e1000e: Program the correct register for ITR when using MSI-X.

When configuring interrupt throttling on 82574 in MSI-X mode, we need to
be programming the EITR registers instead of the ITR register.

-rc2: Renamed e1000_write_itr() to e1000e_write_itr(), fixed whitespace
      issues, and removed unnecessary !! operation.
-rc3: Reduced the scope of the loop variable in e1000e_write_itr().

Signed-off-by: Matthew Vick <matthew.vick@intel.com>
Acked-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>

3 files changed, 31 insertions, 7 deletions

diff --git a/drivers/net/ethernet/intel/e1000e/e1000.h b/drivers/net/ethernet/intel/e1000e/e1000.h
index 6e6fffb34581..cd153326c3cf 100644
--- a/drivers/net/ethernet/intel/e1000e/e1000.h
+++ b/drivers/net/ethernet/intel/e1000e/e1000.h
@@ -514,6 +514,7 @@ extern void e1000e_set_interrupt_capability(struct e1000_adapter *adapter);
 extern void e1000e_reset_interrupt_capability(struct e1000_adapter *adapter);
 extern void e1000e_get_hw_control(struct e1000_adapter *adapter);
 extern void e1000e_release_hw_control(struct e1000_adapter *adapter);
+extern void e1000e_write_itr(struct e1000_adapter *adapter, u32 itr);
 
 extern unsigned int copybreak;
 
diff --git a/drivers/net/ethernet/intel/e1000e/ethtool.c b/drivers/net/ethernet/intel/e1000e/ethtool.c
index 905e2147d918..105d554ea9db 100644
--- a/drivers/net/ethernet/intel/e1000e/ethtool.c
+++ b/drivers/net/ethernet/intel/e1000e/ethtool.c
@@ -1897,7 +1897,6 @@ static int e1000_set_coalesce(struct net_device *netdev,
                               struct ethtool_coalesce *ec)
 {
         struct e1000_adapter *adapter = netdev_priv(netdev);
-        struct e1000_hw *hw = &adapter->hw;
 
         if ((ec->rx_coalesce_usecs > E1000_MAX_ITR_USECS) ||
             ((ec->rx_coalesce_usecs > 4) &&
@@ -1916,9 +1915,9 @@ static int e1000_set_coalesce(struct net_device *netdev,
         }
 
         if (adapter->itr_setting != 0)
-                ew32(ITR, 1000000000 / (adapter->itr * 256));
+                e1000e_write_itr(adapter, adapter->itr);
         else
-                ew32(ITR, 0);
+                e1000e_write_itr(adapter, 0);
 
         return 0;
 }
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index ca477e87eb87..95b245310f17 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -2474,6 +2474,30 @@ set_itr_now:
 }
 
 /**
+ * e1000e_write_itr - write the ITR value to the appropriate registers
+ * @adapter: address of board private structure
+ * @itr: new ITR value to program
+ *
+ * e1000e_write_itr determines if the adapter is in MSI-X mode
+ * and, if so, writes the EITR registers with the ITR value.
+ * Otherwise, it writes the ITR value into the ITR register.
+ **/
+void e1000e_write_itr(struct e1000_adapter *adapter, u32 itr)
+{
+        struct e1000_hw *hw = &adapter->hw;
+        u32 new_itr = itr ? 1000000000 / (itr * 256) : 0;
+
+        if (adapter->msix_entries) {
+                int vector;
+
+                for (vector = 0; vector < adapter->num_vectors; vector++)
+                        writel(new_itr, hw->hw_addr + E1000_EITR_82574(vector));
+        } else {
+                ew32(ITR, new_itr);
+        }
+}
+
+/**
  * e1000_alloc_queues - Allocate memory for all rings
  * @adapter: board private structure to initialize
  **/
@@ -3059,7 +3083,7 @@ static void e1000_configure_rx(struct e1000_adapter *adapter)
         /* irq moderation */
         ew32(RADV, adapter->rx_abs_int_delay);
         if ((adapter->itr_setting != 0) && (adapter->itr != 0))
-                ew32(ITR, 1000000000 / (adapter->itr * 256));
+                e1000e_write_itr(adapter, adapter->itr);
 
         ctrl_ext = er32(CTRL_EXT);
         /* Auto-Mask interrupts upon ICR access */
@@ -3486,14 +3510,14 @@ void e1000e_reset(struct e1000_adapter *adapter)
                                 dev_info(&adapter->pdev->dev,
                                         "Interrupt Throttle Rate turned off\n");
                                 adapter->flags2 |= FLAG2_DISABLE_AIM;
-                                ew32(ITR, 0);
+                                e1000e_write_itr(adapter, 0);
                         }
                 } else if (adapter->flags2 & FLAG2_DISABLE_AIM) {
                         dev_info(&adapter->pdev->dev,
                                  "Interrupt Throttle Rate turned on\n");
                         adapter->flags2 &= ~FLAG2_DISABLE_AIM;
                         adapter->itr = 20000;
-                        ew32(ITR, 1000000000 / (adapter->itr * 256));
+                        e1000e_write_itr(adapter, adapter->itr);
                 }
         }
 
@@ -4576,7 +4600,7 @@ link_up:
                             adapter->gorc - adapter->gotc) / 10000;
                 u32 itr = goc > 0 ? (dif * 6000 / goc + 2000) : 8000;
 
-                ew32(ITR, 1000000000 / (itr * 256));
+                e1000e_write_itr(adapter, itr);
         }
 
         /* Cause software interrupt to ensure Rx ring is cleaned */