em: Fix "Missing Interrupt Following ICR read" errata

IMS should be set to 0 before reading ICR.  It should be noted that
once IMS is 0, ICR.INT_ASSERTED will not be set, which is not mentioned
in the datasheet.

This errata exists on 82571, 82572, 82573, 82574 and 82583.  And the fix
is needed only if the legacy interrupt is used and the interrupt line is
shared with other devices.

hw.emX.irq.unshared tunable is added to give a hint to the driver that
the legacy interrupt is not shared with other devices.

diff --git a/sys/dev/netif/em/if_em.c b/sys/dev/netif/em/if_em.c
index 6abf0f7..2aeb5eb 100644 (file)
--- a/sys/dev/netif/em/if_em.c
+++ b/sys/dev/netif/em/if_em.c
@@ -283,6 +283,8 @@ static int  em_media_change(struct ifnet *);
 static void    em_timer(void *);
 
 static void    em_intr(void *);
+static void    em_intr_mask(void *);
+static void    em_intr_body(struct adapter *, boolean_t);
 static void    em_rxeof(struct adapter *, int);
 static void    em_txeof(struct adapter *);
 static void    em_tx_collect(struct adapter *);
@@ -438,6 +440,7 @@ em_attach(device_t dev)
        int tsize, rsize;
        int error = 0;
        uint16_t eeprom_data, device_id, apme_mask;
+       driver_intr_t *intr_func;
 
        adapter->dev = adapter->osdep.dev = dev;
 
@@ -811,8 +814,25 @@ em_attach(device_t dev)
            adapter->hw.mac.type >= e1000_82571)
                em_get_hw_control(adapter);
 
+       /*
+        * Missing Interrupt Following ICR read:
+        *
+        * 82571/82572 specification update #76
+        * 82573 specification update #31
+        * 82574 specification update #12
+        * 82583 specification update #4
+        */
+       intr_func = em_intr;
+       if ((adapter->flags & EM_FLAG_SHARED_INTR) &&
+           (adapter->hw.mac.type == e1000_82571 ||
+            adapter->hw.mac.type == e1000_82572 ||
+            adapter->hw.mac.type == e1000_82573 ||
+            adapter->hw.mac.type == e1000_82574 ||
+            adapter->hw.mac.type == e1000_82583))
+               intr_func = em_intr_mask;
+
        error = bus_setup_intr(dev, adapter->intr_res, INTR_MPSAFE,
-                              em_intr, adapter, &adapter->intr_tag,
+                              intr_func, adapter, &adapter->intr_tag,
                               ifp->if_serializer);
        if (error) {
                device_printf(dev, "Failed to register interrupt handler");
@@ -1391,7 +1411,12 @@ em_poll(struct ifnet *ifp, enum poll_cmd cmd, int count)
 static void
 em_intr(void *xsc)
 {
-       struct adapter *adapter = xsc;
+       em_intr_body(xsc, TRUE);
+}
+
+static void
+em_intr_body(struct adapter *adapter, boolean_t chk_asserted)
+{
        struct ifnet *ifp = &adapter->arpcom.ac_if;
        uint32_t reg_icr;
 
@@ -1400,9 +1425,10 @@ em_intr(void *xsc)
 
        reg_icr = E1000_READ_REG(&adapter->hw, E1000_ICR);
 
-       if ((adapter->hw.mac.type >= e1000_82571 &&
-            (reg_icr & E1000_ICR_INT_ASSERTED) == 0) ||
-           reg_icr == 0) {
+       if (chk_asserted &&
+           ((adapter->hw.mac.type >= e1000_82571 &&
+             (reg_icr & E1000_ICR_INT_ASSERTED) == 0) ||
+            reg_icr == 0)) {
                logif(intr_end);
                return;
        }
@@ -1448,6 +1474,21 @@ em_intr(void *xsc)
 }
 
 static void
+em_intr_mask(void *xsc)
+{
+       struct adapter *adapter = xsc;
+
+       E1000_WRITE_REG(&adapter->hw, E1000_IMC, 0xffffffff);
+       /*
+        * NOTE:
+        * ICR.INT_ASSERTED bit will never be set if IMS is 0,
+        * so don't check it.
+        */
+       em_intr_body(adapter, FALSE);
+       E1000_WRITE_REG(&adapter->hw, E1000_IMS, IMS_ENABLE_MASK);
+}
+
+static void
 em_media_status(struct ifnet *ifp, struct ifmediareq *ifmr)
 {
        struct adapter *adapter = ifp->if_softc;
@@ -2196,6 +2237,21 @@ em_alloc_pci_res(struct adapter *adapter)
        adapter->intr_type = pci_alloc_1intr(dev, msi_enable,
            &adapter->intr_rid, &intr_flags);
 
+       if (adapter->intr_type == PCI_INTR_TYPE_LEGACY) {
+               int unshared;
+
+               unshared = device_getenv_int(dev, "irq.unshared", 0);
+               if (!unshared) {
+                       adapter->flags |= EM_FLAG_SHARED_INTR;
+                       if (bootverbose)
+                               device_printf(dev, "IRQ shared\n");
+               } else {
+                       intr_flags &= ~RF_SHAREABLE;
+                       if (bootverbose)
+                               device_printf(dev, "IRQ unshared\n");
+               }
+       }
+
        adapter->intr_res = bus_alloc_resource_any(dev, SYS_RES_IRQ,
            &adapter->intr_rid, intr_flags);
        if (adapter->intr_res == NULL) {

diff --git a/sys/dev/netif/em/if_em.h b/sys/dev/netif/em/if_em.h
index 1d8ec54..c5b8112 100644 (file)
--- a/sys/dev/netif/em/if_em.h
+++ b/sys/dev/netif/em/if_em.h
@@ -247,6 +247,8 @@ struct em_dma_alloc {
 struct adapter {
        struct arpcom           arpcom;
        struct e1000_hw         hw;
+       int                     flags;
+#define EM_FLAG_SHARED_INTR    0x1
 
        /* DragonFly operating-system-specific structures. */
        struct e1000_osdep      osdep;