e1000: Fix RSS if enabled in mid-connection

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>

drivers/net/e1000/e1000_hw.c

@@ -4755,8 +4755,36 @@ e1000_rar_set(struct e1000_hw *hw,
     rar_low = ((uint32_t) addr[0] |
                ((uint32_t) addr[1] << 8) |
                ((uint32_t) addr[2] << 16) | ((uint32_t) addr[3] << 24));
+    rar_high = ((uint32_t) addr[4] | ((uint32_t) addr[5] << 8));
 
-    rar_high = ((uint32_t) addr[4] | ((uint32_t) addr[5] << 8) | E1000_RAH_AV);
+    /* Disable Rx and flush all Rx frames before enabling RSS to avoid Rx
+     * unit hang.
+     *
+     * Description:
+     * If there are any Rx frames queued up or otherwise present in the HW
+     * before RSS is enabled, and then we enable RSS, the HW Rx unit will
+     * hang.  To work around this issue, we have to disable receives and
+     * flush out all Rx frames before we enable RSS. To do so, we modify we
+     * redirect all Rx traffic to manageability and then reset the HW.
+     * This flushes away Rx frames, and (since the redirections to
+     * manageability persists across resets) keeps new ones from coming in
+     * while we work.  Then, we clear the Address Valid AV bit for all MAC
+     * addresses and undo the re-direction to manageability.
+     * Now, frames are coming in again, but the MAC won't accept them, so
+     * far so good.  We now proceed to initialize RSS (if necessary) and
+     * configure the Rx unit.  Last, we re-enable the AV bits and continue
+     * on our merry way.
+     */
+    switch (hw->mac_type) {
+    case e1000_82571:
+    case e1000_82572:
+        if (hw->leave_av_bit_off == TRUE)
+            break;
+    default:
+        /* Indicate to hardware the Address is Valid. */
+        rar_high |= E1000_RAH_AV;
+        break;
+    }
 
     E1000_WRITE_REG_ARRAY(hw, RA, (index << 1), rar_low);
     E1000_WRITE_REG_ARRAY(hw, RA, ((index << 1) + 1), rar_high);

drivers/net/e1000/e1000_hw.h

@@ -1361,6 +1361,7 @@ struct e1000_hw {
     boolean_t ifs_params_forced;
     boolean_t in_ifs_mode;
     boolean_t mng_reg_access_disabled;
+    boolean_t leave_av_bit_off;
 };