net: thunderx: Support for internal loopback mode

Support for setting VF's corresponding BGX LMAC in internal
loopback mode. This mode can be used for verifying basic HW
functionality such as packet I/O, RX checksum validation,
CQ/RBDR interrupts, stats e.t.c. Useful when DUT has no external
network connectivity.

'loopback' mode can be enabled or disabled via ethtool.

Note: This feature is not supported when no of VFs enabled are
morethan no of physical interfaces i.e active BGX LMACs
Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@caviumnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cavium/thunder/nic.h

@@ -265,6 +265,7 @@ struct nicvf {
 	u8			node;
 	u8			tns_mode:1;
 	u8			sqs_mode:1;
+	u8			loopback_supported:1;
 	u16			mtu;
 	struct queue_set	*qs;
 #define	MAX_SQS_PER_VF_SINGLE_NODE		5
@@ -344,6 +345,7 @@ struct nicvf {
 #define	NIC_MBOX_MSG_NICVF_PTR		0x13	/* Send nicvf ptr to PF */
 #define	NIC_MBOX_MSG_PNICVF_PTR		0x14	/* Get primary qset nicvf ptr */
 #define	NIC_MBOX_MSG_SNICVF_PTR		0x15	/* Send sqet nicvf ptr to PVF */
+#define	NIC_MBOX_MSG_LOOPBACK		0x16	/* Set interface in loopback */
 #define	NIC_MBOX_MSG_CFG_DONE		0xF0	/* VF configuration done */
 #define	NIC_MBOX_MSG_SHUTDOWN		0xF1	/* VF is being shutdown */
 
@@ -353,6 +355,7 @@ struct nic_cfg_msg {
 	u8    node_id;
 	u8    tns_mode:1;
 	u8    sqs_mode:1;
+	u8    loopback_supported:1;
 	u8    mac_addr[ETH_ALEN];
 };
 
@@ -452,6 +455,13 @@ struct nicvf_ptr {
 	u64   nicvf;
 };
 
+/* Set interface in loopback mode */
+struct set_loopback {
+	u8    msg;
+	u8    vf_id;
+	bool  enable;
+};
+
 /* 128 bit shared memory between PF and each VF */
 union nic_mbx {
 	struct { u8 msg; }	msg;
@@ -468,6 +478,7 @@ union nic_mbx {
 	struct bgx_link_status  link_status;
 	struct sqs_alloc        sqs_alloc;
 	struct nicvf_ptr	nicvf;
+	struct set_loopback	lbk;
 };
 
 #define NIC_NODE_ID_MASK	0x03

drivers/net/ethernet/cavium/thunder/nic_main.c

@@ -154,6 +154,9 @@ static void nic_mbx_send_ready(struct nicpf *nic, int vf)
 	}
 	mbx.nic_cfg.sqs_mode = (vf >= nic->num_vf_en) ? true : false;
 	mbx.nic_cfg.node_id = nic->node;
+
+	mbx.nic_cfg.loopback_supported = vf < MAX_LMAC;
+
 	nic_send_msg_to_vf(nic, vf, &mbx);
 }
 
@@ -579,6 +582,21 @@ static void nic_alloc_sqs(struct nicpf *nic, struct sqs_alloc *sqs)
 	nic_send_msg_to_vf(nic, sqs->vf_id, &mbx);
 }
 
+static int nic_config_loopback(struct nicpf *nic, struct set_loopback *lbk)
+{
+	int bgx_idx, lmac_idx;
+
+	if (lbk->vf_id > MAX_LMAC)
+		return -1;
+
+	bgx_idx = NIC_GET_BGX_FROM_VF_LMAC_MAP(nic->vf_lmac_map[lbk->vf_id]);
+	lmac_idx = NIC_GET_LMAC_FROM_VF_LMAC_MAP(nic->vf_lmac_map[lbk->vf_id]);
+
+	bgx_lmac_internal_loopback(nic->node, bgx_idx, lmac_idx, lbk->enable);
+
+	return 0;
+}
+
 /* Interrupt handler to handle mailbox messages from VFs */
 static void nic_handle_mbx_intr(struct nicpf *nic, int vf)
 {
@@ -702,6 +720,9 @@ static void nic_handle_mbx_intr(struct nicpf *nic, int vf)
 	case NIC_MBOX_MSG_BGX_STATS:
 		nic_get_bgx_stats(nic, &mbx.bgx_stats);
 		goto unlock;
+	case NIC_MBOX_MSG_LOOPBACK:
+		ret = nic_config_loopback(nic, &mbx.lbk);
+		break;
 	default:
 		dev_err(&nic->pdev->dev,
 			"Invalid msg from VF%d, msg 0x%x\n", vf, mbx.msg.msg);

drivers/net/ethernet/cavium/thunder/nicvf_main.c

@@ -202,6 +202,7 @@ static void  nicvf_handle_mbx_intr(struct nicvf *nic)
 			ether_addr_copy(nic->netdev->dev_addr,
 					mbx.nic_cfg.mac_addr);
 		nic->sqs_mode = mbx.nic_cfg.sqs_mode;
+		nic->loopback_supported = mbx.nic_cfg.loopback_supported;
 		nic->link_up = false;
 		nic->duplex = 0;
 		nic->speed = 0;
@@ -1404,6 +1405,30 @@ static void nicvf_reset_task(struct work_struct *work)
 	nic->netdev->trans_start = jiffies;
 }
 
