net/dsa/tag_ksz.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * net/dsa/tag_ksz.c - Microchip KSZ Switch tag format handling
   4  * Copyright (c) 2017 Microchip Technology
   5  */
   6
   7 #include <linux/etherdevice.h>
   8 #include <linux/list.h>
   9 #include <linux/slab.h>
  10 #include <net/dsa.h>
  11 #include "dsa_priv.h"
  12
  13 /* Typically only one byte is used for tail tag. */
  14 #define KSZ_EGRESS_TAG_LEN              1
  15 #define KSZ_INGRESS_TAG_LEN             1
  16
  17 static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
  18                                       struct net_device *dev,
  19                                       unsigned int port, unsigned int len)
  20 {
  21         skb->dev = dsa_master_find_slave(dev, 0, port);
  22         if (!skb->dev)
  23                 return NULL;
  24
  25         pskb_trim_rcsum(skb, skb->len - len);
  26
  27         dsa_default_offload_fwd_mark(skb);
  28
  29         return skb;
  30 }
  31
  32 /*
  33  * For Ingress (Host -> KSZ8795), 1 byte is added before FCS.
  34  * ---------------------------------------------------------------------------
  35  * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag(1byte)|FCS(4bytes)
  36  * ---------------------------------------------------------------------------
  37  * tag : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
  38  *
  39  * For Egress (KSZ8795 -> Host), 1 byte is added before FCS.
  40  * ---------------------------------------------------------------------------
  41  * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
  42  * ---------------------------------------------------------------------------
  43  * tag0 : zero-based value represents port
  44  *        (eg, 0x00=port1, 0x02=port3, 0x06=port7)
  45  */
  46
  47 #define KSZ8795_TAIL_TAG_OVERRIDE       BIT(6)
  48 #define KSZ8795_TAIL_TAG_LOOKUP         BIT(7)
  49
  50 static struct sk_buff *ksz8795_xmit(struct sk_buff *skb, struct net_device *dev)
  51 {
  52         struct dsa_port *dp = dsa_slave_to_port(dev);
  53         u8 *tag;
  54         u8 *addr;
  55
  56         if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
  57                 return NULL;
  58
  59         /* Tag encoding */
  60         tag = skb_put(skb, KSZ_INGRESS_TAG_LEN);
  61         addr = skb_mac_header(skb);
  62
  63         *tag = 1 << dp->index;
  64         if (is_link_local_ether_addr(addr))
  65                 *tag |= KSZ8795_TAIL_TAG_OVERRIDE;
  66
  67         return skb;
  68 }
  69
  70 static struct sk_buff *ksz8795_rcv(struct sk_buff *skb, struct net_device *dev)
  71 {
  72         u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
  73
  74         return ksz_common_rcv(skb, dev, tag[0] & 7, KSZ_EGRESS_TAG_LEN);
  75 }
  76
  77 static const struct dsa_device_ops ksz8795_netdev_ops = {
  78         .name   = "ksz8795",
  79         .proto  = DSA_TAG_PROTO_KSZ8795,
  80         .xmit   = ksz8795_xmit,
  81         .rcv    = ksz8795_rcv,
  82         .needed_tailroom = KSZ_INGRESS_TAG_LEN,
  83 };
  84
  85 DSA_TAG_DRIVER(ksz8795_netdev_ops);
  86 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ8795);
  87
  88 /*
  89  * For Ingress (Host -> KSZ9477), 2 bytes are added before FCS.
  90  * ---------------------------------------------------------------------------
  91  * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
  92  * ---------------------------------------------------------------------------
  93  * tag0 : Prioritization (not used now)
  94  * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
  95  *
  96  * For Egress (KSZ9477 -> Host), 1 byte is added before FCS.
