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_xmit(struct sk_buff *skb,
  18                                        struct net_device *dev, int len)
  19 {
  20         struct sk_buff *nskb;
  21         int padlen;
  22
  23         padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len;
  24
  25         if (skb_tailroom(skb) >= padlen + len) {
  26                 /* Let dsa_slave_xmit() free skb */
  27                 if (__skb_put_padto(skb, skb->len + padlen, false))
  28                         return NULL;
  29
  30                 nskb = skb;
  31         } else {
  32                 nskb = alloc_skb(NET_IP_ALIGN + skb->len +
  33                                  padlen + len, GFP_ATOMIC);
  34                 if (!nskb)
  35                         return NULL;
  36                 skb_reserve(nskb, NET_IP_ALIGN);
  37
  38                 skb_reset_mac_header(nskb);
  39                 skb_set_network_header(nskb,
  40                                        skb_network_header(skb) - skb->head);
  41                 skb_set_transport_header(nskb,
  42                                          skb_transport_header(skb) - skb->head);
  43                 skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len));
  44
  45                 /* Let skb_put_padto() free nskb, and let dsa_slave_xmit() free
  46                  * skb
  47                  */
  48                 if (skb_put_padto(nskb, nskb->len + padlen))
  49                         return NULL;
  50
  51                 consume_skb(skb);
  52         }
  53
  54         return nskb;
  55 }
  56
  57 static struct sk_buff *ksz_common_rcv(struct sk_buff *skb,
  58                                       struct net_device *dev,
  59                                       unsigned int port, unsigned int len)
  60 {
  61         skb->dev = dsa_master_find_slave(dev, 0, port);
  62         if (!skb->dev)
  63                 return NULL;
  64
  65         pskb_trim_rcsum(skb, skb->len - len);
  66
  67         skb->offload_fwd_mark = true;
  68
  69         return skb;
  70 }
  71
  72 /*
  73  * For Ingress (Host -> KSZ8795), 1 byte is added before FCS.
  74  * ---------------------------------------------------------------------------
  75  * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag(1byte)|FCS(4bytes)
  76  * ---------------------------------------------------------------------------
  77  * tag : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
  78  *
  79  * For Egress (KSZ8795 -> Host), 1 byte is added before FCS.
  80  * ---------------------------------------------------------------------------
  81  * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
  82  * ---------------------------------------------------------------------------
  83  * tag0 : zero-based value represents port
  84  *        (eg, 0x00=port1, 0x02=port3, 0x06=port7)
  85  */
  86
  87 #define KSZ8795_TAIL_TAG_OVERRIDE       BIT(6)
  88 #define KSZ8795_TAIL_TAG_LOOKUP         BIT(7)
  89
  90 static struct sk_buff *ksz8795_xmit(struct sk_buff *skb, struct net_device *dev)
  91 {
  92         struct dsa_port *dp = dsa_slave_to_port(dev);
  93         struct sk_buff *nskb;
  94         u8 *tag;
  95         u8 *addr;
  96
  97         nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN);
  98         if (!nskb)
  99                 return NULL;
 100
 101         /* Tag encoding */
 102         tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN);
 103         addr = skb_mac_header(nskb);
 104
 105         *tag = 1 << dp->index;
 106         if (is_link_local_ether_addr(addr))
 107                 *tag |= KSZ8795_TAIL_TAG_OVERRIDE;
 108
 109         return nskb;
 110 }
 111
 112 static struct sk_buff *ksz8795_rcv(struct sk_buff *skb, struct net_device *dev,
 113                                   struct packet_type *pt)
 114 {
 115         u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
 116
 117         return ksz_common_rcv(skb, dev, tag[0] & 7, KSZ_EGRESS_TAG_LEN);
 118 }
 119
 120 static const struct dsa_device_ops ksz8795_netdev_ops = {
 121         .name   = "ksz8795",
 122         .proto  = DSA_TAG_PROTO_KSZ8795,
 123         .xmit   = ksz8795_xmit,
 124         .rcv    = ksz8795_rcv,
 125         .overhead = KSZ_INGRESS_TAG_LEN,
 126 };
 127
 128 DSA_TAG_DRIVER(ksz8795_netdev_ops);
 129 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ8795);
 130
 131 /*
 132  * For Ingress (Host -> KSZ9477), 2 bytes are added before FCS.
 133  * ---------------------------------------------------------------------------
 134  * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes)
 135  * ---------------------------------------------------------------------------
 136  * tag0 : Prioritization (not used now)
 137  * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5)
 138  *
 139  * For Egress (KSZ9477 -> Host), 1 byte is added before FCS.
