Add support for i.MXRT1050's uart.

Cc: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: NJesse Taube <Mr.Bossman075@gmail.com>
Link: https://lore.kernel.org/r/20211215220538.4180616-8-Mr.Bossman075@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Accessing platform device resources directly has long been deprecated for
DT as IRQ resources may not be available at device creation time. Drivers
continuing to use static IRQ resources is blocking removing the static setup
from the DT core code.
Signed-off-by: NRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211215224832.1985402-1-robh@kernel.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The sh-sci driver supports up to four input clocks, of which only the
first one is mandatory.

Replace devm_clk_get() and custom error checking by
devm_clk_get_optional(), to simplify the code and to catch all real
errors.
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/bce27288cb570952dd96b441e1af8768ad8b4870.1639663832.git.geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the dev_err_probe() helper to streamline error handling.
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/5c4dd8df1f8d0d14786f26ee80b77f3eb8e06cd5.1639663832.git.geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 1b463bd5 ("ARM: dts: r8a7794: Rename the serial
port clock to fck") in v4.6, all upstream DTS files call the SCIF
functional clock "fck".

Hence the time is ripe to drop backward-compatibility with old DTBs that
use the old "sci_ick" name.
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/b4103e44d6ac46b6c1c264e2aeac80b39941fe74.1639663832.git.geert+renesas@glider.beSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the preferred platform_get_irq() call to retrieve the interrupts. These
have the advantage of working with deferred probe and gets us one step
closer to removing of_irq_to_resource_table().
Signed-off-by: NRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211215224800.1984391-1-robh@kernel.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add serial support for R-Car Gen4 SoC.
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20211209070817.1223888-3-yoshihiro.shimoda.uh@renesas.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace kthread_create/kthread_bind/wake_up_process() with
kthread_run_on_cpu() to simplify the code.
Signed-off-by: NCai Huoqing <cai.huoqing@linux.dev>
Link: https://lore.kernel.org/r/20211202140737.94832-1-cai.huoqing@linux.devSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a small window in time during resume where the hardware
flow control signal RTS can be asserted (which allows a sender to
resume sending data to the UART) but the baud rate has not yet
been restored. This will cause corrupted data and FRAMING, OVERRUN
and BREAK errors. This is happening because the MCTRL register is
shadowed in uart_port struct and is later used during resume to set
the MCTRL register during both serial8250_do_startup() and
uart_resume_port(). Unfortunately, serial8250_do_startup()
happens before the UART baud rate is restored. The fix is to clear
the shadowed mctrl value at the end of suspend and restore it at the
end of resume.

Fixes: 41a46948 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NAl Cooper <alcooperx@gmail.com>
Link: https://lore.kernel.org/r/20211201201402.47446-1-alcooperx@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With commit 3873e2d7 ("drivers: PL011: refactor pl011_probe()") the
function devm_ioremap() called from pl011_setup_port() was replaced with
devm_ioremap_resource(). Since this function not only remaps but also
requests the ports io memory region it now collides with the .config_port()
callback which requests the same region at uart port registration.

Since devm_ioremap_resource() already claims the memory successfully, the
request in .config_port() fails.

Later at uart port deregistration the attempt to release the unclaimed
memory also fails. The failure results in a “Trying to free nonexistent
resource" warning.

Fix these issues by removing the callbacks that implement the redundant
memory allocation/release. Also make sure that changing the drivers io
memory base address via TIOCSSERIAL is not allowed any more.

Fixes: 3873e2d7 ("drivers: PL011: refactor pl011_probe()")
Signed-off-by: NLino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20211129174238.8333-1-LinoSanfilippo@gmx.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The base address of uartlite registers could be 64 bit address which is from
device resource. When ulite_probe() calls ulite_assign(), this 64 bit
address is casted to 32-bit. The fix is to replace "u32" type with
"phys_addr_t" type for the base address in ulite_assign() argument list.

Fixes: 8fa7b610 ("[POWERPC] Uartlite: Separate the bus binding from the driver proper")
Signed-off-by: NLizhi Hou <lizhi.hou@xilinx.com>
Link: https://lore.kernel.org/r/20211129202302.1319033-1-lizhi.hou@xilinx.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use wait_event_interruptible in lpuart_dma_shutdown isn't a reasonable
behavior, since it may cause the system hang here if the condition
!sport->dma_tx_in_progress never to be true in some corner case, such as
when enable the flow control, the dma tx request may never be completed
due to the peer's CTS setting when run .shutdown().

