If we get an exeption interrupt. i.e. UART_IIR_RLSI, stop any ongoing RX DMA
transfer otherwise it might generates more spurious interrupts and make port
unavailable anymore.
As has been seen on Intel Broxton system:
...
[ 168.526281] serial8250: too much work for irq5
[ 168.535908] serial8250: too much work for irq5
[ 173.449464] serial8250_interrupt: 4439 callbacks suppressed
[ 173.455694] serial8250: too much work for irq5
...
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_dma.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index 9d80bb1..b134bec 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -110,6 +110,16 @@ err:
return ret;
}
+static void __dma_rx_stop(struct uart_8250_port *p, struct uart_8250_dma *dma)
+{
+ if (!dma->rx_running)
+ return;
+
+ dmaengine_pause(dma->rxchan);
+ __dma_rx_complete(p);
+ dmaengine_terminate_async(dma->rxchan);
+}
+
int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
{
struct uart_8250_dma *dma = p->dma;
@@ -118,17 +128,14 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
switch (iir & 0x3f) {
case UART_IIR_RLSI:
/* 8250_core handles errors and break interrupts */
+ __dma_rx_stop(p, dma);
return -EIO;
case UART_IIR_RX_TIMEOUT:
/*
* If RCVR FIFO trigger level was not reached, complete the
* transfer and let 8250_core copy the remaining data.
*/
- if (dma->rx_running) {
- dmaengine_pause(dma->rxchan);
- __dma_rx_complete(p);
- dmaengine_terminate_async(dma->rxchan);
- }
+ __dma_rx_stop(p, dma);
return -ETIMEDOUT;
default:
break;
--
2.8.0.rc3
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