[RFC net-next v1 5/5] net: phy: nxp-c45-tja11xx: implement mdo_insert_tx_tag

[Radu Pirea (NXP OSS)]

Implement mdo_insert_tx_tag to insert the TLV header in the ethernet
frame.

The TLV header contains the TX SC that will be used to encrypt the
frame.

Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@xxxxxxxxxxx>
---
 drivers/net/phy/nxp-c45-tja11xx-macsec.c | 59 ++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/drivers/net/phy/nxp-c45-tja11xx-macsec.c b/drivers/net/phy/nxp-c45-tja11xx-macsec.c
index da63e35571d0..53f8706bc572 100644
--- a/drivers/net/phy/nxp-c45-tja11xx-macsec.c
+++ b/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"
@@ -23,6 +24,7 @@
 #define VEND1_MACSEC_BASE		0x9000
 
 #define MACSEC_CFG			0x0000
+#define MACSEC_CFG_EXTSCS		BIT(26)
 #define MACSEC_CFG_BYPASS		BIT(1)
 #define MACSEC_CFG_S0I			BIT(0)
 
@@ -121,6 +123,8 @@
 #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
@@ -167,6 +171,14 @@
 #define MACSEC_INPBTS			0x0638
 #define MACSEC_IPSNFS			0x063C
 
+#define TJA11XX_TLV_TX_NEEDED_HEADROOM	(32)
+#define TJA11XX_TLV_NEEDED_TAILROOM	(0)
+
+#define MACSEC_TLV_CP			BIT(0)
+#define MACSEC_TLV_SC_ID_OFF		(2)
+
+#define ETH_P_TJA11XX_TLV		(0x4e58)
+
 struct nxp_c45_rx_sc {
 	struct macsec_rx_sc *rx_sc;
 	struct macsec_rx_sa *rx_sa_a;
@@ -310,6 +322,7 @@ void nxp_c45_macsec_config_init(struct phy_device *phydev)
 			 MACSEC_EN | ADAPTER_EN);
 
 	nxp_c45_macsec_write(phydev, ADPTR_CNTRL, ADPTR_CNTRL_CONFIG_EN);
+	nxp_c45_macsec_write(phydev, ADPTR_TX_TAG_CNTRL, ADPTR_TX_TAG_CNTRL_ENA);
 	nxp_c45_macsec_write(phydev, ADPTR_CNTRL, ADPTR_CNTRL_CONFIG_EN |
 			     ADPTR_CNTRL_ADPTR_EN);
 	nxp_c45_macsec_write(phydev, ADPTR_CNTRL,
@@ -322,6 +335,8 @@ void nxp_c45_macsec_config_init(struct phy_device *phydev)
 	nxp_c45_macsec_write(phydev, MACSEC_UPFR0M1, MACSEC_OVP);
 	nxp_c45_macsec_write(phydev, MACSEC_UPFR0M2, ETYPE_MASK);
 	nxp_c45_macsec_write(phydev, MACSEC_UPFR0R, MACSEC_UPFR_EN);
+
+	nxp_c45_macsec_write(phydev, MACSEC_CFG, MACSEC_CFG_EXTSCS);
 }
 
 static void nxp_c45_macsec_cfg_ptp(struct phy_device *phydev, bool enable)
@@ -1750,6 +1765,47 @@ 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 macsec_context *ctx)
+{
+	struct nxp_c45_phy *priv = ctx->phydev->priv;
+	struct sk_buff *skb = ctx->skb;
+	struct tja11xx_tlv_header *tlv;
+	struct nxp_c45_secy *phy_secy;
+	struct metadata_dst *md_dst;
+	struct ethhdr *eth;
+	sci_t sci;
+
+	md_dst = skb_metadata_dst(skb);
+	if (!md_dst)
+		return -EINVAL;
+
+	sci = md_dst->u.macsec_info.sci;
+	phy_secy = nxp_c45_find_secy(&priv->macsec->secy_list, sci);
+	if (IS_ERR(phy_secy))
+		return PTR_ERR(phy_secy);
+
+	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));
+
+	tlv->payload[3] = phy_secy->secy_id << MACSEC_TLV_SC_ID_OFF |
+		MACSEC_TLV_CP;
+
+	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,
@@ -1770,6 +1826,9 @@ 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_probe(struct phy_device *phydev)
-- 
2.34.1