1 files changed, 32 insertions, 26 deletions

diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index f2db9e2069e7..d7df00c2dbd6 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -641,8 +641,8 @@ void e1000_reset(struct e1000_adapter *adapter)
 {
         struct e1000_hw *hw = &adapter->hw;
         u32 pba = 0, tx_space, min_tx_space, min_rx_space;
-        u16 fc_high_water_mark = E1000_FC_HIGH_DIFF;
         bool legacy_pba_adjust = false;
+        u16 hwm;
 
         /* Repartition Pba for greater than 9k mtu
          * To take effect CTRL.RST is required.
@@ -686,7 +686,7 @@ void e1000_reset(struct e1000_adapter *adapter)
         }
 
         if (legacy_pba_adjust) {
-                if (adapter->netdev->mtu > E1000_RXBUFFER_8192)
+                if (hw->max_frame_size > E1000_RXBUFFER_8192)
                         pba -= 8; /* allocate more FIFO for Tx */
 
                 if (hw->mac_type == e1000_82547) {
@@ -696,14 +696,14 @@ void e1000_reset(struct e1000_adapter *adapter)
                                 (E1000_PBA_40K - pba) << E1000_PBA_BYTES_SHIFT;
                         atomic_set(&adapter->tx_fifo_stall, 0);
                 }
-        } else if (hw->max_frame_size > MAXIMUM_ETHERNET_FRAME_SIZE) {
+        } else if (hw->max_frame_size >  ETH_FRAME_LEN + ETH_FCS_LEN) {
                 /* adjust PBA for jumbo frames */
                 ew32(PBA, pba);
 
                 /* To maintain wire speed transmits, the Tx FIFO should be
-                 * large enough to accomodate two full transmit packets,
+                 * large enough to accommodate two full transmit packets,
                  * rounded up to the next 1KB and expressed in KB.  Likewise,
-                 * the Rx FIFO should be large enough to accomodate at least
+                 * the Rx FIFO should be large enough to accommodate at least
                  * one full receive packet and is similarly rounded up and
                  * expressed in KB. */
                 pba = er32(PBA);
@@ -711,13 +711,17 @@ void e1000_reset(struct e1000_adapter *adapter)
                 tx_space = pba >> 16;
                 /* lower 16 bits has Rx packet buffer allocation size in KB */
                 pba &= 0xffff;
-                /* don't include ethernet FCS because hardware appends/strips */
-                min_rx_space = adapter->netdev->mtu + ENET_HEADER_SIZE +
-                               VLAN_TAG_SIZE;
-                min_tx_space = min_rx_space;
-                min_tx_space *= 2;
+                /*
+                 * the tx fifo also stores 16 bytes of information about the tx
+                 * but don't include ethernet FCS because hardware appends it
+                 */
+                min_tx_space = (hw->max_frame_size +
+                                sizeof(struct e1000_tx_desc) -
+                                ETH_FCS_LEN) * 2;
                 min_tx_space = ALIGN(min_tx_space, 1024);
                 min_tx_space >>= 10;
+                /* software strips receive CRC, so leave room for it */
+                min_rx_space = hw->max_frame_size;
                 min_rx_space = ALIGN(min_rx_space, 1024);
                 min_rx_space >>= 10;
 
@@ -754,19 +758,21 @@ void e1000_reset(struct e1000_adapter *adapter)
 
         ew32(PBA, pba);
 
-        /* flow control settings */
-        /* Set the FC high water mark to 90% of the FIFO size.
-         * Required to clear last 3 LSB */
-        fc_high_water_mark = ((pba * 9216)/10) & 0xFFF8;
-        /* We can't use 90% on small FIFOs because the remainder
-         * would be less than 1 full frame.  In this case, we size
-         * it to allow at least a full frame above the high water
-         *  mark. */
-        if (pba < E1000_PBA_16K)
-                fc_high_water_mark = (pba * 1024) - 1600;
-
-        hw->fc_high_water = fc_high_water_mark;
-        hw->fc_low_water = fc_high_water_mark - 8;
+        /*
+         * flow control settings:
+         * The high water mark must be low enough to fit one full frame
+         * (or the size used for early receive) above it in the Rx FIFO.
+         * Set it to the lower of:
+         * - 90% of the Rx FIFO size, and
+         * - the full Rx FIFO size minus the early receive size (for parts
+         *   with ERT support assuming ERT set to E1000_ERT_2048), or
+         * - the full Rx FIFO size minus one full frame
+         */
+        hwm = min(((pba << 10) * 9 / 10),
+                  ((pba << 10) - hw->max_frame_size));
+
+        hw->fc_high_water = hwm & 0xFFF8;       /* 8-byte granularity */
+        hw->fc_low_water = hw->fc_high_water - 8;
         hw->fc_pause_time = E1000_FC_PAUSE_TIME;
         hw->fc_send_xon = 1;
         hw->fc = hw->original_fc;
@@ -3474,7 +3480,7 @@ static int e1000_change_mtu(struct net_device *netdev, int new_mtu)
         switch (hw->mac_type) {
         case e1000_undefined ... e1000_82542_rev2_1:
         case e1000_ich8lan:
-                if (max_frame > MAXIMUM_ETHERNET_FRAME_SIZE) {
+                if (max_frame > (ETH_FRAME_LEN + ETH_FCS_LEN)) {
                         DPRINTK(PROBE, ERR, "Jumbo Frames not supported.\n");
                         return -EINVAL;
                 }
@@ -3487,7 +3493,7 @@ static int e1000_change_mtu(struct net_device *netdev, int new_mtu)
                                   &eeprom_data);
                 if ((hw->device_id != E1000_DEV_ID_82573L) ||
                     (eeprom_data & EEPROM_WORD1A_ASPM_MASK)) {
-                        if (max_frame > MAXIMUM_ETHERNET_FRAME_SIZE) {
+                        if (max_frame > (ETH_FRAME_LEN + ETH_FCS_LEN)) {
                                 DPRINTK(PROBE, ERR,
                                         "Jumbo Frames not supported.\n");
                                 return -EINVAL;
@@ -3535,7 +3541,7 @@ static int e1000_change_mtu(struct net_device *netdev, int new_mtu)
 
         /* adjust allocation if LPE protects us, and we aren't using SBP */
         if (!hw->tbi_compatibility_on &&
-            ((max_frame == MAXIMUM_ETHERNET_FRAME_SIZE) ||
+            ((max_frame == (ETH_FRAME_LEN + ETH_FCS_LEN)) ||
              (max_frame == MAXIMUM_ETHERNET_VLAN_SIZE)))
                 adapter->rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE;