[PATCH RFC 6/6] Modify tag_ksz.c to support other KSZ switch drivers

[Tristram.Ha]

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

The KSZ tail tag code can be used by different KSZ switch drivers.

Signed-off-by: Tristram Ha <tristram...@microchip.com>
---
diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c index 010ca0a..d5faf14 100644
--- a/net/dsa/tag_ksz.c
+++ b/net/dsa/tag_ksz.c
@@ -13,35 +13,21 @@
 #include <linux/slab.h>
 #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)
- */
-
-#define        KSZ_INGRESS_TAG_LEN     2
-#define        KSZ_EGRESS_TAG_LEN      1
+#include "../../drivers/net/dsa/microchip/ksz_priv.h"
 
 static struct sk_buff *ksz_xmit(struct sk_buff *skb, struct net_device *dev)  {
        struct dsa_slave_priv *p = netdev_priv(dev);
+       struct dsa_switch *ds = p->dp->ds;
+       struct ksz_device *swdev = ds->priv;
        struct sk_buff *nskb;
+       int len;
        int padlen;
-       u8 *tag;
 
        padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;
 
-       if (skb_tailroom(skb) >= padlen + KSZ_INGRESS_TAG_LEN) {
+       len = swdev->dev_ops->get_tx_len(swdev);
+       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 +35,7 @@ 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);
@@ -70,9 +56,7 @@ 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 << p->dp->index; /* destination port */
+       swdev->dev_ops->add_tail_tag(swdev, nskb, p->dp->index);
 
        return nskb;
 }
@@ -83,16 +67,16 @@ static struct sk_buff *ksz_rcv(struct sk_buff *skb, struct 
net_device *dev,
        struct dsa_switch_tree *dst = dev->dsa_ptr;
        struct dsa_port *cpu_dp = dsa_get_cpu_port(dst);
        struct dsa_switch *ds = cpu_dp->ds;
-       u8 *tag;
+       struct ksz_device *swdev = ds->priv;
+       int len;
        int source_port;
 
-       tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
+       len = swdev->dev_ops->get_tail_tag(swdev, skb, &source_port);
 
-       source_port = tag[0] & 7;
        if (source_port >= ds->num_ports || !ds->ports[source_port].netdev)
                return NULL;
 
-       pskb_trim_rcsum(skb, skb->len - KSZ_EGRESS_TAG_LEN);
+       pskb_trim_rcsum(skb, skb->len - len);
 
        skb->dev = ds->ports[source_port].netdev;