There is a special register that shows interrupt status by source. In
particular case the source can be a combination of DMA Tx, DMA Rx, and UART.
Read the register and call the handlers only for sources that request an
interrupt.
Fixes: 6ede6dcd87aa ("serial: 8250_mid: add support for DMA engine handling from UART MMIO")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_mid.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_mid.c b/drivers/tty/serial/8250/8250_mid.c
index 7aa6ef8..ed48988 100644
--- a/drivers/tty/serial/8250/8250_mid.c
+++ b/drivers/tty/serial/8250/8250_mid.c
@@ -25,6 +25,7 @@
#define PCI_DEVICE_ID_INTEL_DNV_UART 0x19d8
/* Intel MID Specific registers */
+#define INTEL_MID_UART_DNV_FISR 0x08
#define INTEL_MID_UART_PS 0x30
#define INTEL_MID_UART_MUL 0x34
#define INTEL_MID_UART_DIV 0x38
@@ -90,16 +91,16 @@ static int tng_setup(struct mid8250 *mid, struct uart_port *p)
static int dnv_handle_irq(struct uart_port *p)
{
struct mid8250 *mid = p->private_data;
- int ret;
-
- ret = hsu_dma_irq(&mid->dma_chip, 0);
- ret |= hsu_dma_irq(&mid->dma_chip, 1);
-
- /* For now, letting the HW generate separate interrupt for the UART */
- if (ret)
- return ret;
-
- return serial8250_handle_irq(p, serial_port_in(p, UART_IIR));
+ unsigned int fisr = serial_port_in(p, INTEL_MID_UART_DNV_FISR);
+ int ret = IRQ_NONE;
+
+ if (fisr & BIT(2))
+ ret |= hsu_dma_irq(&mid->dma_chip, 1);
+ if (fisr & BIT(1))
+ ret |= hsu_dma_irq(&mid->dma_chip, 0);
+ if (fisr & BIT(0))
+ ret |= serial8250_handle_irq(p, serial_port_in(p, UART_IIR));
+ return ret;
}
#define DNV_DMA_CHAN_OFFSET 0x80
--
2.8.0.rc3
--
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