can: kvaser_pciefd: Use TX FIFO size read from CAN controller

Use the TX FIFO size read from CAN controller register, instead of using
hard coded value.
Signed-off-by: Jimmy Assarsson <extja@kvaser.com>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20230529134248.752036-15-extja@kvaser.comSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/kvaser_pciefd.c

@@ -658,8 +658,7 @@ static netdev_tx_t kvaser_pciefd_start_xmit(struct sk_buff *skb,
 	/* No room for a new message, stop the queue until at least one
 	 * successful transmit
 	 */
-	if (count >= KVASER_PCIEFD_CAN_TX_MAX_COUNT ||
-	    can->can.echo_skb[can->echo_idx])
+	if (count >= can->can.echo_skb_max || can->can.echo_skb[can->echo_idx])
 		netif_stop_queue(netdev);
 	spin_unlock_irqrestore(&can->echo_lock, irq_flags);
 
@@ -802,16 +801,9 @@ static int kvaser_pciefd_setup_can_ctrls(struct kvaser_pciefd *pcie)
 		tx_nr_packets_max =
 			FIELD_GET(KVASER_PCIEFD_KCAN_TX_NR_PACKETS_MAX_MASK,
 				  ioread32(can->reg_base + KVASER_PCIEFD_KCAN_TX_NR_PACKETS_REG));
-		if (tx_nr_packets_max < KVASER_PCIEFD_CAN_TX_MAX_COUNT) {
-			dev_err(&pcie->pci->dev,
-				"Max Tx count is smaller than expected\n");
-
-			free_candev(netdev);
-			return -ENODEV;
-		}
 
 		can->can.clock.freq = pcie->freq;
-		can->can.echo_skb_max = KVASER_PCIEFD_CAN_TX_MAX_COUNT;
+		can->can.echo_skb_max = min(KVASER_PCIEFD_CAN_TX_MAX_COUNT, tx_nr_packets_max - 1);
 		can->echo_idx = 0;
 		spin_lock_init(&can->echo_lock);
 		spin_lock_init(&can->lock);
@@ -1311,8 +1303,7 @@ static int kvaser_pciefd_handle_ack_packet(struct kvaser_pciefd *pcie,
 		count = FIELD_GET(KVASER_PCIEFD_KCAN_TX_NR_PACKETS_CURRENT_MASK,
 				  ioread32(can->reg_base + KVASER_PCIEFD_KCAN_TX_NR_PACKETS_REG));
 
-		if (count < KVASER_PCIEFD_CAN_TX_MAX_COUNT &&
-		    netif_queue_stopped(can->can.dev))
+		if (count < can->can.echo_skb_max && netif_queue_stopped(can->can.dev))
 			netif_wake_queue(can->can.dev);
 
 		if (!one_shot_fail) {