[PATCH] e1000: Fix PBA allocation calculations

Assign the PBA to be large enough to contain at least 2 jumbo frames on
all adapters. This dramatically increases performance on several adapters
and fixes TX performance degradation issues where the PBA was misallocated
in the old algorithm.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 86 insertions, 14 deletions

diff --git a/drivers/net/e1000/e1000_hw.h b/drivers/net/e1000/e1000_hw.h
index f4d01e169c48..15b8625c40c1 100644
--- a/drivers/net/e1000/e1000_hw.h
+++ b/drivers/net/e1000/e1000_hw.h
@@ -2422,6 +2422,7 @@ struct e1000_host_command_info {
 #define E1000_PBA_8K 0x0008    /* 8KB, default Rx allocation */
 #define E1000_PBA_12K 0x000C    /* 12KB, default Rx allocation */
 #define E1000_PBA_16K 0x0010    /* 16KB, default TX allocation */
+#define E1000_PBA_20K 0x0014
 #define E1000_PBA_22K 0x0016
 #define E1000_PBA_24K 0x0018
 #define E1000_PBA_30K 0x001E
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index e04f1ba847fd..6c3618d55d15 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -661,16 +661,34 @@ e1000_reinit_locked(struct e1000_adapter *adapter)
 void
 e1000_reset(struct e1000_adapter *adapter)
 {
-        uint32_t pba;
+        uint32_t pba = 0, tx_space, min_tx_space, min_rx_space;
         uint16_t fc_high_water_mark = E1000_FC_HIGH_DIFF;
+        boolean_t legacy_pba_adjust = FALSE;
 
         /* Repartition Pba for greater than 9k mtu
          * To take effect CTRL.RST is required.
          */
 
         switch (adapter->hw.mac_type) {
+        case e1000_82542_rev2_0:
+        case e1000_82542_rev2_1:
+        case e1000_82543:
+        case e1000_82544:
+        case e1000_82540:
+        case e1000_82541:
+        case e1000_82541_rev_2:
+                legacy_pba_adjust = TRUE;
+                pba = E1000_PBA_48K;
+                break;
+        case e1000_82545:
+        case e1000_82545_rev_3:
+        case e1000_82546:
+        case e1000_82546_rev_3:
+                pba = E1000_PBA_48K;
+                break;
         case e1000_82547:
         case e1000_82547_rev_2:
+                legacy_pba_adjust = TRUE;
                 pba = E1000_PBA_30K;
                 break;
         case e1000_82571:
@@ -679,27 +697,80 @@ e1000_reset(struct e1000_adapter *adapter)
                 pba = E1000_PBA_38K;
                 break;
         case e1000_82573:
-                pba = E1000_PBA_12K;
+                pba = E1000_PBA_20K;
                 break;
         case e1000_ich8lan:
                 pba = E1000_PBA_8K;
-                break;
-        default:
-                pba = E1000_PBA_48K;
+        case e1000_undefined:
+        case e1000_num_macs:
                 break;
         }
 
-        if ((adapter->hw.mac_type != e1000_82573) &&
-           (adapter->netdev->mtu > E1000_RXBUFFER_8192))
-                pba -= 8; /* allocate more FIFO for Tx */
+        if (legacy_pba_adjust == TRUE) {
+                if (adapter->netdev->mtu > E1000_RXBUFFER_8192)
+                        pba -= 8; /* allocate more FIFO for Tx */
 
+                if (adapter->hw.mac_type == e1000_82547) {
+                        adapter->tx_fifo_head = 0;
+                        adapter->tx_head_addr = pba << E1000_TX_HEAD_ADDR_SHIFT;
+                        adapter->tx_fifo_size =
+                                (E1000_PBA_40K - pba) << E1000_PBA_BYTES_SHIFT;
+                        atomic_set(&adapter->tx_fifo_stall, 0);
+                }
+        } else if (adapter->hw.max_frame_size > MAXIMUM_ETHERNET_FRAME_SIZE) {
+                /* adjust PBA for jumbo frames */
+                E1000_WRITE_REG(&adapter->hw, PBA, pba);
+
+                /* To maintain wire speed transmits, the Tx FIFO should be
+                 * large enough to accomodate 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
+                 * one full receive packet and is similarly rounded up and
+                 * expressed in KB. */
+                pba = E1000_READ_REG(&adapter->hw, PBA);
+                /* upper 16 bits has Tx packet buffer allocation size in KB */
+                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;
+                E1000_ROUNDUP(min_tx_space, 1024);
+                min_tx_space >>= 10;
+                E1000_ROUNDUP(min_rx_space, 1024);
+                min_rx_space >>= 10;
+
+                /* If current Tx allocation is less than the min Tx FIFO size,
+                 * and the min Tx FIFO size is less than the current Rx FIFO
+                 * allocation, take space away from current Rx allocation */
+                if (tx_space < min_tx_space &&
+                    ((min_tx_space - tx_space) < pba)) {
+                        pba = pba - (min_tx_space - tx_space);
+
+                        /* PCI/PCIx hardware has PBA alignment constraints */
+                        switch (adapter->hw.mac_type) {
+                        case e1000_82545 ... e1000_82546_rev_3:
+                                pba &= ~(E1000_PBA_8K - 1);
+                                break;
+                        default:
+                                break;
+                        }
 
-        if (adapter->hw.mac_type == e1000_82547) {
-                adapter->tx_fifo_head = 0;
-                adapter->tx_head_addr = pba << E1000_TX_HEAD_ADDR_SHIFT;
-                adapter->tx_fifo_size =
-                        (E1000_PBA_40K - pba) << E1000_PBA_BYTES_SHIFT;
-                atomic_set(&adapter->tx_fifo_stall, 0);
+                        /* if short on rx space, rx wins and must trump tx
+                         * adjustment or use Early Receive if available */
+                        if (pba < min_rx_space) {
+                                switch (adapter->hw.mac_type) {
+                                case e1000_82573:
+                                        /* ERT enabled in e1000_configure_rx */
+                                        break;
+                                default:
+                                        pba = min_rx_space;
+                                        break;
+                                }
+                        }
+                }
         }
 
         E1000_WRITE_REG(&adapter->hw, PBA, pba);