can: sun4i: handle overrun in RX FIFO

SUN4Is CAN IP has a 64 byte deep FIFO buffer. If the buffer is not
drained fast enough (overrun) it's getting mangled. Already received
frames are dropped - the data can't be restored.

Signed-off-by: Gerhard Bertelsmann <info@gerhard-bertelsmann.de>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/sun4i_can.c b/drivers/net/can/sun4i_can.c
index b0c8085..1ac2090 100644 (file)
--- a/drivers/net/can/sun4i_can.c
+++ b/drivers/net/can/sun4i_can.c
@@ -539,6 +539,13 @@ static int sun4i_can_err(struct net_device *dev, u8 isrc, u8 status)
                }
                stats->rx_over_errors++;
                stats->rx_errors++;
+
+               /* reset the CAN IP by entering reset mode
+                * ignoring timeout error
+                */
+               set_reset_mode(dev);
+               set_normal_mode(dev);
+
                /* clear bit */
                sun4i_can_write_cmdreg(priv, SUN4I_CMD_CLEAR_OR_FLAG);
        }
@@ -653,8 +660,9 @@ static irqreturn_t sun4i_can_interrupt(int irq, void *dev_id)
                        netif_wake_queue(dev);
                        can_led_event(dev, CAN_LED_EVENT_TX);
                }
-               if (isrc & SUN4I_INT_RBUF_VLD) {
-                       /* receive interrupt */
+               if ((isrc & SUN4I_INT_RBUF_VLD) &&
+                   !(isrc & SUN4I_INT_DATA_OR)) {
+                       /* receive interrupt - don't read if overrun occurred */
                        while (status & SUN4I_STA_RBUF_RDY) {
                                /* RX buffer is not empty */
                                sun4i_can_rx(dev);