e1000e: fix IPMI traffic

Some users reported that they have machines with BMCs enabled that cannot
receive IPMI traffic after e1000e is loaded.
http://marc.info/?l=e1000-devel&m=121909039127414&w=2
http://marc.info/?l=e1000-devel&m=121365543823387&w=2

This fixes the issue if they load with the new parameter = 0 by disabling
crc stripping, but leaves the performance feature on for most users.
Based on work done by Hong Zhang.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 2 deletions

diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index f6ebebb8cfa5..91795f78c3e4 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -499,6 +499,10 @@ static bool e1000_clean_rx_irq(struct e1000_adapter *adapter,
                         goto next_desc;
                 }
 
+                /* adjust length to remove Ethernet CRC */
+                if (!(adapter->flags2 & FLAG2_CRC_STRIPPING))
+                        length -= 4;
+
                 total_rx_bytes += length;
                 total_rx_packets++;
 
@@ -804,6 +808,10 @@ static bool e1000_clean_rx_irq_ps(struct e1000_adapter *adapter,
                         pci_dma_sync_single_for_device(pdev, ps_page->dma,
                                 PAGE_SIZE, PCI_DMA_FROMDEVICE);
 
+                        /* remove the CRC */
+                        if (!(adapter->flags2 & FLAG2_CRC_STRIPPING))
+                                l1 -= 4;
+
                         skb_put(skb, l1);
                         goto copydone;
                 } /* if */
@@ -825,6 +833,12 @@ static bool e1000_clean_rx_irq_ps(struct e1000_adapter *adapter,
                         skb->truesize += length;
                 }
 
+                /* strip the ethernet crc, problem is we're using pages now so
+                 * this whole operation can get a little cpu intensive
+                 */
+                if (!(adapter->flags2 & FLAG2_CRC_STRIPPING))
+                        pskb_trim(skb, skb->len - 4);
+
 copydone:
                 total_rx_bytes += skb->len;
                 total_rx_packets++;
@@ -2301,8 +2315,12 @@ static void e1000_setup_rctl(struct e1000_adapter *adapter)
         else
                 rctl |= E1000_RCTL_LPE;
 
-        /* Enable hardware CRC frame stripping */
-        rctl |= E1000_RCTL_SECRC;
+        /* Some systems expect that the CRC is included in SMBUS traffic. The
+         * hardware strips the CRC before sending to both SMBUS (BMC) and to
+         * host memory when this is enabled
+         */
+        if (adapter->flags2 & FLAG2_CRC_STRIPPING)
+                rctl |= E1000_RCTL_SECRC;
 
         /* Setup buffer sizes */
         rctl &= ~E1000_RCTL_SZ_4096;
@@ -4766,6 +4784,7 @@ static int __devinit e1000_probe(struct pci_dev *pdev,
         adapter->ei = ei;
         adapter->pba = ei->pba;
         adapter->flags = ei->flags;
+        adapter->flags2 = ei->flags2;
         adapter->hw.adapter = adapter;
         adapter->hw.mac.type = ei->mac;
         adapter->msg_enable = (1 << NETIF_MSG_DRV | NETIF_MSG_PROBE) - 1;