ice: Implement control of FCS/CRC stripping

The driver can allow the user to configure whether the CRC aka the FCS (Frame Check Sequence) is DMA'd to the host as part of the receive buffer. The driver usually wants this feature disabled so that the hardware checks the FCS and strips it in order to save PCI bandwidth. Control the reception of FCS to the host using the command: ethtool -K eth0 rx-fcs <on|off> The default shown in ethtool -k eth0 | grep fcs; should be "off", as the hardware will drop any frame with a bad checksum, and DMA of the checksum is useless overhead especially for small packets. Testing Hints: test the FCS/CRC arrives with received packets using tcpdump -nnpi eth0 -xxxx and it should show crc data as the last 4 bytes of the packet. Can also use wireshark to turn on CRC checking and check the data is correct. Signed-off-by: Jesse Brandeburg <[email protected]> Co-developed-by: Grzegorz Nitka <[email protected]> Signed-off-by: Grzegorz Nitka <[email protected]> Co-developed-by: Benjamin Mikailenko <[email protected]> Signed-off-by: Benjamin Mikailenko <[email protected]> Co-developed-by: Anatolii Gerasymenko <[email protected]> Signed-off-by: Anatolii Gerasymenko <[email protected]> Tested-by: Gurucharan <[email protected]> (A Contingent worker at Intel) Signed-off-by: Tony Nguyen <[email protected]>
kawasaki · Aug 18, 2022 · dddd406 · dddd406
1 parent e34cfee
commit dddd406
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Showing 7 changed files with 69 additions and 6 deletions.
diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
@@ -854,6 +854,7 @@ ice_fetch_u64_stats_per_ring(struct u64_stats_sync *syncp,
 			     struct ice_q_stats stats, u64 *pkts, u64 *bytes);
 int ice_up(struct ice_vsi *vsi);
 int ice_down(struct ice_vsi *vsi);
+int ice_down_up(struct ice_vsi *vsi);
 int ice_vsi_cfg(struct ice_vsi *vsi);
 struct ice_vsi *ice_lb_vsi_setup(struct ice_pf *pf, struct ice_port_info *pi);
 int ice_vsi_determine_xdp_res(struct ice_vsi *vsi);

diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
@@ -417,7 +417,7 @@ static int ice_setup_rx_ctx(struct ice_rx_ring *ring)
 	/* Strip the Ethernet CRC bytes before the packet is posted to host
 	 * memory.
 	 */
-	rlan_ctx.crcstrip = 1;
+	rlan_ctx.crcstrip = !(ring->flags & ICE_RX_FLAGS_CRC_STRIP_DIS);
 
 	/* L2TSEL flag defines the reported L2 Tags in the receive descriptor
 	 * and it needs to remain 1 for non-DVM capable configurations to not

diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c
@@ -1289,10 +1289,7 @@ static int ice_set_priv_flags(struct net_device *netdev, u32 flags)
 	}
 	if (test_bit(ICE_FLAG_LEGACY_RX, change_flags)) {
 		/* down and up VSI so that changes of Rx cfg are reflected. */
-		if (!test_and_set_bit(ICE_VSI_DOWN, vsi->state)) {
-			ice_down(vsi);
-			ice_up(vsi);
-		}
+		ice_down_up(vsi);
 	}
 	/* don't allow modification of this flag when a single VF is in
 	 * promiscuous mode because it's not supported

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -1562,6 +1562,22 @@ void ice_vsi_manage_rss_lut(struct ice_vsi *vsi, bool ena)
 	kfree(lut);
 }
 
