1) The function drains the fifo for the given user tty/DLCI without
considering 'TX_THRESH_HI' and different to gsm_dlci_data_output_framed(),
which moves only one packet from the user side to the internal transmission
queue. We can only handle one packet at a time here if we want to allow
DLCI priority handling in gsm_dlci_data_sweep() to avoid link starvation.
2) Furthermore, the additional header octet from convergence layer type 2
is not counted against MTU. It is part of the UI/UIH frame message which
needs to be limited to MTU. Hence, it is wrong not to consider this octet.
3) Finally, the waiting user tty is not informed about freed space in its
send queue.

Take at most one packet worth of data out of the DLCI fifo to fix 1).
Limit the max user data size per packet to MTU - 1 in case of convergence
layer type 2 to leave space for the control signal octet which is added in
the later part of the function. This fixes 2).
Add tty_port_tty_wakeup() to wake up the user tty if new write space has
been made available to fix 3).

Fixes: 268e526b ("tty/n_gsm: avoid fifo overflow in gsm_dlci_data_output")
Signed-off-by: NDaniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-3-daniel.starke@siemens.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current implementation registers/deregisters the user ttys at mux
attach/detach. That means that the user devices are available before any
control channel is open. However, user channel initialization requires an
open control channel. Furthermore, the user is not informed if the mux
restarts due to configuration changes.
Put the registration/deregistration procedure into separate function to
improve readability.
Move registration to mux activation and deregistration to mux cleanup to
keep the user devices only open as long as a control channel exists. The
user will be informed via the device driver if the mux was reconfigured in
a way that required a mux re-activation.
This makes it necessary to add T2 initialization to gsmld_open() for the
ldisc open code path (not the reconfiguration code path) to avoid deletion
of an uninitialized T2 at mux cleanup.

Fixes: d50f6dca ("tty: n_gsm: expose gsmtty device nodes at ldisc open time")
Signed-off-by: NDaniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-2-daniel.starke@siemens.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

After setting up the control channel on both sides the responder side may
want to open a virtual tty to listen on until the initiator starts an
application on a user channel. The current implementation allows the
open() but no other operation, like termios. These fail with EINVAL.
The responder sided application has no means to detect an open by the
initiator sided application this way. And the initiator sided applications
usually expect the responder sided application to listen on the user
channel upon open.
Set the user channel into half-open state on responder side once a user
application opens the virtual tty to allow IO operations on it.
Furthermore, keep the user channel constipated until the initiator side
opens it to give the responder sided application the chance to detect the
new connection and to avoid data loss if the responder sided application
starts sending before the user channel is open.

Fixes: e1eaea46 ("tty: n_gsm line discipline")
Signed-off-by: NDaniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220701061652.39604-1-daniel.starke@siemens.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Place dw8250_serial_out() before dw8250_serial_out38x() so that it can
be called from dw8250_serial_out38x() to do the actual write.
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220628134234.53771-2-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of open-coding, use BIT(), GENMASK(), and FIELD_GET() helpers.
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220630100536.41329-1-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Drop CONFIG_PM and CONFIG_PM_SLEEP ifdeffery while converting dw8250_pm_ops
to use new PM macros. Since we are using runtime PM, wrap dw8250_pm_ops into
pm_ptr().
Reviewed-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220630100507.31113-1-andriy.shevchenko@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For the sake of better maintenance, sort included headers alphabetically.
While at it, split the serial group of headers which makes clear the
subsystem the driver belongs to.
Reviewed-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220630093816.28271-1-andriy.shevchenko@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If the earlycon parameter is given twice, the kernel will spit out a
WARN() in register_console() because it was already registered. The
non-dt variant setup_earlycon() already handles that gracefully. The dt
variant of_setup_earlycon() doesn't. Add the check there and add the
-EALREADY handling in early_init_dt_scan_chosen_stdout().

FWIW, this doesn't happen if CONFIG_ACPI_SPCR_TABLE is set. In that case
the registration is delayed until after earlycon parameter(s) are
parsed.
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NMichael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20220628120705.200617-1-michael@walle.ccSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Accessing LSR requires port lock because it mutates lsr_saved_flags
in serial_lsr_in().

