When DMA is enabled the receive handler runs in a threaded handler, but
the primary handler up until very recently neither disabled interrupts
in the device or used IRQF_ONESHOT. This would lead to a deadlock if an
interrupt comes in while the threaded receive handler is running under
the port lock.
Commit ad76768124 ("serial: stm32: fix a deadlock condition with
wakeup event") claimed to fix an unrelated deadlock, but unfortunately
also disabled interrupts in the threaded handler. While this prevents
the deadlock mentioned in the previous paragraph it also defeats the
purpose of using a threaded handler in the first place.
Fix this by making the interrupt one-shot and not disabling interrupts
in the threaded handler.
Note that (receive) DMA must not be used for a console port as the
threaded handler could be interrupted while holding the port lock,
something which could lead to a deadlock in case an interrupt handler
ends up calling printk.
Fixes: ad76768124 ("serial: stm32: fix a deadlock condition with wakeup event")
Fixes: 3489187204 ("serial: stm32: adding dma support")
Cc: stable@vger.kernel.org # 4.9
Cc: Alexandre TORGUE <alexandre.torgue@st.com>
Cc: Gerald Baeza <gerald.baeza@st.com>
Reviewed-by: Valentin Caron<valentin.caron@foss.st.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210416140557.25177-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The wakeup specific IRQ management is no more needed to wake up the stm32
plaform. A relationship has been established between the EXTI and
the EVENT IRQ, just need to declare the EXTI interrupt instead of the
UART event IRQ.
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210319184253.5841-5-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove useless call to stm32_usart_serial_en_wakeup() routine in suspend
callback. When called with "false" argument, this routine is clearing UESM
and WUFIE bits if usart is not wakeup source. Those bits are already
cleared in set_termios(), and then in serial_resume() callback when usart
is wakeup source.
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210319184253.5841-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rework wakeup management by activating uart as wakeup source when usart
device OR its tty virtual device parent is wakeup source.
This patch aim to avoid potential misalignment between serial and tty
wakeup flags.
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210319184253.5841-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the support for "flush_buffer" ops in order to flush any write buffers,
reset any DMA state and stop any ongoing DMA transfers when the
port->state->xmit circular buffer is cleared.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-14-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In "tx_empty", we should poll TC bit in both DMA and PIO modes (instead of
TXE) to check transmission data register has been transmitted independently
of the FIFO mode. TC indicates that both transmit register and shift
register are empty. When shift register is empty, tx_empty should return
TIOCSER_TEMT instead of TC value.
Cleans the USART_CR_TC TCCF register define (transmission complete clear
flag) as it is duplicate of USART_ICR_TCCF.
Fixes: 48a6092fb4 ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-13-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Transmission complete error is sent when ISR_TC is not set. If port closure
is requested despite data in TDR / TX FIFO has not been sent (because of
flow control), ISR_TC is not set and error message is sent on port closure
but also when a new port is opened.
Flush the data when port is closed, so the error isn't printed twice upon
next port opening.
Fixes: 64c32eab66 ("serial: stm32: Add support of TC bit status check")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-12-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fifo flush set USART_RQR register by calling stm32_usart_set_bits
routine (Read/Modify/Write). USART_RQR register is a write only
register. So, read before write isn't correct / relevant to flush
the FIFOs.
Replace stm32_usart_set_bits call by writel_relaxed.
Fixes: 84872dc448 ("serial: stm32: add RX and TX FIFO flush")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-11-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
stm32_transmit_chars should be called under lock also in tx DMA callback.
Fixes: 3489187204 ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-10-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CTS/RTS GPIOs support that has been added recently to STM32 UART driver has
introduced scheduled code in a set_termios part protected by a spin lock.
This generates a potential deadlock scenario:
Chain exists of:
&irq_desc_lock_class --> console_owner --> &port_lock_key
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&port_lock_key);
lock(console_owner);
lock(&port_lock_key);
lock(&irq_desc_lock_class);
*** DEADLOCK ***
4 locks held by stty/766:
Move the scheduled code after the spinlock.
