It is worth noting that the devname ttyS is a widely recognized tty name
and is commonly used by many uart device drivers. Given the established
usage and compatibility concerns, it may not be feasible to change the
devname for older SoCs. However, for new definitions, it is acceptable
and even recommended to use a new devname to help ensure clarity and
avoid any potential conflicts on lower or upper software levels.
For more information please refer to IRC discussion at [1].
Links:
[1]: https://libera.irclog.whitequark.org/linux-amlogic/2023-07-03
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Link: https://lore.kernel.org/r/20230705181833.16137-4-ddrokosov@sberdevices.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Actually, the meson_uart module is already a platform_driver, but it is
currently registered manually and the uart core registration is run
outside the probe() scope, which results in some restrictions. For
instance, it is not possible to communicate with the OF subsystem
because it requires an initialized device object.
To address this issue, apply module_platform_driver() instead of direct
module init/exit routines. Additionally, move uart_register_driver() to
the driver probe(), and destroy manual console registration because it's
already run in the uart_register_driver() flow.
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230705181833.16137-3-ddrokosov@sberdevices.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the Tegra serial driver is probe before clocks are available then the
following error is seen on boot:
serial-tegra 3100000.serial: Couldn't get the clock
This has been observed on Jetson AGX Orin. Fix this by calling
dev_err_probe() instead of dev_err() to avoid printing an error on probe
deferral.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20230703113759.75608-1-jonathanh@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # for imx
Link: https://lore.kernel.org/r/20230724205440.767071-1-robh@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* move the declaration of flg (with the initializer) to the loop, so
there is no need to reset it to TTY_NORMAL by an 'else' branch.
* use TTY_NORMAL as initializer above, not a magic zero constant
* remove the outer 'if' from this construct:
if (S & (A | B)) {
if (S & A)
X;
if (S & B)
Y;
}
* drop unlikely() as I doubt it has any benefits here. If it does,
provide numbers.
All four make the code easier to read.
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Cc: Vineet Gupta <vgupta@kernel.org>
Acked-by: Vineet Gupta <vgupta@kernel.org>
Link: https://lore.kernel.org/r/20230712081811.29004-9-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Make 'tty' parameter const as we only look at tty flags here.
* Make 'size' parameter of size_t type as everyone passes that and
memset() (the consumer) expects size_t too. So be consistent.
* Remove redundant local variables, place the content directly to the
'if'.
* Use 0 instead of 0x00 in memset(). The former is more obvious.
No functional changes expected.
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230712064216.12150-3-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull tty/serial driver updates from Greg KH:
"Here is the big set of tty/serial driver updates for 6.5-rc1.
Included in here are:
- tty_audit code cleanups from Jiri
- more 8250 cleanups from Ilpo
- samsung_tty driver bugfixes
- 8250 lock port updates
- usual fsl_lpuart driver updates and fixes
- other small serial driver fixes and updates, full details in the
shortlog
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (58 commits)
tty_audit: make data of tty_audit_log() const
tty_audit: make tty pointers in exposed functions const
tty_audit: make icanon a bool
tty_audit: invert the condition in tty_audit_log()
tty_audit: use kzalloc() in tty_audit_buf_alloc()
tty_audit: use TASK_COMM_LEN for task comm
Revert "8250: add support for ASIX devices with a FIFO bug"
serial: atmel: don't enable IRQs prematurely
tty: serial: Add Nuvoton ma35d1 serial driver support
tty: serial: fsl_lpuart: add earlycon for imx8ulp platform
tty: serial: imx: fix rs485 rx after tx
selftests: tty: add selftest for tty timestamp updates
tty: tty_io: update timestamps on all device nodes
tty: fix hang on tty device with no_room set
serial: core: fix -EPROBE_DEFER handling in init
serial: 8250_omap: Use force_suspend and resume for system suspend
tty: serial: samsung_tty: Use abs() to simplify some code
tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() when iterating clk
tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() in case of error
serial: 8250: Apply FSL workarounds also without SERIAL_8250_CONSOLE
...
Pull driver core updates from Greg KH:
"Here are a small set of changes for 6.5-rc1 for some driver core
changes. Included in here are:
- device property cleanups to make it easier to write "agnostic"
drivers when regards to the firmware layer underneath them (DT vs.
