sky2: sky2 FE+ receive status workaround

The Yukon FE+ chip appears to have a hardware glitch that causes bogus
receive status values to be posted. The data in the packet is good, but
the status value is random garbage.  As a temporary workaround until the
problem is better understood, implement the workaround the vendor driver
used of ignoring the status value on this chip.

Since this means trusting dodgy hardware values; add additional checking
of the receive packet length.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 0792031a5cf959a1543f32f4e0f2ab4ccb7b0ec2..a3de0b6127ebb537b87a1849e207909fcc333ee4 100644 (file)
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -2148,6 +2148,18 @@ static struct sk_buff *sky2_receive(struct net_device *dev,
        sky2->rx_next = (sky2->rx_next + 1) % sky2->rx_pending;
        prefetch(sky2->rx_ring + sky2->rx_next);
 
+       if (length < ETH_ZLEN || length > sky2->rx_data_size)
+               goto len_error;
+
+       /* This chip has hardware problems that generates bogus status.
+        * So do only marginal checking and expect higher level protocols
+        * to handle crap frames.
+        */
+       if (sky2->hw->chip_id == CHIP_ID_YUKON_FE_P &&
+           sky2->hw->chip_rev == CHIP_REV_YU_FE2_A0 &&
+           length != count)
+               goto okay;
+
        if (status & GMR_FS_ANY_ERR)
                goto error;
 
@@ -2156,8 +2168,9 @@ static struct sk_buff *sky2_receive(struct net_device *dev,
 
        /* if length reported by DMA does not match PHY, packet was truncated */
        if (length != count)
-               goto len_mismatch;
+               goto len_error;
 
+okay:
        if (length < copybreak)
                skb = receive_copy(sky2, re, length);
        else
@@ -2167,13 +2180,13 @@ resubmit:
 
        return skb;
 
-len_mismatch:
+len_error:
        /* Truncation of overlength packets
           causes PHY length to not match MAC length */
        ++sky2->net_stats.rx_length_errors;
        if (netif_msg_rx_err(sky2) && net_ratelimit())
-               pr_info(PFX "%s: rx length mismatch: length %d status %#x\n",
-                       dev->name, length, status);
+               pr_info(PFX "%s: rx length error: status %#x length %d\n",
+                       dev->name, status, length);
        goto resubmit;
 
 error:
@@ -3934,13 +3947,6 @@ static __devinit struct net_device *sky2_init_netdev(struct sky2_hw *hw,
        sky2->hw = hw;
        sky2->msg_enable = netif_msg_init(debug, default_msg);
 
-       /* This chip has hardware problems that generates
-        * bogus PHY receive status so by default shut up the message.
-        */
-       if (hw->chip_id == CHIP_ID_YUKON_FE_P &&
-           hw->chip_rev == CHIP_REV_YU_FE2_A0)
-               sky2->msg_enable &= ~NETIF_MSG_RX_ERR;
-
        /* Auto speed and flow control */
        sky2->autoneg = AUTONEG_ENABLE;
        sky2->flow_mode = FC_BOTH;