i40e/i40evf: Add legacy-rx private flag to allow fallback to old Rx flow

This patch adds a control which will allow us to toggle into and out of the
legacy Rx mode.  The legacy Rx mode is what we currently do when performing
Rx.  As I make further changes what should happen is that the driver will
fall back to the behavior for Rx as of this patch should the "legacy-rx"
flag be set to on.

Change-ID: I0342998849bbb31351cce05f6e182c99174e7751
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e.h

@@ -430,6 +430,7 @@ struct i40e_pf {
 #define I40E_FLAG_TEMP_LINK_POLLING		BIT_ULL(55)
 #define I40E_FLAG_CLIENT_L2_CHANGE		BIT_ULL(56)
 #define I40E_FLAG_WOL_MC_MAGIC_PKT_WAKE		BIT_ULL(57)
+#define I40E_FLAG_LEGACY_RX			BIT_ULL(58)
 
 	/* Tracks features that are disabled due to hw limitations.
 	 * If a bit is set here, it means that the corresponding

drivers/net/ethernet/intel/i40e/i40e_ethtool.c

@@ -226,6 +226,7 @@ static const struct i40e_priv_flags i40e_gstrings_priv_flags[] = {
 	I40E_PRIV_FLAG("flow-director-atr", I40E_FLAG_FD_ATR_ENABLED, 0),
 	I40E_PRIV_FLAG("veb-stats", I40E_FLAG_VEB_STATS_ENABLED, 0),
 	I40E_PRIV_FLAG("hw-atr-eviction", I40E_FLAG_HW_ATR_EVICT_CAPABLE, 0),
+	I40E_PRIV_FLAG("legacy-rx", I40E_FLAG_LEGACY_RX, 0),
 };
 
 #define I40E_PRIV_FLAGS_STR_LEN ARRAY_SIZE(i40e_gstrings_priv_flags)
@@ -4055,6 +4056,7 @@ static int i40e_set_priv_flags(struct net_device *dev, u32 flags)
 	}
 
 flags_complete:
+	/* check for flags that changed */
 	changed_flags ^= pf->flags;
 
 	/* Process any additional changes needed as a result of flag changes.
@@ -4095,7 +4097,8 @@ flags_complete:
 	/* Issue reset to cause things to take effect, as additional bits
 	 * are added we will need to create a mask of bits requiring reset
 	 */
-	if (changed_flags & I40E_FLAG_VEB_STATS_ENABLED)
+	if ((changed_flags & I40E_FLAG_VEB_STATS_ENABLED) ||
+	    ((changed_flags & I40E_FLAG_LEGACY_RX) && netif_running(dev)))
 		i40e_do_reset(pf, BIT(__I40E_PF_RESET_REQUESTED));
 
 	return 0;

drivers/net/ethernet/intel/i40evf/i40evf.h

@@ -222,6 +222,7 @@ struct i40evf_adapter {
 #define I40EVF_FLAG_CLIENT_NEEDS_L2_PARAMS	BIT(17)
 #define I40EVF_FLAG_PROMISC_ON			BIT(18)
 #define I40EVF_FLAG_ALLMULTI_ON			BIT(19)
+#define I40EVF_FLAG_LEGACY_RX			BIT(20)
 /* duplicates for common code */
 #define I40E_FLAG_FDIR_ATR_ENABLED		0
 #define I40E_FLAG_DCB_ENABLED			0
@@ -229,6 +230,7 @@ struct i40evf_adapter {
 #define I40E_FLAG_RX_CSUM_ENABLED		I40EVF_FLAG_RX_CSUM_ENABLED
 #define I40E_FLAG_WB_ON_ITR_CAPABLE		I40EVF_FLAG_WB_ON_ITR_CAPABLE
 #define I40E_FLAG_OUTER_UDP_CSUM_CAPABLE	I40EVF_FLAG_OUTER_UDP_CSUM_CAPABLE
+#define I40E_FLAG_LEGACY_RX			I40EVF_FLAG_LEGACY_RX
 	/* flags for admin queue service task */
 	u32 aq_required;
 #define I40EVF_FLAG_AQ_ENABLE_QUEUES		BIT(0)

drivers/net/ethernet/intel/i40evf/i40evf_ethtool.c

@@ -63,6 +63,29 @@ static const struct i40evf_stats i40evf_gstrings_stats[] = {
 #define I40EVF_STATS_LEN(_dev) \
 	(I40EVF_GLOBAL_STATS_LEN + I40EVF_QUEUE_STATS_LEN(_dev))
 
