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 -> KSZ9477), 2 bytes are added before FCS. 74 * --------------------------------------------------------------------------- 75 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes) 76 * --------------------------------------------------------------------------- 77 * tag0 : Prioritization (not used now) 78 * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5) 79 * 80 * For Egress (KSZ9477 -> Host), 1 byte is added before FCS. 81 * --------------------------------------------------------------------------- 82 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes) 83 * --------------------------------------------------------------------------- 84 * tag0 : zero-based value represents port 85 * (eg, 0x00=port1, 0x02=port3, 0x06=port7) 86 */ 87 88 #define KSZ9477_INGRESS_TAG_LEN 2 89 #define KSZ9477_PTP_TAG_LEN 4 90 #define KSZ9477_PTP_TAG_INDICATION 0x80 91 92 #define KSZ9477_TAIL_TAG_OVERRIDE BIT(9) 93 #define KSZ9477_TAIL_TAG_LOOKUP BIT(10) 94 95 static struct sk_buff *ksz9477_xmit(struct sk_buff *skb, 96 struct net_device *dev) 97 { 98 struct dsa_port *dp = dsa_slave_to_port(dev); 99 struct sk_buff *nskb; 100 u16 *tag; 101 u8 *addr; 102 103 nskb = ksz_common_xmit(skb, dev, KSZ9477_INGRESS_TAG_LEN); 104 if (!nskb) 105 return NULL; 106 107 /* Tag encoding */ 108 tag = skb_put(nskb, KSZ9477_INGRESS_TAG_LEN); 109 addr = skb_mac_header(nskb); 110 111 *tag = BIT(dp->index); 112 113 if (is_link_local_ether_addr(addr)) 114 *tag |= KSZ9477_TAIL_TAG_OVERRIDE; 115 116 *tag = cpu_to_be16(*tag); 117 118 return nskb; 119 } 120 121 static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev, 122 struct packet_type *pt) 123 { 124 /* Tag decoding */ 125 u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN; 126 unsigned int port = tag[0] & 7; 127 unsigned int len = KSZ_EGRESS_TAG_LEN; 128 129 /* Extra 4-bytes PTP timestamp */ 130 if (tag[0] & KSZ9477_PTP_TAG_INDICATION) 131 len += KSZ9477_PTP_TAG_LEN; 132 133 return ksz_common_rcv(skb, dev, port, len); 134 } 135 136 static const struct dsa_device_ops ksz9477_netdev_ops = { 137 .name = "ksz9477", 138 .proto = DSA_TAG_PROTO_KSZ9477, 139 .xmit = ksz9477_xmit, 140 .rcv = ksz9477_rcv, 141 .overhead = KSZ9477_INGRESS_TAG_LEN, 142 }; 143 144 DSA_TAG_DRIVER(ksz9477_netdev_ops); 145 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9477); 146 147 #define KSZ9893_TAIL_TAG_OVERRIDE BIT(5) 148 #define KSZ9893_TAIL_TAG_LOOKUP BIT(6) 149 150 static struct sk_buff *ksz9893_xmit(struct sk_buff *skb, 151 struct net_device *dev) 152 { 153 struct dsa_port *dp = dsa_slave_to_port(dev); 154 struct sk_buff *nskb; 155 u8 *addr; 156 u8 *tag; 157 158 nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN); 159 if (!nskb) 160 return NULL; 161 162 /* Tag encoding */ 163 tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN); 164 addr = skb_mac_header(nskb); 165 166 *tag = BIT(dp->index); 167 168 if (is_link_local_ether_addr(addr)) 169 *tag |= KSZ9893_TAIL_TAG_OVERRIDE; 170 171 return nskb; 172 } 173 174 static const struct dsa_device_ops ksz9893_netdev_ops = { 175 .name = "ksz9893", 176 .proto = DSA_TAG_PROTO_KSZ9893, 177 .xmit = ksz9893_xmit, 178 .rcv = ksz9477_rcv, 179 .overhead = KSZ_INGRESS_TAG_LEN, 180 }; 181 182 DSA_TAG_DRIVER(ksz9893_netdev_ops); 183 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KSZ9893); 184 185 static struct dsa_tag_driver *dsa_tag_driver_array[] = { 186 &DSA_TAG_DRIVER_NAME(ksz9477_netdev_ops), 187 &DSA_TAG_DRIVER_NAME(ksz9893_netdev_ops), 188 }; 189 190 module_dsa_tag_drivers(dsa_tag_driver_array); 191 192 MODULE_LICENSE("GPL"); 193