Fixes: 197eb5c4 ("serial: 8250_dw: Use serial_lsr_in() in dw8250_handle_irq()")
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/c5879db7-bee9-93f-526e-872a292442@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Change 'timeing' to 'timing'.
Change 'Characteres' to 'Characters'.
Reviewed-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NZhang Jiaming <jiaming@nfschina.com>
Link: https://lore.kernel.org/r/20220629094411.39066-1-jiaming@nfschina.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Internal loopback mode can be supported by setting
UCON register's Loopback Mode bit. The mode & bit can be supported
since s3c2410 and later SoCs. The prefix of LOOPBACK / BIT(5) naming
should be also changed to S3C2410_ in order to avoid confusion.
Reviewed-by: NKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NChanho Park <chanho61.park@samsung.com>
Link: https://lore.kernel.org/r/20220629004141.51484-1-chanho61.park@samsung.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Regarding Exynos Auto v9 SoC, it supports uarts up to 12. However, the
maximum number of the ports has been derived from
CONFIG_SERIAL_SAMSUNG_UARTS and tightly coupled with the config for
previous Samsung SoCs such as s3c24xx and s3c64xx. To overcome this
limitation, this changes the usage of the definition to UART_NR which is
widely used from other serial drivers. This also defines the value to 12
only for ARM64 SoCs to not affect the change to previous arm32 SoCs.

Instead of enumerating all the ports as predefined arrays, this
introduces s3c24xx_serial_init_port_default that is initializing the
structure as the default value.
Reviewed-by: NHector Martin <marcan@marcan.st>
Reviewed-by: NKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: NChanho Park <chanho61.park@samsung.com>
Link: https://lore.kernel.org/r/20220629005538.60132-1-chanho61.park@samsung.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add 9th bit multipoint addressing mode for DW UART. 9th bit addressing
can be used only when HW RS485 is available.

Updating RAR (receive address register) is bit tricky because busy
indication is not be available when DW UART is strictly 16550
compatible, which is the case with the hardware I was testing with. RAR
should not be updated while receive is in progress which is now
achieved by deasserting RE and waiting for one frame (in case rx would
be in progress, the driver seems to have no way of knowing it w/o busy
indication). Because of this complexity, it's better to avoid doing it
unless really needed.
Co-developed-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Co-developed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Co-developed-by: NRaymond Tan <raymond.tan@intel.com>
Co-developed-by: NLakshmi Sowjanya <lakshmi.sowjanya.d@intel.com>
Signed-off-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NRaymond Tan <raymond.tan@intel.com>
Signed-off-by: NLakshmi Sowjanya <lakshmi.sowjanya.d@intel.com>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-7-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support for RS-485 multipoint addressing using 9th bit [*]. The
addressing mode is configured through ->rs485_config().

ADDRB in termios indicates 9th bit addressing mode is enabled. In this
mode, 9th bit is used to indicate an address (byte) within the
communication line. ADDRB can only be enabled/disabled through
->rs485_config() that is also responsible for setting the destination and
receiver (filter) addresses.

Add traps to detect unwanted changes to struct serial_rs485 layout using
static_assert().

[*] Technically, RS485 is just an electronic spec and does not itself
specify the 9th bit addressing mode but 9th bit seems at least
"semi-standard" way to do addressing with RS485.
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-6-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

To be able to alter ADDRB within ->rs485_config(), take termios_rwsem
before calling ->rs485_config() and pass termios.
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-5-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use 32-bit reads in order to not lose higher bits of DW UART regs. This
change does not fix any known issue as the high bits are not used for
anything related to 8250 driver (dw8250_readl_ext and dw8250_writel_ext
used within the dwlib are already doing
readl/writel/ioread32be/iowrite32be anyway).

This change is necessary to enables 9th bit address mode. DW UART
reports address frames with BIT(8) of LSR.
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-4-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Allow drivers to alter LSR save mask.
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-3-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

DW flags address received as BIT(8) in LSR. In order to not lose that
on read, enlarge lsr_saved_flags to u16.

Adjust lsr/status variables and related call chains to use u16.
Technically, some of these type conversion would not be needed but it
doesn't hurt to be consistent.
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-2-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Per file BOTH_EMPTY defines are littering our source code here and
there. Define once in serial.h and create helper for the check
too.
Reviewed-by: NJiri Slaby <jirislaby@kernel.org>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624205424.12686-7-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Both UART_XMIT_SIZE and SERIAL_XMIT_SIZE are defined. Make them all
UART_XMIT_SIZE.
Reviewed-by: NJiri Slaby <jirislaby@kernel.org>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624205424.12686-6-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use C99 array initializer insteads of comments and make unmapped checks
more obvious.
Reviewed-by: NJiri Slaby <jirislaby@kernel.org>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624205424.12686-5-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Using UART_* to name defines is a bit problematic. When trying to do
unrelated cleanup which also involved tweaking header inclusion logic,
caused UART_CSR from serial_reg.h to leak into msm's namespace which is
also among msm defines. Thus, rename all UART_* ones to MSM_UART_* to
eliminate possibility of collisions.
Reviewed-by: NJiri Slaby <jirislaby@kernel.org>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624205424.12686-3-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Create static inline instead of define as it provides type safety and
is safer wrt. macros expansion.
Reviewed-by: NJiri Slaby <jirislaby@kernel.org>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624205424.12686-2-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

