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>
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: 6bf4e42f1d ("serial: 8250: Add support for higher baud rates to Pericom chips")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Jay Dolan <jay.dolan@accesio.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211122120604.3909-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit f45709df77 ("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: f45709df77 ("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: Su Bao Cheng <baocheng.su@siemens.com>
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Tested-by: Su Bao Cheng <baocheng.su@siemens.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/21170e622a1aaf842a50b32146008b5374b3dd1d.1637596432.git.lukas@wunner.de
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>
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>
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>
Revert commit b4b844930f ("tty: serial: fsl_lpuart: drop earlycon entry
for i.MX8QXP"), because this breaks earlycon support on imx8qm/imx8qxp.
While it is true that for earlycon there is no difference between
i.MX8QXP and i.MX7ULP (for now at least), there are differences
regarding clocks and fixups for wakeup support. For that reason it was
deemed unacceptable to add the imx7ulp compatible to device tree in
order to get earlycon working again.
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/20211124073109.805088-1-alexander.stein@ew.tq-group.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current implementation uses 0 as lower limit for the baud rate
tolerance for tegra20 and tegra30 chips which causes isses on UART
initialization as soon as baud rate clock is lower than required even
when within the standard UART tolerance of +/- 4%.
This fix aligns the implementation with the initial commit description
of +/- 4% tolerance for tegra chips other than tegra186 and
tegra194.
Fixes: d781ec21ba ("serial: tegra: report clk rate errors")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Patrik John <patrik.john@u-blox.com>
Link: https://lore.kernel.org/r/sig.19614244f8.20211123132737.88341-1-patrik.john@u-blox.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The LITEX symbol is neither a build or runtime dependency for the
liteuart serial driver.
LITEX is selected by the "LiteX SoC Controller" driver, which does a
probe-time register-access sanity check and panics if the SoC has not
been configured correctly. That driver's Kconfig entry asserts that any
LiteX driver using the LiteX register accessors should depend on LITEX,
but currently only the serial driver complies.
Relax this LITEX "dependency" in order to make it easier to compile test
the driver.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20211117100512.5058-4-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The CONSOLE_POLLING mode is used for tools like k(g)db. In this kind of
setup, it is often sharing a serial device with the normal system console.
This is usually no problem because the polling helpers can consume input
values directly (when in kgdb context) and the normal Linux handlers can
only consume new input values after kgdb switched back.
This is not true anymore when RX DMA is enabled for UARTDM controllers.
Single input values can no longer be received correctly. Instead following
seems to happen:
* on 1. input, some old input is read (continuously)
* on 2. input, two old inputs are read (continuously)
* on 3. input, three old input values are read (continuously)
* on 4. input, 4 previous inputs are received
This repeats then for each group of 4 input values.
This behavior changes slightly depending on what state the controller was
when the first input was received. But this makes working with kgdb
basically impossible because control messages are always corrupted when
kgdboc tries to parse them.
RX DMA should therefore be off when CONSOLE_POLLING is enabled to avoid
these kind of problems. No such problem was noticed for TX DMA.
Fixes: 9969394501 ("tty: serial: msm: Add RX DMA support")
Cc: stable@vger.kernel.org
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Link: https://lore.kernel.org/r/20211113121050.7266-1-sven@narfation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The document 'ACPI for Arm Components 1.0' defines the following
_HID mappings:
-'Prime cell UART (PL011)': ARMH0011
-'SBSA UART': ARMHB000
Use the sbsa-uart driver when a device is described with
the 'ARMHB000' _HID.
Note:
PL011 devices currently use the sbsa-uart driver instead of the
uart-pl011 driver. Indeed, PL011 devices are not bound to a clock
in ACPI. It is not possible to change their baudrate.
Cc: <stable@vger.kernel.org>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Link: https://lore.kernel.org/r/20211109172248.19061-1-Pierre.Gondois@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 761ed4a945 ("tty: serial_core: convert uart_close to use
tty_port_close") converted serial core to use tty_port_close() but
failed to notice that the transmit buffer still needs to be freed on
final close.
Not freeing the transmit buffer means that the buffer is no longer
cleared on next open so that any ioctl() waiting for the buffer to drain
might wait indefinitely (e.g. on termios changes) or that stale data can
end up being transmitted in case tx is restarted.
