Re: [PATCH LINUX v3 08/10] tty: xuartps: Move RX path into helper function
From: Peter Hurley <hidden>
Date: 2015-12-05 17:40:13
Also in:
linux-arm-kernel, lkml
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 <redacted> 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().
quoted hunk ↗ jump to hunk
Signed-off-by: Soren Brinkmann <redacted> --- 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.
quoted hunk ↗ jump to hunk
- - 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) {