Fixes: 6cf61b9bd7 ("tty: serial: Add modem control gpio support for STM32 UART")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-8-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch fixes several issue with wake-up handling:
- the WUF irq is handled several times at wake-up
- the USART is disabled / enabled at suspend to set wake-up flag.
It can cause glitches during RX.
This patch fix those issues:
- clear wake-up flag and disable wake-up irq in WUF irq handling
- enable wake-up from low power on start bit detection at port
configuration
- Unmask the wake-up flag irq at suspend and mask it at resume
In addition, pm_wakeup_event handling is moved from receice_chars to WUF
irq handling.
Fixes: 270e5a74fe ("serial: stm32: add wakeup mechanism")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-7-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Deadlock issue is seen when enabling CONFIG_PROVE_LOCKING=Y, and uart
console as wakeup source. Deadlock occurs when resuming from low power
mode if system is waked up via usart console.
The deadlock is triggered 100% when also disabling console suspend prior
to go to suspend.
Simplified call stack, deadlock condition:
- stm32_console_write <-- spin_lock already held
- print_circular_bug
- pm_wakeup_dev_event <-- triggers lockdep as seen above
- stm32_receive_chars
- stm32_interrupt <-- wakeup via uart console, takes the lock
So, revisit spin_lock in stm32-usart driver:
- there is no need to hold the lock to access ICR (atomic clear of status
flags)
- only hold the lock inside stm32_receive_chars() routine (no need to
call pm_wakeup_dev_event with lock held)
- keep stm32_transmit_chars() routine called with lock held
Fixes: 48a6092fb4 ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-6-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
TX and RX FIFO thresholds may be cleared after suspend/resume, depending
on the low power mode.
Those configurations (done in startup) are not effective for UART console,
as:
- the reference manual indicates that FIFOEN bit can only be written when
the USART is disabled (UE=0)
- a set_termios (where UE is set) is requested firstly for console
enabling, before the startup.
Fixes: 84872dc448 ("serial: stm32: add RX and TX FIFO flush")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-5-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Incorrect characters are observed on console during boot. This issue occurs
when init/main.c is modifying termios settings to open /dev/console on the
rootfs.
This patch adds a waiting loop in set_termios to wait for TX shift register
empty (and TX FIFO if any) before stopping serial port.
Fixes: 48a6092fb4 ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-4-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
RX is configured, but usart is not enabled in startup function.
Kernel documentation specifies that startup should enable the port for
reception.
Fix the startup by enabling usart for reception.
Fixes: 84872dc448 ("serial: stm32: add RX and TX FIFO flush")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The probe and remove orders are wrong as the uart_port is registered
before saving device data in the probe, and unregistered after DMA
resource deallocation in the remove. uart_port registering should be
done at the end of probe and unregistering should be done at the begin of
remove to avoid resource allocation issues.
Fix probe and remove orders. This enforce resource allocation occur at
proper time.
Terminate both DMA rx and tx transfers before removing device.
Move pm_runtime after uart_remove_one_port() call in remove() to keep the
probe error path.
Fixes: 3489187204 ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- Sync dtc to upstream version v1.6.0-51-g183df9e9c2b9 and build
host fdtoverlay
- Add kbuild support to build DT overlays (%.dtbo)
- Drop NULLifying match table in of_match_device(). In preparation for
this, there are several driver cleanups to use
(of_)?device_get_match_data().
- Drop pointless wrappers from DT struct device API
- Convert USB binding schemas to use graph schema and remove old plain
text graph binding doc
- Convert spi-nor and v3d GPU bindings to DT schema
- Tree wide schema fixes for if/then schemas, array size constraints,
and undocumented compatible strings in examples
- Handle 'no-map' correctly for already reserved memblock regions
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Merge tag 'devicetree-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux
Pull devicetree updates from Rob Herring:
- Sync dtc to upstream version v1.6.0-51-g183df9e9c2b9 and build host
fdtoverlay
- Add kbuild support to build DT overlays (%.dtbo)
- Drop NULLifying match table in of_match_device().