Furthermore, the buffer of any port that has been opened would leak on
driver unbind.
Note that the port lock is held when clearing the buffer pointer due to
the ldisc race worked around by commit a5ba1d95e4 ("uart: fix race
between uart_put_char() and uart_shutdown()").
Also note that the tty-port shutdown() callback is not called for
console ports so it is not strictly necessary to free the buffer page
after releasing the lock (cf. d72402145a ("tty/serial: do not free
trasnmit buffer page under port lock")).
Link: https://lore.kernel.org/r/319321886d97c456203d5c6a576a5480d07c3478.1635781688.git.baruch@tkos.co.il
Fixes: 761ed4a945 ("tty: serial_core: convert uart_close to use tty_port_close")
Cc: stable@vger.kernel.org # 4.9
Cc: Rob Herring <robh@kernel.org>
Reported-by: Baruch Siach <baruch@tkos.co.il>
Tested-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20211108085431.12637-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
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>
If CONSOLE_POLL=n, CONFIG_SERIAL_SUNZILOG_CONSOLE=n, and CONFIG_SERIO=m:
drivers/tty/serial/sunzilog.c:1128:13: error: ‘sunzilog_putchar’ defined but not used [-Werror=unused-function]
1128 | static void sunzilog_putchar(struct uart_port *port, int ch)
| ^~~~~~~~~~~~~~~~
Fix this by marking sunzilog_putchar() __maybe_unused.
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20211026080426.2444756-1-geert@linux-m68k.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The driver was updating the port uartclk before setting the new rate in
an attempt to avoid having the clock notifier redundantly update the
divisors.
The set_termios() callback is however called under the termios semaphore
and tty-port mutex so the worker scheduled by the clock notifier will
block in serial8250_update_uartclk() until the uartclk and divisors have
been updated anyway.
Drop the unnecessary swaps and incorrect comment and simply update the
uartclk field if the clock-rate change was successful.
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20211015111422.1027-4-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch reworks RX support over DMA to improve reliability:
- change dma buffer cyclic configuration by using 2 periods. DMA buffer
data are handled by a flip-flop between the 2 periods in order to avoid
risk of data loss/corruption
- change the size of dma buffer to 4096 to limit overruns
- add rx errors management (breaks, parity, framing and overrun).
When an error occurs on the uart line, the dma request line is masked at
HW level. The SW must 1st clear DMAR (dma request line enable), to
handle the error, then re-enable DMAR to recover. So, any correct data
is taken from the DMA buffer, before handling the error itself. Then
errors are handled from RDR/ISR/FIFO (e.g. in PIO mode). Last, DMA
reception is resumed.
- add a condition on DMA request line in DMA RX routines in order to
switch to PIO mode when no DMA request line is disabled, even if the DMA
channel is still enabled.
When the UART is wakeup source and is configured to use DMA for RX, any
incoming data that wakes up the system isn't correctly received.
At data reception, the irq_handler handles the WUF irq, and then the
data reception over DMA.
As the DMA transfer has been terminated at suspend, and will be restored
by resume callback (which has no yet been called by system), the data
can't be received.
The wake-up data has to be handled in PIO mode while suspend callback
has not been called.
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/20211020150332.10214-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Re-introduce an irq flag condition in usart_receive_chars.
This condition has been deleted by commit 75f4e830fa ("serial: do not
restore interrupt state in sysrq helper").
This code was present to handle threaded case, and has been removed
because it is no more needed in this case. Nevertheless an irq safe lock
is still needed in some cases, when DMA should be stopped to receive errors
or breaks in PIO mode.
This patch is a precursor to the complete rework or stm32 serial driver
DMA implementation.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20211020150332.10214-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During console setup imx_uart_console_setup() enables clocks, but they
are never disabled when the console is unregistered, this leads to
clk_prepare_enable() being called multiple times without a matching
clk_disable_unprepare() in case of console unregister.
Ensure that clock enable/disable are balanced adding
clk_disable_unprepare() in the console exit callback.
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20211020192643.476895-3-francesco.dolcini@toradex.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
