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: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-13-jslaby@suse.cz
Signed-off-by: Greg 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: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-12-jslaby@suse.cz
Signed-off-by: Greg 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: 34df42f59a ("serial: at91: add rx dma support")
Fixes: 08f738be88 ("serial: at91: add tx dma support")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20211125090028.786832-4-tudor.ambarus@microchip.com
Signed-off-by: Greg 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: 08f738be88 ("serial: at91: add tx dma support")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Link: https://lore.kernel.org/r/20211125090028.786832-3-tudor.ambarus@microchip.com
Signed-off-by: Greg 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: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20211125020349.4980-1-sherry.sun@nxp.com
Signed-off-by: Greg 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: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20211125014306.4432-1-sherry.sun@nxp.com
Signed-off-by: Greg 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: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211122094529.24171-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since commit a9c3f68f3c (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: Johan Hovold <johan@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211122111648.30379-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since commit a9c3f68f3c (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: Johan Hovold <johan@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211122111648.30379-2-jslaby@suse.cz
Signed-off-by: Greg 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: Emil Renner Berthing <kernel@esmil.dk>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20211116150119.2171-15-kernel@esmil.dk
Signed-off-by: Greg 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: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-20-jslaby@suse.cz
Signed-off-by: Greg 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: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-19-jslaby@suse.cz
Signed-off-by: Greg 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: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-18-jslaby@suse.cz
Signed-off-by: Greg 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: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-17-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After the previous change (no plays with of tty->receive_room), the tty
parameter is unused.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-16-jslaby@suse.cz
Signed-off-by: Greg 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: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-15-jslaby@suse.cz
Signed-off-by: Greg 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: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-14-jslaby@suse.cz
Signed-off-by: Greg 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: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-13-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
And move it to new mxser_tx_empty(), because:
1) it simplifies the code (esp. the locking), and
2) serial_core needs such a hook anyway, so have it ready.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-12-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Finally, the mxser_close() code in is mostly identical to
tty_port_close(), so replace the code by a single call to the function.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-11-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I fail to see the point of calling mxser_flush_buffer() from
mxser_close():
1) The SW xmit buffer is freed in mxser_shutdown_port() right after the
call to mxser_flush_buffer(). And all 'cnt', 'head', and 'tail' are
properly initialized to 0 in mxser_activate().
2) The HW buffer is flushed in mxser_shutdown_port() via
mxser_disable_and_clear_FIFO() too.
So the effect of doing it by mxser_flush_buffer() in mxser_close() is
none. Hence remove it, so that when we use tty_port_close() later, the
code is 1:1 identical.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-10-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mxser_stop_rx() should be called from mxser_shutdown_port() for several
reasons:
1) info->slock is held while manipulating IER (as on other places),
2) hangup now stops rx too,
3) mxser_close() will use tty_port_close() and there is no place except
tty_port_operations::shutdown() where this can be done,
4) this is the same sequence as serial_core does. So we can map this
code 1:1 when switching the driver to it.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-9-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Noone sets tty->driver_data to NULL in the driver, so there is no point
to check that in mxser_close(). Remove the check.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xmit_buf is supposed to exist in all these functions. I.e. from
tty_port_operations::activate() to ::shutdown(). So remove these checks.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The port->icount.tx is handled in a too complicated manner. Instead of
remembering the original count and subtracting the new one from it,
simply increase tx for each character in the loop. No need for cnt
variable then.
Change also the "X = X & Y" assignment to simpler "X &= Y".
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-6-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The MSR read is currently performed on both places where
mxser_check_modem_status() is called. So move it there to avoid code
duplication.
Rename the variable to msr while we move it, to actually see what
"status" we are testing.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The others are superfluous with tty refcounting in place now. And they
are racy in fact:
* tty_port_initialized() reports false for a small moment after
interrupts are enabled.
* closing is 1 while the port is still alive.
The queues are flushed later during close anyway. So there is no need
for this special handling. Actually, the ISR should not flush the
queues. It should behave as every other driver, just queue the chars
into tty buffer and go on. But this will be changed later. There is
still a lot code depending on having tty in ISR (and not only tty_port).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As it is the only thing it does now. This is one of the future
serial_core hooks.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mxser_close() behaves like this:
-> tty_port_close_start()
-> tty_wait_until_sent()
-> mxser_wait_until_sent()
-> mxser_close_port
-> wait for TEMT
So it is already waited for TEMT through mxser_wait_until_sent() and
there is another round of waiting in mxser_close_port(). The latter one
is superfluous as nothing could be filled into the output FIFO. Remove
the call.
