Subject: [PATCH] tty/serial: at91: BUG: disable interrupts when !UART_ENABLE_MS()

From: [email-masked] (Nicolas Ferre)
Date: Fri, 5 Sep 2014 11:15:26 +0200

On 03/09/2014 18:09, Richard Genoud :
> In set_termios(), interrupts where not disabled if UART_ENABLE_MS() was
> false.
> 
> Tested on at91sam9g35.
> 
> CC: stable at vger.kernel.org # >= 3.16
> 
> Signed-off-by: Richard Genoud <[email-masked]>
> ---
>  drivers/tty/serial/atmel_serial.c | 43 ++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 42 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 7b63677475c1..d7d4584549a5 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -527,6 +527,45 @@ static void atmel_enable_ms(struct uart_port *port)
>  }
>  
>  /*
> + * Disable modem status interrupts
> + */
> +static void atmel_disable_ms(struct uart_port *port)
> +{
> +	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> +	uint32_t idr = 0;
> +
> +	/*
> +	 * Interrupt should not be disabled twice
> +	 */
> +	if (!atmel_port->ms_irq_enabled)
> +		return;
> +
> +	atmel_port->ms_irq_enabled = false;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_CTS] >= 0)
> +		disable_irq(atmel_port->gpio_irq[UART_GPIO_CTS]);
> +	else
> +		idr |= ATMEL_US_CTSIC;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_DSR] >= 0)
> +		disable_irq(atmel_port->gpio_irq[UART_GPIO_DSR]);
> +	else
> +		idr |= ATMEL_US_DSRIC;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_RI] >= 0)
> +		disable_irq(atmel_port->gpio_irq[UART_GPIO_RI]);
> +	else
> +		idr |= ATMEL_US_RIIC;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_DCD] >= 0)
> +		disable_irq(atmel_port->gpio_irq[UART_GPIO_DCD]);
> +	else
> +		idr |= ATMEL_US_DCDIC;
> +
> +	UART_PUT_IDR(port, idr);
> +}
> +
> +/*
>   * Control the transmission of a break signal
>   */
>  static void atmel_break_ctl(struct uart_port *port, int break_state)
> @@ -1993,7 +2032,9 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
>  
>  	/* CTS flow-control and modem-status interrupts */
>  	if (UART_ENABLE_MS(port, termios->c_cflag))
> -		port->ops->enable_ms(port);
> +		atmel_enable_ms(port);
> +	else
> +		atmel_disable_ms(port);
>  
>  	spin_unlock_irqrestore(&port->lock, flags);
>  }

Richard,

Indeed it seems needed:

Acked-by: Nicolas Ferre <[email-masked]>

But BTW, I see just below a call to the atmel_enable_ms() function in
atmel_set_ldisc(). My question is, shouldn't we also add this
atmel_disable_ms() in the alternative that disables the PPS in this
ldisc function?

Thanks, bye,
-- 
Nicolas Ferre