linux.git/drivers/tty/serial, branch v6.11-rc2

Merge tag 'driver-core-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2024-07-25T17:42:22+00:00

Pull driver core updates from Greg KH:
 "Here is the big set of driver core changes for 6.11-rc1.

  Lots of stuff in here, with not a huge diffstat, but apis are evolving
  which required lots of files to be touched. Highlights of the changes
  in here are:

   - platform remove callback api final fixups (Uwe took many releases
     to get here, finally!)

   - Rust bindings for basic firmware apis and initial driver-core
     interactions.

     It's not all that useful for a "write a whole driver in rust" type
     of thing, but the firmware bindings do help out the phy rust
     drivers, and the driver core bindings give a solid base on which
     others can start their work.

     There is still a long way to go here before we have a multitude of
     rust drivers being added, but it's a great first step.

   - driver core const api changes.

     This reached across all bus types, and there are some fix-ups for
     some not-common bus types that linux-next and 0-day testing shook
     out.

     This work is being done to help make the rust bindings more safe,
     as well as the C code, moving toward the end-goal of allowing us to
     put driver structures into read-only memory. We aren't there yet,
     but are getting closer.

   - minor devres cleanups and fixes found by code inspection

   - arch_topology minor changes

   - other minor driver core cleanups

  All of these have been in linux-next for a very long time with no
  reported problems"

* tag 'driver-core-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits)
  ARM: sa1100: make match function take a const pointer
  sysfs/cpu: Make crash_hotplug attribute world-readable
  dio: Have dio_bus_match() callback take a const *
  zorro: make match function take a const pointer
  driver core: module: make module_[add|remove]_driver take a const *
  driver core: make driver_find_device() take a const *
  driver core: make driver_[create|remove]_file take a const *
  firmware_loader: fix soundness issue in `request_internal`
  firmware_loader: annotate doctests as `no_run`
  devres: Correct code style for functions that return a pointer type
  devres: Initialize an uninitialized struct member
  devres: Fix memory leakage caused by driver API devm_free_percpu()
  devres: Fix devm_krealloc() wasting memory
  driver core: platform: Switch to use kmemdup_array()
  driver core: have match() callback in struct bus_type take a const *
  MAINTAINERS: add Rust device abstractions to DRIVER CORE
  device: rust: improve safety comments
  MAINTAINERS: add Danilo as FIRMWARE LOADER maintainer
  MAINTAINERS: add Rust FW abstractions to FIRMWARE LOADER
  firmware: rust: improve safety comments
  ...

Merge tag 'tty-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2024-07-19T22:22:14+00:00

Pull tty / serial updates from Greg KH:
 "Here is a small set of tty and serial driver updates for 6.11-rc1. Not
  much happened this cycle, unlike the previous kernel release which had
  lots of "excitement" in this part of the kernel. Included in here are
  the following changes:

   - dt binding updates for new platforms

   - 8250 driver updates

   - various small serial driver fixes and updates

   - printk/console naming and matching attempt #2 (was reverted for
     6.10-final, should be good to go this time around, acked by the
     relevant maintainers).

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (22 commits)
  Documentation: kernel-parameters: Add DEVNAME:0.0 format for serial ports
  serial: core: Add serial_base_match_and_update_preferred_console()
  printk: Add match_devname_and_update_preferred_console()
  serial: sc16is7xx: hardware reset chip if reset-gpios is defined in DT
  dt-bindings: serial: sc16is7xx: add reset-gpios
  dt-bindings: serial: vt8500-uart: convert to json-schema
  serial: 8250_platform: Explicitly show we initialise ISA ports only once
  tty: add missing MODULE_DESCRIPTION() macros
  dt-bindings: serial: mediatek,uart: add MT7988
  serial: sh-sci: Add support for RZ/V2H(P) SoC
  dt-bindings: serial: Add documentation for Renesas RZ/V2H(P) (R9A09G057) SCIF support
  dt-bindings: serial: renesas,scif: Make 'interrupt-names' property as required
  dt-bindings: serial: renesas,scif: Validate 'interrupts' and 'interrupt-names'
  dt-bindings: serial: renesas,scif: Move ref for serial.yaml at the end
  riscv: dts: starfive: jh7110: Add the core reset and jh7110 compatible for uarts
  serial: 8250_dw: Use reset array API to get resets
  dt-bindings: serial: snps-dw-apb-uart: Add one more reset signal for StarFive JH7110 SoC
  serial: 8250: Extract platform driver
  serial: 8250: Extract RSA bits
  serial: imx: stop casting struct uart_port to struct imx_port
  ...

serial: core: Add serial_base_match_and_update_preferred_console()

2024-07-04T13:41:44+00:00

Let's add serial_base_match_and_update_preferred_console() for consoles
using DEVNAME:0.0 style naming.

The earlier approach to add it caused issues in the kernel command line
ordering as we were calling __add_preferred_console() again for the
deferred consoles.

Signed-off-by: Tony Lindgren 
Reviewed-by: Petr Mladek 
Tested-by: Petr Mladek 
Link: https://lore.kernel.org/r/20240703100615.118762-3-tony.lindgren@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

serial: qcom-geni: do not kill the machine on fifo underrun

2024-07-04T10:30:30+00:00

The Qualcomm GENI serial driver did not handle buffer flushing and used
to print discarded characters when the circular buffer was cleared.
Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo")
this instead resulted in a hard lockup due to
qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the
interrupt handler.

The underlying bugs have now been fixed, but make sure to output NUL
characters instead of killing the machine if a similar driver bug is
ever reintroduced.

Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20240704101805.30612-4-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: qcom-geni: fix hard lockup on buffer flush

2024-07-04T10:30:30+00:00

The Qualcomm GENI serial driver does not handle buffer flushing and used
to continue printing discarded characters when the circular buffer was
cleared. Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf
to kfifo") this instead results in a hard lockup due to
qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the
interrupt handler.

This is easily triggered by interrupting a command such as dmesg in a
serial console but can also happen when stopping a serial getty on
reboot.

Implement the flush_buffer() callback and use it to cancel any active TX
command when the write buffer has been emptied.

Reported-by: Douglas Anderson 
Link: https://lore.kernel.org/lkml/20240610222515.3023730-1-dianders@chromium.org/
Fixes: 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo")
Fixes: a1fee899e5be ("tty: serial: qcom_geni_serial: Fix softlock")
Cc: stable@vger.kernel.org	# 5.0
Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20240704101805.30612-3-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: qcom-geni: fix soft lockup on sw flow control and suspend

2024-07-04T10:30:30+00:00

The stop_tx() callback is used to implement software flow control and
must not discard data as the Qualcomm GENI driver is currently doing
when there is an active TX command.

Cancelling an active command can also leave data in the hardware FIFO,
which prevents the watermark interrupt from being enabled when TX is
later restarted. This results in a soft lockup and is easily triggered
by stopping TX using software flow control in a serial console but this
can also happen after suspend.

Fix this by only stopping any active command, and effectively clearing
the hardware fifo, when shutting down the port. When TX is later
restarted, a transfer command may need to be issued to discard any stale
data that could prevent the watermark interrupt from firing.

Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
Cc: stable@vger.kernel.org	# 4.17
Signed-off-by: Johan Hovold 
Link: https://lore.kernel.org/r/20240704101805.30612-2-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman

serial: imx: ensure RTS signal is not left active after shutdown

2024-07-03T14:12:49+00:00

If a process is killed while writing to a /dev/ttymxc* device in RS485
mode, we observe that the RTS signal is left high, thus making it
impossible for other devices to transmit anything.

Moreover, the ->tx_state variable is left in state SEND, which means
that when one next opens the device and configures baud rate etc., the
initialization code in imx_uart_set_termios dutifully ensures the RTS
pin is pulled down, but since ->tx_state is already SEND, the logic in
imx_uart_start_tx() does not in fact pull the pin high before
transmitting, so nothing actually gets on the wire on the other side
of the transceiver. Only when that transmission is allowed to complete
is the state machine then back in a consistent state.

This is completely reproducible by doing something as simple as

  seq 10000 > /dev/ttymxc0

and hitting ctrl-C, and watching with a logic analyzer.

Signed-off-by: Rasmus Villemoes 
Cc: stable 
Reviewed-by: Marek Vasut 
Link: https://lore.kernel.org/r/20240625184206.508837-1-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman

tty: serial: ma35d1: Add a NULL check for of_node

2024-07-03T14:12:06+00:00

The pdev->dev.of_node can be NULL if the "serial" node is absent.
Add a NULL check to return an error in such cases.

Fixes: 930cbf92db01 ("tty: serial: Add Nuvoton ma35d1 serial driver support")
Reported-by: Dan Carpenter 
Closes: https://lore.kernel.org/all/8df7ce45-fd58-4235-88f7-43fe7cd67e8f@moroto.mountain/
Signed-off-by: Jacky Huang 
Reviewed-by: Dan Carpenter 
Cc: stable 
Link: https://lore.kernel.org/r/20240625064128.127-1-ychuang570808@gmail.com
Signed-off-by: Greg Kroah-Hartman

serial: 8250_omap: Fix Errata i2310 with RX FIFO level check

2024-07-03T14:10:57+00:00

Errata i2310[0] says, Erroneous timeout can be triggered,
if this Erroneous interrupt is not cleared then it may leads
to storm of interrupts.

Commit 9d141c1e6157 ("serial: 8250_omap: Implementation of Errata i2310")
which added the workaround but missed ensuring RX FIFO is really empty
before applying the errata workaround as recommended in the errata text.
Fix this by adding back check for UART_OMAP_RX_LVL to be 0 for
workaround to take effect.

[0] https://www.ti.com/lit/pdf/sprz536 page 23

Fixes: 9d141c1e6157 ("serial: 8250_omap: Implementation of Errata i2310")
Cc: stable@vger.kernel.org
Reported-by: Vignesh Raghavendra 
Closes: https://lore.kernel.org/all/e96d0c55-0b12-4cbf-9d23-48963543de49@ti.com/
Signed-off-by: Udit Kumar 
Link: https://lore.kernel.org/r/20240625160725.2102194-1-u-kumar1@ti.com
Signed-off-by: Greg Kroah-Hartman

serial: imx: only set receiver level if it is zero

2024-07-03T13:55:03+00:00

With commit a81dbd0463ec ("serial: imx: set receiver level before
starting uart") we set the receiver level to its default value. This
caused a regression when using SDMA, where the receiver level is 9
instead of 8 (default). This change will first check if the receiver
level is zero and only then set it to the default. This still avoids the
interrupt storm when the receiver level is zero.

Fixes: a81dbd0463ec ("serial: imx: set receiver level before starting uart")
Cc: stable 
Signed-off-by: Stefan Eichenberger 
Link: https://lore.kernel.org/r/20240703112543.148304-1-eichest@gmail.com
Signed-off-by: Greg Kroah-Hartman