ACPI)
- debugfs documentation updates
- devres additions
- sysfs documentation and changes to handle empty directory creation
logic better
- tiny kernfs optimizations
- other tiny changes
All of these have been in linux-next for a while with no reported
problems"
* tag 'driver-core-6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
sysfs: Skip empty folders creation
sysfs: Improve readability by following the kernel coding style
drivers: fwnode: fix fwnode_irq_get[_byname]()
ata: ahci_platform: Make code agnostic to OF/ACPI
device property: Implement device_is_compatible()
ACPI: Move ACPI_DEVICE_CLASS() to mod_devicetable.h
base/node: Use 'property' to identify an access parameter
driver core: device.h: add some missing kerneldocs
kernfs: fix missing kernfs_idr_lock to remove an ID from the IDR
isa: Remove unnecessary checks
MAINTAINERS: add entry for auxiliary bus
debugfs: Correct the 'debugfs_create_str' docs
serial: qcom_geni: Comment use of devm_krealloc rather than devm_krealloc_array
iio: adc: Use devm_krealloc_array
hwmon: pmbus: Use devm_krealloc_array
Pull arm documentation move from Jonathan Corbet:
"Move the Arm architecture documentation under Documentation/arch/.
This brings some order to the documentation directory, declutters the
top-level directory, and makes the documentation organization more
closely match that of the source"
* tag 'docs-arm-move' of git://git.lwn.net/linux:
dt-bindings: Update Documentation/arm references
docs: update some straggling Documentation/arm references
crypto: update some Arm documentation references
mips: update a reference to a moved Arm Document
arm64: Update Documentation/arm references
arm: update in-source documentation references
arm: docs: Move Arm documentation to Documentation/arch/
Pull splice updates from Jens Axboe:
"This kills off ITER_PIPE to avoid a race between truncate,
iov_iter_revert() on the pipe and an as-yet incomplete DMA to a bio
with unpinned/unref'ed pages from an O_DIRECT splice read. This causes
memory corruption.
Instead, we either use (a) filemap_splice_read(), which invokes the
buffered file reading code and splices from the pagecache into the
pipe; (b) copy_splice_read(), which bulk-allocates a buffer, reads
into it and then pushes the filled pages into the pipe; or (c) handle
it in filesystem-specific code.
Summary:
- Rename direct_splice_read() to copy_splice_read()
- Simplify the calculations for the number of pages to be reclaimed
in copy_splice_read()
- Turn do_splice_to() into a helper, vfs_splice_read(), so that it
can be used by overlayfs and coda to perform the checks on the
lower fs
- Make vfs_splice_read() jump to copy_splice_read() to handle
direct-I/O and DAX
- Provide shmem with its own splice_read to handle non-existent pages
in the pagecache. We don't want a ->read_folio() as we don't want
to populate holes, but filemap_get_pages() requires it
- Provide overlayfs with its own splice_read to call down to a lower
layer as overlayfs doesn't provide ->read_folio()
- Provide coda with its own splice_read to call down to a lower layer
as coda doesn't provide ->read_folio()
- Direct ->splice_read to copy_splice_read() in tty, procfs, kernfs
and random files as they just copy to the output buffer and don't
splice pages
- Provide wrappers for afs, ceph, ecryptfs, ext4, f2fs, nfs, ntfs3,
ocfs2, orangefs, xfs and zonefs to do locking and/or revalidation
- Make cifs use filemap_splice_read()
- Replace pointers to generic_file_splice_read() with pointers to
filemap_splice_read() as DIO and DAX are handled in the caller;
filesystems can still provide their own alternate ->splice_read()
op
- Remove generic_file_splice_read()
- Remove ITER_PIPE and its paraphernalia as generic_file_splice_read
was the only user"
* tag 'for-6.5/splice-2023-06-23' of git://git.kernel.dk/linux: (31 commits)
splice: kdoc for filemap_splice_read() and copy_splice_read()
iov_iter: Kill ITER_PIPE
splice: Remove generic_file_splice_read()
splice: Use filemap_splice_read() instead of generic_file_splice_read()
cifs: Use filemap_splice_read()
trace: Convert trace/seq to use copy_splice_read()
zonefs: Provide a splice-read wrapper
xfs: Provide a splice-read wrapper
orangefs: Provide a splice-read wrapper
ocfs2: Provide a splice-read wrapper
ntfs3: Provide a splice-read wrapper
nfs: Provide a splice-read wrapper
f2fs: Provide a splice-read wrapper
ext4: Provide a splice-read wrapper
ecryptfs: Provide a splice-read wrapper
ceph: Provide a splice-read wrapper
afs: Provide a splice-read wrapper
9p: Add splice_read wrapper
net: Make sock_splice_read() use copy_splice_read() by default
tty, proc, kernfs, random: Use copy_splice_read()
...
