Commit 3f6c02fa authored by Marek Vasut's avatar Marek Vasut Committed by Greg Kroah-Hartman
Browse files

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: e359b441 ("serial: stm32: fix threaded interrupt handling")
Reviewed-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Valentin Caron <valentin.caron@foss.st.com> # V3
Signed-off-by: default avatarMarek Vasut <marex@denx.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230120160332.57930-1-marex@denx.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2241ab53

drivers/tty/serial/stm32-usart.c

+5 −28
Original line number Diff line number Diff line
@@ -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);