[PATCH v3 07/15] can: kvaser_usb_leaf: Set Warning state even without bus errors

[Jimmy Assarsson <extja@kvaser.com>]

From: Anssi Hannula <anssi.hannula@bitwise.fi>

kvaser_usb_leaf_rx_error_update_can_state() sets error state according
to error counters when the hardware does not indicate a specific state
directly.

However, this is currently gated behind a check for
M16C_STATE_BUS_ERROR which does not always seem to be set when error
counters are increasing, and may not be set when error counters are
decreasing.

This causes the CAN_STATE_ERROR_WARNING state to not be set in some
cases even when appropriate.

Change the code to set error state from counters even without
M16C_STATE_BUS_ERROR.

The Error-Passive case seems superfluous as it is already set via
M16C_STATE_BUS_PASSIVE flag above, but it is kept for now.

Tested with 0bfd:0124 Kvaser Mini PCI Express 2xHS FW 4.18.778.

Cc: stable@vger.kernel.org
Fixes: 080f40a6fa28 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
Tested-by: Jimmy Assarsson <extja@kvaser.com>
Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Signed-off-by: Jimmy Assarsson <extja@kvaser.com>
---
Changes in v3:
 - Rebased on 1d5eeda23f36 ("can: kvaser_usb: advertise timestamping capabilities and add ioctl support")
 - Add stable to CC
 - Add S-o-b

Changes in v2:
  - Rebased on b3b6df2c56d8 ("can: kvaser_usb: kvaser_usb_leaf: fix bittiming limits")

 .../net/can/usb/kvaser_usb/kvaser_usb_leaf.c  | 20 ++++++++-----------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
index cd5b67f48534..b4acd9427967 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
@@ -961,20 +961,16 @@ kvaser_usb_leaf_rx_error_update_can_state(struct kvaser_usb_net_priv *priv,
 		new_state = CAN_STATE_BUS_OFF;
 	} else if (es->status & M16C_STATE_BUS_PASSIVE) {
 		new_state = CAN_STATE_ERROR_PASSIVE;
-	} else if (es->status & M16C_STATE_BUS_ERROR) {
+	} else if ((es->status & M16C_STATE_BUS_ERROR) &&
+		   cur_state >= CAN_STATE_BUS_OFF) {
 		/* Guard against spurious error events after a busoff */
-		if (cur_state < CAN_STATE_BUS_OFF) {
-			if (es->txerr >= 128 || es->rxerr >= 128)
-				new_state = CAN_STATE_ERROR_PASSIVE;
-			else if (es->txerr >= 96 || es->rxerr >= 96)
-				new_state = CAN_STATE_ERROR_WARNING;
-			else if (cur_state > CAN_STATE_ERROR_ACTIVE)
-				new_state = CAN_STATE_ERROR_ACTIVE;
-		}
-	}
-
-	if (!es->status)
+	} else if (es->txerr >= 128 || es->rxerr >= 128) {
+		new_state = CAN_STATE_ERROR_PASSIVE;
+	} else if (es->txerr >= 96 || es->rxerr >= 96) {
+		new_state = CAN_STATE_ERROR_WARNING;
+	} else {
 		new_state = CAN_STATE_ERROR_ACTIVE;
+	}
 
 	if (new_state != cur_state) {
 		tx_state = (es->txerr >= es->rxerr) ? new_state : 0;
-- 
2.37.3