In preparation for this, there are several driver cleanups to use
(of_)?device_get_match_data().
- Drop pointless wrappers from DT struct device API
- Convert USB binding schemas to use graph schema and remove old plain
text graph binding doc
- Convert spi-nor and v3d GPU bindings to DT schema
- Tree wide schema fixes for if/then schemas, array size constraints,
and undocumented compatible strings in examples
- Handle 'no-map' correctly for already reserved memblock regions
* tag 'devicetree-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (35 commits)
driver core: platform: Drop of_device_node_put() wrapper
of: Remove of_dev_{get,put}()
dt-bindings: usb: Change descibe to describe in usbmisc-imx.txt
dt-bindings: can: rcar_canfd: Group tuples in pin control properties
dt-bindings: power: renesas,apmu: Group tuples in cpus properties
dt-bindings: mtd: spi-nor: Convert to DT schema format
dt-bindings: Use portable sort for version cmp
dt-bindings: ethernet-controller: fix fixed-link specification
dt-bindings: irqchip: Add node name to PRUSS INTC
dt-bindings: interconnect: Fix the expected number of cells
dt-bindings: Fix errors in 'if' schemas
dt-bindings: iommu: renesas,ipmmu-vmsa: Make 'power-domains' conditionally required
dt-bindings: Fix undocumented compatible strings in examples
kbuild: Add support to build overlays (%.dtbo)
scripts: dtc: Remove the unused fdtdump.c file
scripts: dtc: Build fdtoverlay tool
scripts/dtc: Update to upstream version v1.6.0-51-g183df9e9c2b9
scripts: dtc: Fetch fdtoverlay.c from external DTC project
dt-bindings: thermal: sun8i: Fix misplaced schema keyword in compatible strings
dt-bindings: iio: dac: Fix AD5686 references
...
Replace "ret" variable by "irq" variable from platform_get_irq condition
handling in stm32_init_port as suggested by Jiri in "STM32 uart cleanup and
improvement" series review.
This change will prevent port->irq to be unexpectly modified by a potential
change of "ret" value introduced by a new patch.
Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210121142309.6327-1-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This driver casts away the constness of struct stm32_usart_info that is
pointed to by the of match table. Use of_device_get_match_data() instead
of of_match_device() here and push the const throughout the code so that
we don't cast away const. This nicely avoids referencing the match table
when it is undefined with configurations where CONFIG_OF=n and fixes the
const issues.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: <linux-serial@vger.kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210123034428.2841052-4-swboyd@chromium.org
The transmission complete error message provides the status of the
ISR_USART_TC bit. This bit, when set, indicates that the transmission
has not been completed.
The bit status indication is not a very understandable information.
The error message sent on console should indicate that the transmission is
not complete, instead of providing USART_TC bit status.
Update the error message and add a comment for better understanding.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-9-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Clean probe and remove port deinit by moving clk_disable_unprepare in a
new dedicated deinit_port function.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-8-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The comment for conflicting RTS/CTS config refers to "st, hw-flow-ctrl",
but this property is deprecated since the generic RTS/CTS property has
been introduced by the patch 'serial: stm32: Use generic DT binding for
announcing RTS/CTS lines'.
Update the comment to refer to both generic and deprecated RTS/CTS
properties.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-7-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adds the prefix "_usart" in the name of stm32 usart functions in order to
ease the usage of kernel trace and tools, such as f-trace.
Allows to trace "stm32_usart_*" functions with f-trace. Without this patch,
all the driver functions needs to be added manually in f-trace filter.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-4-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes checkpatch --strict warnings and checks:
- checkpatch --strict "Unnecessary parentheses"
- checkpatch --strict "Blank lines aren't necessary before a close brace
- checkpatch --strict "Alignment should match open parenthesis"
- checkpatch --strict "Please don't use multiple blank lines"
- checkpatch --strict "Comparison to NULL could be written ..."
- visual check code ordering warning
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-3-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
DMA initialization error handling is not properly implemented in the
driver.
Fix DMA initialization error handling by:
- moving TX DMA descriptor request error handling in a new dedicated
fallback_err label
- adding error handling to TX DMA descriptor submission
- adding error handling to RX DMA descriptor submission
This patch depends on '24832ca3ee85 ("tty: serial: stm32-usart: Remove set
but unused 'cookie' variables")' which unfortunately doesn't include a
"Fixes" tag.
Fixes: 3489187204 ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210106162203.28854-2-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes the following W=1 kernel build warning(s):
drivers/tty/serial/stm32-usart.c: In function ‘stm32_transmit_chars_dma’:
drivers/tty/serial/stm32-usart.c:353:15: warning: variable ‘cookie’ set but not used [-Wunused-but-set-variable]
drivers/tty/serial/stm32-usart.c: In function ‘stm32_of_dma_rx_probe’:
drivers/tty/serial/stm32-usart.c:1090:15: warning: variable ‘cookie’ set but not used [-Wunused-but-set-variable]
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Gerald Baeza <gerald.baeza@st.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20201104193549.4026187-29-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While the STM32 does support RS485 drive-enable control within the
UART IP itself, some systems have the drive-enable line connected
to a pin which cannot be pinmuxed as RTS. Add support for toggling
the RTS GPIO line using the modem control GPIOs to provide at least
some sort of emulation.
Fixes: 7df5081cbf ("serial: stm32: Add RS485 RTS GPIO control")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: linux-stm32@st-md-mailman.stormreply.com
Link: https://lore.kernel.org/r/20200831171045.205691-1-marex@denx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
stm32_init_port() of the stm32-usart may trigger a warning in
platform_get_irq() when the device tree specifies no wakeup interrupt.
The wakeup interrupt is usually a board-specific GPIO and the driver
functions correctly in its absence. The mainline stm32mp151.dtsi does
not specify it, so all mainline device trees trigger an unnecessary
kernel warning. Use of platform_get_irq_optional() avoids this.
Fixes: 2c58e56096 ("serial: stm32: fix the get_irq error case")
Signed-off-by: Holger Assmann <h.assmann@pengutronix.de>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200813152757.32751-1-h.assmann@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While the STM32 does support RS485 drive-enable control within the
UART IP itself, some systems have the drive-enable line connected
to a pin which cannot be pinmuxed as RTS. Add support for toggling
the RTS GPIO line using the modem control GPIOs to provide at least
some sort of emulation.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-stm32@st-md-mailman.stormreply.com
Link: https://lore.kernel.org/r/20200725144947.537007-1-marex@denx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support of generic DT binding for annoucing RTS/CTS lines. The initial
binding 'st,hw-flow-control' is not needed anymore since generic binding
is available, but is kept for backward compatibility.
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Link: https://lore.kernel.org/r/20200520133932.30441-3-erwan.leray@st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In order to display console messages in low power mode, console pins
must be kept active after suspend call.
Initial patch "serial: stm32: add support for no_console_suspend" was part
of "STM32 usart power improvement" series, but as dependancy to
console_suspend pinctl state has been removed to fit with Rob comment [1],
this patch has no more dependancy with any other patch of this series.
[1] https://lkml.org/lkml/2019/7/9/451
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Link: https://lore.kernel.org/r/20200519094104.27082-1-erwan.leray@st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We're about to amend uart_get_rs485_mode() to support a GPIO pin for
rs485 bus termination. Retrieving the GPIO descriptor may fail, so
allow uart_get_rs485_mode() to return an errno and change all callers
to check for failure.
The GPIO descriptor is going to be stored in struct uart_port. Pass
that struct to uart_get_rs485_mode() in lieu of a struct device and
struct serial_rs485, both of which are directly accessible from struct
uart_port.
A few drivers call uart_get_rs485_mode() before setting the struct
device pointer in struct uart_port. Shuffle those calls around where
necessary.
[Heiko Stuebner did the ar933x_uart.c portion, hence his Signed-off-by.]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
STM32 UART controllers have the built in modem control support using
dedicated gpios which can be enabled using 'st,hw-flow-ctrl' flag in DT.