+/* For now we have one and only one private flag and it is only defined
+ * when we have support for the SKIP_CPU_SYNC DMA attribute.  Instead
+ * of leaving all this code sitting around empty we will strip it unless
+ * our one private flag is actually available.
+ */
+struct i40evf_priv_flags {
+	char flag_string[ETH_GSTRING_LEN];
+	u32 flag;
+	bool read_only;
+};
+
+#define I40EVF_PRIV_FLAG(_name, _flag, _read_only) { \
+	.flag_string = _name, \
+	.flag = _flag, \
+	.read_only = _read_only, \
+}
+
+static const struct i40evf_priv_flags i40evf_gstrings_priv_flags[] = {
+	I40EVF_PRIV_FLAG("legacy-rx", I40EVF_FLAG_LEGACY_RX, 0),
+};
+
+#define I40EVF_PRIV_FLAGS_STR_LEN ARRAY_SIZE(i40evf_gstrings_priv_flags)
+
 /**
  * i40evf_get_link_ksettings - Get Link Speed and Duplex settings
  * @netdev: network interface device structure
@@ -124,6 +147,8 @@ static int i40evf_get_sset_count(struct net_device *netdev, int sset)
 {
 	if (sset == ETH_SS_STATS)
 		return I40EVF_STATS_LEN(netdev);
+	else if (sset == ETH_SS_PRIV_FLAGS)
+		return I40EVF_PRIV_FLAGS_STR_LEN;
 	else
 		return -EINVAL;
 }
@@ -189,7 +214,83 @@ static void i40evf_get_strings(struct net_device *netdev, u32 sset, u8 *data)
 			snprintf(p, ETH_GSTRING_LEN, "rx-%u.bytes", i);
 			p += ETH_GSTRING_LEN;
 		}
+	} else if (sset == ETH_SS_PRIV_FLAGS) {
+		for (i = 0; i < I40EVF_PRIV_FLAGS_STR_LEN; i++) {
+			snprintf(p, ETH_GSTRING_LEN, "%s",
+				 i40evf_gstrings_priv_flags[i].flag_string);
+			p += ETH_GSTRING_LEN;
+		}
+	}
+}
+
+/**
+ * i40evf_get_priv_flags - report device private flags
+ * @dev: network interface device structure
+ *
+ * The get string set count and the string set should be matched for each
+ * flag returned.  Add new strings for each flag to the i40e_gstrings_priv_flags
+ * array.
+ *
+ * Returns a u32 bitmap of flags.
+ **/
+static u32 i40evf_get_priv_flags(struct net_device *netdev)
+{
+	struct i40evf_adapter *adapter = netdev_priv(netdev);
+	u32 i, ret_flags = 0;
+
+	for (i = 0; i < I40EVF_PRIV_FLAGS_STR_LEN; i++) {
+		const struct i40evf_priv_flags *priv_flags;
+
+		priv_flags = &i40evf_gstrings_priv_flags[i];
+
+		if (priv_flags->flag & adapter->flags)
+			ret_flags |= BIT(i);
+	}
+
+	return ret_flags;
+}
+
+/**
+ * i40evf_set_priv_flags - set private flags
+ * @dev: network interface device structure
+ * @flags: bit flags to be set
+ **/
+static int i40evf_set_priv_flags(struct net_device *netdev, u32 flags)
+{
+	struct i40evf_adapter *adapter = netdev_priv(netdev);
+	u64 changed_flags;
+	u32 i;
+
+	changed_flags = adapter->flags;
+
+	for (i = 0; i < I40EVF_PRIV_FLAGS_STR_LEN; i++) {
+		const struct i40evf_priv_flags *priv_flags;
+
+		priv_flags = &i40evf_gstrings_priv_flags[i];
+
+		if (priv_flags->read_only)
+			continue;
+
+		if (flags & BIT(i))
+			adapter->flags |= priv_flags->flag;
+		else
+			adapter->flags &= ~(priv_flags->flag);
+	}
+
+	/* check for flags that changed */
+	changed_flags ^= adapter->flags;
+
+	/* Process any additional changes needed as a result of flag changes. */
+
+	/* issue a reset to force legacy-rx change to take effect */
+	if (changed_flags & I40EVF_FLAG_LEGACY_RX) {
+		if (netif_running(netdev)) {
+			adapter->flags |= I40EVF_FLAG_RESET_NEEDED;
+			schedule_work(&adapter->reset_task);
+		}
 	}
+
+	return 0;
 }
 
 /**
@@ -238,6 +339,7 @@ static void i40evf_get_drvinfo(struct net_device *netdev,
 	strlcpy(drvinfo->version, i40evf_driver_version, 32);
 	strlcpy(drvinfo->fw_version, "N/A", 4);
 	strlcpy(drvinfo->bus_info, pci_name(adapter->pdev), 32);
+	drvinfo->n_priv_flags = I40EVF_PRIV_FLAGS_STR_LEN;
 }
 
 /**
@@ -649,6 +751,8 @@ static const struct ethtool_ops i40evf_ethtool_ops = {
 	.get_strings		= i40evf_get_strings,
 	.get_ethtool_stats	= i40evf_get_ethtool_stats,
 	.get_sset_count		= i40evf_get_sset_count,
+	.get_priv_flags		= i40evf_get_priv_flags,
+	.set_priv_flags		= i40evf_set_priv_flags,
 	.get_msglevel		= i40evf_get_msglevel,
 	.set_msglevel		= i40evf_set_msglevel,
 	.get_coalesce		= i40evf_get_coalesce,