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>

1 files changed, 17 insertions, 11 deletions

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 0792031a5cf9..a3de0b6127eb 100644
--- 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;