This reverts commit eb26dfe8aa.
Commit eb26dfe8aa ("8250: add support for ASIX devices with a FIFO
bug") merged on Jul 13, 2012 adds a quirk for PCI_VENDOR_ID_ASIX
(0x9710). But that ID is the same as PCI_VENDOR_ID_NETMOS defined in
1f8b061050c7 ("[PATCH] Netmos parallel/serial/combo support") merged
on Mar 28, 2005. In pci_serial_quirks array, the NetMos entry always
takes precedence over the ASIX entry even since it was initially
merged, code in that commit is always unreachable.
In my tests, adding the FIFO workaround to pci_netmos_init() makes no
difference, and the vendor driver also does not have such workaround.
Given that the code was never used for over a decade, it's safe to
revert it.
Also, the real PCI_VENDOR_ID_ASIX should be 0x125b, which is used on
their newer AX99100 PCIe serial controllers released on 2016. The FIFO
workaround should not be intended for these newer controllers, and it
was never implemented in vendor driver.
Fixes: eb26dfe8aa ("8250: add support for ASIX devices with a FIFO bug")
Cc: stable <stable@kernel.org>
Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230619155743.827859-1-jiaqing.zhao@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since commit 79d0224f6b ("tty: serial: imx: Handle RS485 DE signal
active high") RS485 reception no longer works after a transmission.
The following scenario shows the problem:
1) Open a port in RS485 mode
2) Receive data from remote (OK)
3) Transmit data to remote (OK)
4) Receive data from remote (Nothing received)
In RS485 mode, imx_uart_start_tx() calls imx_uart_stop_rx() and, when the
transmission is complete, imx_uart_stop_tx() calls imx_uart_start_rx().
Since the above commit imx_uart_stop_rx() now sets the loopback bit but
imx_uart_start_rx() does not clear it causing the hardware to remain in
loopback mode and not receive external data.
Fix this by moving the existing loopback disable code to a helper function
and calling it from imx_uart_start_rx() too.
Fixes: 79d0224f6b ("tty: serial: imx: Handle RS485 DE signal active high")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230616104838.2729694-1-martin.fuzzey@flowbird.group
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
User space applications watch for timestamp changes on character device
files in order to determine idle time of a given terminal session. For
example, "w" program uses this information to populate the IDLE column
of its output [1]. Similarly, systemd-logind has optional feature where
it uses atime of the tty character device to determine if there was
activity on the terminal associated with the logind's session object. If
there was no activity for a configured period of time then logind will
terminate such session [2].
Now, usually (e.g. bash running on the terminal) the use of the terminal
will update timestamps (atime and mtime) on the corresponding terminal
character device. However, if access to the terminal, e.g. /dev/pts/0,
is performed through magic character device /dev/tty then such access
obviously changes the state of the terminal, however timestamps on the
device that correspond to the terminal (/dev/pts/0) are not updated.
This patch makes sure that we update timestamps on *all* character
devices that correspond to the given tty, because outside observers (w,
systemd-logind) are maybe checking these timestamps. Obviously, they can
not check timestamps on /dev/tty as that has per-process meaning.
[1] https://gitlab.com/procps-ng/procps/-/blob/v4.0.0/w.c#L286
[2] https://github.com/systemd/systemd/blob/v252/NEWS#L477
Signed-off-by: Michal Sekletar <msekleta@redhat.com>
Message-ID: <20230613172107.78138-1-msekleta@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It is possible to hang pty devices in this case, the reader was
blocking at epoll on master side, the writer was sleeping at
wait_woken inside n_tty_write on slave side, and the write buffer
on tty_port was full, we found that the reader and writer would
never be woken again and blocked forever.