+/**
+ * ice_vsi_cfg_crc_strip - Configure CRC stripping for a VSI
+ * @vsi: VSI to be configured
+ * @disable: set to true to have FCS / CRC in the frame data
+ */
+void ice_vsi_cfg_crc_strip(struct ice_vsi *vsi, bool disable)
+{
+	int i;
+
+	ice_for_each_rxq(vsi, i)
+		if (disable)
+			vsi->rx_rings[i]->flags |= ICE_RX_FLAGS_CRC_STRIP_DIS;
+		else
+			vsi->rx_rings[i]->flags &= ~ICE_RX_FLAGS_CRC_STRIP_DIS;
+}
+
 /**
  * ice_vsi_cfg_rss_lut_key - Configure RSS params for a VSI
  * @vsi: VSI to be configured
@@ -3277,6 +3293,12 @@ int ice_vsi_rebuild(struct ice_vsi *vsi, bool init_vsi)
 			 */
 			if (test_bit(ICE_FLAG_RSS_ENA, pf->flags))
 				ice_vsi_cfg_rss_lut_key(vsi);
+
+		/* disable or enable CRC stripping */
+		if (vsi->netdev)
+			ice_vsi_cfg_crc_strip(vsi, !!(vsi->netdev->features &
+					      NETIF_F_RXFCS));
+
 		break;
 	case ICE_VSI_VF:
 		ret = ice_vsi_alloc_q_vectors(vsi);

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.h b/drivers/net/ethernet/intel/ice/ice_lib.h
@@ -89,6 +89,8 @@ void ice_vsi_free_tx_rings(struct ice_vsi *vsi);
 
 void ice_vsi_manage_rss_lut(struct ice_vsi *vsi, bool ena);
 
+void ice_vsi_cfg_crc_strip(struct ice_vsi *vsi, bool disable);
+
 void ice_update_tx_ring_stats(struct ice_tx_ring *ring, u64 pkts, u64 bytes);
 
 void ice_update_rx_ring_stats(struct ice_rx_ring *ring, u64 pkts, u64 bytes);

diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -3374,6 +3374,11 @@ static void ice_set_netdev_features(struct net_device *netdev)
 	if (is_dvm_ena)
 		netdev->hw_features |= NETIF_F_HW_VLAN_STAG_RX |
 			NETIF_F_HW_VLAN_STAG_TX;
+
+	/* Leave CRC / FCS stripping enabled by default, but allow the value to
+	 * be changed at runtime
+	 */
+	netdev->hw_features |= NETIF_F_RXFCS;
 }
 
 /**
@@ -5977,6 +5982,16 @@ ice_set_features(struct net_device *netdev, netdev_features_t features)
 	if (ret)
 		return ret;
 
+	/* Turn on receive of FCS aka CRC, and after setting this
+	 * flag the packet data will have the 4 byte CRC appended
+	 */
+	if (changed & NETIF_F_RXFCS) {
+		ice_vsi_cfg_crc_strip(vsi, !!(features & NETIF_F_RXFCS));
+		ret = ice_down_up(vsi);
+		if (ret)
+			return ret;
+	}
+
 	if (changed & NETIF_F_NTUPLE) {
 		bool ena = !!(features & NETIF_F_NTUPLE);
 
@@ -6680,6 +6695,31 @@ int ice_down(struct ice_vsi *vsi)
 	return 0;
 }
 
+/**
+ * ice_down_up - shutdown the VSI connection and bring it up
+ * @vsi: the VSI to be reconnected
+ */
+int ice_down_up(struct ice_vsi *vsi)
+{
+	int ret;
+
+	/* if DOWN already set, nothing to do */
+	if (test_and_set_bit(ICE_VSI_DOWN, vsi->state))
+		return 0;
+
+	ret = ice_down(vsi);
+	if (ret)
+		return ret;
+
+	ret = ice_up(vsi);
+	if (ret) {
+		netdev_err(vsi->netdev, "reallocating resources failed during netdev features change, may need to reload driver\n");
+		return ret;
+	}
+
+	return 0;
+}
+
 /**
  * ice_vsi_setup_tx_rings - Allocate VSI Tx queue resources
  * @vsi: VSI having resources allocated

diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
@@ -295,10 +295,11 @@ struct ice_rx_ring {
 	struct xsk_buff_pool *xsk_pool;
 	struct sk_buff *skb;
 	dma_addr_t dma;			/* physical address of ring */
-#define ICE_RX_FLAGS_RING_BUILD_SKB	BIT(1)
 	u64 cached_phctime;
 	u8 dcb_tc;			/* Traffic class of ring */
 	u8 ptp_rx;
+#define ICE_RX_FLAGS_RING_BUILD_SKB	BIT(1)
+#define ICE_RX_FLAGS_CRC_STRIP_DIS	BIT(2)
 	u8 flags;
 } ____cacheline_internodealigned_in_smp;