This helps unification among drivers (so that all behave the same) and
future use of tty_port_close().
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On RZ/G2L SoC we need to explicitly deassert the reset line
for the device to work, use this opportunity to deassert/assert
reset line in sh-sci driver.
This patch adds support to read the "resets" property (if available)
from DT and perform deassert/assert when required.
Also, propagate the error to the caller of sci_parse_dt() instead of
returning NULL in case of failure.
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211110232920.19198-4-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are two consequent checks of uport != NULL in
uart_port_shutdown(). Join these two under a single block.
De-multiline the comments when shuffling with them anyway.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118071911.12059-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Both do_SAK_work() and vc_SAK() provide a valid tty to __do_SAK(), so
remove the check.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118071911.12059-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove the TTY_SOFT_SAK part. It is never defined, so this is only
confusing.
It was actually never defined since its introduction in
0.99.14g.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118071911.12059-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 89d4f98ae9 ("ARM: remove zte zx platform") missed to remove some
definitions for this platform's debug and serial, e.g., code dependent on
the config DEBUG_ZTE_ZX.
Fortunately, ./scripts/checkkconfigsymbols.py detects this and warns:
DEBUG_ZTE_ZX
Referencing files: arch/arm/include/debug/pl01x.S
Further review by Arnd Bergmann identified even more dead code in the
amba serial driver.
Remove all this left-over from the zte zx platform.
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20211102063810.932-1-lukas.bulwahn@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
coccicheck complains about the use of snprintf() in sysfs show
functions:
WARNING use scnprintf or sprintf
Use sysfs_emit instead of scnprintf or sprintf makes more sense.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Jing Yao <yao.jing2@zte.com.cn>
Link: https://lore.kernel.org/r/20211104114754.30983-1-yao.jing2@zte.com.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here is the big set of tty and serial driver updates for 5.16-rc1.
Nothing major in here at all, just lots of tiny serial and tty driver
updates for various reported things, and some good cleanups. These
include:
- more good tty api cleanups from Jiri
- stm32 serial driver updates
- softlockup fix for non-preempt systems under high serial load
- rpmsg serial driver update
- 8250 drivers updates and fixes
- n_gsm line discipline fixes and updates as people are finally
starting to use it.
All of these have been in linux-next for a while now with no reported
issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty / serial driver updates from Greg KH:
"Here is the big set of tty and serial driver updates for 5.16-rc1.
Nothing major in here at all, just lots of tiny serial and tty driver
updates for various reported things, and some good cleanups. These
include:
- more good tty api cleanups from Jiri
- stm32 serial driver updates
- softlockup fix for non-preempt systems under high serial load
- rpmsg serial driver update
- 8250 drivers updates and fixes
- n_gsm line discipline fixes and updates as people are finally
starting to use it.
All of these have been in linux-next for a while now with no reported
issues"
* tag 'tty-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (86 commits)
tty: Fix extra "not" in TTY_DRIVER_REAL_RAW description
serial: cpm_uart: Protect udbg definitions by CONFIG_SERIAL_CPM_CONSOLE
tty: rpmsg: Define tty name via constant string literal
tty: rpmsg: Add pr_fmt() to prefix messages
tty: rpmsg: Use dev_err_probe() in ->probe()
tty: rpmsg: Unify variable used to keep an error code
tty: rpmsg: Assign returned id to a local variable
serial: stm32: push DMA RX data before suspending
serial: stm32: terminate / restart DMA transfer at suspend / resume
serial: stm32: rework RX dma initialization and release
serial: 8250_pci: Remove empty stub pci_quatech_exit()
serial: 8250_pci: Replace custom pci_match_id() implementation
serial: xilinx_uartps: Fix race condition causing stuck TX
serial: sunzilog: Mark sunzilog_putchar() __maybe_unused
Revert "tty: hvc: pass DMA capable memory to put_chars()"
Revert "virtio-console: remove unnecessary kmemdup()"
serial: 8250_pci: Replace dev_*() by pci_*() macros
serial: 8250_pci: Get rid of redundant 'else' keyword
serial: 8250_pci: Refactor the loop in pci_ite887x_init()
tty: add rpmsg driver
...
