1 files changed, 20 insertions, 57 deletions

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 2c68b1a60887..20595b7141af 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -379,16 +379,6 @@ m_can_txe_fifo_read(struct m_can_classdev *cdev, u32 fgi, u32 offset, u32 *val)
 	return cdev->ops->read_fifo(cdev, addr_offset, val, 1);
 }
 
-static inline bool _m_can_tx_fifo_full(u32 txfqs)
-{
-	return !!(txfqs & TXFQS_TFQF);
-}
-
-static inline bool m_can_tx_fifo_full(struct m_can_classdev *cdev)
-{
-	return _m_can_tx_fifo_full(m_can_read(cdev, M_CAN_TXFQS));
-}
-
 static void m_can_config_endisable(struct m_can_classdev *cdev, bool enable)
 {
 	u32 cccr = m_can_read(cdev, M_CAN_CCCR);
@@ -1077,17 +1067,31 @@ static void m_can_finish_tx(struct m_can_classdev *cdev, int transmitted)
 	unsigned long irqflags;
 
 	spin_lock_irqsave(&cdev->tx_handling_spinlock, irqflags);
+	if (cdev->tx_fifo_in_flight >= cdev->tx_fifo_size && transmitted > 0)
+		netif_wake_queue(cdev->net);
 	cdev->tx_fifo_in_flight -= transmitted;
 	spin_unlock_irqrestore(&cdev->tx_handling_spinlock, irqflags);
 }
 
-static void m_can_start_tx(struct m_can_classdev *cdev)
+static netdev_tx_t m_can_start_tx(struct m_can_classdev *cdev)
 {
 	unsigned long irqflags;
+	int tx_fifo_in_flight;
 
 	spin_lock_irqsave(&cdev->tx_handling_spinlock, irqflags);
-	++cdev->tx_fifo_in_flight;
+	tx_fifo_in_flight = cdev->tx_fifo_in_flight + 1;
+	if (tx_fifo_in_flight >= cdev->tx_fifo_size) {
+		netif_stop_queue(cdev->net);
+		if (tx_fifo_in_flight > cdev->tx_fifo_size) {
+			netdev_err_once(cdev->net, "hard_xmit called while TX FIFO full\n");
+			spin_unlock_irqrestore(&cdev->tx_handling_spinlock, irqflags);
+			return NETDEV_TX_BUSY;
+		}
+	}
+	cdev->tx_fifo_in_flight = tx_fifo_in_flight;
 	spin_unlock_irqrestore(&cdev->tx_handling_spinlock, irqflags);
+
+	return NETDEV_TX_OK;
 }
 
 static int m_can_echo_tx_event(struct net_device *dev)
@@ -1218,7 +1222,6 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
 			if (cdev->is_peripheral)
 				timestamp = m_can_get_timestamp(cdev);
 			m_can_tx_update_stats(cdev, 0, timestamp);
-			netif_wake_queue(dev);
 			m_can_finish_tx(cdev, 1);
 		}
 	} else  {
@@ -1226,10 +1229,6 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
 			/* New TX FIFO Element arrived */
 			if (m_can_echo_tx_event(dev) != 0)
 				goto out_fail;
-
-			if (netif_queue_stopped(dev) &&
-			    !m_can_tx_fifo_full(cdev))
-				netif_wake_queue(dev);
 		}
 	}
 
@@ -1729,20 +1728,6 @@ static int m_can_close(struct net_device *dev)
 	return 0;
 }
 
-static int m_can_next_echo_skb_occupied(struct net_device *dev, u32 putidx)
-{
-	struct m_can_classdev *cdev = netdev_priv(dev);
-	/*get wrap around for loopback skb index */
-	unsigned int wrap = cdev->can.echo_skb_max;
-	u32 next_idx;
-
-	/* calculate next index */
-	next_idx = (++putidx >= wrap ? 0 : putidx);
-
-	/* check if occupied */
-	return !!cdev->can.echo_skb[next_idx];
-}
-
 static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev,
 				    struct sk_buff *skb)
 {
@@ -1751,7 +1736,6 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev,
 	struct m_can_fifo_element fifo_element;
 	struct net_device *dev = cdev->net;
 	u32 cccr, fdflags;
-	u32 txfqs;
 	int err;
 	u32 putidx;
 
@@ -1806,24 +1790,6 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev,
 	} else {
 		/* Transmit routine for version >= v3.1.x */
 
-		txfqs = m_can_read(cdev, M_CAN_TXFQS);
-
-		/* Check if FIFO full */
-		if (_m_can_tx_fifo_full(txfqs)) {
-			/* This shouldn't happen */
-			netif_stop_queue(dev);
-			netdev_warn(dev,
-				    "TX queue active although FIFO is full.");
-
-			if (cdev->is_peripheral) {
-				kfree_skb(skb);
-				dev->stats.tx_dropped++;
-				return NETDEV_TX_OK;
-			} else {
-				return NETDEV_TX_BUSY;
-			}
-		}
-
 		/* get put index for frame */
 		putidx = cdev->tx_fifo_putidx;
 
@@ -1861,11 +1827,6 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev,
 		m_can_write(cdev, M_CAN_TXBAR, (1 << putidx));
 		cdev->tx_fifo_putidx = (++cdev->tx_fifo_putidx >= cdev->can.echo_skb_max ?
 					0 : cdev->tx_fifo_putidx);
-
-		/* stop network queue if fifo full */
-		if (m_can_tx_fifo_full(cdev) ||
-		    m_can_next_echo_skb_occupied(dev, putidx))
-			netif_stop_queue(dev);
 	}
 
 	return NETDEV_TX_OK;
@@ -1899,7 +1860,6 @@ static void m_can_tx_queue_skb(struct m_can_classdev *cdev, struct sk_buff *skb)
 static netdev_tx_t m_can_start_peripheral_xmit(struct m_can_classdev *cdev,
 					       struct sk_buff *skb)
 {
-	netif_stop_queue(cdev->net);
 	m_can_tx_queue_skb(cdev, skb);
 
 	return NETDEV_TX_OK;
@@ -1909,6 +1869,7 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
 				    struct net_device *dev)
 {
 	struct m_can_classdev *cdev = netdev_priv(dev);
+	netdev_tx_t ret;
 
 	if (can_dev_dropped_skb(dev, skb))
 		return NETDEV_TX_OK;
@@ -1918,7 +1879,9 @@ static netdev_tx_t m_can_start_xmit(struct sk_buff *skb,
 		return NETDEV_TX_OK;
 	}
 
-	m_can_start_tx(cdev);
+	ret = m_can_start_tx(cdev);
+	if (ret != NETDEV_TX_OK)
+		return ret;
 
 	if (cdev->is_peripheral)
 		return m_can_start_peripheral_xmit(cdev, skb);