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path: root/drivers/tty/serial/stm32-usart.c
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2022-09-30serial: stm32: Fix unused-variable warningRen Zhijie1-3/+3
If CONFIG_SERIAL_EARLYCON and CONFIG_OF are both not set, gcc warns about unused variable: drivers/tty/serial/stm32-usart.c:83:32: error: ‘stm32h7_info’ defined but not used [-Werror=unused-variable] static struct stm32_usart_info stm32h7_info = { ^~~~~~~~~~~~ drivers/tty/serial/stm32-usart.c:61:32: error: ‘stm32f7_info’ defined but not used [-Werror=unused-variable] static struct stm32_usart_info stm32f7_info = { ^~~~~~~~~~~~ drivers/tty/serial/stm32-usart.c:40:32: error: ‘stm32f4_info’ defined but not used [-Werror=unused-variable] static struct stm32_usart_info stm32f4_info = { ^~~~~~~~~~~~ cc1: all warnings being treated as errors Mark these variables as __maybe_unused to fix this. Fixes: c7039ce904c0 ("serial: stm32: make info structs static to avoid sparse warnings") Signed-off-by: Ren Zhijie <renzhijie2@huawei.com> Link: https://lore.kernel.org/r/20220926025826.44145-1-renzhijie2@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-22serial: stm32: Deassert Transmit Enable on ->rs485_config()Lukas Wunner1-47/+53
The STM32 USART can control RS-485 Transmit Enable in hardware. Since commit 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control"), it can alternatively be controlled in software. That was done to allow RS-485 even if the RTS pin is unavailable because it's pinmuxed to a different function. However the commit neglected to deassert Transmit Enable upon invocation of the ->rs485_config() callback. Fix it. Avoid forward declarations by moving stm32_usart_tx_empty(), stm32_usart_rs485_rts_enable() and stm32_usart_rs485_rts_disable() further up in the driver. Fixes: 7df5081cbf5e ("serial: stm32: Add RS485 RTS GPIO control") Cc: stable@vger.kernel.org # v5.9+ Cc: Marek Vasut <marex@denx.de> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/6059eab35dba394468335ef640df8b0050fd9dbd.1662886616.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-30serial: Make ->set_termios() old ktermios constIlpo Järvinen1-1/+1
There should be no reason to adjust old ktermios which is going to get discarded anyway. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220816115739.10928-7-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-08Merge tag 'tty-6.0-rc1' of ↵Linus Torvalds1-1/+78
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 changes for 6.0-rc1. It was delayed from last week as I wanted to make sure the last commit here got some good testing in linux-next and elsewhere as it seemed to show up only late in testing for some reason. Nothing major here, just lots of cleanups from Jiri and Ilpo to make the tty core cleaner (Jiri) and the rs485 code simpler to use (Ilpo). Also included in here is the obligatory n_gsm updates from Daniel Starke and lots of tiny driver updates and minor fixes and tweaks for other smaller serial drivers. All of these have been in linux-next for a while with no reported problems" * tag 'tty-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (186 commits) tty: serial: qcom-geni-serial: Fix %lu -> %u in print statements tty: amiserial: Fix comment typo tty: serial: document uart_get_console() tty: serial: serial_core, reformat kernel-doc for functions Documentation: serial: link uart_ops properly Documentation: serial: move GPIO kernel-doc to the functions Documentation: serial: dedup kernel-doc for uart functions Documentation: serial: move uart_ops documentation to the struct dt-bindings: serial: snps-dw-apb-uart: Document Rockchip RV1126 serial: mvebu-uart: uart2 error bits clearing tty: serial: fsl_lpuart: correct the count of break characters serial: stm32: make info structs static to avoid sparse warnings serial: fsl_lpuart: zero out parity bit in CS7 mode tty: serial: qcom-geni-serial: Fix get_clk_div_rate() which otherwise could return a sub-optimal clock rate. serial: 8250_bcm2835aux: Add missing clk_disable_unprepare() tty: vt: initialize unicode screen buffer serial: remove VR41XX serial driver serial: 8250: lpc18xx: Remove redundant sanity check for RS485 flags serial: 8250_dwlib: remove redundant sanity check for RS485 flags dt_bindings: rs485: Correct delay values ...
