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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2024-04-17 12:03:27 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-04-17 14:26:45 +0300
commit13c785323b36b845300b256d0e5963c3727667d7 (patch)
treeddba327a81f987725ab336b1c67f8d689cd24442 /drivers/tty
parent1aa4ad4eb695bac1b0a7ba542a16d6833c9c8dd8 (diff)
downloadlinux-13c785323b36b845300b256d0e5963c3727667d7.tar.xz
serial: stm32: Return IRQ_NONE in the ISR if no handling happend
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: 48a6092fb41f ("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>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/stm32-usart.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 58d169e5c1db..d60cbac69194 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -861,6 +861,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
u32 sr;
unsigned int size;
+ irqreturn_t ret = IRQ_NONE;
sr = readl_relaxed(port->membase + ofs->isr);
@@ -869,11 +870,14 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
(sr & USART_SR_TC)) {
stm32_usart_tc_interrupt_disable(port);
stm32_usart_rs485_rts_disable(port);
+ ret = IRQ_HANDLED;
}
- if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
+ if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) {
writel_relaxed(USART_ICR_RTOCF,
port->membase + ofs->icr);
+ ret = IRQ_HANDLED;
+ }
if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) {
/* Clear wake up flag and disable wake up interrupt */
@@ -882,6 +886,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
pm_wakeup_event(tport->tty->dev, 0);
+ ret = IRQ_HANDLED;
}
/*
@@ -896,6 +901,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
uart_unlock_and_check_sysrq(port);
if (size)
tty_flip_buffer_push(tport);
+ ret = IRQ_HANDLED;
}
}
@@ -903,6 +909,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
uart_port_lock(port);
stm32_usart_transmit_chars(port);
uart_port_unlock(port);
+ ret = IRQ_HANDLED;
}
/* Receiver timeout irq for DMA RX */
@@ -912,9 +919,10 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
uart_unlock_and_check_sysrq(port);
if (size)
tty_flip_buffer_push(tport);
+ ret = IRQ_HANDLED;
}
- return IRQ_HANDLED;
+ return ret;
}
static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)