e1000e: additional error handling on PHY register accesses

PHY reads/writes via the MDIC register could potentially return results
from a previous PHY register access.  If that happens, the offset in the
returned results will be that of the previous access and if that is
different from the expected offset, log a debug message and error out.

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>

diff --git a/drivers/net/ethernet/intel/e1000e/defines.h b/drivers/net/ethernet/intel/e1000e/defines.h
index b7c664f..a6aeb19 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/defines.h
+++ b/drivers/net/ethernet/intel/e1000e/defines.h
@@ -788,6 +788,7 @@
        GG82563_REG(194, 18) /* Inband Control */
 
 /* MDI Control */
+#define E1000_MDIC_REG_MASK    0x001F0000
 #define E1000_MDIC_REG_SHIFT 16
 #define E1000_MDIC_PHY_SHIFT 21
 #define E1000_MDIC_OP_WRITE  0x04000000

diff --git a/drivers/net/ethernet/intel/e1000e/phy.c b/drivers/net/ethernet/intel/e1000e/phy.c
index 60dbf02..cbb310f 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/phy.c
+++ b/drivers/net/ethernet/intel/e1000e/phy.c
@@ -178,6 +178,12 @@ s32 e1000e_read_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 *data)
                e_dbg("MDI Error\n");
                return -E1000_ERR_PHY;
        }
+       if (((mdic & E1000_MDIC_REG_MASK) >> E1000_MDIC_REG_SHIFT) != offset) {
+               e_dbg("MDI Read offset error - requested %d, returned %d\n",
+                     offset,
+                     (mdic & E1000_MDIC_REG_MASK) >> E1000_MDIC_REG_SHIFT);
+               return -E1000_ERR_PHY;
+       }
        *data = (u16)mdic;
 
        /* Allow some time after each MDIC transaction to avoid
@@ -236,6 +242,12 @@ s32 e1000e_write_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 data)
                e_dbg("MDI Error\n");
                return -E1000_ERR_PHY;
        }
+       if (((mdic & E1000_MDIC_REG_MASK) >> E1000_MDIC_REG_SHIFT) != offset) {
+               e_dbg("MDI Write offset error - requested %d, returned %d\n",
+                     offset,
+                     (mdic & E1000_MDIC_REG_MASK) >> E1000_MDIC_REG_SHIFT);
+               return -E1000_ERR_PHY;
+       }
 
        /* Allow some time after each MDIC transaction to avoid
         * reading duplicate data in the next MDIC transaction.