st-asc driver doesn't use helpers from pm_runtime.h thus remove its
include.
Reviewed-by: NPatrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: NClaudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220616140024.2081238-5-claudiu.beznea@microchip.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need for clk_prepare_enable() at the beginning of
atmel_console_setup() and clk_disable_unprepare() at the end of
atmel_console_setup() as the clock is already enabled when calling
atmel_console_setup() and its disablement is done at the end
of probe.
Acked-by: NRichard Genoud <richard.genoud@gmail.com>
Signed-off-by: NClaudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220616140024.2081238-4-claudiu.beznea@microchip.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use devm_clk_get() for serial clock instead of clk_get()/clk_put().
With this move the clk_get in driver's probe function.
Acked-by: NRichard Genoud <richard.genoud@gmail.com>
Signed-off-by: NClaudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220616140024.2081238-3-claudiu.beznea@microchip.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Stop using legacy PM ops and switch using dev_pm_ops. Along with
it #ifdef CONFIG_PM are removed and __maybe_unused and pm_ptr() used
instead. Coding style recommends (at chapter Conditional Compilation)
to avoid using preprocessor conditional and use __maybe_unused
instead.
Acked-by: NRichard Genoud <richard.genoud@gmail.com>
Signed-off-by: NClaudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220616140024.2081238-2-claudiu.beznea@microchip.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Delete the redundant word 'the'.
Signed-off-by: NXiang wangx <wangxiang@cdjrlc.com>
Link: https://lore.kernel.org/r/20220620104653.5451-1-wangxiang@cdjrlc.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In soc_info(), of_find_node_by_type() will return a node pointer
with refcount incremented. We should use of_node_put() when it is
not used anymore.
Acked-by: NTimur Tabi <timur@kernel.org>
Signed-off-by: NLiang He <windhl@126.com>
Link: https://lore.kernel.org/r/20220618060850.4058525-1-windhl@126.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In tegra_uart_init(), of_find_matching_node() will return a node
pointer with refcount incremented. We should use of_node_put()
when it is not used anymore.
Signed-off-by: NLiang He <windhl@126.com>
Link: https://lore.kernel.org/r/20220615111747.3963930-1-windhl@126.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 31f6bd7f ("serial: Store character timing information
to uart_port"), per frame timing information is available on uart_port.
Uart port's timeout can be derived from frame_time by multiplying with
fifosize.

Most callers of uart_poll_timeout are not made under port's lock. To be
on the safe side, make sure frame_time is only accessed once. As
fifo_size is effectively a constant, it shouldn't cause any issues.
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220613113905.22962-1-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use UART_LCR_DLAB instead of literal.
Reviewed-by: NJiri Slaby <jirislaby@kernel.org>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220613075736.12283-2-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use UART_LCR_WLEN8 instead of literal 0x03 in size_fifo().
Reviewed-by: NJiri Slaby <jirislaby@kernel.org>
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220613075736.12283-1-ilpo.jarvinen@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

An SPDX-License-Identifier is already in place. There is no need to
duplicate part of the corresponding license.
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/dbc54eff6f4e077d9126054f395d5bc5b3405917.1654936915.git.christophe.jaillet@wanadoo.frSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The code expects "translations" to have 256 (E_TABSZ) values. Use the
macro instead of the constant to be explicit about this.
Suggested-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220614090537.15557-8-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

con_do_clear_unimap() sets dflt to NULL and then calls
con_release_unimap() which does the very same as the first thing. So
remove the former as it is apparently superfluous.
Suggested-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220614090537.15557-7-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use FIELD_GET() and GENMASK() helpers instead of direct shifts and ANDs.
This makes the code even more obvious. I didn't know about the helpers
at the time of writing the macros.
Suggested-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220614090537.15557-6-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As a follow-up to the commit 4173f018 (tty/vt: consolemap: rename
and document struct uni_pagedir), rename also the members of struct
vc_data. I.e. pagedir -> pagedict. And while touching all the places,
remove also the unnecessary vc_ prefix.
Suggested-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220614090537.15557-5-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The function uses too vague variable names like i, j, k for iterators, p,
q, p1, p2 for pointers etc.

Rename all these, so that it is clear what is going on:
- dict: for dictionaries.
- d, r, g: for dir, row, glyph iterators -- these are unsigned now.
- dir, row: for directory and row pointers.
- glyph: for the glyph.
- and so on...

This is a lot of shuffling, but the result pays off, IMO.
Reviewed-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220614090537.15557-4-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The function still uses too vague parameter name after commit
50c92a1b (tty/vt: consolemap: saner variable names in
set_inverse_trans_unicode()).

So use "dict" instead of "p" for that parameter too.
Reviewed-by: NIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220614090537.15557-3-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>