So here change to use wait_event_interruptible_timeout instead of
wait_event_interruptible, the tx dma will be forcibly terminated if the
tx dma request cannot be completed within 300ms.
Considering the worst tx dma case is to have a 4K bytes tx buffer, which
would require about 300ms to complete when the baudrate is 115200.
Signed-off-by: NSherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20211203030441.22873-1-sherry.sun@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It is the only missing exported function which is not documented. Fix
it.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-23-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

From the main tty_port functions, only tty_port_destroy() was
documented. Document more of them, so that we can reference them in
Documentation/ later in this series.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-19-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The only documented function for tty_driver structure
allocation/registration was __tty_alloc_driver(). Fix highlighting in
that comment.

And add kernel-doc headers to all tty_driver_kref_put(),
tty_register_driver(), and tty_unregister_driver() -- i.e. the main
ones. More to follow later.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-18-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Kernel-doc is a bit strict about some formatting. So fix these:
1) When there is a tab in comments, it thinks the line is a continuation
   one. So the description of the functions end up as descriptions of
   the last parameter described. Remove the tabs.

2) Remove newlines before parameters description and after the comments.
   This was not wrong per se, only inconsistent with the rest of the
   file.

3) Add periods to the end of sentences where appropriate.

4) Add "()" to function names and "%" to constants, so that they are
   properly highlighted.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-17-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

* process_echoes doc was a misnomer
* isig and n_tty_receive_char docs were misplaced
* n_tty_read parameters were incorrect (from pre-cookie times)

So fix all the warnings at once:
624: warning: expecting prototype for process_echoes(). Prototype was for __process_echoes() instead
1110: warning: expecting prototype for isig(). Prototype was for __isig() instead
1264: warning: expecting prototype for n_tty_receive_char(). Prototype was for n_tty_receive_char_special() instead
2067: warning: Excess function parameter 'buf' description in 'n_tty_read'
624: warning: expecting prototype for process_echoes(). Prototype was for __process_echoes() instead
1110: warning: expecting prototype for isig(). Prototype was for __isig() instead
1264: warning: expecting prototype for n_tty_receive_char(). Prototype was for n_tty_receive_char_special() instead
2067: warning: Function parameter or member 'kbuf' not described in 'n_tty_read'
2067: warning: Function parameter or member 'cookie' not described in 'n_tty_read'
2067: warning: Function parameter or member 'offset' not described in 'n_tty_read'
2067: warning: Excess function parameter 'buf' description in 'n_tty_read'
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-16-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Kernel-doc is a bit strict about some formatting. So fix these:
1) When there is a tab in comments, it thinks the line is a continuation
   one. So the description of the functions end up as descriptions of
   the last parameter described. Remove the tabs.

2) Remove newlines before parameters description and after the comments.
   This was not wrong per se, only inconsistent with the rest of the
   file.

3) Add periods to the end of sentences where appropriate.

4) Add "()" to function names and "%" to constants, so that they are
   properly highlighted.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-15-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Kernel-doc is a bit strict about some formatting. So fix these:
1) When there is a tab in comments, it thinks the line is a continuation
   one. So the description of the functions end up as descriptions of
   the last parameter described. Remove the tabs.

2) Remove newlines before parameters description and after the comments.
   This was not wrong per se, only inconsistent with the rest of the
   file.

3) Add periods to the end of sentences where appropriate.

4) Add "()" to function names and "%" to constants, so that they are
   properly highlighted.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-14-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Kernel-doc is a bit strict about some formatting. So fix these:
1) When there is a tab in comments, it thinks the line is a continuation
   one. So the description of the functions end up as descriptions of
   the last parameter described. Remove the tabs.

2) Remove newlines before parameters description and after the comments.
   This was not wrong per se, only inconsistent with the rest of the
   file.

3) Add periods to the end of sentences where appropriate.

4) Add "()" to function names and "%" to constants, so that they are
   properly highlighted.

By the above, this patch also unifies these docs with the other
kernel-doc's in this file.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-13-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Kernel-doc is a bit strict about some formatting. So fix these:
1) When there is a tab in comments, it thinks the line is a continuation
   one. So the description of the functions end up as descriptions of
   the last parameter described. Remove the tabs.

2) Remove newlines before parameters description. This was not wrong per
   se, only inconsistent with the rest of the file.

3) Add periods to the end of sentences where appropriate.

4) Use recognized "Note" instead of "NB" (nota bene).

5) Add "()" to function names and "%" to constants, so that they are
   properly highlighted.

By the above, this patch also unifies these docs with the other
kernel-doc's in this file.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-12-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The driver wrongly assummed that tx_submit() will start the transfer,
which is not the case, now that the at_xdmac driver is fixed. tx_submit
is supposed to push the current transaction descriptor to a pending queue,
waiting for issue_pending to be called. issue_pending must start the
transfer, not tx_submit.

