrq once the port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-13-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Handle sysrq requests sysrq once the port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-unisoc@lists.infradead.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-12-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Handle sysrq requests sysrq once the port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Cc: Andreas Färber <afaerber@suse.de>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-actions@lists.infradead.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-11-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Handle sysrq requests sysrq once the port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-10-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Cc: Hammer Hsieh <hammerh0314@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-9-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-8-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-7-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Cc: Bjorn Andersson <andersson@kernel.org>
Cc: Konrad Dybcio <konrad.dybcio@linaro.org>
Cc: linux-arm-msm@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-6-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-amlogic@lists.infradead.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-5-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-4-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-3-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
The driver splits the locking function into two parts: local_irq_save() and
uart_port_lock() and this breaks PREEMPT_RT.

Delay handling sysrq until port lock is dropped.
Remove the special case in the console write routine an always use the
complete locking function.

Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240301215246.891055-2-bigeasy@linutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of silently giving up, at least tell what the problem is.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240222111922.2016122-2-u.kleine-koenig@pengutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

'clocks' property is required regarding the device. Convert st,asc
binding to DT schema format in order to add this property, and update
example.
Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240226152135.8671-1-rgallaispou@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The serial8250_update_uartclk() body was created based on the several
method calls copied from the serial8250_do_set_termios() function. Seeing
aside with some other things the later method can update the baud rate
based on the new reference clock let's just call it instead thus
simplifying the code a bit.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/linux-serial/ZczD7KPbeRnY4CFc@black.fi.intel.comSigned-off-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20240222145058.28307-1-fancer.lancer@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 1f2bcb8c ("gpio: protect the descriptor label with
SRCU") gpiod_set_consumer_name() calls synchronize_srcu() which led to
a "sleeping in atomic context" smatch warning.

This function (along with gpiod_get/put() and all other GPIO APIs apart
from gpiod_get/set_value() and gpiod_direction_input/output()) should
have never been called with a spinlock taken. We're only fixing this now
as GPIOLIB has been rebuilt to use SRCU for access serialization which
uncovered this problem.

Move the calls to gpiod_get/put() outside the spinlock critical section.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/linux-gpio/deee1438-efc1-47c4-8d80-0ab2cf01d60a@moroto.mountain/Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://lore.kernel.org/r/20240220113410.16613-1-brgl@bgdev.plSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently for platforms which passes UART fifosize from DT gets
override by local driver structure "s3c24xx_serial_drv_data",
which is not intended. Change the code to honor fifosize from
device tree at first.
Signed-off-by: Tamseel Shams <m.shams@samsung.com>
Link: https://lore.kernel.org/r/20240220101227.80741-1-m.shams@samsung.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Compiling a kernel for the ColdFire causes a compiler warning:

drivers/tty/serial/mcf.c:473:12: warning: no previous prototype for
 ‘early_mcf_setup’ [-Wmissing-prototypes]
  473 | int __init early_mcf_setup(struct mcf_platform_uart *platp)
      |            ^~~~~~~~~~~~~~~

This function seems to be completely unused, so let's remove it
to silence the warning.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Acked-by: Greg Ungerer <gerg@linux-m68k.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20240219164002.520342-1-thuth@redhat.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We are not supposed to spread quirks in 8250_port module especially
when we have a separate driver for the hardware in question.

Move quirk from generic module to the driver that uses it.

While at it, move IO to ->set_divisor() callback as it has to be from
day 1. ->get_divisor() is not supposed to perform any IO as UART port:
- might not be powered on
- is not locked by a spin lock

Fixes: 1ed67ecd ("8250: microchip: Add 4 Mbps support in PCI1XXXX UART")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Rengarajan S <rengarajan.s@microchip.com>
Link: https://lore.kernel.org/r/20240219162917.2159736-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Update header inclusions to follow IWYU (Include What You Use)
principle.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240219150627.2101198-8-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

8250 PCI library provides a common code to map and assign resources.
Use it in order to deduplicate existing code and support IO port
variants.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240219150627.2101198-7-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

SIMPLE_DEV_PM_OPS() is deprecated, replace it with DEFINE_SIMPLE_DEV_PM_OPS()
and use pm_sleep_ptr() for setting the driver's PM routines. We can now
remove the __maybe_unused qualifier in the suspend and resume functions.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240219150627.2101198-6-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use generic function to set firmware node instead of ACPI specific one.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240219150627.2101198-5-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

While now there is no issue if IRQ is fired before we clearing
the interrupts as the handler does the same, but strictly speaking
it might be problematic if IRQ handler wants to do something more.

