Merge branch 'mediatek-stress-test-fixes'

John Crispin says:

====================
net: mediatek: make the driver pass stress tests

While testing the driver we managed to get the TX path to stall and fail
to recover. When dual MAC support was added to the driver, the whole queue
stop/wake code was not properly adapted. There was also a regression in the
locking of the xmit function. The fact that watchdog_timeo was not set and
that the tx_timeout code failed to properly reset the dma, irq and queue
just made the mess complete.

This series make the driver pass stress testing. With this series applied
the testbed has been running for several days and still has not locked up.
We have a second setup that has a small hack patch applied to randomly stop
irqs and/or one of the queues and successfully manages to recover from these
simulated tx stalls.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -536,7 +536,6 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
 	struct mtk_eth *eth = mac->hw;
 	struct mtk_tx_dma *itxd, *txd;
 	struct mtk_tx_buf *tx_buf;
-	unsigned long flags;
 	dma_addr_t mapped_addr;
 	unsigned int nr_frags;
 	int i, n_desc = 1;
@@ -568,11 +567,6 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
 	if (unlikely(dma_mapping_error(&dev->dev, mapped_addr)))
 		return -ENOMEM;
 
-	/* normally we can rely on the stack not calling this more than once,
-	 * however we have 2 queues running ont he same ring so we need to lock
-	 * the ring access
-	 */
-	spin_lock_irqsave(&eth->page_lock, flags);
 	WRITE_ONCE(itxd->txd1, mapped_addr);
 	tx_buf->flags |= MTK_TX_FLAGS_SINGLE0;
 	dma_unmap_addr_set(tx_buf, dma_addr0, mapped_addr);
@@ -609,8 +603,7 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
 			WRITE_ONCE(txd->txd1, mapped_addr);
 			WRITE_ONCE(txd->txd3, (TX_DMA_SWC |
 					       TX_DMA_PLEN0(frag_map_size) |
-					       last_frag * TX_DMA_LS0) |
-					       mac->id);
+					       last_frag * TX_DMA_LS0));
 			WRITE_ONCE(txd->txd4, 0);
 
 			tx_buf->skb = (struct sk_buff *)MTK_DMA_DUMMY_DESC;
@@ -632,8 +625,6 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
 	WRITE_ONCE(itxd->txd3, (TX_DMA_SWC | TX_DMA_PLEN0(skb_headlen(skb)) |
 				(!nr_frags * TX_DMA_LS0)));
 
-	spin_unlock_irqrestore(&eth->page_lock, flags);
-
 	netdev_sent_queue(dev, skb->len);
 	skb_tx_timestamp(skb);
 
@@ -661,8 +652,6 @@ static int mtk_tx_map(struct sk_buff *skb, struct net_device *dev,
 		itxd = mtk_qdma_phys_to_virt(ring, itxd->txd2);
 	} while (itxd != txd);
 
-	spin_unlock_irqrestore(&eth->page_lock, flags);
-
 	return -ENOMEM;
 }
 
@@ -681,7 +670,29 @@ static inline int mtk_cal_txd_req(struct sk_buff *skb)
 		nfrags += skb_shinfo(skb)->nr_frags;
 	}
 
-	return DIV_ROUND_UP(nfrags, 2);
+	return nfrags;
+}
+
+static void mtk_wake_queue(struct mtk_eth *eth)
+{
+	int i;
+
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!eth->netdev[i])
+			continue;
+		netif_wake_queue(eth->netdev[i]);
+	}
+}
+
+static void mtk_stop_queue(struct mtk_eth *eth)
+{
+	int i;
+
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!eth->netdev[i])
+			continue;
+		netif_stop_queue(eth->netdev[i]);
+	}
 }
 
 static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -690,14 +701,22 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct mtk_eth *eth = mac->hw;
 	struct mtk_tx_ring *ring = &eth->tx_ring;
 	struct net_device_stats *stats = &dev->stats;
+	unsigned long flags;
 	bool gso = false;
 	int tx_num;
 
+	/* normally we can rely on the stack not calling this more than once,
+	 * however we have 2 queues running on the same ring so we need to lock
+	 * the ring access
+	 */
+	spin_lock_irqsave(&eth->page_lock, flags);
+
 	tx_num = mtk_cal_txd_req(skb);
 	if (unlikely(atomic_read(&ring->free_count) <= tx_num)) {
-		netif_stop_queue(dev);
+		mtk_stop_queue(eth);
 		netif_err(eth, tx_queued, dev,
 			  "Tx Ring full when queue awake!\n");
+		spin_unlock_irqrestore(&eth->page_lock, flags);
 		return NETDEV_TX_BUSY;
 	}
 
@@ -720,15 +739,17 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto drop;
 
 	if (unlikely(atomic_read(&ring->free_count) <= ring->thresh)) {
-		netif_stop_queue(dev);
+		mtk_stop_queue(eth);
 		if (unlikely(atomic_read(&ring->free_count) >
 			     ring->thresh))
-			netif_wake_queue(dev);
+			mtk_wake_queue(eth);
 	}
+	spin_unlock_irqrestore(&eth->page_lock, flags);
 
 	return NETDEV_TX_OK;
 
 drop:
+	spin_unlock_irqrestore(&eth->page_lock, flags);
 	stats->tx_dropped++;
 	dev_kfree_skb(skb);
 	return NETDEV_TX_OK;
@@ -897,13 +918,8 @@ static int mtk_poll_tx(struct mtk_eth *eth, int budget, bool *tx_again)
 	if (!total)
 		return 0;
 
