e1000e: 82579: workaround for link drop issue
authorBruce Allan <bruce.w.allan@intel.com>
Fri, 16 Dec 2011 00:46:06 +0000 (00:46 +0000)
committerJeff Kirsher <jeffrey.t.kirsher@intel.com>
Thu, 26 Jan 2012 07:12:59 +0000 (23:12 -0800)
When connected to certain switches, the 82579 PHY might drop link
unexpectedly.  Work around the issue by setting the Mean Square Error
higher than the hardware default.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
drivers/net/ethernet/intel/e1000e/ich8lan.c

index e2a80a283fd313e0e76fa87a8470c09b37415f27..1b69c2d6b4179b04b6bf83815573bcebf36430ce 100644 (file)
 #define I82579_EMI_ADDR         0x10
 #define I82579_EMI_DATA         0x11
 #define I82579_LPI_UPDATE_TIMER 0x4805 /* in 40ns units + 40 ns base value */
+#define I82579_MSE_THRESHOLD    0x084F /* Mean Square Error Threshold */
+#define I82579_MSE_LINK_DOWN    0x2411 /* MSE count before dropping link */
 
 /* Strapping Option Register - RO */
 #define E1000_STRAP                     0x0000C
@@ -1669,6 +1671,26 @@ static s32 e1000_lv_phy_workarounds_ich8lan(struct e1000_hw *hw)
        /* Set MDIO slow mode before any other MDIO access */
        ret_val = e1000_set_mdio_slow_mode_hv(hw);
 
+       ret_val = hw->phy.ops.acquire(hw);
+       if (ret_val)
+               goto out;
+       ret_val = hw->phy.ops.write_reg_locked(hw, I82579_EMI_ADDR,
+                                              I82579_MSE_THRESHOLD);
+       if (ret_val)
+               goto release;
+       /* set MSE higher to enable link to stay up when noise is high */
+       ret_val = hw->phy.ops.write_reg_locked(hw, I82579_EMI_DATA, 0x0034);
+       if (ret_val)
+               goto release;
+       ret_val = hw->phy.ops.write_reg_locked(hw, I82579_EMI_ADDR,
+                                              I82579_MSE_LINK_DOWN);
+       if (ret_val)
+               goto release;
+       /* drop link after 5 times MSE threshold was reached */
+       ret_val = hw->phy.ops.write_reg_locked(hw, I82579_EMI_DATA, 0x0005);
+release:
+       hw->phy.ops.release(hw);
+
 out:
        return ret_val;
 }