Move clearing interrupt code to be called before registering the
IRQ handler.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240219150627.2101198-4-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM callbacks take struct device pointer as a parameter, use
dev_get_drvdata() to retrieve it instead of unneeded double
loop of referencing via pci_get_drvdata(to_pci_dev(dev)).
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240219150627.2101198-3-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

It seems a copy&paste mistake that suspend callback removes the GPIO
device. There is no counterpart of this action, means once suspended
there is no more GPIO device available untile full unbind-bind cycle
is performed. Remove suspicious GPIO device removal in suspend.

Fixes: d0aeaa83 ("serial: exar: split out the exar code from 8250_pci")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240219150627.2101198-2-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge tag 'w1-drv-6.9' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-w1 into tty-next

Krzysztof writes:

1-Wire bus drivers for v6.9

1. Few cleanups: constifying, convert platform remove callback returning
   void.

2. Add UART 1-Wire bus driver which uses UART interface to create the
   1-Wire timing patterns.

* tag 'w1-drv-6.9' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-w1:
  w1: w1-gpio: Convert to platform remove callback returning void
  w1: sgi_w1: Convert to platform remove callback returning void
  w1: omap_hdq: Convert to platform remove callback returning void
  w1: mxc_w1: Convert to platform remove callback returning void
  w1: add UART w1 bus driver
  dt-bindings: w1: UART 1-Wire bus
  dt-bindings: serial: allow onewire as child node
  w1: make w1_bus_type const

We need the tty/serial fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull bcachefs fixes from Kent Overstreet:
 "Some more mostly boring fixes, but some not

  User reported ones:

   - the BTREE_ITER_FILTER_SNAPSHOTS one fixes a really nasty
     performance bug; user reported an untar initially taking two
     seconds and then ~2 minutes

   - kill a __GFP_NOFAIL in the buffered read path; this was a leftover
     from the trickier fix to kill __GFP_NOFAIL in readahead, where we
     can't return errors (and have to silently truncate the read
     ourselves).

     bcachefs can't use GFP_NOFAIL for folio state unlike iomap based
     filesystems because our folio state is just barely too big, 2MB
     hugepages cause us to exceed the 2 page threshhold for GFP_NOFAIL.

     additionally, the flags argument was just buggy, we weren't
     supplying GFP_KERNEL previously (!)"

* tag 'bcachefs-2024-02-25' of https://evilpiepirate.org/git/bcachefs:
  bcachefs: fix bch2_save_backtrace()
  bcachefs: Fix check_snapshot() memcpy
  bcachefs: Fix bch2_journal_flush_device_pins()
  bcachefs: fix iov_iter count underflow on sub-block dio read
  bcachefs: Fix BTREE_ITER_FILTER_SNAPSHOTS on inodes btree
  bcachefs: Kill __GFP_NOFAIL in buffered read path
  bcachefs: fix backpointer_to_text() when dev does not exist

Missed a call in the previous fix.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Pull two documentation build fixes from Jonathan Corbet:

 - The XFS online fsck documentation uses incredibly deeply nested
   subsection and list nesting; that broke the PDF docs build. Tweak a
   parameter to tell LaTeX to allow the deeper nesting.

 - Fix a 6.8 PDF-build regression

* tag 'docs-6.8-fixes3' of git://git.lwn.net/linux:
  docs: translations: use attribute to store current language
  docs: Instruct LaTeX to cope with deeper nesting

Pull USB fixes from Greg KH:
 "Here are some small USB fixes for 6.8-rc6 to resolve some reported
  problems. These include:

   - regression fixes with typec tpcm code as reported by many

   - cdnsp and cdns3 driver fixes

   - usb role setting code bugfixes

   - build fix for uhci driver

   - ncm gadget driver bugfix

   - MAINTAINERS entry update

  All of these have been in linux-next all week with no reported issues
  and there is at least one fix in here that is in Thorsten's regression
  list that is being tracked"

* tag 'usb-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: typec: tpcm: Fix issues with power being removed during reset
  MAINTAINERS: Drop myself as maintainer of TYPEC port controller drivers
  usb: gadget: ncm: Avoid dropping datagrams of properly parsed NTBs
  Revert "usb: typec: tcpm: reset counter when enter into unattached state after try role"
  usb: gadget: omap_udc: fix USB gadget regression on Palm TE
  usb: dwc3: gadget: Don't disconnect if not started
  usb: cdns3: fix memory double free when handle zero packet
  usb: cdns3: fixed memory use after free at cdns3_gadget_ep_disable()
  usb: roles: don't get/set_role() when usb_role_switch is unregistered
  usb: roles: fix NULL pointer issue when put module's reference
  usb: cdnsp: fixed issue with incorrect detecting CDNSP family controllers
  usb: cdnsp: blocked some cdns3 specific code
  usb: uhci-grlib: Explicitly include linux/platform_device.h