The system could deadlock handling RX IRQs when RX-related IRQ
conditions became true while the receiver was disabled. To avoid this,
enable/disable the RX/TX IRQs together with the receiver/transmitter.
Signed-off-by: Soren Brinkmann <soren.brinkm...@xilinx.com>
---
drivers/tty/serial/xilinx_uartps.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/tty/serial/xilinx_uartps.c
b/drivers/tty/serial/xilinx_uartps.c
index 3780d1cf207e..1229bb3a275e 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -126,6 +126,10 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
#define CDNS_UART_IXR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt. */
#define CDNS_UART_IXR_MASK 0x00001FFF /* Valid bit mask */
+#define CDNS_UART_RX_IRQS (CDNS_UART_IXR_PARITY | CDNS_UART_IXR_FRAMING |
\
+ CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_RXTRIG |
\
+ CDNS_UART_IXR_TOUT)
+
/* Goes in read_status_mask for break detection as the HW doesn't do it*/
#define CDNS_UART_IXR_BRK 0x80000000
@@ -169,6 +173,7 @@ struct cdns_uart {
unsigned int baud;
struct notifier_block clk_rate_change_nb;
};
+
#define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
clk_rate_change_nb);
@@ -272,7 +277,8 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
*/
isrstatus = readl(port->membase + CDNS_UART_ISR_OFFSET);
- cdns_uart_handle_rx(port, isrstatus);
+ if (isrstatus & CDNS_UART_RX_IRQS)
+ cdns_uart_handle_rx(port, isrstatus);
/* Dispatch an appropriate handler */
if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY) {
@@ -580,9 +586,12 @@ static void cdns_uart_stop_rx(struct uart_port *port)
{
unsigned int regval;
+ /* Disable RX IRQs */
+ writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IDR_OFFSET);
+
+ /* Disable the receiver */
regval = readl(port->membase + CDNS_UART_CR_OFFSET);
regval |= CDNS_UART_CR_RX_DIS;
- /* Disable the receiver */
writel(regval, port->membase + CDNS_UART_CR_OFFSET);
}
@@ -810,10 +819,7 @@ static int cdns_uart_startup(struct uart_port *port)
port->membase + CDNS_UART_ISR_OFFSET);
/* Set the Interrupt Registers with desired interrupts */
- writel(CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_PARITY |
- CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN |
- CDNS_UART_IXR_RXTRIG | CDNS_UART_IXR_TOUT,
- port->membase + CDNS_UART_IER_OFFSET);
+ writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER_OFFSET);
spin_unlock_irqrestore(&port->lock, flags);
--
2.6.3.3.g9bb996a
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