 140  * ---------------------------------------------------------------------------
 141  * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes)
 142  * ---------------------------------------------------------------------------
 143  * tag0 : zero-based value represents port
 144  *        (eg, 0x00=port1, 0x02=port3, 0x06=port7)
 145  */
 146
 147 #define KSZ9477_INGRESS_TAG_LEN         2
 148 #define KSZ9477_PTP_TAG_LEN             4
 149 #define KSZ9477_PTP_TAG_INDICATION      0x80
 150
 151 #define KSZ9477_TAIL_TAG_OVERRIDE       BIT(9)
 152 #define KSZ9477_TAIL_TAG_LOOKUP         BIT(10)
 153
 154 static struct sk_buff *ksz9477_xmit(struct sk_buff *skb,
 155                                     struct net_device *dev)
 156 {
 157         struct dsa_port *dp = dsa_slave_to_port(dev);
 158         struct sk_buff *nskb;
 159         u16 *tag;
 160         u8 *addr;
 161
 162         nskb = ksz_common_xmit(skb, dev, KSZ9477_INGRESS_TAG_LEN);
 163         if (!nskb)
 164                 return NULL;
 165
 166         /* Tag encoding */
 167         tag = skb_put(nskb, KSZ9477_INGRESS_TAG_LEN);
 168         addr = skb_mac_header(nskb);
 169
 170         *tag = BIT(dp->index);
 171
 172         if (is_link_local_ether_addr(addr))
 173                 *tag |= KSZ9477_TAIL_TAG_OVERRIDE;
 174
 175         *tag = cpu_to_be16(*tag);
 176
 177         return nskb;
 178 }
 179
 180 static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev,
 181                                    struct packet_type *pt)
 182 {
 183         /* Tag decoding */
 184         u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN;
 185         unsigned int port = tag[0] & 7;
 186         unsigned int len = KSZ_EGRESS_TAG_LEN;
 187
 188         /* Extra 4-bytes PTP timestamp */
 189         if (tag[0] & KSZ9477_PTP_TAG_INDICATION)
 190                 len += KSZ9477_PTP_TAG_LEN;
 191
 192         return ksz_common_rcv(skb, dev, port, len);
 193 }
 194
 195 static const struct dsa_device_ops ksz9477_netdev_ops = {
 196         .name   = "ksz9477",
 197         .proto  = DSA_TAG_PROTO_KSZ9477,
 198         .xmit   = ksz9477_xmit,
 199         .rcv    = ksz9477_rcv,
 200         .overhead = KSZ9477_INGRESS_TAG_LEN,
 201 };
 202
 203 DSA_TAG_DRIVER(ksz9477_netdev_ops);
 204 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9477);
 205
 206 #define KSZ9893_TAIL_TAG_OVERRIDE       BIT(5)
 207 #define KSZ9893_TAIL_TAG_LOOKUP         BIT(6)
 208
 209 static struct sk_buff *ksz9893_xmit(struct sk_buff *skb,
 210                                     struct net_device *dev)
 211 {
 212         struct dsa_port *dp = dsa_slave_to_port(dev);
 213         struct sk_buff *nskb;
 214         u8 *addr;
 215         u8 *tag;
 216
 217         nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN);
 218         if (!nskb)
 219                 return NULL;
 220
 221         /* Tag encoding */
 222         tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN);
 223         addr = skb_mac_header(nskb);
 224
 225         *tag = BIT(dp->index);
 226
 227         if (is_link_local_ether_addr(addr))
 228                 *tag |= KSZ9893_TAIL_TAG_OVERRIDE;
 229
 230         return nskb;
 231 }
 232
 233 static const struct dsa_device_ops ksz9893_netdev_ops = {
 234         .name   = "ksz9893",
 235         .proto  = DSA_TAG_PROTO_KSZ9893,
 236         .xmit   = ksz9893_xmit,
 237         .rcv    = ksz9477_rcv,
 238         .overhead = KSZ_INGRESS_TAG_LEN,
 239 };
 240
 241 DSA_TAG_DRIVER(ksz9893_netdev_ops);
 242 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9893);
 243
 244 static struct dsa_tag_driver *dsa_tag_driver_array[] = {
 245         &DSA_TAG_DRIVER_NAME(ksz8795_netdev_ops),
 246         &DSA_TAG_DRIVER_NAME(ksz9477_netdev_ops),
 247         &DSA_TAG_DRIVER_NAME(ksz9893_netdev_ops),
 248 };
 249
 250 module_dsa_tag_drivers(dsa_tag_driver_array);
 251
 252 MODULE_LICENSE("GPL");