Fixes: 34df42f5 ("serial: at91: add rx dma support")
Fixes: 08f738be ("serial: at91: add tx dma support")
Signed-off-by: NTudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211125090028.786832-4-tudor.ambarus@microchip.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The tx_submit() method of struct dma_async_tx_descriptor is entitled
to do sanity checks and return errors if encountered. It's not the
case for the DMA controller drivers that this client is using
(at_h/xdmac), because they currently don't do sanity checks and always
return a positive cookie at tx_submit() method. In case the controller
drivers will implement sanity checks and return errors, print a message
so that the client will be informed that something went wrong at
tx_submit() level.

Fixes: 08f738be ("serial: at91: add tx dma support")
Signed-off-by: NTudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: NRichard Genoud <richard.genoud@gmail.com>
Link: https://lore.kernel.org/r/20211125090028.786832-3-tudor.ambarus@microchip.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Have pericom_do_set_divisor() use the uartclk instead of a hard coded
value to work with different speed crystals. Tested with 14.7456 and 24
MHz crystals.

Have pericom_do_set_divisor() always calculate the divisor rather than
call serial8250_do_set_divisor() for rates below baud_base.

Do not write registers or call serial8250_do_set_divisor() if valid
divisors could not be found.

Fixes: 6bf4e42f ("serial: 8250: Add support for higher baud rates to Pericom chips")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJay Dolan <jay.dolan@accesio.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211122120604.3909-3-andriy.shevchenko@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix error in table for PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4S that caused it
and PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_4 to be missing their fourth port.

Fixes: 78d3820b ("serial: 8250_pci: Have ACCES cards that use the four port Pericom PI7C9X7954 chip use the pci_pericom_setup()")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJay Dolan <jay.dolan@accesio.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211122120604.3909-2-andriy.shevchenko@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit f45709df ("serial: 8250: Don't touch RTS modem control while
in rs485 mode") sought to prevent user space from interfering with rs485
communication by ignoring a TIOCMSET ioctl() which changes RTS polarity.

It did so in serial8250_do_set_mctrl(), which turns out to be too deep
in the call stack:  When a uart_port is opened, RTS polarity is set by
the rs485-aware function uart_port_dtr_rts().  It calls down to
serial8250_do_set_mctrl() and that particular RTS polarity change should
*not* be ignored.

The user-visible result is that on 8250_omap ports which use rs485 with
inverse polarity (RTS bit in MCR register is 1 to receive, 0 to send),
a newly opened port initially sets up RTS for sending instead of
receiving.  That's because omap_8250_startup() sets the cached value
up->mcr to 0 and omap_8250_restore_regs() subsequently writes it to the
MCR register.  Due to the commit, serial8250_do_set_mctrl() preserves
that incorrect register value:

do_sys_openat2
  do_filp_open
    path_openat
      vfs_open
        do_dentry_open
	  chrdev_open
	    tty_open
	      uart_open
	        tty_port_open
		  uart_port_activate
		    uart_startup
		      uart_port_startup
		        serial8250_startup
			  omap_8250_startup # up->mcr = 0
			uart_change_speed
			  serial8250_set_termios
			    omap_8250_set_termios
			      omap_8250_restore_regs
			        serial8250_out_MCR # up->mcr written
		  tty_port_block_til_ready
		    uart_dtr_rts
		      uart_port_dtr_rts
		        serial8250_set_mctrl
			  omap8250_set_mctrl
			    serial8250_do_set_mctrl # mcr[1] = 1 ignored

Fix by intercepting RTS changes from user space in uart_tiocmset()
instead.

Link: https://lore.kernel.org/linux-serial/20211027111644.1996921-1-baocheng.su@siemens.com/
Fixes: f45709df ("serial: 8250: Don't touch RTS modem control while in rs485 mode")
Cc: Chao Zeng <chao.zeng@siemens.com>
Cc: stable@vger.kernel.org # v5.7+
Reported-by: NSu Bao Cheng <baocheng.su@siemens.com>
Reported-by: NJan Kiszka <jan.kiszka@siemens.com>
Tested-by: NSu Bao Cheng <baocheng.su@siemens.com>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/21170e622a1aaf842a50b32146008b5374b3dd1d.1637596432.git.lukas@wunner.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The UCR4_OREN should be disabled before disabling the uart receiver in
.stop_rx() instead of in the .shutdown().

