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[CFT,28/30] net: fec: add support for dumping transmit ring on timeout

Message ID E1X0Xxk-0001P1-BS@rmk-PC.arm.linux.org.uk
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

Russell King June 27, 2014, 3:21 p.m. UTC
When we timeout on transmit, it would be useful to dump the transmit
ring, so we can see the ring state.  This can be helpful to diagnose
the cause of transmit timeouts.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 drivers/net/ethernet/freescale/fec_main.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
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Patch

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 9af9350565be..1e0eeb43ff6a 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -320,6 +320,27 @@  static void *swap_buffer(void *bufaddr, int len)
 	return bufaddr;
 }
 
+static void fec_dump(struct net_device *ndev)
+{
+	struct fec_enet_private *fep = netdev_priv(ndev);
+	struct bufdesc *bdp = fep->tx_bd_base;
+	unsigned int index = 0;
+
+	netdev_info(ndev, "TX ring dump\n");
+	pr_info("Nr     SC     addr       len  SKB\n");
+
+	do {
+		pr_info("%3u %c%c 0x%04x 0x%08lx %4u %p\n",
+			index,
+			bdp == fep->cur_tx ? 'S' : ' ',
+			bdp == fep->dirty_tx ? 'H' : ' ',
+			bdp->cbd_sc, bdp->cbd_bufaddr, bdp->cbd_datlen,
+			fep->tx_skbuff[index]);
+		bdp = fec_enet_get_nextdesc(bdp, fep);
+		index++;
+	} while (bdp != fep->tx_bd_base);
+}
+
 static inline bool is_ipv4_pkt(struct sk_buff *skb)
 {
 	return skb->protocol == htons(ETH_P_IP) && ip_hdr(skb)->version == 4;
@@ -1018,6 +1039,8 @@  fec_timeout(struct net_device *ndev)
 {
 	struct fec_enet_private *fep = netdev_priv(ndev);
 
+	fec_dump(ndev);
+
 	ndev->stats.tx_errors++;
 
 	schedule_work(&fep->tx_timeout_work);