+static int nicvf_config_loopback(struct nicvf *nic,
+				 netdev_features_t features)
+{
+	union nic_mbx mbx = {};
+
+	mbx.lbk.msg = NIC_MBOX_MSG_LOOPBACK;
+	mbx.lbk.vf_id = nic->vf_id;
+	mbx.lbk.enable = (features & NETIF_F_LOOPBACK) != 0;
+
+	return nicvf_send_msg_to_pf(nic, &mbx);
+}
+
+static netdev_features_t nicvf_fix_features(struct net_device *netdev,
+					    netdev_features_t features)
+{
+	struct nicvf *nic = netdev_priv(netdev);
+
+	if ((features & NETIF_F_LOOPBACK) &&
+	    netif_running(netdev) && !nic->loopback_supported)
+		features &= ~NETIF_F_LOOPBACK;
+
+	return features;
+}
+
 static int nicvf_set_features(struct net_device *netdev,
 			      netdev_features_t features)
 {
@@ -1413,6 +1438,9 @@ static int nicvf_set_features(struct net_device *netdev,
 	if (changed & NETIF_F_HW_VLAN_CTAG_RX)
 		nicvf_config_vlan_stripping(nic, features);
 
+	if ((changed & NETIF_F_LOOPBACK) && netif_running(netdev))
+		return nicvf_config_loopback(nic, features);
+
 	return 0;
 }
 
@@ -1424,6 +1452,7 @@ static const struct net_device_ops nicvf_netdev_ops = {
 	.ndo_set_mac_address	= nicvf_set_mac_address,
 	.ndo_get_stats64	= nicvf_get_stats64,
 	.ndo_tx_timeout         = nicvf_tx_timeout,
+	.ndo_fix_features       = nicvf_fix_features,
 	.ndo_set_features       = nicvf_set_features,
 };
 
@@ -1518,6 +1547,7 @@ static int nicvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	netdev->hw_features |= NETIF_F_RXHASH;
 
 	netdev->features |= netdev->hw_features;
+	netdev->hw_features |= NETIF_F_LOOPBACK;
 
 	netdev->vlan_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
 

drivers/net/ethernet/cavium/thunder/thunder_bgx.c

@@ -329,6 +329,37 @@ static void bgx_flush_dmac_addrs(struct bgx *bgx, int lmac)
 	}
 }
 
+/* Configure BGX LMAC in internal loopback mode */
+void bgx_lmac_internal_loopback(int node, int bgx_idx,
+				int lmac_idx, bool enable)
+{
+	struct bgx *bgx;
+	struct lmac *lmac;
+	u64    cfg;
+
+	bgx = bgx_vnic[(node * MAX_BGX_PER_CN88XX) + bgx_idx];
+	if (!bgx)
+		return;
+
+	lmac = &bgx->lmac[lmac_idx];
+	if (lmac->is_sgmii) {
+		cfg = bgx_reg_read(bgx, lmac_idx, BGX_GMP_PCS_MRX_CTL);
+		if (enable)
+			cfg |= PCS_MRX_CTL_LOOPBACK1;
+		else
+			cfg &= ~PCS_MRX_CTL_LOOPBACK1;
+		bgx_reg_write(bgx, lmac_idx, BGX_GMP_PCS_MRX_CTL, cfg);
+	} else {
+		cfg = bgx_reg_read(bgx, lmac_idx, BGX_SPUX_CONTROL1);
+		if (enable)
+			cfg |= SPU_CTL_LOOPBACK;
+		else
+			cfg &= ~SPU_CTL_LOOPBACK;
+		bgx_reg_write(bgx, lmac_idx, BGX_SPUX_CONTROL1, cfg);
+	}
+}
+EXPORT_SYMBOL(bgx_lmac_internal_loopback);
+
 static int bgx_lmac_sgmii_init(struct bgx *bgx, int lmacid)
 {
 	u64 cfg;

drivers/net/ethernet/cavium/thunder/thunder_bgx.h

@@ -72,6 +72,7 @@
 
 #define BGX_SPUX_CONTROL1		0x10000
 #define  SPU_CTL_LOW_POWER			BIT_ULL(11)
+#define  SPU_CTL_LOOPBACK			BIT_ULL(14)
 #define  SPU_CTL_RESET				BIT_ULL(15)
 #define BGX_SPUX_STATUS1		0x10008
 #define  SPU_STATUS1_RCV_LNK			BIT_ULL(2)
@@ -126,6 +127,7 @@
 #define	 PCS_MRX_CTL_RST_AN			BIT_ULL(9)
 #define	 PCS_MRX_CTL_PWR_DN			BIT_ULL(11)
 #define	 PCS_MRX_CTL_AN_EN			BIT_ULL(12)
+#define	 PCS_MRX_CTL_LOOPBACK1			BIT_ULL(14)
 #define	 PCS_MRX_CTL_RESET			BIT_ULL(15)
 #define BGX_GMP_PCS_MRX_STATUS		0x30008
 #define	 PCS_MRX_STATUS_AN_CPT			BIT_ULL(5)
@@ -186,6 +188,8 @@ int bgx_get_lmac_count(int node, int bgx);
 const u8 *bgx_get_lmac_mac(int node, int bgx_idx, int lmacid);
 void bgx_set_lmac_mac(int node, int bgx_idx, int lmacid, const u8 *mac);
 void bgx_get_lmac_link_state(int node, int bgx_idx, int lmacid, void *status);
+void bgx_lmac_internal_loopback(int node, int bgx_idx,
+				int lmac_idx, bool enable);
 u64 bgx_get_rx_stats(int node, int bgx_idx, int lmac, int idx);
 u64 bgx_get_tx_stats(int node, int bgx_idx, int lmac, int idx);
 #define BGX_RX_STATS_COUNT 11