2022-07-28serial: stm32: make info structs static to avoid sparse warningsBen Dooks1-0/+69
The info structs are local only to the stm32-usart.c driver and are triggering sparse warnings about being undecalred. Move these into the main driver code and make them static to avoid the following warnings: drivers/tty/serial/stm32-usart.h:42:25: warning: symbol 'stm32f4_info' was not declared. Should it be static? drivers/tty/serial/stm32-usart.h:63:25: warning: symbol 'stm32f7_info' was not declared. Should it be static? drivers/tty/serial/stm32-usart.h:85:25: warning: symbol 'stm32h7_info' was not declared. Should it be static? Signed-off-by: Ben Dooks <ben-linux@fluff.org> Link: https://lore.kernel.org/r/20220721212430.453192-1-ben-linux@fluff.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-08serial: Embed rs485_supported to uart_portIlpo Järvinen1-1/+1
Embed rs485_supported to uart_port to allow serial core to tweak it as needed. Reviewed-by: Lino Sanfilippo <l.sanfilippo@kunbus.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220704094515.6831-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-30serial: stm32: Clear prev values before setting RTS delaysIlpo Järvinen1-0/+2
The code lacks clearing of previous DEAT/DEDT values. Thus, changing values on the fly results in garbage delays tending towards the maximum value as more and more bits are ORed together. (Leaving RS485 mode would have cleared the old values though). Fixes: 1bcda09d2910 ("serial: stm32: add support for RS485 hardware control mode") Cc: stable <stable@kernel.org> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220627150753.34510-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-27serial: take termios_rwsem for ->rs485_config() & pass termios as paramIlpo Järvinen1-1/+1
To be able to alter ADDRB within ->rs485_config(), take termios_rwsem before calling ->rs485_config() and pass termios. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220624204210.11112-5-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-10serial: stm32: Fill in rs485_supportedIlpo Järvinen1-0/+8
Add information on supported serial_rs485 features. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-22-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-19serial: stm32-usart: Correct CSIZE, bits, and parityIlpo Järvinen1-3/+12
Add CSIZE sanitization for unsupported CSIZE configurations. In addition, if parity is asked for but CSx was unsupported, the sensible result is CS8+parity which requires setting USART_CR1_M0 like with 9 bits. Incorrect CSIZE results in miscalculation of the frame bits in tty_get_char_size() or in its predecessor where the roughly the same code is directly within uart_update_timeout(). Fixes: c8a9d043947b (serial: stm32: fix word length configuration) Cc: Erwan Le Ray <erwan.leray@st.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220519081808.3776-9-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-05serial: stm32: Use TC interrupt to deassert GPIO RTS in RS485 modeMarek Vasut1-2/+40
In case the RS485 mode is emulated using GPIO RTS, use the TC interrupt to deassert the GPIO RTS, otherwise the GPIO RTS stays asserted after a transmission ended and the RS485 cannot work. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: Erwan Le Ray <erwan.leray@foss.st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jean Philippe Romain <jean-philippe.romain@foss.st.com> Cc: Valentin Caron <valentin.caron@foss.st.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-stm32@st-md-mailman.stormreply.com To: linux-serial@vger.kernel.org Link: https://lore.kernel.org/r/20220430162845.244655-2-marex@denx.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-05serial: stm32: Factor out GPIO RTS toggling into separate functionMarek Vasut1-21/+38
Pull out the GPIO RTS enable and disable handling into separate function. Limit the scope of GPIO RTS toggling only to GPIO emulated RS485 too. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: Erwan Le Ray <erwan.leray@foss.st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jean Philippe Romain <jean-philippe.romain@foss.st.com> Cc: Valentin Caron <valentin.caron@foss.st.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-stm32@st-md-mailman.stormreply.com To: linux-serial@vger.kernel.org Link: https://lore.kernel.org/r/20220430162845.244655-1-marex@denx.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-22serial: stm32: add earlycon supportValentin Caron1-0/+51
Add early console support in stm32 uart driver. Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com> Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Link: https://lore.kernel.org/r/20220419085330.1178925-4-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-22serial: stm32: add KGDB supportValentin Caron1-2/+35
Add support for KGDB in stm32 serial driver by implementing characters polling callbacks (poll_init, poll_get_char and poll_put_char). Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Signed-off-by: Jean Philippe Romain <jean-philippe.romain@foss.st.com> Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Link: https://lore.kernel.org/r/20220419085330.1178925-3-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-22serial: stm32: remove infinite loop possibility in putchar functionValentin Caron1-3/+9
