gianfar: Fix reported number of sent bytes to BQL

This is a backported patch for the gianfar ethernet driver
used in TPLink 4900 v1. It is supposed to fix the error which
show up in dmesg with:
NETDEV WATCHDOG: eth0 (fsl-gianfar): transmit queue xy timed out
Full upstream patch is at: http://patchwork.ozlabs.org/patch/271242

Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39692 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 77 insertions, 0 deletions

diff --git a/target/linux/mpc85xx/patches-3.10/220-fix_gianfar_reported_number_of_sent_bytes_to_BQL.patch b/target/linux/mpc85xx/patches-3.10/220-fix_gianfar_reported_number_of_sent_bytes_to_BQL.patch
new file mode 100644
index 0000000000..d0380ff8ac
--- /dev/null
+++ b/target/linux/mpc85xx/patches-3.10/220-fix_gianfar_reported_number_of_sent_bytes_to_BQL.patch
@@ -0,0 +1,77 @@
+--- a/drivers/net/ethernet/freescale/gianfar.c
++++ b/drivers/net/ethernet/freescale/gianfar.c
+@@ -2064,7 +2064,7 @@ static int gfar_start_xmit(struct sk_buf
+ 	int i, rq = 0, do_tstamp = 0;
+ 	u32 bufaddr;
+ 	unsigned long flags;
+-	unsigned int nr_frags, nr_txbds, length, fcb_length = GMAC_FCB_LEN;
++	unsigned int nr_frags, nr_txbds, bytes_sent, fcb_length = GMAC_FCB_LEN;
+ 
+ 	/* TOE=1 frames larger than 2500 bytes may see excess delays
+ 	 * before start of transmission.
+@@ -2130,7 +2130,10 @@ static int gfar_start_xmit(struct sk_buf
+ 	}
+ 
+ 	/* Update transmit stats */
+-	tx_queue->stats.tx_bytes += skb->len;
++	bytes_sent = skb->len;
++	tx_queue->stats.tx_bytes += bytes_sent;
++	/* keep Tx bytes on wire for BQL accounting */
++	GFAR_CB(skb)->bytes_sent = bytes_sent;
+ 	tx_queue->stats.tx_packets++;
+ 
+ 	txbdp = txbdp_start = tx_queue->cur_tx;
+@@ -2150,12 +2153,13 @@ static int gfar_start_xmit(struct sk_buf
+ 	} else {
+ 		/* Place the fragment addresses and lengths into the TxBDs */
+ 		for (i = 0; i < nr_frags; i++) {
++			unsigned int frag_len;
+ 			/* Point at the next BD, wrapping as needed */
+ 			txbdp = next_txbd(txbdp, base, tx_queue->tx_ring_size);
+ 
+-			length = skb_shinfo(skb)->frags[i].size;
++			frag_len = skb_shinfo(skb)->frags[i].size;
+ 
+-			lstatus = txbdp->lstatus | length |
++			lstatus = txbdp->lstatus | frag_len |
+ 				  BD_LFLAG(TXBD_READY);
+ 
+ 			/* Handle the last BD specially */
+@@ -2165,7 +2169,7 @@ static int gfar_start_xmit(struct sk_buf
+ 			bufaddr = skb_frag_dma_map(priv->dev,
+ 						   &skb_shinfo(skb)->frags[i],
+ 						   0,
+-						   length,
++						   frag_len,
+ 						   DMA_TO_DEVICE);
+ 
+ 			/* set the TxBD length and buffer pointer */
+@@ -2231,7 +2235,7 @@ static int gfar_start_xmit(struct sk_buf
+ 		lstatus |= BD_LFLAG(TXBD_CRC | TXBD_READY) | skb_headlen(skb);
+ 	}
+ 
+-	netdev_tx_sent_queue(txq, skb->len);
++	netdev_tx_sent_queue(txq, bytes_sent);
+ 
+ 	/* We can work in parallel with gfar_clean_tx_ring(), except
+ 	 * when modifying num_txbdfree. Note that we didn't grab the lock
+@@ -2551,7 +2555,7 @@ static void gfar_clean_tx_ring(struct gf
+ 			bdp = next_txbd(bdp, base, tx_ring_size);
+ 		}
+ 
+-		bytes_sent += skb->len;
++		bytes_sent += GFAR_CB(skb)->bytes_sent;
+ 
+ 		dev_kfree_skb_any(skb);
+ 
+--- a/drivers/net/ethernet/freescale/gianfar.h
++++ b/drivers/net/ethernet/freescale/gianfar.h
+@@ -571,7 +571,7 @@ struct rxfcb {
+ };
+ 
+ struct gianfar_skb_cb {
+-	int alignamount;
++	unsigned int bytes_sent; /* bytes-on-wire (i.e. no FCB) */
+ };
+ 
+ #define GFAR_CB(skb) ((struct gianfar_skb_cb *)((skb)->cb))