The problem was caused by a race between reader and kworker:
n_tty_read(reader): n_tty_receive_buf_common(kworker):
copy_from_read_buf()|
|room = N_TTY_BUF_SIZE - (ldata->read_head - tail)
|room <= 0
n_tty_kick_worker() |
|ldata->no_room = true
After writing to slave device, writer wakes up kworker to flush
data on tty_port to reader, and the kworker finds that reader
has no room to store data so room <= 0 is met. At this moment,
reader consumes all the data on reader buffer and calls
n_tty_kick_worker to check ldata->no_room which is false and
reader quits reading. Then kworker sets ldata->no_room=true
and quits too.
If write buffer is not full, writer will wake kworker to flush data
again after following writes, but if write buffer is full and writer
goes to sleep, kworker will never be woken again and tty device is
blocked.
This problem can be solved with a check for read buffer size inside
n_tty_receive_buf_common, if read buffer is empty and ldata->no_room
is true, a call to n_tty_kick_worker is necessary to keep flushing
data to reader.
Cc: <stable@vger.kernel.org>
Fixes: 42458f41d0 ("n_tty: Ensure reader restarts worker for next reader")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Hui Li <caelli@tencent.com>
Message-ID: <1680749090-14106-1-git-send-email-caelli@tencent.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The -EPROBE_DEFER error path in serial_base_device_init() is a bit
awkward. Before the call to device_initialize(dev) then we need to
manually release all the device resources. And after the call then we
need to call put_device() to release the resources. Doing either one
wrong will result in a leak or a use after free.
So let's wait to return -EPROBE_DEFER until after the call to
device_initialize(dev) so that way callers do not have to handle
-EPROBE_DEFER as a special case. Now callers can just use put_device()
for clean up.
The second issue with the -EPROBE_DEFER path is that deferring is not
supposed to be a fatal error, but instead it's normal part of the
init process and the kernel recovers from it automatically. That means
we should not print an error message but just a debug message on this
path.
Fixes: 539914240a ("serial: core: Fix probing serial_base_bus devices")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Message-ID: <18318adb-ab2c-4dcc-9f96-498a13d16b80@moroto.mountain>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We should not rely on autosuspend timeout for system suspend. Instead,
let's use force_suspend and force_resume functions. Otherwise the serial
port controller device may not be idled on suspend.
As we are doing a register write on suspend to configure the serial port,
we still need to runtime PM resume the port on suspend.
While at it, let's switch to pm_runtime_resume_and_get() and check for
errors returned. And let's add the missing line break before return to the
suspend function while at it.
Fixes: 09d8b2bdbc ("serial: 8250: omap: Provide ability to enable/disable UART as wakeup source")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Tested-by: Dhruva Gole <d-gole@ti.com>
Message-ID: <20230614045922.4798-1-tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LS1028A is using DMA with LPUART. Having RX watermark set to 1, means
DMA transactions are started only after receiving the second character.
On other platforms with newer LPUART IP, Receiver Idle Empty function
initiates the DMA request after the receiver is idling for 4 characters.
But this feature is missing on LS1028A, which is causing a 1-character
delay in the RX direction on this platform.
Set RX watermark to 0 to initiate RX DMA after each character.
Link: https://lore.kernel.org/linux-serial/20230607103459.1222426-1-robert.hodaszi@digi.com/
Fixes: 9ad9df8447 ("tty: serial: fsl_lpuart: Fix the wrong RXWATER setting for rx dma case")
Cc: stable <stable@kernel.org>
Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
Message-ID: <20230609121334.1878626-1-robert.hodaszi@digi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The need to handle the FSL variant of 8250 in a special way is also
present without console support. So soften the dependency for
SERIAL_8250_FSL from SERIAL_8250_CONSOLE to SERIAL_8250. To handle
SERIAL_8250=m, the FSL code can be modular, too, thus SERIAL_8250_FSL
becomes tristate.
Compiling 8250_fsl as a module requires adding a module license so this
is added, too. While add it also add a appropriate module description.
As then SERIAL_OF_PLATFORM=y + SERIAL_8250_FSL=m is a valid combination
(if COMPILE_TEST is enabled on a platform that is neither PPC, ARM nor
ARM64), the check in 8250_of.c must be weakened a bit.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Message-ID: <20230609133932.786117-3-u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The put_device() function will call serial_base_ctrl_release() or
serial_base_port_release() so these kfrees() are a double free bug.
Fixes: 84a9582fd2 ("serial: core: Start managing serial controllers to enable runtime PM")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Message-ID: <ZH7tsTmWY5b/4m+6@moroto>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
