net: phy: nxp-c45-tja11xx: implement mdo_insert_tx_tag

Implement mdo_insert_tx_tag to insert the TLV header in the ethernet
frame.
Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/nxp-c45-tja11xx-macsec.c

@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/phy.h>
 #include <linux/processor.h>
+#include <net/dst_metadata.h>
 #include <net/macsec.h>
 
 #include "nxp-c45-tja11xx.h"
@@ -118,6 +119,8 @@
 #define ADPTR_CNTRL			0x0F00
 #define ADPTR_CNTRL_CONFIG_EN		BIT(14)
 #define ADPTR_CNTRL_ADPTR_EN		BIT(12)
+#define ADPTR_TX_TAG_CNTRL		0x0F0C
+#define ADPTR_TX_TAG_CNTRL_ENA		BIT(31)
 
 #define TX_SC_FLT_BASE			0x800
 #define TX_SC_FLT_SIZE			0x10
@@ -166,6 +169,11 @@
 #define MACSEC_INPBTS			0x0638
 #define MACSEC_IPSNFS			0x063C
 
+#define TJA11XX_TLV_TX_NEEDED_HEADROOM	(32)
+#define TJA11XX_TLV_NEEDED_TAILROOM	(0)
+
+#define ETH_P_TJA11XX_TLV		(0x4e58)
+
 enum nxp_c45_sa_type {
 	TX_SA,
 	RX_SA,
@@ -1543,6 +1551,31 @@ static int nxp_c45_mdo_get_rx_sa_stats(struct macsec_context *ctx)
 	return 0;
 }
 
+struct tja11xx_tlv_header {
+	struct ethhdr eth;
+	u8 subtype;
+	u8 len;
+	u8 payload[28];
+};
+
+static int nxp_c45_mdo_insert_tx_tag(struct phy_device *phydev,
+				     struct sk_buff *skb)
+{
+	struct tja11xx_tlv_header *tlv;
+	struct ethhdr *eth;
+
+	eth = eth_hdr(skb);
+	tlv = skb_push(skb, TJA11XX_TLV_TX_NEEDED_HEADROOM);
+	memmove(tlv, eth, sizeof(*eth));
+	skb_reset_mac_header(skb);
+	tlv->eth.h_proto = htons(ETH_P_TJA11XX_TLV);
+	tlv->subtype = 1;
+	tlv->len = sizeof(tlv->payload);
+	memset(tlv->payload, 0, sizeof(tlv->payload));
+
+	return 0;
+}
+
 static const struct macsec_ops nxp_c45_macsec_ops = {
 	.mdo_dev_open = nxp_c45_mdo_dev_open,
 	.mdo_dev_stop = nxp_c45_mdo_dev_stop,
@@ -1563,6 +1596,9 @@ static const struct macsec_ops nxp_c45_macsec_ops = {
 	.mdo_get_tx_sa_stats = nxp_c45_mdo_get_tx_sa_stats,
 	.mdo_get_rx_sc_stats = nxp_c45_mdo_get_rx_sc_stats,
 	.mdo_get_rx_sa_stats = nxp_c45_mdo_get_rx_sa_stats,
+	.mdo_insert_tx_tag = nxp_c45_mdo_insert_tx_tag,
+	.needed_headroom = TJA11XX_TLV_TX_NEEDED_HEADROOM,
+	.needed_tailroom = TJA11XX_TLV_NEEDED_TAILROOM,
 };
 
 int nxp_c45_macsec_config_init(struct phy_device *phydev)
@@ -1583,6 +1619,11 @@ int nxp_c45_macsec_config_init(struct phy_device *phydev)
 	if (ret)
 		return ret;
 
+	ret = nxp_c45_macsec_write(phydev, ADPTR_TX_TAG_CNTRL,
+				   ADPTR_TX_TAG_CNTRL_ENA);
+	if (ret)
+		return ret;
+
 	ret = nxp_c45_macsec_write(phydev, ADPTR_CNTRL, ADPTR_CNTRL_ADPTR_EN);
 	if (ret)
 		return ret;