From: Anssi Hannula anssi.hannula@bitwise.fi

With 0bfd:0124 Kvaser Mini PCI Express 2xHS FW 4.18.778 it was observed that if the device was bus-off when stopped, at next start (either via interface down/up or manual bus-off restart) the initial CMD_CHIP_STATE_EVENT received just after CMD_START_CHIP_REPLY will have the M16C_STATE_BUS_OFF bit still set, causing the interface to immediately go bus-off again.

The bit seems to internally clear quickly afterwards but we do not get another CMD_CHIP_STATE_EVENT.

Fix the issue by ignoring any initial bus-off state until we see at least one bus-on state. Also, poll the state periodically until that occurs.

It is possible we lose one actual immediately occurring bus-off event here in which case the HW will auto-recover and we see the recovery event. We will then catch the next bus-off event, if any.

This issue did not reproduce with 0bfd:0017 Kvaser Memorator Professional HS/HS FW 2.0.50.

Cc: stable@vger.kernel.org Fixes: 71873a9b38d1 ("can: kvaser_usb: Add support for more Kvaser Leaf v2 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 Link: https://lore.kernel.org/all/20220903182559.189-12-extja@kvaser.com Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- .../net/can/usb/kvaser_usb/kvaser_usb_leaf.c | 31 ++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-)

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 4f9c76f4d0da..f8a12a285050 100644 --- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c +++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c @@ -427,6 +427,9 @@ struct kvaser_usb_net_leaf_priv { struct kvaser_usb_net_priv *net;

struct delayed_work chip_state_req_work; + + /* started but not reported as bus-on yet */ + bool joining_bus; };

static const struct can_bittiming_const kvaser_usb_leaf_m16c_bittiming_const = { @@ -966,6 +969,7 @@ kvaser_usb_leaf_rx_error_update_can_state(struct kvaser_usb_net_priv *priv, const struct kvaser_usb_err_summary *es, struct can_frame *cf) { + struct kvaser_usb_net_leaf_priv *leaf = priv->sub_priv; struct kvaser_usb *dev = priv->dev; struct net_device_stats *stats = &priv->netdev->stats; enum can_state cur_state, new_state, tx_state, rx_state; @@ -990,6 +994,22 @@ kvaser_usb_leaf_rx_error_update_can_state(struct kvaser_usb_net_priv *priv, new_state = CAN_STATE_ERROR_ACTIVE; }

+ /* 0bfd:0124 FW 4.18.778 was observed to send the initial + * CMD_CHIP_STATE_EVENT after CMD_START_CHIP with M16C_STATE_BUS_OFF + * bit set if the channel was bus-off when it was last stopped (even + * across chip resets). This bit will clear shortly afterwards, without + * triggering a second unsolicited chip state event. + * Ignore this initial bus-off. + */ + if (leaf->joining_bus) { + if (new_state == CAN_STATE_BUS_OFF) { + netdev_dbg(priv->netdev, "ignoring bus-off during startup"); + new_state = cur_state; + } else { + leaf->joining_bus = false; + } + } + if (new_state != cur_state) { tx_state = (es->txerr >= es->rxerr) ? new_state : 0; rx_state = (es->txerr <= es->rxerr) ? new_state : 0; @@ -1065,9 +1085,12 @@ static void kvaser_usb_leaf_rx_error(const struct kvaser_usb *dev,

/* If there are errors, request status updates periodically as we do * not get automatic notifications of improved state. + * Also request updates if we saw a stale BUS_OFF during startup + * (joining_bus). */ if (new_state < CAN_STATE_BUS_OFF && - (es->rxerr || es->txerr || new_state == CAN_STATE_ERROR_PASSIVE)) + (es->rxerr || es->txerr || new_state == CAN_STATE_ERROR_PASSIVE || + leaf->joining_bus)) schedule_delayed_work(&leaf->chip_state_req_work, msecs_to_jiffies(500));

@@ -1587,8 +1610,11 @@ static int kvaser_usb_leaf_set_opt_mode(const struct kvaser_usb_net_priv *priv)

static int kvaser_usb_leaf_start_chip(struct kvaser_usb_net_priv *priv) { + struct kvaser_usb_net_leaf_priv *leaf = priv->sub_priv; int err;

+ leaf->joining_bus = true; + reinit_completion(&priv->start_comp);

err = kvaser_usb_leaf_send_simple_cmd(priv->dev, CMD_START_CHIP, @@ -1719,12 +1745,15 @@ static int kvaser_usb_leaf_set_mode(struct net_device *netdev, enum can_mode mode) { struct kvaser_usb_net_priv *priv = netdev_priv(netdev); + struct kvaser_usb_net_leaf_priv *leaf = priv->sub_priv; int err;

switch (mode) { case CAN_MODE_START: kvaser_usb_unlink_tx_urbs(priv);

+ leaf->joining_bus = true; + err = kvaser_usb_leaf_simple_cmd_async(priv, CMD_START_CHIP); if (err) return err;