mediatek: update patches

Signed-off-by: John Crispin <blogic@openwrt.org>

SVN-Revision: 49243

1 files changed, 98 insertions, 0 deletions

diff --git a/target/linux/mediatek/patches-4.4/0075-net-mediatek-fix-TX-locking.patch b/target/linux/mediatek/patches-4.4/0075-net-mediatek-fix-TX-locking.patch
new file mode 100644
index 0000000000..b14d8fab71
--- /dev/null
+++ b/target/linux/mediatek/patches-4.4/0075-net-mediatek-fix-TX-locking.patch
@@ -0,0 +1,98 @@
+From 25e46afc7324196c89dfb6f83a9c518942e23b33 Mon Sep 17 00:00:00 2001
+From: John Crispin <blogic@openwrt.org>
+Date: Tue, 29 Mar 2016 17:20:01 +0200
+Subject: [PATCH 75/91] net: mediatek: fix TX locking
+
+Inside the TX path there is a lock inside the tx_map function. This is
+however too late. The patch moves the lock to the start of the xmit
+function right before the free count check of the DMA ring happens.
+If we do not do this, the code becomes racy leading to TX stalls and
+dropped packets. This happens as there are 2 netdevs running on the
+same physical DMA ring.
+
+Signed-off-by: John Crispin <blogic@openwrt.org>
+---
+ drivers/net/ethernet/mediatek/mtk_eth_soc.c |   20 ++++++++++----------
+ 1 file changed, 10 insertions(+), 10 deletions(-)
+
+diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+index 26eeb1a..67b18f9 100644
+--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
++++ b/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);
+@@ -632,8 +626,6 @@ 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 +653,6 @@ err_dma:
+ 		itxd = mtk_qdma_phys_to_virt(ring, itxd->txd2);
+ 	} while (itxd != txd);
+ 
+-	spin_unlock_irqrestore(&eth->page_lock, flags);
+-
+ 	return -ENOMEM;
+ }
+ 
+@@ -712,14 +702,22 @@ 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 ont he 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)) {
+ 		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;
+ 	}
+ 
+@@ -747,10 +745,12 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
+ 			     ring->thresh))
+ 			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;
+-- 
+1.7.10.4
+