But there might be cases where the board design need to use different
gpios for modem control.
For supporting such cases, this commit adds modem control gpio support
to STM32 UART controller using mctrl_gpio driver.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Link: https://lore.kernel.org/r/20200420170204.24541-3-mani@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The SUPPORT_SYSRQ ifdeffery is not nice as:
- May create misunderstanding about sizeof(struct uart_port) between
different objects
- Prevents moving functions from serial_core.h
- Reduces readability (well, it's ifdeffery - it's hard to follow)
In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added.
Initialise it in driver's probe and remove ifdeffery.
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20191213000657.931618-45-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The interrupt clear flag register is a "write 1 to clear" register.
So, only writing ones allows to clear flags:
- Replace buggy stm32_clr_bits() by a simple write to clear error flags
- Replace useless read/modify/write stm32_set_bits() routine by a
simple write to clear TC (transfer complete) flag.
Fixes: 4f01d833fd ("serial: stm32: fix rx error handling")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1574323849-1909-1-git-send-email-fabrice.gasnier@st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.
// <smpl>
@@
expression ret;
struct platform_device *E;
@@
ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);
if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>
While we're here, remove braces on if statements that only have one
statement (manually).
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-45-swboyd@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Select either pinctrl sleep state in suspend function or default state in
resume function.
Signed-off-by: Bich Hemon <bich.hemon@st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Link: https://lore.kernel.org/r/1560433800-12255-4-git-send-email-erwan.leray@st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adds a flush of RX and TX FIFOs, and fixes some errors:
- adds RX FIFO flush in startup fonction
- removes the useless transmitter enabling in startup fonction
(e.g. receiver only, see Documentation/serial/driver)
- configures FIFO threshold before enabling it, rather than after
- flushes both TX and RX in set_termios function
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adds the support of RX FIFO threshold in order to improve the RX FIFO
management.
This is done by enabling fifo threshold interrupt, instead of relying
on rx empty/fifo not full irq. That basically generates one irq/char
currently. With this patch:
- RXCFG is set to half fifo size (e.g. 16/2 = 8 data for a 16 data depth
FIFO)
- irq rate may be reduced by up to 1/RXCFG, e.g. 1 over 8 with current
RXCFG setting.
- Receiver timeout is used to gather chars when FIFO threshold isn't
reached.
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adds the support of TX FIFO threshold in order to improve the TX FIFO
management:
- TX FIFO threshold irq enabling (instead of relying on tx empty / fifo
not full irq that generates one irq/char)
- TXCFG is set to half fifo size (e.g. 16/2 = 8 data for a 16 data depth
FIFO)
- irq rate may be reduced by up to 1/TXCFG, e.g. 1 over 8 with current
TXCFG setting.
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Improves PIO transmission:
- Replaces the FIFO filling per character by a filling per blocks of
characters, which provides better performances
- Replaces the active waiting loop by TX empty interrupt dynamic handling.
TXE interrupt is now enabled when data has to be sent (ie when
uart_circ is not empty), and inhibited when there is no more data to
send (ie when uart_circ is empty).
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support of RX timeout interrupts to limit the number of interrupts.
RX timeout is a number of bits (baud clock cycles) without
transmission seen in the receiver. One character is used as an arbitrary
RX timeout value.
If parity is enabled, the number of bits has to include parity bit.
Signed-off-by: Gerald Baeza <gerald.baeza@st.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit c70669ecef as it
breaks the build.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Bich Hemon <bich.hemon@st.com>
Cc: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove spin_lock_irqsave in stm32_config_rs485, it cause recursive locking.
Already locked in uart_set_rs485_config.
Fixes: 1bcda09d29 ("serial: stm32: add support for RS485 hardware control mode")
Signed-off-by: Borut Seljak <borut.seljak@t-2.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix sparse warning:
drivers/tty/serial/stm32-usart.c:603:14: warning:
symbol 'stm32_get_databits' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
