[PATCH v2 3/3] serial: 8250_mid: Read RX buffer on RX DMA timeout for DNV

From: Chuah Kim Tatt
Date: Wed Jun 15 2016 - 01:46:09 EST


From: "Chuah, Kim Tatt" <kim.tatt.chuah@xxxxxxxxx>

In DNV, when RX DMA is used and number of bytes received is less than
transfer size, only RX DMA timeout interrupt is sent. When this happens,
read the RX buffer.

Signed-off-by: Chuah, Kim Tatt <kim.tatt.chuah@xxxxxxxxx>
---
drivers/tty/serial/8250/8250_mid.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mid.c b/drivers/tty/serial/8250/8250_mid.c
index b218ff5..339de9c 100644
--- a/drivers/tty/serial/8250/8250_mid.c
+++ b/drivers/tty/serial/8250/8250_mid.c
@@ -96,6 +96,7 @@ 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;
+ struct uart_8250_port *up = up_to_u8250p(p);
unsigned int fisr = serial_port_in(p, INTEL_MID_UART_DNV_FISR);
u32 status;
int ret = IRQ_NONE;
@@ -103,9 +104,10 @@ static int dnv_handle_irq(struct uart_port *p)

if (fisr & BIT(2)) {
err = hsu_dma_get_status(&mid->dma_chip, 1, &status);
- if (err > 0)
+ if (err > 0) {
+ serial8250_rx_dma_flush(up);
ret |= IRQ_HANDLED;
- else if (err == 0)
+ } else if (err == 0)
ret |= hsu_dma_do_irq(&mid->dma_chip, 1, status);
}
if (fisr & BIT(1)) {
--
1.9.1