-	for (i = 0; i < MTK_MAC_COUNT; i++) {
-		if (!eth->netdev[i] ||
-		    unlikely(!netif_queue_stopped(eth->netdev[i])))
-			continue;
 	if (atomic_read(&ring->free_count) > ring->thresh)
-			netif_wake_queue(eth->netdev[i]);
-	}
+		mtk_wake_queue(eth);
 
 	return total;
 }
@@ -1176,7 +1192,7 @@ static void mtk_tx_timeout(struct net_device *dev)
 	eth->netdev[mac->id]->stats.tx_errors++;
 	netif_err(eth, tx_err, dev,
 		  "transmit timed out\n");
-	schedule_work(&mac->pending_work);
+	schedule_work(&eth->pending_work);
 }
 
 static irqreturn_t mtk_handle_irq(int irq, void *_eth)
@@ -1413,19 +1429,30 @@ static int mtk_do_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 
 static void mtk_pending_work(struct work_struct *work)
 {
-	struct mtk_mac *mac = container_of(work, struct mtk_mac, pending_work);
-	struct mtk_eth *eth = mac->hw;
-	struct net_device *dev = eth->netdev[mac->id];
-	int err;
+	struct mtk_eth *eth = container_of(work, struct mtk_eth, pending_work);
+	int err, i;
+	unsigned long restart = 0;
 
 	rtnl_lock();
-	mtk_stop(dev);
 
-	err = mtk_open(dev);
+	/* stop all devices to make sure that dma is properly shut down */
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!eth->netdev[i])
+			continue;
+		mtk_stop(eth->netdev[i]);
+		__set_bit(i, &restart);
+	}
+
+	/* restart DMA and enable IRQs */
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!test_bit(i, &restart))
+			continue;
+		err = mtk_open(eth->netdev[i]);
 		if (err) {
-		netif_alert(eth, ifup, dev,
+			netif_alert(eth, ifup, eth->netdev[i],
 			      "Driver up/down cycle failed, closing device.\n");
-		dev_close(dev);
+			dev_close(eth->netdev[i]);
+		}
 	}
 	rtnl_unlock();
 }
@@ -1435,15 +1462,13 @@ static int mtk_cleanup(struct mtk_eth *eth)
 	int i;
 
 	for (i = 0; i < MTK_MAC_COUNT; i++) {
-		struct mtk_mac *mac = netdev_priv(eth->netdev[i]);
-
 		if (!eth->netdev[i])
 			continue;
 
 		unregister_netdev(eth->netdev[i]);
 		free_netdev(eth->netdev[i]);
-		cancel_work_sync(&mac->pending_work);
 	}
+	cancel_work_sync(&eth->pending_work);
 
 	return 0;
 }
@@ -1631,7 +1656,6 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
 	mac->id = id;
 	mac->hw = eth;
 	mac->of_node = np;
-	INIT_WORK(&mac->pending_work, mtk_pending_work);
 
 	mac->hw_stats = devm_kzalloc(eth->dev,
 				     sizeof(*mac->hw_stats),
@@ -1645,6 +1669,7 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
 	mac->hw_stats->reg_offset = id * MTK_STAT_OFFSET;
 
 	SET_NETDEV_DEV(eth->netdev[id], eth->dev);
+	eth->netdev[id]->watchdog_timeo = HZ;
 	eth->netdev[id]->netdev_ops = &mtk_netdev_ops;
 	eth->netdev[id]->base_addr = (unsigned long)eth->base;
 	eth->netdev[id]->vlan_features = MTK_HW_FEATURES &
@@ -1678,10 +1703,6 @@ static int mtk_probe(struct platform_device *pdev)
 	struct mtk_eth *eth;
 	int err;
 
-	err = device_reset(&pdev->dev);
-	if (err)
-		return err;
-
 	match = of_match_device(of_mtk_match, &pdev->dev);
 	soc = (struct mtk_soc_data *)match->data;
 
@@ -1736,6 +1757,7 @@ static int mtk_probe(struct platform_device *pdev)
 
 	eth->dev = &pdev->dev;
 	eth->msg_enable = netif_msg_init(mtk_msg_level, MTK_DEFAULT_MSG_ENABLE);
+	INIT_WORK(&eth->pending_work, mtk_pending_work);
 
 	err = mtk_hw_init(eth);
 	if (err)

drivers/net/ethernet/mediatek/mtk_eth_soc.h

@@ -363,6 +363,7 @@ struct mtk_rx_ring {
  * @clk_gp1:		The gmac1 clock
  * @clk_gp2:		The gmac2 clock
  * @mii_bus:		If there is a bus we need to create an instance for it
+ * @pending_work:	The workqueue used to reset the dma ring
  */
 
 struct mtk_eth {
@@ -389,6 +390,7 @@ struct mtk_eth {
 	struct clk			*clk_gp1;
 	struct clk			*clk_gp2;
 	struct mii_bus			*mii_bus;
+	struct work_struct		pending_work;
 };
 
 /* struct mtk_mac -	the structure that holds the info about the MACs of the
@@ -398,7 +400,6 @@ struct mtk_eth {
  * @hw:			Backpointer to our main datastruture
  * @hw_stats:		Packet statistics counter
  * @phy_dev:		The attached PHY if available
- * @pending_work:	The workqueue used to reset the dma ring
  */
 struct mtk_mac {
 	int				id;
@@ -406,7 +407,6 @@ struct mtk_mac {
 	struct mtk_eth			*hw;
 	struct mtk_hw_stats		*hw_stats;
 	struct phy_device		*phy_dev;
-	struct work_struct		pending_work;
 };
 
 /* the struct describing the SoC. these are declared in the soc_xyz.c files */