  97  * ---------------------------------------------------------------------------
  98  * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
  99  * ---------------------------------------------------------------------------
 100  * tag0 : zero-based value represents port
 101  *        (eg, 0x00=port1, 0x02=port3, 0x06=port7)
 102  */
 103
 104 #define KSZ9477_INGRESS_TAG_LEN         2
 105 #define KSZ9477_PTP_TAG_LEN             4
 106 #define KSZ9477_PTP_TAG_INDICATION      0x80
 107
 108 #define KSZ9477_TAIL_TAG_OVERRIDE       BIT(9)
 109 #define KSZ9477_TAIL_TAG_LOOKUP         BIT(10)
 110
 111 static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
 112                                     struct net_device *dev)
 113 {
 114         struct dsa_port *dp = dsa_slave_to_port(dev);
 115         __be16 *tag;
 116         u8 *addr;
 117         u16 val;
 118
 119         if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
 120                 return NULL;
 121
 122         /* Tag encoding */
 123         tag = skb_put(skb, KSZ9477_INGRESS_TAG_LEN);
 124         addr = skb_mac_header(skb);
 125
 126         val = BIT(dp->index);
 127
 128         if (is_link_local_ether_addr(addr))
 129                 val |= KSZ9477_TAIL_TAG_OVERRIDE;
 130
 131         *tag = cpu_to_be16(val);
 132
 133         return skb;
 134 }
 135
 136 static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev)
 137 {
 138         /* Tag decoding */
 139         u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
 140         unsigned int port = tag[0] & 7;
 141         unsigned int len = KSZ_EGRESS_TAG_LEN;
 142
 143         /* Extra 4-bytes PTP timestamp */
 144         if (tag[0] & KSZ9477_PTP_TAG_INDICATION)
 145                 len += KSZ9477_PTP_TAG_LEN;
 146
 147         return ksz_common_rcv(skb, dev, port, len);
 148 }
 149
 150 static const struct dsa_device_ops ksz9477_netdev_ops = {
 151         .name   = "ksz9477",
 152         .proto  = DSA_TAG_PROTO_KSZ9477,
 153         .xmit   = ksz9477_xmit,
 154         .rcv    = ksz9477_rcv,
 155         .needed_tailroom = KSZ9477_INGRESS_TAG_LEN,
 156 };
 157
 158 DSA_TAG_DRIVER(ksz9477_netdev_ops);
 159 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9477);
 160
 161 #define KSZ9893_TAIL_TAG_OVERRIDE       BIT(5)
 162 #define KSZ9893_TAIL_TAG_LOOKUP         BIT(6)
 163
 164 static struct sk_buff *ksz9893_xmit(struct sk_buff *skb,
 165                                     struct net_device *dev)
 166 {
 167         struct dsa_port *dp = dsa_slave_to_port(dev);
 168         u8 *addr;
 169         u8 *tag;
 170
 171         if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
 172                 return NULL;
 173
 174         /* Tag encoding */
 175         tag = skb_put(skb, KSZ_INGRESS_TAG_LEN);
 176         addr = skb_mac_header(skb);
 177
 178         *tag = BIT(dp->index);
 179
 180         if (is_link_local_ether_addr(addr))
 181                 *tag |= KSZ9893_TAIL_TAG_OVERRIDE;
 182
 183         return skb;
 184 }
 185
 186 static const struct dsa_device_ops ksz9893_netdev_ops = {
 187         .name   = "ksz9893",
 188         .proto  = DSA_TAG_PROTO_KSZ9893,
 189         .xmit   = ksz9893_xmit,
 190         .rcv    = ksz9477_rcv,
 191         .needed_tailroom = KSZ_INGRESS_TAG_LEN,
 192 };
 193
 194 DSA_TAG_DRIVER(ksz9893_netdev_ops);
 195 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9893);
 196
 197 static struct dsa_tag_driver *dsa_tag_driver_array[] = {
 198         &DSA_TAG_DRIVER_NAME(ksz8795_netdev_ops),
 199         &DSA_TAG_DRIVER_NAME(ksz9477_netdev_ops),
 200         &DSA_TAG_DRIVER_NAME(ksz9893_netdev_ops),
 201 };
 202
 203 module_dsa_tag_drivers(dsa_tag_driver_array);
 204
 205 MODULE_LICENSE("GPL");