serial: stm32: Return IRQ_NONE in the ISR if no handling happend
commit13c785323b
upstream. If there is a stuck irq that the handler doesn't address, returning IRQ_HANDLED unconditionally makes it impossible for the irq core to detect the problem and disable the irq. So only return IRQ_HANDLED if an event was handled. A stuck irq is still problematic, but with this change at least it only makes the UART nonfunctional instead of occupying the (usually only) CPU by 100% and so stall the whole machine. Fixes:48a6092fb4
("serial: stm32-usart: Add STM32 USART Driver") Cc: stable@vger.kernel.org Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/5f92603d0dfd8a5b8014b2b10a902d91e0bb881f.1713344161.git.u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -857,6 +857,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
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const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
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u32 sr;
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unsigned int size;
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irqreturn_t ret = IRQ_NONE;
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sr = readl_relaxed(port->membase + ofs->isr);
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@ -865,11 +866,14 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
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(sr & USART_SR_TC)) {
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stm32_usart_tc_interrupt_disable(port);
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stm32_usart_rs485_rts_disable(port);
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ret = IRQ_HANDLED;
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}
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if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
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if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) {
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writel_relaxed(USART_ICR_RTOCF,
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port->membase + ofs->icr);
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ret = IRQ_HANDLED;
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}
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if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) {
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/* Clear wake up flag and disable wake up interrupt */
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@ -878,6 +882,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
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stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
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if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
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pm_wakeup_event(tport->tty->dev, 0);
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ret = IRQ_HANDLED;
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}
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/*
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@ -892,6 +897,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
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uart_unlock_and_check_sysrq(port);
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if (size)
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tty_flip_buffer_push(tport);
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ret = IRQ_HANDLED;
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}
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}
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@ -899,6 +905,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
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uart_port_lock(port);
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stm32_usart_transmit_chars(port);
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uart_port_unlock(port);
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ret = IRQ_HANDLED;
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}
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/* Receiver timeout irq for DMA RX */
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@ -908,9 +915,10 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
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uart_unlock_and_check_sysrq(port);
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if (size)
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tty_flip_buffer_push(tport);
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ret = IRQ_HANDLED;
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}
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return IRQ_HANDLED;
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return ret;
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}
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static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)
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