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Subject[PATCH 4.4 53/56] can: sun4i: handle overrun in RX FIFO
Date
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gerhard Bertelsmann <info@gerhard-bertelsmann.de>

commit 4dcf924c2eda0c47a5c53b7703e3dc65ddaa8920 upstream.

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>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/can/sun4i_can.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

--- 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_devi
}
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(i
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);

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