Rework stm32_usart_console_putchar() function in order to anticipate the case where the character can never be sent. Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Link: https://lore.kernel.org/r/20220419085330.1178925-2-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-15serial: stm32: remove redundant code in rs485_configLino Sanfilippo1-7/+2
In uart_set_rs485_config() the serial core already ensures that only one of both options RTS on send or RTS after send is set. It also assigns the passed serial_rs485 struct to the uart port. So remove the check and the assignment from the drivers rs485_config() function to avoid redundancy. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Link: https://lore.kernel.org/r/20220410104642.32195-4-LinoSanfilippo@gmx.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-03serial: make uart_console_write->putchar()'s character an unsigned charJiri Slaby1-1/+1
Currently, uart_console_write->putchar's second parameter (the character) is of type int. It makes little sense, provided uart_console_write() accepts the input string as "const char *s" and passes its content -- the characters -- to putchar(). So switch the character's type to unsigned char. We don't use char as that is signed on some platforms. That would cause troubles for drivers which (implicitly) cast the char to u16 when writing to the device. Sign extension would happen in that case and the value written would be completely different to the provided char. DZ is an example of such a driver -- on MIPS, it uses u16 for dz_out in dz_console_putchar(). Note we do the char -> uchar conversion implicitly in uart_console_write(). Provided we do not change size of the data type, sign extension does not happen there, so the problem is void. This makes the types consistent and unified with the rest of the uart layer, which uses unsigned char in most places already. One exception is xmit_buf, but that is going to be converted later. Cc: Paul Cercueil <paul@crapouillou.net> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Russell King <linux@armlinux.org.uk> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Nicolas Ferre <nicolas.ferre@microchip.com> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Ludovic Desroches <ludovic.desroches@microchip.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: bcm-kernel-feedback-list@broadcom.com Cc: Alexander Shiyan <shc_work@mail.ru> Cc: Baruch Siach <baruch@tkos.co.il> Cc: "Maciej W. Rozycki" <macro@orcam.me.uk> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Pengutronix Kernel Team <kernel@pengutronix.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: NXP Linux Team <linux-imx@nxp.com> Cc: Karol Gugala <kgugala@antmicro.com> Cc: Mateusz Holenko <mholenko@antmicro.com> Cc: Vladimir Zapolskiy <vz@mleia.com> Cc: Neil Armstrong <narmstrong@baylibre.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: Jerome Brunet <jbrunet@baylibre.com> Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Cc: Taichi Sugaya <sugaya.taichi@socionext.com> Cc: Takao Orito <orito.takao@socionext.com> Cc: Liviu Dudau <liviu.dudau@arm.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: "Andreas Färber" <afaerber@suse.de> Cc: Manivannan Sadhasivam <mani@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Andy Gross <agross@kernel.org> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> Cc: Orson Zhai <orsonzhai@gmail.com> Cc: Baolin Wang <baolin.wang7@gmail.com> Cc: Chunyan Zhang <zhang.lyra@gmail.com> Cc: Patrice Chotard <patrice.chotard@foss.st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Korsgaard <peter@korsgaard.com> Cc: Michal Simek <michal.simek@xilinx.com> Acked-by: Richard Genoud <richard.genoud@gmail.com> [atmel_serial] Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Paul Cercueil <paul@crapouillou.net> Acked-by: Neil Armstrong <narmstrong@baylibre.com> # meson_serial Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220303080831.21783-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-08serial: stm32: enable / disable wake irqs for mcrtl_gpio wakeup sourcesErwan Le Ray1-1/+2
Enable mctrl_gpio wake_irq if device_may_wakeup when usart is suspended, and disable mctrl_gpios wake_irq if device_may_wakeup when usart is resumed. Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20220203171644.12231-3-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-26serial: stm32: fix software flow control transferValentin Caron1-1/+1
x_char is ignored by stm32_usart_start_tx() when xmit buffer is empty. Fix start_tx condition to allow x_char to be sent. Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver") Cc: stable <stable@vger.kernel.org> 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/20220111164441.6178-3-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-26serial: stm32: prevent TDR register overwrite when sending x_charValentin Caron1-0/+12
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: 48a6092fb41f ("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>
2022-01-06serial: stm32: correct loop for dma error handlingValentin Caron1-3/+2