Otherwise, if we have the overrun error during the receiver disable
process, the overrun interrupt will keep trigging until we disable the
OREN interrupt in the .shutdown(), because the ORE status can only be
cleared when read the rx FIFO or reset the controller.  Although the
called time between the receiver disable and OREN disable in .shutdown()
is very short, there is still the risk of endless interrupt during this
short period of time. So here change to disable OREN before the receiver
been disabled in .stop_rx().
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Signed-off-by: NSherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20211125020349.4980-1-sherry.sun@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Clear RTSD status before enabling the irq event for RTSD in
imx_uart_enable_wakeup function.
Since RTSD can be set as the wakeup source, this can avoid any risk of
false triggering of a wake-up interrupts.
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Signed-off-by: NSherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20211125014306.4432-1-sherry.sun@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

After the previous patches, noone needs 'file' parameter in neither
ioctl hook from tty_ldisc_ops. So remove 'file' from both of them.

Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Andreas Koensgen <ajk@comnets.uni-bremen.de>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> [NFC]
Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211122094529.24171-1-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit a9c3f68f (tty: Fix low_latency BUG) in 2014,
tty_flip_buffer_push() is only a wrapper to tty_schedule_flip(). All
users were converted in the previous patches, so remove
tty_schedule_flip() completely while inlining its body into
tty_flip_buffer_push().

One less exported function.
Reviewed-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211122111648.30379-4-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit a9c3f68f (tty: Fix low_latency BUG) in 2014,
tty_flip_buffer_push() is only a wrapper to tty_schedule_flip(). We are
going to remove the latter (as it is used less), so call the former in
drivers/tty/.

Cc: Vladimir Zapolskiy <vz@mleia.com>
Reviewed-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211122111648.30379-2-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

On the StarFive JH7100 RISC-V SoC the UART core clocks can't be set to
exactly 16 * 115200Hz and many other common bitrates. Trying this will
only result in a higher input clock, but low enough that the UART's
internal divisor can't come close enough to the baud rate target.
So rather than try to set the input clock it's better to skip the
clk_set_rate call and rely solely on the UART's internal divisor.
Signed-off-by: NEmil Renner Berthing <kernel@esmil.dk>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20211116150119.2171-15-kernel@esmil.dkSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that we have all the PCI device IDs unified, we can use
PCI_DEVICE_DATA() macro to simplify mxser's pci_device_id list, i.e.
mxser_pcibrds.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-20-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no point having MOXA PCI device IDs in include/linux/pci_ids.h.
Move them to the driver and sort them all by the ID.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-19-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Some of the MOXA PCI device IDs contain _MOXA_, some don't. Add it to
the latter, so that they are all unified.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-18-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

mxser doesn't increase port->icount.buf_overrun at all. Do so if overrun
happens, so that it can be read from the stats.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-17-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

After the previous change (no plays with of tty->receive_room), the tty
parameter is unused.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-16-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

First, checking tty->receive_room to signalize whether there is enough space
in the tty buffers does not make much sense. Provided the tty buffers
are in tty_port and those are not checked at all.

Second, if the rx path is throttled, with CRTSCTS, RTS is deasserted,
but is never asserted again. This leads to port "lockup", not accepting
any more input.

So:
1) stty -F /dev/ttyMI0 crtscts # the mxser port
2) stty -F /dev/ttyS6 crtscts # the connected port
3) cat /dev/ttyMI0
4) "write in a loop" to /dev/ttyS6
5) cat from 3) produces the bytes from 4)
6) killall -STOP cat (the 3)'s one)
7) wait for RTS to drop on /dev/ttyMI0
8) killall -CONT cat (again the 3)'s one)

cat erroneously produces no more output now (i.e. no data sent from
ttyS6 to ttyMI can be seen).

Note that the step 7) is performed twice: once from n_tty by
tty_throttle_safe(), once by mxser_stoprx() from the receive path. Then
after step 7), n_tty correctly unthrottles the input, but mxser calls
mxser_stoprx() again as there is still only a little space in n_tty
buffers (tty->receive_room mentioned at the beginning), but the device's
FIFO is/can be already filled.

After this patch, the output is correctly resumed, i.e. n_tty both
throttles and unthrottles without interfering with mxser's attempts.

This allows us to get rid of the non-standard ldisc_stop_rx flag from
struct mxser_port.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-15-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

timeout cannot be zero at the point of use. So no need to check for
zero. Also precompute the expiration time (into expire) and use it. This
makes the code more clear.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-14-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of schedule_timeout_interruptible(), because:
1) we don't have to bother with the task state, and
2) msleep* guarantees to sleep that time (if not interrupted).
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-13-jslaby@suse.czSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>