e1000e: perform 10/100 adaptive IFS only on parts that support it

Adaptive IFS which involves writing to the Adaptive IFS Throttle register
was being done for all devices supported by the driver even though it is
not supported (i.e. the register doesn't even exist) on some devices.  The
feature is supported on 8257x/82583 and ICH/PCH based devices, but not
on ESB2.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 21 insertions, 0 deletions

diff --git a/drivers/net/e1000e/82571.c b/drivers/net/e1000e/82571.c
index b979464091b..02d67d047d9 100644
--- a/drivers/net/e1000e/82571.c
+++ b/drivers/net/e1000e/82571.c
@@ -237,6 +237,8 @@ static s32 e1000_init_mac_params_82571(struct e1000_adapter *adapter)
         /* Set if manageability features are enabled. */
         mac->arc_subsystem_valid = (er32(FWSM) & E1000_FWSM_MODE_MASK)
                         ? true : false;
+        /* Adaptive IFS supported */
+        mac->adaptive_ifs = true;
 
         /* check for link */
         switch (hw->phy.media_type) {
diff --git a/drivers/net/e1000e/es2lan.c b/drivers/net/e1000e/es2lan.c
index 3028f23da89..e2aa3b78856 100644
--- a/drivers/net/e1000e/es2lan.c
+++ b/drivers/net/e1000e/es2lan.c
@@ -224,6 +224,8 @@ static s32 e1000_init_mac_params_80003es2lan(struct e1000_adapter *adapter)
         /* Set if manageability features are enabled. */
         mac->arc_subsystem_valid = (er32(FWSM) & E1000_FWSM_MODE_MASK)
                         ? true : false;
+        /* Adaptive IFS not supported */
+        mac->adaptive_ifs = false;
 
         /* check for link */
         switch (hw->phy.media_type) {
diff --git a/drivers/net/e1000e/hw.h b/drivers/net/e1000e/hw.h
index 2784cf44a6f..eccf29b75c4 100644
--- a/drivers/net/e1000e/hw.h
+++ b/drivers/net/e1000e/hw.h
@@ -818,6 +818,7 @@ struct e1000_mac_info {
 
         u8  forced_speed_duplex;
 
+        bool adaptive_ifs;
         bool arc_subsystem_valid;
         bool autoneg;
         bool autoneg_failed;
diff --git a/drivers/net/e1000e/ich8lan.c b/drivers/net/e1000e/ich8lan.c
index 9b09246af06..ad08cf3f40c 100644
--- a/drivers/net/e1000e/ich8lan.c
+++ b/drivers/net/e1000e/ich8lan.c
@@ -454,6 +454,8 @@ static s32 e1000_init_mac_params_ich8lan(struct e1000_adapter *adapter)
                 mac->rar_entry_count--;
         /* Set if manageability features are enabled. */
         mac->arc_subsystem_valid = true;
+        /* Adaptive IFS supported */
+        mac->adaptive_ifs = true;
 
         /* LED operations */
         switch (mac->type) {
diff --git a/drivers/net/e1000e/lib.c b/drivers/net/e1000e/lib.c
index a86c17548c1..56b59e4a687 100644
--- a/drivers/net/e1000e/lib.c
+++ b/drivers/net/e1000e/lib.c
@@ -1609,6 +1609,11 @@ void e1000e_reset_adaptive(struct e1000_hw *hw)
 {
         struct e1000_mac_info *mac = &hw->mac;
 
+        if (!mac->adaptive_ifs) {
+                e_dbg("Not in Adaptive IFS mode!\n");
+                goto out;
+        }
+
         mac->current_ifs_val = 0;
         mac->ifs_min_val = IFS_MIN;
         mac->ifs_max_val = IFS_MAX;
@@ -1617,6 +1622,8 @@ void e1000e_reset_adaptive(struct e1000_hw *hw)
 
         mac->in_ifs_mode = false;
         ew32(AIT, 0);
+out:
+        return;
 }
 
 /**
@@ -1630,6 +1637,11 @@ void e1000e_update_adaptive(struct e1000_hw *hw)
 {
         struct e1000_mac_info *mac = &hw->mac;
 
+        if (!mac->adaptive_ifs) {
+                e_dbg("Not in Adaptive IFS mode!\n");
+                goto out;
+        }
+
         if ((mac->collision_delta * mac->ifs_ratio) > mac->tx_packet_delta) {
                 if (mac->tx_packet_delta > MIN_NUM_XMITS) {
                         mac->in_ifs_mode = true;
@@ -1650,6 +1662,8 @@ void e1000e_update_adaptive(struct e1000_hw *hw)
                         ew32(AIT, 0);
                 }
         }
+out:
+        return;
 }
 
 /**