net: fec: add support for dumping transmit ring on timeout

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.

Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index c6b1bf797a39878e4cd0b1ca4438d22caf5b6438..09fcdc768931ea192637e0cee6771c9f463bd156 100644 (file)
--- 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);