can: xilinx_can: only report warning and passive states on state changes

The xilinx_can driver currently increments error-warning and
error-passive statistics on every error interrupt regardless of whether
the interface was already in the same state. Similarly, the error frame
sent on error interrupts is always sent with
CAN_ERR_CRTL_(RX|TX)_(PASSIVE|WARNING) bit set.

To make the error-warning and error-passive statistics more useful, add
a check to only set the error state when the state has actually been
changed.

Tested with the integrated CAN on Zynq-7000 SoC.

Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
index 545f69476866cfa3160e2288cde46faab75b4b52..32e49acd4ebd72e8d17fca6d686f8a1eccb5a13d 100644 (file)
--- a/drivers/net/can/xilinx_can.c
+++ b/drivers/net/can/xilinx_can.c
@@ -703,7 +703,8 @@ static void xcan_err_interrupt(struct net_device *ndev, u32 isr)
        } else {
                enum can_state new_state = xcan_current_error_state(ndev);
 
-               xcan_set_error_state(ndev, new_state, skb ? cf : NULL);
+               if (new_state != priv->can.state)
+                       xcan_set_error_state(ndev, new_state, skb ? cf : NULL);
        }
 
        /* Check for Arbitration lost interrupt */