e1000: add dynamic generic MSI interrupt routine

Add a generic MSI interrupt routine that is IO read-free, speeding up
MSI interrupt handling.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>

1 files changed, 88 insertions, 2 deletions

diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index fe22ae8f0a3d..35e4e32c7702 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -157,6 +157,9 @@ static struct net_device_stats * e1000_get_stats(struct net_device *netdev);
 static int e1000_change_mtu(struct net_device *netdev, int new_mtu);
 static int e1000_set_mac(struct net_device *netdev, void *p);
 static irqreturn_t e1000_intr(int irq, void *data);
+#ifdef CONFIG_PCI_MSI
+static irqreturn_t e1000_intr_msi(int irq, void *data);
+#endif
 static boolean_t e1000_clean_tx_irq(struct e1000_adapter *adapter,
                                     struct e1000_tx_ring *tx_ring);
 #ifdef CONFIG_E1000_NAPI
@@ -288,7 +291,7 @@ static int e1000_request_irq(struct e1000_adapter *adapter)
 
         flags = IRQF_SHARED;
 #ifdef CONFIG_PCI_MSI
-        if (adapter->hw.mac_type > e1000_82547_rev_2) {
+        if (adapter->hw.mac_type >= e1000_82571) {
                 adapter->have_msi = TRUE;
                 if ((err = pci_enable_msi(adapter->pdev))) {
                         DPRINTK(PROBE, ERR,
@@ -296,8 +299,14 @@ static int e1000_request_irq(struct e1000_adapter *adapter)
                         adapter->have_msi = FALSE;
                 }
         }
-        if (adapter->have_msi)
+        if (adapter->have_msi) {
                 flags &= ~IRQF_SHARED;
+                err = request_irq(adapter->pdev->irq, &e1000_intr_msi, flags,
+                                  netdev->name, netdev);
+                if (err)
+                        DPRINTK(PROBE, ERR,
+                               "Unable to allocate interrupt Error: %d\n", err);
+        } else
 #endif
         if ((err = request_irq(adapter->pdev->irq, &e1000_intr, flags,
                                netdev->name, netdev)))
@@ -3466,6 +3475,83 @@ e1000_update_stats(struct e1000_adapter *adapter)
 
         spin_unlock_irqrestore(&adapter->stats_lock, flags);
 }
+#ifdef CONFIG_PCI_MSI
+
+/**
+ * e1000_intr_msi - Interrupt Handler
+ * @irq: interrupt number
+ * @data: pointer to a network interface device structure
+ **/
+
+static
+irqreturn_t e1000_intr_msi(int irq, void *data)
+{
+        struct net_device *netdev = data;
+        struct e1000_adapter *adapter = netdev_priv(netdev);
+        struct e1000_hw *hw = &adapter->hw;
+#ifndef CONFIG_E1000_NAPI
+        int i;
+#endif
+
+        /* this code avoids the read of ICR but has to get 1000 interrupts
+         * at every link change event before it will notice the change */
+        if (++adapter->detect_link >= 1000) {
+                uint32_t icr = E1000_READ_REG(hw, ICR);
+#ifdef CONFIG_E1000_NAPI
+                /* read ICR disables interrupts using IAM, so keep up with our
+                 * enable/disable accounting */
+                atomic_inc(&adapter->irq_sem);
+#endif
+                adapter->detect_link = 0;
+                if ((icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC)) &&
+                    (icr & E1000_ICR_INT_ASSERTED)) {
+                        hw->get_link_status = 1;
+                        /* 80003ES2LAN workaround--
+                        * For packet buffer work-around on link down event;
+                        * disable receives here in the ISR and
+                        * reset adapter in watchdog
+                        */
+                        if (netif_carrier_ok(netdev) &&
+                            (adapter->hw.mac_type == e1000_80003es2lan)) {
+                                /* disable receives */
+                                uint32_t rctl = E1000_READ_REG(hw, RCTL);
+                                E1000_WRITE_REG(hw, RCTL, rctl & ~E1000_RCTL_EN);
+                        }
+                        /* guard against interrupt when we're going down */
+                        if (!test_bit(__E1000_DOWN, &adapter->flags))
+                                mod_timer(&adapter->watchdog_timer,
+                                          jiffies + 1);
+                }
+        } else {
+                E1000_WRITE_REG(hw, ICR, (0xffffffff & ~(E1000_ICR_RXSEQ |
+                                                         E1000_ICR_LSC)));
+                /* bummer we have to flush here, but things break otherwise as
+                 * some event appears to be lost or delayed and throughput
+                 * drops.  In almost all tests this flush is un-necessary */
+                E1000_WRITE_FLUSH(hw);
+#ifdef CONFIG_E1000_NAPI
+                /* Interrupt Auto-Mask (IAM)...upon writing ICR, interrupts are
+                 * masked.  No need for the IMC write, but it does mean we
+                 * should account for it ASAP. */
+                atomic_inc(&adapter->irq_sem);
+#endif
+        }
+
+#ifdef CONFIG_E1000_NAPI
+        if (likely(netif_rx_schedule_prep(netdev)))
+                __netif_rx_schedule(netdev);
+        else
+                e1000_irq_enable(adapter);
+#else
+        for (i = 0; i < E1000_MAX_INTR; i++)
+                if (unlikely(!adapter->clean_rx(adapter, adapter->rx_ring) &
+                   !e1000_clean_tx_irq(adapter, adapter->tx_ring)))
+                        break;
+#endif
+
+        return IRQ_HANDLED;
+}
+#endif
 
 /**
  * e1000_intr - Interrupt Handler