In this error handling, "transmit_chars_dma" function will call "transmit_chars_pio" once per characters. But "transmit_chars_pio" will continue to send characters while xmit buffer is not empty. Remove this useless loop, one call is sufficient. Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Link: https://lore.kernel.org/r/20220104182445.4195-5-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-06serial: stm32: fix flow control transfer in DMA modeValentin Caron1-0/+3
If flow control is enabled, framework will call stop_tx to pause transfer and then call start_tx to resume transfer. Clear USART_CR3_DMAT bit in stop_tx ops to pause DMA transfer. 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/20220104182445.4195-4-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-06serial: stm32: rework TX DMA state conditionValentin Caron1-18/+48
TX DMA state condition is handled by tx_dma_busy boolean. This boolean is set when dma descriptor is requested and reset when dma channel is stopped (dma_terminate). In stm32_usart_serial_remove(), stm32_usart_stop_tx() and stm32_usart_transmit_chars_dma() fallback error case, DMA channel is stopped but tx_dma_busy is not handled. Rework the driver by using two new functions to solve this issue: - stm32_usart_tx_dma_started return true if DMA TX have a descriptor. - stm32_usart_tx_dma_enabled return true if DMAT bit is set. stm32_usart_tx_dma_started uses tx_dma_busy flag to prevent dual DMA transaction at the same time. This flag is set when a DMA transaction begins and is unset when dmaengine_terminate_async function is called. A new DMA transaction cannot be created if this flag is set. Create a new function "stm32_usart_tx_dma_terminate" to be sure the flag is unset after each call of dmaengine_terminate_async. 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/20220104182445.4195-3-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-06serial: stm32: move tx dma terminate DMA to shutdownValentin Caron1-1/+5
Terminate DMA transaction and clear CR3_DMAT when shutdown is requested, instead of when remove is requested. If DMA transfer is not stopped in shutdown ops, driver will fail to start a new DMA transfer after next startup ops. Fixes: 3489187204eb ("serial: stm32: adding dma support") 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/20220104182445.4195-2-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: stm32: push DMA RX data before suspendingErwan Le Ray1-27/+53
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>
2021-10-26serial: stm32: terminate / restart DMA transfer at suspend / resumeErwan Le Ray1-43/+84
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>
2021-10-26serial: stm32: rework RX dma initialization and releaseErwan Le Ray1-28/+41
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>
2021-10-21serial: stm32: update throttle and unthrottle ops for dma modeErwan Le Ray1-4/+33
Disable DMA request line (if enabled) to switch in PIO mode in throttle ops, so the RX data gets queues into the FIFO. The hardware flow control is triggered when the RX FIFO is full. Switch back to DMA mode (re-enable DMA request line) in unthrottle ops. Hardware flow control is stopped when FIFO is not full anymore. 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/20211020150332.10214-4-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21serial: stm32: rework RX over DMAErwan Le Ray1-48/+158
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>
2021-10-21serial: stm32: re-introduce an irq flag condition in usart_receive_charsErwan Le Ray1-8/+13
Re-introduce an irq flag condition in usart_receive_chars. This condition has been deleted by commit 75f4e830fa9c ("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>
2021-08-16serial: stm32: use devm_platform_get_and_ioremap_resource()Tang Bin1-2/+1
Use devm_platform_get_and_ioremap_resource() to simplify code. Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com> Link: https://lore.kernel.org/r/20210814131418.13608-1-tangbin@cmss.chinamobile.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-16serial: stm32: use the defined variable to simplify codeTang Bin1-2/+2
Use the defined variable 'dev' to make the code cleaner. Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com> Link: https://lore.kernel.org/r/20210814124951.30084-1-tangbin@cmss.chinamobile.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-13serial: stm32: fix the conditional expression writingTang Bin1-2/+2
In the function stm32_usart_init_port, intent of the code maybe when irq returns a value of zero, the return should be '-ENODEV'. But the conditional expression '? :' maybe clerical error, it should be '?:' to make '-ENODEV' work. But in fact, as the example in platform.c is * int irq = platform_get_irq(pdev, 0); * if (irq < 0) * return irq; So the return value of zero is unnecessary to check, at last remove the unnecessary '?: -ENODEV'. Co-developed-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com> Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com> Link: https://lore.kernel.org/r/20210811105136.25392-1-tangbin@cmss.chinamobile.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-15tty: make use of tty_get_{char,frame}_sizeJiri Slaby1-31/+1
