Xilinx: ARM: EmacPs: Fix a potential bug for multi-BD packets

For multi-BD packets the clearing of BD fields and freeing of BDs
 was not happening properly. This patch fixes this issue.

Also the patch makes minor changes to read and use the length field
of BD appropriately.

Signed-off-by: Anirudha <anirudh@xilinx.com>

diff --git a/drivers/net/ethernet/xilinx/xilinx_emacps.c b/drivers/net/ethernet/xilinx/xilinx_emacps.c
index 456eefb0387003cb4b000b95c7da1b469ce2e792..1016a6aa673c492f24fdf58d5f864a39d1b56259 100755 (executable)
--- a/drivers/net/ethernet/xilinx/xilinx_emacps.c
+++ b/drivers/net/ethernet/xilinx/xilinx_emacps.c
@@ -1196,10 +1196,12 @@ u32 xemacps_bdringfromhwtx(struct xemacps_bdring *ringptr, unsigned bdlimit,
                /* Read the status */
                bdstr = xemacps_read(curbdptr, XEMACPS_BD_STAT_OFFSET);
 
-               if ((sop == 0) && (bdstr & XEMACPS_TXBUF_USED_MASK))
-                       sop = 1;
-               else
-                       break;
+               if (sop == 0) {
+                               if (bdstr & XEMACPS_TXBUF_USED_MASK)
+                                       sop = 1;
+                               else
+                                       break;
+               }
 
                if (sop == 1) {
                        bdcount++;
@@ -1626,13 +1628,13 @@ static int xemacps_rx_poll(struct napi_struct *napi, int budget)
 }
 
 /**
- * xemacps_tx_poll - tasklet poll routine
+ * xemacps_tx_poll - tx isr handler routine
  * @data: pointer to network interface device structure
  **/
 static void xemacps_tx_poll(struct net_device *ndev)
 {
        struct net_local *lp = netdev_priv(ndev);
-       u32 regval, len = 0;
+       u32 regval, bdlen = 0;
        struct xemacps_bd *bdptr, *bdptrfree;
        struct ring_info *rp;
        struct sk_buff *skb;
@@ -1667,18 +1669,16 @@ static void xemacps_tx_poll(struct net_device *ndev)
        bdptrfree = bdptr;
 
        while (numbd) {
-               rmb();
                regval  = xemacps_read(bdptr, XEMACPS_BD_STAT_OFFSET);
+               rmb();
+               bdlen = regval & XEMACPS_TXBUF_LEN_MASK;
                bdidx = XEMACPS_BD_TO_INDEX(&lp->tx_ring, bdptr);
                rp = &lp->tx_skb[bdidx];
                skb = rp->skb;
 
                BUG_ON(skb == NULL);
 
-               len += skb->len;
-               rmb();
-
-               #ifdef CONFIG_XILINX_PS_EMAC_HWTSTAMP
+#ifdef CONFIG_XILINX_PS_EMAC_HWTSTAMP
                if ((lp->hwtstamp_config.tx_type == HWTSTAMP_TX_ON) &&
                        (ntohs(skb->protocol) == 0x800)) {
                        unsigned ip_proto, dest_port, msg_type;
@@ -1695,7 +1695,7 @@ static void xemacps_tx_poll(struct net_device *ndev)
                                xemacps_tx_hwtstamp(lp, skb, msg_type & 0x2);
                        }
                }
-               #endif /* CONFIG_XILINX_PS_EMAC_HWTSTAMP */
+#endif /* CONFIG_XILINX_PS_EMAC_HWTSTAMP */
 
                dma_unmap_single(&lp->pdev->dev, rp->mapping, skb->len,
                        DMA_TO_DEVICE);
@@ -1711,11 +1711,10 @@ static void xemacps_tx_poll(struct net_device *ndev)
                if (regval & XEMACPS_TXBUF_LAST_MASK) {
                        if (!(regval & XEMACPS_TXBUF_ERR_MASK)) {
                                lp->stats.tx_packets++;
-                               lp->stats.tx_bytes += len;
+                               lp->stats.tx_bytes += bdlen;
                        } else {
                                lp->stats.tx_errors++;
                        }
-                       len = 0;
                }
 
                /* Preserve used and wrap bits; clear everything else. */