tty: xuartps: Refactor IRQ handling
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.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 5da1c51..a0039cb 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -126,6 +126,10 @@
#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
@@ -272,7 +276,8 @@
*/
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 +585,12 @@
{
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);
}
@@ -820,10 +828,7 @@
}
/* 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);
return 0;
}