e1000: Fix lem(4)/em(4) TSO6

* Fix TSO6 by specializing IP checksum insertion and following Intel SDM
  values for IPv6.
* Remove unnecessary 82544 IP-bit handling
* Remove TSO6 from lem(4) capabilitities

Reviewed by:	erj (earlier version)
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D41170

2 files changed, 28 insertions, 21 deletions

diff --git a/sys/dev/e1000/em_txrx.c b/sys/dev/e1000/em_txrx.c
index 0e433f388ac5..b90ab21cd825 100644
--- a/sys/dev/e1000/em_txrx.c
+++ b/sys/dev/e1000/em_txrx.c
@@ -141,7 +141,6 @@ em_tso_setup(struct e1000_softc *sc, if_pkt_info_t pi, uint32_t *txd_upper,
 	if_softc_ctx_t scctx = sc->shared;
 	struct em_tx_queue *que = &sc->tx_queues[pi->ipi_qsidx];
 	struct tx_ring *txr = &que->txr;
-	struct e1000_hw *hw = &sc->hw;
 	struct e1000_context_desc *TXD;
 	int cur, hdr_len;
 	uint32_t cmd_type_len;
@@ -151,27 +150,39 @@ em_tso_setup(struct e1000_softc *sc, if_pkt_info_t pi, uint32_t *txd_upper,
 		      E1000_TXD_DTYP_D |	/* Data descr type */
 		      E1000_TXD_CMD_TSE);	/* Do TSE on this packet */
 
-	/* IP and/or TCP header checksum calculation and insertion. */
-	*txd_upper = (E1000_TXD_POPTS_IXSM | E1000_TXD_POPTS_TXSM) << 8;
-
 	cur = pi->ipi_pidx;
 	TXD = (struct e1000_context_desc *)&txr->tx_base[cur];
 
 	/*
-	 * Start offset for header checksum calculation.
-	 * End offset for header checksum calculation.
-	 * Offset of place put the checksum.
+	 * ipcss - Start offset for header checksum calculation.
+	 * ipcse - End offset for header checksum calculation.
+	 * ipcso - Offset of place to put the checksum.
 	 */
+	switch(pi->ipi_etype) {
+	case ETHERTYPE_IP:
+		/* IP and/or TCP header checksum calculation and insertion. */
+		*txd_upper = (E1000_TXD_POPTS_IXSM | E1000_TXD_POPTS_TXSM) << 8;
+
+		TXD->lower_setup.ip_fields.ipcse =
+		    htole16(pi->ipi_ehdrlen + pi->ipi_ip_hlen - 1);
+		break;
+	case ETHERTYPE_IPV6:
+		/* TCP header checksum calculation and insertion. */
+		*txd_upper = E1000_TXD_POPTS_TXSM << 8;
+
+		TXD->lower_setup.ip_fields.ipcse = htole16(0);
+		break;
+	default:
+		break;
+	}
 	TXD->lower_setup.ip_fields.ipcss = pi->ipi_ehdrlen;
-	TXD->lower_setup.ip_fields.ipcse =
-	    htole16(pi->ipi_ehdrlen + pi->ipi_ip_hlen - 1);
 	TXD->lower_setup.ip_fields.ipcso =
 	    pi->ipi_ehdrlen + offsetof(struct ip, ip_sum);
 
 	/*
-	 * Start offset for payload checksum calculation.
-	 * End offset for payload checksum calculation.
-	 * Offset of place to put the checksum.
+	 * tucss - Start offset for payload checksum calculation.
+	 * tucse - End offset for payload checksum calculation.
+	 * tucso - Offset of place to put the checksum.
 	 */
 	TXD->upper_setup.tcp_fields.tucss = pi->ipi_ehdrlen + pi->ipi_ip_hlen;
 	TXD->upper_setup.tcp_fields.tucse = 0;
@@ -188,16 +199,13 @@ em_tso_setup(struct e1000_softc *sc, if_pkt_info_t pi, uint32_t *txd_upper,
 	/*
 	 * "PCI/PCI-X SDM 4.0" page 45, and "PCIe GbE SDM 2.5" page 63
 	 * - Set up basic TUCMDs
-	 * - Enable IP bit on 82544
 	 * - For others IP bit on indicates IPv4, while off indicates IPv6
 	*/
 	cmd_type_len = sc->txd_cmd |
 	    E1000_TXD_CMD_DEXT | /* Extended descr */
 	    E1000_TXD_CMD_TSE |  /* TSE context */
 	    E1000_TXD_CMD_TCP;   /* Do TCP checksum */
-	if (hw->mac.type == e1000_82544)
-		cmd_type_len |= E1000_TXD_CMD_IP;
-	else if (pi->ipi_etype == ETHERTYPE_IP)
+	if (pi->ipi_etype == ETHERTYPE_IP)
 		cmd_type_len |= E1000_TXD_CMD_IP;
 	TXD->cmd_and_length = htole32(cmd_type_len |
 	    (pi->ipi_len - hdr_len)); /* Total len */
diff --git a/sys/dev/e1000/if_em.c b/sys/dev/e1000/if_em.c
index 1f6100cff293..40579b0a5a55 100644
--- a/sys/dev/e1000/if_em.c
+++ b/sys/dev/e1000/if_em.c
@@ -784,8 +784,7 @@ em_set_num_queues(if_ctx_t ctx)
 #define LEM_CAPS \
     IFCAP_HWCSUM | IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | \
     IFCAP_VLAN_HWCSUM | IFCAP_WOL | IFCAP_VLAN_HWFILTER | IFCAP_TSO4 | \
-    IFCAP_LRO | IFCAP_VLAN_HWTSO| IFCAP_JUMBO_MTU | IFCAP_HWCSUM_IPV6 | \
-    IFCAP_TSO6
+    IFCAP_LRO | IFCAP_VLAN_HWTSO | IFCAP_JUMBO_MTU | IFCAP_HWCSUM_IPV6
 
 #define EM_CAPS \
     IFCAP_HWCSUM | IFCAP_VLAN_MTU | IFCAP_VLAN_HWTAGGING | \
@@ -937,14 +936,14 @@ em_if_attach_pre(if_ctx_t ctx)
 		scctx->isc_tx_tso_segments_max = EM_MAX_SCATTER;
 		scctx->isc_tx_tso_size_max = EM_TSO_SIZE;
 		scctx->isc_tx_tso_segsize_max = EM_TSO_SEG_SIZE;
-		scctx->isc_capabilities = scctx->isc_capenable = EM_CAPS;
+		scctx->isc_capabilities = scctx->isc_capenable = LEM_CAPS;
 		/*
-		 * For LEM-class devices, don't enable IFCAP_{TSO4,VLAN_HWTSO,TSO6}
+		 * For LEM-class devices, don't enable IFCAP_{TSO4,VLAN_HWTSO}
 		 * by default as we don't have workarounds for all associated
 		 * silicon errata.  TSO4 may work on > 82544 but its status
 		 * is unknown by the authors.  Please report any success or failures.
 		 */
-		scctx->isc_capenable &= ~(IFCAP_TSO4 | IFCAP_VLAN_HWTSO | IFCAP_TSO6);
+		scctx->isc_capenable &= ~(IFCAP_TSO4 | IFCAP_VLAN_HWTSO);
 		scctx->isc_tx_csum_flags = CSUM_TCP | CSUM_UDP | CSUM_IP_TSO |
 		    CSUM_IP6_TCP | CSUM_IP6_UDP;