[PATCH 3/5] net: dsa: ksz: Factor out common tag code

[Marek Vasut <marex@denx.de>]

From: Tristram Ha <Tristram.Ha@microchip.com>

Factor out common code from the tag_ksz , so that the code can be used
with other KSZ family switches which use differenly sized tags.

Signed-off-by: Tristram Ha <Tristram.Ha@microchip.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Cc: Woojung Huh <woojung.huh@microchip.com>
Cc: David S. Miller <davem@davemloft.net>
---
 net/dsa/tag_ksz.c | 125 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 90 insertions(+), 35 deletions(-)

diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c
index 036bc62198f28..d94bad1ab7e53 100644
--- a/net/dsa/tag_ksz.c
+++ b/net/dsa/tag_ksz.c
@@ -14,34 +14,30 @@
 #include <net/dsa.h>
 #include "dsa_priv.h"
 
-/* For Ingress (Host -> KSZ), 2 bytes are added before FCS.
- * ---------------------------------------------------------------------------
- * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
- * ---------------------------------------------------------------------------
- * tag0 : Prioritization (not used now)
- * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
- *
- * For Egress (KSZ -> Host), 1 byte is added before FCS.
- * ---------------------------------------------------------------------------
- * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
- * ---------------------------------------------------------------------------
- * tag0 : zero-based value represents port
- *	  (eg, 0x00=port1, 0x02=port3, 0x06=port7)
- */
+struct ksz_tag_ops {
+	void	(*get_tag)(u8 *tag, unsigned int *port, unsigned int *len);
+	void	(*set_tag)(struct sk_buff *skb, struct net_device *dev);
+};
 
-#define	KSZ_INGRESS_TAG_LEN	2
-#define	KSZ_EGRESS_TAG_LEN	1
+/* Typically only one byte is used for tail tag. */
+#define KSZ_EGRESS_TAG_LEN		1
 
-static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev)
+/* Frames with following addresse may need to be sent even when the port is
+ * closed.
+ */
+static const u8 special_mult_addr[] = {
+	0x01, 0x80, 0xC2, 0x00, 0x00, 0x00
+};
+
+static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev,
+				struct ksz_tag_ops *ops, int len)
 {
-	struct dsa_port *dp = dsa_slave_to_port(dev);
 	struct sk_buff *nskb;
 	int padlen;
-	u8 *tag;
 
 	padlen = (skb->len >= VLAN_ETH_ZLEN) ? 0 : VLAN_ETH_ZLEN - skb->len;
 
-	if (skb_tailroom(skb) >= padlen + KSZ_INGRESS_TAG_LEN) {
+	if (skb_tailroom(skb) >= padlen + len) {
 		/* Let dsa_slave_xmit() free skb */
 		if (__skb_put_padto(skb, skb->len + padlen, false))
 			return NULL;
@@ -49,7 +45,7 @@ static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev)
 		nskb = skb;
 	} else {
 		nskb = alloc_skb(NET_IP_ALIGN + skb->len +
-				 padlen + KSZ_INGRESS_TAG_LEN, GFP_ATOMIC);
+				 padlen + len, GFP_ATOMIC);
 		if (!nskb)
 			return NULL;
 		skb_reserve(nskb, NET_IP_ALIGN);
@@ -70,34 +66,93 @@ static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev)
 		consume_skb(skb);
 	}
 
-	tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN);
-	tag[0] = 0;
-	tag[1] = 1 << dp->index; /* destination port */
+	ops->set_tag(nskb, dev);
 
 	return nskb;
 }
 
 static struct sk_buff *ksz_rcv(struct sk_buff *skb, struct net_device *dev,
-			       struct packet_type *pt)
+			       struct packet_type *pt, struct ksz_tag_ops *ops)
 {
-	u8 *tag;
-	int source_port;
+	int sp, len;
+	u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
 
-	tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
+	ops->get_tag(tag, &sp, &len);
 
-	source_port = tag[0] & 7;
-
-	skb->dev = dsa_master_find_slave(dev, 0, source_port);
+	skb->dev = dsa_master_find_slave(dev, 0, sp);
 	if (!skb->dev)
 		return NULL;
 
-	pskb_trim_rcsum(skb, skb->len - KSZ_EGRESS_TAG_LEN);
+	pskb_trim_rcsum(skb, skb->len - len);
 
 	return skb;
 }
 
+/*
+ * For Ingress (Host -> KSZ9477), 2 bytes are added before FCS.
+ * ---------------------------------------------------------------------------
+ * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
+ * ---------------------------------------------------------------------------
+ * tag0 : Prioritization (not used now)
+ * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
+ *
+ * For Egress (KSZ9477 -> Host), 1 byte is added before FCS.
+ * ---------------------------------------------------------------------------
+ * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
+ * ---------------------------------------------------------------------------
+ * tag0 : zero-based value represents port
+ *	  (eg, 0x00=port1, 0x02=port3, 0x06=port7)
+ */
+
+#define KSZ9477_INGRESS_TAG_LEN		2
+#define KSZ9477_PTP_TAG_LEN		4
+#define KSZ9477_PTP_TAG_INDICATION	0x80
+
+#define KSZ9477_TAIL_TAG_OVERRIDE	BIT(9)
+#define KSZ9477_TAIL_TAG_LOOKUP		BIT(10)
+
+static void ksz9477_get_tag(u8 *tag, unsigned int *port, unsigned int *len)
+{
+	*port = tag[0] & 7;
+	*len = KSZ_EGRESS_TAG_LEN;
+
+	/* Extra 4-bytes PTP timestamp */
+	if (tag[0] & KSZ9477_PTP_TAG_INDICATION)
+		*len += KSZ9477_PTP_TAG_LEN;
+}
+
+static void ksz9477_set_tag(struct sk_buff *skb, struct net_device *dev)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	u16 *tag = skb_put(skb, KSZ9477_INGRESS_TAG_LEN);
+	u8 *addr = skb_mac_header(skb);
+
+	*tag = 1 << dp->index;
+	if (!memcmp(addr, special_mult_addr, ETH_ALEN))
+		*tag |= KSZ9477_TAIL_TAG_OVERRIDE;
+
+	*tag = cpu_to_be16(*tag);
+}
+
+static struct ksz_tag_ops ksz9477_tag_ops = {
+	.get_tag	= ksz9477_get_tag,
+	.set_tag	= ksz9477_set_tag,
+};
+
+static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
+				    struct net_device *dev)
+{
+	return ksz_xmit(skb, dev, &ksz9477_tag_ops, KSZ9477_INGRESS_TAG_LEN);
+}
+
+static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev,
+				   struct packet_type *pt)
+{
+	return ksz_rcv(skb, dev, pt, &ksz9477_tag_ops);
+}
+
 const struct dsa_device_ops ksz9477_netdev_ops = {
-	.xmit	= ksz_xmit,
-	.rcv	= ksz_rcv,
-	.overhead = KSZ_INGRESS_TAG_LEN,
+	.xmit	= ksz9477_xmit,
+	.rcv	= ksz9477_rcv,
+	.overhead = KSZ9477_INGRESS_TAG_LEN,
 };
-- 
2.18.0