[ Upstream commit d3d079bde07e1b7deaeb57506dc0b86010121d17 ]
When sending x_char in stm32_usart_transmit_chars(), driver can overwrite
the value of TDR register by the value of x_char. If this happens, the
previous value that was present in TDR register will not be sent through
uart.
This code checks if the previous value in TDR register is sent before
writing the x_char value into register.
Fixes: 48a6092fb4 ("serial: stm32-usart: Add STM32 USART Driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220111164441.6178-2-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e359b4411c2836cf87c8776682d1b594635570de ]
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 ad7676812437 ("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: ad7676812437 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3db1d52466dc11dca4e47ef12a6e6e97f846af62 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9f77d19207a0e8ba814c8ceb22e90ce7cb2aef64 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 315e2d8a125ad77a1bc28f621162713f3e7aef48 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 436c97936001776f16153771ee887f125443e974 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 12761869f0efa524348e2ae31827fd52eebf3f0d ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ad7676812437a00a4c6be155fc17926069f99084 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 25a8e7611da5513b388165661b17173c26e12c04 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f264c6f6aece81a9f8fbdf912b20bd3feb476a7a ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 87fd0741d6dcf63ebdb14050c2b921ae14c7f307 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.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>
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>
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>
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>
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>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Checks the returned values of platform_get_irq() for both required
"event" and optional "wakeup" IRQs during probe. This allows the driver
probe to be deferred if needed.
Removes redundant checks for 'cfg.has_wakeup'.
Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adds a check on the Transmission Complete bit status before closing the
com port. Prevents the port closure before the end of the transmission.
TC poll loop is moved from stm32_tx_dma_complete to stm32_shutdown
routine, in order to check TC before shutdown in both dma and
PIO tx modes.
TC clear is added in stm32_transmit_char routine, in order to be cleared
before transmitting in both dma and PIO tx modes.
Fixes: 3489187204 ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Disables the tx irq when the transmission is ended and updates stop_tx
conditions for code cleanup.
Fixes: 48a6092fb4 ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- Fixes a rx data error when data length < 8 bits and parity is enabled.
RDR register MSB is used for parity bit reception.
- Adds a mask to ignore MSB when data is get from RDR.
Fixes: 3489187204 ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- Fixes parity and framing error bit by clearing parity and framing error
flag. The current implementation doesn't clear the error bits when an
error is detected.
- Fixes the incorrect name of framing error clearing flag in header file.
- Fixes misalignement between data frame and errors status. The status
read for "n" frame was the status of "n+1" frame".
- Fixes break detection was not triggered by the expected register.
Fixes: 48a6092fb4 ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
STM32 supports either:
- 8 and 9 bits word length (including parity bit) for stm32f4 compatible
devices
- 7, 8 and 9 bits word length (including parity bit) for stm32f7 and
stm32h7 compatible devices.
As a consequence STM32 supports the following termios configurations:
- CS7 with parity bit, and CS8 (with or without parity bit) for stm32f4
compatible devices.
- CS6 with parity bit, CS7 and CS8 (with or without parity bit) for
stm32f7 and stm32h7 compatible devices.
This patch is fixing word length by configuring correctly the SoC with
supported configurations.
Fixes: ada8618ff3 ("serial: stm32: adding support for stm32f7")
Signed-off-by: Erwan Le Ray <erwan.leray@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
