On 11/21/2015 09:59 PM, Soren Brinkmann wrote:
> Move RX-related IRQ handling into a helper function.
Fixes a problem where every char received after a parity or frame error
in the current isr will also be tagged as a parity or frame error.
Reviewed-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
NB: the sysrq problem in cdns_uart_isr() with needing to drop the
locks is because cdns_uart_console_write() tries to take the port->lock.
The 8250 driver handles this problem by not trying to take the
port->lock if port->sysrq is non-zero. See serial8250_console_write().
> Signed-off-by: Soren Brinkmann <soren.brinkmann@xxxxxxxxxx>
> ---
> drivers/tty/serial/xilinx_uartps.c | 50 +++++++++++++++++++++-----------------
> 1 file changed, 28 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
> index f3ac69387b0a..db9e23eaf300 100644
> --- a/drivers/tty/serial/xilinx_uartps.c
> +++ b/drivers/tty/serial/xilinx_uartps.c
> @@ -172,28 +172,8 @@ struct cdns_uart {
> #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
> clk_rate_change_nb);
>
> -/**
> - * cdns_uart_isr - Interrupt handler
> - * @irq: Irq number
> - * @dev_id: Id of the port
> - *
> - * Return: IRQHANDLED
> - */
> -static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
> +static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus)
> {
> - struct uart_port *port = (struct uart_port *)dev_id;
> - unsigned long flags;
> - unsigned int isrstatus, numbytes;
> - unsigned int data;
> - char status = TTY_NORMAL;
See, the previous code never reset the status back to TTY_NORMAL after any other
status.
> -
> - spin_lock_irqsave(&port->lock, flags);
> -
> - /* Read the interrupt status register to determine which
> - * interrupt(s) is/are active.
> - */
> - isrstatus = readl(port->membase + CDNS_UART_ISR_OFFSET);
> -
> /*
> * There is no hardware break detection, so we interpret framing
> * error with all-zeros data as a break sequence. Most of the time,
> @@ -223,6 +203,9 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
> /* Receive Timeout Interrupt */
> while (!(readl(port->membase + CDNS_UART_SR_OFFSET) &
> CDNS_UART_SR_RXEMPTY)) {
> + u32 data;
> + char status = TTY_NORMAL;
> +
> data = readl(port->membase + CDNS_UART_FIFO_OFFSET);
>
> /* Non-NULL byte after BREAK is garbage (99%) */
> @@ -263,10 +246,33 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
> }
>
> uart_insert_char(port, isrstatus, CDNS_UART_IXR_OVERRUN,
> - data, status);
> + data, status);
> }
> tty_flip_buffer_push(&port->state->port);
> }
> +}
> +
> +/**
> + * cdns_uart_isr - Interrupt handler
> + * @irq: Irq number
> + * @dev_id: Id of the port
> + *
> + * Return: IRQHANDLED
> + */
> +static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
> +{
> + struct uart_port *port = (struct uart_port *)dev_id;
> + unsigned long flags;
> + unsigned int isrstatus, numbytes;
> +
> + spin_lock_irqsave(&port->lock, flags);
> +
> + /* Read the interrupt status register to determine which
> + * interrupt(s) is/are active.
> + */
> + isrstatus = readl(port->membase + CDNS_UART_ISR_OFFSET);
> +
> + cdns_uart_handle_rx(port, isrstatus);
>
> /* Dispatch an appropriate handler */
> if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY) {
>
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