The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

3f6c02fa712b ("serial: stm32: Merge hard IRQ and threaded IRQ handling into single IRQ handler") 6333a4850621 ("serial: stm32: push DMA RX data before suspending") 6eeb348c8482 ("serial: stm32: terminate / restart DMA transfer at suspend / resume") e0abc903deea ("serial: stm32: rework RX dma initialization and release") d1ec8a2eabe9 ("serial: stm32: update throttle and unthrottle ops for dma mode") 33bb2f6ac308 ("serial: stm32: rework RX over DMA") cc58d0a3f0a4 ("serial: stm32: re-introduce an irq flag condition in usart_receive_chars") 59bd4eedf118 ("serial: stm32: use the defined variable to simplify code") a7770a4bfcf4 ("serial: stm32: defer probe for dma devices") cea37afd28f1 ("serial: stm32: defer sysrq processing") e359b4411c28 ("serial: stm32: fix threaded interrupt handling") 3d530017bef1 ("serial: stm32: update wakeup IRQ management") c0f3332cb5f2 ("serial: stm32: clean wakeup handling in serial_suspend") 1631eeeaf084 ("serial: stm32: rework wakeup management") 9f77d19207a0 ("serial: stm32: add FIFO flush when port is closed") 12761869f0ef ("serial: stm32: fix wake-up flag handling") ad7676812437 ("serial: stm32: fix a deadlock condition with wakeup event") 25a8e7611da5 ("serial: stm32: fix TX and RX FIFO thresholds") f4518a8a75f5 ("serial: stm32: fix startup by enabling usart for reception") 87fd0741d6dc ("serial: stm32: fix probe and remove order for dma")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 3f6c02fa712bd453871877fe1d1969625617471e Mon Sep 17 00:00:00 2001 From: Marek Vasut marex@denx.de Date: Fri, 20 Jan 2023 17:03:32 +0100 Subject: [PATCH] serial: stm32: Merge hard IRQ and threaded IRQ handling into single IRQ handler

Requesting an interrupt with IRQF_ONESHOT will run the primary handler in the hard-IRQ context even in the force-threaded mode. The force-threaded mode is used by PREEMPT_RT in order to avoid acquiring sleeping locks (spinlock_t) in hard-IRQ context. This combination makes it impossible and leads to "sleeping while atomic" warnings.

Use one interrupt handler for both handlers (primary and secondary) and drop the IRQF_ONESHOT flag which is not needed.

Fixes: e359b4411c283 ("serial: stm32: fix threaded interrupt handling") Reviewed-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Tested-by: Valentin Caron valentin.caron@foss.st.com # V3 Signed-off-by: Marek Vasut marex@denx.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230120160332.57930-1-marex@denx.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index a1490033aa16..409e91d6829a 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -797,25 +797,11 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) spin_unlock(&port->lock); }

- if (stm32_usart_rx_dma_enabled(port)) - return IRQ_WAKE_THREAD; - else - return IRQ_HANDLED; -} - -static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr) -{ - struct uart_port *port = ptr; - struct tty_port *tport = &port->state->port; - struct stm32_port *stm32_port = to_stm32_port(port); - unsigned int size; - unsigned long flags; - /* Receiver timeout irq for DMA RX */ - if (!stm32_port->throttled) { - spin_lock_irqsave(&port->lock, flags); + if (stm32_usart_rx_dma_enabled(port) && !stm32_port->throttled) { + spin_lock(&port->lock); size = stm32_usart_receive_chars(port, false); - uart_unlock_and_check_sysrq_irqrestore(port, flags); + uart_unlock_and_check_sysrq(port); if (size) tty_flip_buffer_push(tport); } @@ -1015,10 +1001,8 @@ static int stm32_usart_startup(struct uart_port *port) u32 val; int ret;

- ret = request_threaded_irq(port->irq, stm32_usart_interrupt, - stm32_usart_threaded_interrupt, - IRQF_ONESHOT | IRQF_NO_SUSPEND, - name, port); + ret = request_irq(port->irq, stm32_usart_interrupt, + IRQF_NO_SUSPEND, name, port); if (ret) return ret;

@@ -1601,13 +1585,6 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port, struct dma_slave_config config; int ret;

- /* - * Using DMA and threaded handler for the console could lead to - * deadlocks. - */ - if (uart_console(port)) - return -ENODEV; - stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L, &stm32port->rx_dma_buf, GFP_KERNEL);