2 files changed, 13 insertions, 0 deletions

diff --git a/drivers/net/e1000e/82571.c b/drivers/net/e1000e/82571.c
index 0890162953e9..25f6bc94e69b 100644
--- a/drivers/net/e1000e/82571.c
+++ b/drivers/net/e1000e/82571.c
@@ -980,6 +980,18 @@ static void e1000_initialize_hw_bits_82571(struct e1000_hw *hw)
                 reg |= E1000_PBA_ECC_CORR_EN;
                 ew32(PBA_ECC, reg);
         }
+        /*
+         * Workaround for hardware errata.
+         * Ensure that DMA Dynamic Clock gating is disabled on 82571 and 82572
+         */
+
+        if ((hw->mac.type == e1000_82571) ||
+           (hw->mac.type == e1000_82572)) {
+                reg = er32(CTRL_EXT);
+                reg &= ~E1000_CTRL_EXT_DMA_DYN_CLK_EN;
+                ew32(CTRL_EXT, reg);
+        }
+
 
         /* PCI-Ex Control Registers */
         if (hw->mac.type == e1000_82574) {
diff --git a/drivers/net/e1000e/defines.h b/drivers/net/e1000e/defines.h
index e6caf29d4252..243aa499fe90 100644
--- a/drivers/net/e1000e/defines.h
+++ b/drivers/net/e1000e/defines.h
@@ -69,6 +69,7 @@
 #define E1000_CTRL_EXT_SDP7_DATA 0x00000080 /* Value of SW Definable Pin 7 */
 #define E1000_CTRL_EXT_EE_RST    0x00002000 /* Reinitialize from EEPROM */
 #define E1000_CTRL_EXT_RO_DIS    0x00020000 /* Relaxed Ordering disable */
+#define E1000_CTRL_EXT_DMA_DYN_CLK_EN 0x00080000 /* DMA Dynamic Clock Gating */
 #define E1000_CTRL_EXT_LINK_MODE_MASK 0x00C00000
 #define E1000_CTRL_EXT_LINK_MODE_PCIE_SERDES  0x00C00000
 #define E1000_CTRL_EXT_EIAME          0x01000000