nfp: implement xfrm callbacks and expose ipsec offload feature to upper layer

Xfrm callbacks are implemented to offload SA info into firmware
by mailbox. It supports 16K SA info in total.

Expose ipsec offload feature to upper layer, this feature will
signal the availability of the offload.

Based on initial work of Norm Bagley <norman.bagley@netronome.com>.
Signed-off-by: Huanhuan Wang <huanhuan.wang@corigine.com>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -2371,6 +2371,12 @@ static void nfp_net_netdev_init(struct nfp_net *nn)
 	}
 	if (nn->cap & NFP_NET_CFG_CTRL_RSS_ANY)
 		netdev->hw_features |= NETIF_F_RXHASH;
+
+#ifdef CONFIG_NFP_NET_IPSEC
+	if (nn->cap_w1 & NFP_NET_CFG_CTRL_IPSEC)
+		netdev->hw_features |= NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM;
+#endif
+
 	if (nn->cap & NFP_NET_CFG_CTRL_VXLAN) {
 		if (nn->cap & NFP_NET_CFG_CTRL_LSO) {
 			netdev->hw_features |= NETIF_F_GSO_UDP_TUNNEL |

drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h

@@ -402,14 +402,14 @@
  */
 #define NFP_NET_CFG_MBOX_BASE		0x1800
 #define NFP_NET_CFG_MBOX_VAL_MAX_SZ	0x1F8
-
+#define NFP_NET_CFG_MBOX_VAL		0x1808
 #define NFP_NET_CFG_MBOX_SIMPLE_CMD	0x0
 #define NFP_NET_CFG_MBOX_SIMPLE_RET	0x4
 #define NFP_NET_CFG_MBOX_SIMPLE_VAL	0x8
 
 #define NFP_NET_CFG_MBOX_CMD_CTAG_FILTER_ADD 1
 #define NFP_NET_CFG_MBOX_CMD_CTAG_FILTER_KILL 2
-
+#define NFP_NET_CFG_MBOX_CMD_IPSEC 3
 #define NFP_NET_CFG_MBOX_CMD_PCI_DSCP_PRIOMAP_SET	5
 #define NFP_NET_CFG_MBOX_CMD_TLV_CMSG			6