In the previous patch, we introduced tty_get_char_size() and tty_get_frame_size() for computing character and frame sizes, respectively. Here, we make use of them in various tty drivers where applicable. The stats look nice: 12 insertions, 169 deletions. Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Lin <dtwlin@gmail.com> Cc: Johan Hovold <johan@kernel.org> Cc: Alex Elder <elder@kernel.org> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Andy Gross <agross@kernel.org> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: Oliver Neukum <oneukum@suse.com> Acked-by: Alex Elder <elder@kernel.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20210610090247.2593-4-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-15serial: stm32: defer probe for dma devicesErwan Le Ray1-86/+77
Defer device probe operation when a DMA channel request probe deferral. With this change both DMA channels are acquired before DMA channels are configured. Once no probe deferral is expected, DMAs are configured and any failure in their configuration will make the driver to fallback to interrupt mode as prior this change. 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/20210610100020.2318-1-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-20serial: drop irq-flags initialisationsJohan Hovold1-1/+1
There's no need to initialise irq-flags variables before saving the interrupt state. Drop the redundant initialisations from drivers that got this wrong. Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210519092541.10137-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-22serial: stm32: add FIFO threshold configurationFabrice Gasnier1-6/+47
Add the support for two optional DT properties, to configure RX and TX FIFO thresholds: - rx-threshold - tx-threshold This replaces hard-coded 8 bytes threshold. Keep 8 as the default value if not specified, for backward compatibility. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Changes in v2: Change added properties naming as proposed by Rob Herring. Link: https://lore.kernel.org/r/20210413174015.23011-5-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-22serial: stm32: defer sysrq processingJohan Hovold1-10/+6
Use the uart_unlock_and_check_sysrq() helper to defer sysrq processing until receive processing is done and the port lock has been released. This allows cleaning up the console_write() implementation by not having to work around the recursive sysrq case (by dropping locking completely) and also makes the console code work with PREEMPT_RT by no longer relying on local_irq_save(). Reviewed-by: Valentin Caron<valentin.caron@foss.st.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210416140557.25177-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-22serial: stm32: fix threaded interrupt handlingJohan Hovold1-10/+12
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: 3489187204eb ("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>
2021-04-05tty/serial: Add rx-tx-swap OF option to stm32-usartMartin Devera1-1/+10
STM32 F7/H7 usarts supports RX & TX pin swapping. Add option to turn it on. Tested on STM32MP157. Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: Martin Devera <devik@eaxlabs.cz> Link: https://lore.kernel.org/r/20210328154306.22674-2-devik@eaxlabs.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-23serial: stm32: update wakeup IRQ managementAlexandre Torgue1-21/+11
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>
2021-03-23serial: stm32: clean wakeup handling in serial_suspendErwan Le Ray1-2/+0
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>
2021-03-23serial: stm32: rework wakeup managementErwan Le Ray1-3/+3
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>
2021-03-10serial: stm32: add support for "flush_buffer" opsErwan Le Ray1-0/+14
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>
2021-03-10serial: stm32: fix tx_empty conditionErwan Le Ray1-1/+4
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: 48a6092fb41f ("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>
2021-03-10serial: stm32: add FIFO flush when port is closedErwan Le Ray1-0/+5
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: 64c32eab6603 ("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>
2021-03-10serial: stm32: fix FIFO flush in startup and set_termiosErwan Le Ray1-3/+3
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: 84872dc448fe ("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>
2021-03-10serial: stm32: call stm32_transmit_chars lockedErwan Le Ray1-0/+3
stm32_transmit_chars should be called under lock also in tx DMA callback. Fixes: 3489187204eb ("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>
2021-03-10serial: stm32: fix tx dma completion, release channelErwan Le Ray1-0/+1
This patch add a proper release of dma channels when completing dma tx. Fixes: 3489187204eb ("serial: stm32: adding dma support") Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20210304162308.8984-9-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10serial: stm32: fix a deadlock in set_termiosErwan Le Ray1-6/+6
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: 6cf61b9bd7cc ("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>
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