If CONFIG_CONSOLE_POLL=y, and CONFIG_SERIAL_CPM=m (hence
CONFIG_SERIAL_CPM_CONSOLE=n):
drivers/tty/serial/cpm_uart/cpm_uart_core.c:1109:12: warning: ‘udbg_cpm_getc’ defined but not used [-Wunused-function]
1109 | static int udbg_cpm_getc(void)
| ^~~~~~~~~~~~~
drivers/tty/serial/cpm_uart/cpm_uart_core.c:1095:13: warning: ‘udbg_cpm_putc’ defined but not used [-Wunused-function]
1095 | static void udbg_cpm_putc(char c)
| ^~~~~~~~~~~~~
Fix this by making the udbg definitions depend on
CONFIG_SERIAL_CPM_CONSOLE, in addition to CONFIG_CONSOLE_POLL.
Fixes: a60526097f ("tty: serial: cpm_uart: Add udbg support for enabling xmon")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20211027075326.3270785-1-geert@linux-m68k.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Driver uses already twice the same string literal.
Define it in one place, so every user will have this
name consistent.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211025135148.53944-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of putting garbage in the data structure, assign allocated id
or an error code to a temporary variable. This makes code cleaner.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211025135148.53944-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Data may be stored in DMA RX buffer, when suspending. The data needs
to be pushed to the upper layer. We can't rely on the timeout IRQ (RTOR)
that can't be triggered into low power state. So safely clear DMA request
(DMAR), force the DMA reception routines to push RX buffer content, before
disabling RX DMA. This way, handover to pio mode is safe.
Only call tty_flip_buffer_push() when there is RX data to handle.
Move the locking outside of stm32_usart_receive_chars() to prevent a race
condition, when disabling DMA request upon suspend / pm_runtime_suspend.
Data may be received under IRQ and pushed before
stm32_usart_receive_chars() has pushed older data from DMA rx_buf upon
suspend.
The sequence in suspend routine needs proper locking to avoid this.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211025134229.8456-4-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
DMA prevents the system to suspend when an UART RX wake-up source is
using DMA. DMA can't suspend while DMA channels are still active.
Terminate DMA transfer at suspend, and restart a new DMA transfer at
resume. Create stm32_usart_start_rx_dma_cyclic function to factorize
dma RX initialization. Move RX DMA code related to wakeup into
stm32_usart_serial_en_wakeup() routine to ease further improvements
on wakeup from low power modes.
Don't enable/disable wakeup on uninitialized port.
There may be data residue in the RX FIFO while suspending. Flush it at
suspend time. Receiver timeout interrupt won't trigger later in low power
mode, so call stm32_usart_receive_chars() in case there's data to handle.
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211025134229.8456-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The RX DMA channel is kept active forever (from the probe). That prevents
going to low power mode when it is used. This change moves the
DMA configuration and enabling procedures to startup routine to allow
transition to low power mode.
The DMA disabling procedure is implemented in stop_rx routine as this
ops has to stop characters reception, and DMA transation in shutdown.
Clean useless dma_async_tx_descriptor initialization to NULL value.
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211025134229.8456-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xilinx_uartps .start_tx() clears TXEMPTY when enabling TXEMPTY to avoid
any previous TXEVENT event asserting the UART interrupt. This clear
operation is done immediately after filling the TX FIFO.
However, if the bytes inserted by cdns_uart_handle_tx() are consumed by
the UART before the TXEMPTY is cleared, the clear operation eats the new
TXEMPTY event as well, causing cdns_uart_isr() to never receive the
TXEMPTY event. If there are bytes still queued in circbuf, TX will get
stuck as they will never get transferred to FIFO (unless new bytes are
queued to circbuf in which case .start_tx() is called again).
While the racy missed TXEMPTY occurs fairly often with short data
sequences (e.g. write 1 byte), in those cases circbuf is usually empty
so no action on TXEMPTY would have been needed anyway. On the other
hand, longer data sequences make the race much more unlikely as UART
takes longer to consume the TX FIFO. Therefore it is rare for this race
to cause visible issues in general.
Fix the race by clearing the TXEMPTY bit in ISR *before* filling the
FIFO.
The TXEMPTY bit in ISR will only get asserted at the exact moment the
TX FIFO *becomes* empty, so clearing the bit before filling FIFO does
not cause an extra immediate assertion even if the FIFO is initially
empty.
This is hard to reproduce directly on a normal system, but inserting
e.g. udelay(200) after cdns_uart_handle_tx(port), setting 4000000 baud,
and then running "dd if=/dev/zero bs=128 of=/dev/ttyPS0 count=50"
reliably reproduces the issue on my ZynqMP test system unless this fix
is applied.
Fixes: 85baf542d5 ("tty: xuartps: support 64 byte FIFO size")
Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Link: https://lore.kernel.org/r/20211026102741.2910441-1-anssi.hannula@bitwise.fi
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
