> > > +static netdev_tx_t nct6694_canfd_start_xmit(struct sk_buff *skb, > > > + struct net_device *ndev) > > > +{ > > > + struct nct6694_canfd_priv *priv = netdev_priv(ndev); > > > + struct nct6694 *nct6694 = priv->nct6694; > > > + struct canfd_frame *cf = (struct canfd_frame *)skb->data; > > > + struct net_device_stats *stats = &ndev->stats; > > > + int can_idx = priv->can_idx; > > > + u32 txid = 0; > > > + int i; > > > + unsigned int echo_byte; > > > + u8 data_buf[REQUEST_CAN_CMD10_LEN] = {0}; > > > + > > > + if (can_dropped_invalid_skb(ndev, skb)) > > > + return NETDEV_TX_OK; > > > + > > > + /* > > > + * No check for NCT66794 because the TX bit is read-clear > > > + * and may be read-cleared by other function > > > + * Just check the result of tx command. > > > + */ > > > > Where do you check the result of the TX command? > > > > > + /* Check if the TX buffer is full */ > > > > Where's the check if the TX buffer is full? > > Sorry for the missing code. It will be checked in tx_work(). If nct6694_write_msg() for CMD10 returns an error related to CAN_Deliver, I will add error handling in the next patch. > > > + netif_stop_queue(ndev); > > > + > > > + if (can_idx == 0) > > > + data_buf[CAN_TAG_IDX] = CAN_TAG_CAN0; > > > + else > > > + data_buf[CAN_TAG_IDX] = CAN_TAG_CAN1; > > > + > > > + if (cf->can_id & CAN_EFF_FLAG) { > > > + txid = cf->can_id & CAN_EFF_MASK; > > > + /* > > > + * In case the Extended ID frame is transmitted, the > > > + * standard and extended part of the ID are swapped > > > + * in the register, so swap them back to send the > > > + * correct ID. > > > + */ > > > + data_buf[CAN_FLAG_IDX] |= CAN_FLAG_EFF; > > > + } else { > > > + txid = cf->can_id & CAN_SFF_MASK; > > > + } > > > + > > > + set_buf32(&data_buf[CAN_ID_IDX], txid); > > > + > > > + data_buf[CAN_DLC_IDX] = cf->len; > > > + > > > + if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) && can_is_canfd_skb(skb)) { > > > + data_buf[CAN_FLAG_IDX] |= CAN_FLAG_FD; > > > + if (cf->flags & CANFD_BRS) > > > + data_buf[CAN_FLAG_IDX] |= CAN_FLAG_BRS; > > > + } > > > + > > > + if (cf->can_id & CAN_RTR_FLAG) > > > + data_buf[CAN_FLAG_IDX] |= CAN_FLAG_RTR; > > > + > > > + /* set data to buf */ > > > + for (i = 0; i < cf->len; i++) > > > + data_buf[CAN_DATA_IDX + i] = *(u8 *)(cf->data + i); > > > + > > > + can_put_echo_skb(skb, ndev, 0, 0); > > > + > > > + memcpy(priv->data_buf, data_buf, REQUEST_CAN_CMD10_LEN); > > > + queue_work(nct6694->async_workqueue, &priv->tx_work); > > > + > > > + stats->tx_bytes += cf->len; > > > + stats->tx_packets++; > > > + echo_byte = can_get_echo_skb(ndev, 0, NULL); > > > + > > > + netif_wake_queue(ndev); > > > > How do you make sure that the tx_work has finished? > > Once you wake the queue, the xmit function can be called again. If your > > tx_work has not finished, you'll overwrite the priv->data_buf. > > Do you get a CAN TX complete message/IRQ from your device? > I will move the code that needs to confirm the completion of TX transmission to tx_work(). In tx_work(), CMD2 CAN_Event's TX_EVT will first confirm TX_FIFO_EMPTY, ensuring transmission is complete. Best regards, Ming