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>

3 files changed, 51 insertions, 2 deletions

diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h
index c55de1c027af..c55fd6fdb91c 100644
--- a/drivers/net/e1000e/e1000.h
+++ b/drivers/net/e1000e/e1000.h
@@ -299,6 +299,7 @@ struct e1000_adapter {
         unsigned long led_status;
 
         unsigned int flags;
+        unsigned int flags2;
         struct work_struct downshift_task;
         struct work_struct update_phy_task;
 };
@@ -306,6 +307,7 @@ struct e1000_adapter {
 struct e1000_info {
         enum e1000_mac_type     mac;
         unsigned int            flags;
+        unsigned int            flags2;
         u32                     pba;
         s32                     (*get_variants)(struct e1000_adapter *);
         struct e1000_mac_operations *mac_ops;
@@ -347,6 +349,9 @@ struct e1000_info {
 #define FLAG_RX_RESTART_NOW               (1 << 30)
 #define FLAG_MSI_TEST_FAILED              (1 << 31)
 
+/* CRC Stripping defines */
+#define FLAG2_CRC_STRIPPING               (1 << 0)
+
 #define E1000_RX_DESC_PS(R, i)      \
         (&(((union e1000_rx_desc_packet_split *)((R).desc))[i]))
 #define E1000_GET_DESC(R, i, type)      (&(((struct type *)((R).desc))[i]))
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;
diff --git a/drivers/net/e1000e/param.c b/drivers/net/e1000e/param.c
index 77a3d7207a5f..e909f96698e8 100644
--- a/drivers/net/e1000e/param.c
+++ b/drivers/net/e1000e/param.c
@@ -151,6 +151,16 @@ E1000_PARAM(KumeranLockLoss, "Enable Kumeran lock loss workaround");
  */
 E1000_PARAM(WriteProtectNVM, "Write-protect NVM [WARNING: disabling this can lead to corrupted NVM]");
 
+/*
+ * Enable CRC Stripping
+ *
+ * Valid Range: 0, 1
+ *
+ * Default Value: 1 (enabled)
+ */
+E1000_PARAM(CrcStripping, "Enable CRC Stripping, disable if your BMC needs " \
+                          "the CRC");
+
 struct e1000_option {
         enum { enable_option, range_option, list_option } type;
         const char *name;
@@ -404,6 +414,21 @@ void __devinit e1000e_check_options(struct e1000_adapter *adapter)
                                 adapter->flags |= FLAG_SMART_POWER_DOWN;
                 }
         }
+        { /* CRC Stripping */
+                const struct e1000_option opt = {
+                        .type = enable_option,
+                        .name = "CRC Stripping",
+                        .err  = "defaulting to enabled",
+                        .def  = OPTION_ENABLED
+                };
+
+                if (num_CrcStripping > bd) {
+                        unsigned int crc_stripping = CrcStripping[bd];
+                        e1000_validate_option(&crc_stripping, &opt, adapter);
+                        if (crc_stripping == OPTION_ENABLED)
+                                adapter->flags2 |= FLAG2_CRC_STRIPPING;
+                }
+        }
         { /* Kumeran Lock Loss Workaround */
                 const struct e1000_option opt = {
                         .type = enable_option,