1 /* 2 * net/dsa/tag_ksz.c - Microchip KSZ Switch tag format handling 3 * Copyright (c) 2017 Microchip Technology 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 */ 10 11 #include <linux/etherdevice.h> 12 #include <linux/list.h> 13 #include <linux/slab.h> 14 #include <net/dsa.h> 15 #include "dsa_priv.h" 16 17 /* Typically only one byte is used for tail tag. */ 18 #define KSZ_EGRESS_TAG_LEN 1 19 #define KSZ_INGRESS_TAG_LEN 1 20 21 static struct sk_buff *ksz_common_xmit(struct sk_buff *skb, 22 struct net_device *dev, int len) 23 { 24 struct sk_buff *nskb; 25 int padlen; 26 27 padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len; 28 29 if (skb_tailroom(skb) >= padlen + len) { 30 /* Let dsa_slave_xmit() free skb */ 31 if (__skb_put_padto(skb, skb->len + padlen, false)) 32 return NULL; 33 34 nskb = skb; 35 } else { 36 nskb = alloc_skb(NET_IP_ALIGN + skb->len + 37 padlen + len, GFP_ATOMIC); 38 if (!nskb) 39 return NULL; 40 skb_reserve(nskb, NET_IP_ALIGN); 41 42 skb_reset_mac_header(nskb); 43 skb_set_network_header(nskb, 44 skb_network_header(skb) - skb->head); 45 skb_set_transport_header(nskb, 46 skb_transport_header(skb) - skb->head); 47 skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len)); 48 49 /* Let skb_put_padto() free nskb, and let dsa_slave_xmit() free 50 * skb 51 */ 52 if (skb_put_padto(nskb, nskb->len + padlen)) 53 return NULL; 54 55 consume_skb(skb); 56 } 57 58 return nskb; 59 } 60 61 static struct sk_buff *ksz_common_rcv(struct sk_buff *skb, 62 struct net_device *dev, 63 unsigned int port, unsigned int len) 64 { 65 skb->dev = dsa_master_find_slave(dev, 0, port); 66 if (!skb->dev) 67 return NULL; 68 69 pskb_trim_rcsum(skb, skb->len - len); 70 71 skb->offload_fwd_mark = true; 72 73 return skb; 74 } 75 76 /* 77 * For Ingress (Host -> KSZ9477), 2 bytes are added before FCS. 78 * --------------------------------------------------------------------------- 79 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|tag1(1byte)|FCS(4bytes) 80 * --------------------------------------------------------------------------- 81 * tag0 : Prioritization (not used now) 82 * tag1 : each bit represents port (eg, 0x01=port1, 0x02=port2, 0x10=port5) 83 * 84 * For Egress (KSZ9477 -> Host), 1 byte is added before FCS. 85 * --------------------------------------------------------------------------- 86 * DA(6bytes)|SA(6bytes)|....|Data(nbytes)|tag0(1byte)|FCS(4bytes) 87 * --------------------------------------------------------------------------- 88 * tag0 : zero-based value represents port 89 * (eg, 0x00=port1, 0x02=port3, 0x06=port7) 90 */ 91 92 #define KSZ9477_INGRESS_TAG_LEN 2 93 #define KSZ9477_PTP_TAG_LEN 4 94 #define KSZ9477_PTP_TAG_INDICATION 0x80 95 96 #define KSZ9477_TAIL_TAG_OVERRIDE BIT(9) 97 #define KSZ9477_TAIL_TAG_LOOKUP BIT(10) 98 99 static struct sk_buff *ksz9477_xmit(struct sk_buff *skb, 100 struct net_device *dev) 101 { 102 struct dsa_port *dp = dsa_slave_to_port(dev); 103 struct sk_buff *nskb; 104 u16 *tag; 105 u8 *addr; 106 107 nskb = ksz_common_xmit(skb, dev, KSZ9477_INGRESS_TAG_LEN); 108 if (!nskb) 109 return NULL; 110 111 /* Tag encoding */ 112 tag = skb_put(nskb, KSZ9477_INGRESS_TAG_LEN); 113 addr = skb_mac_header(nskb); 114 115 *tag = BIT(dp->index); 116 117 if (is_link_local_ether_addr(addr)) 118 *tag |= KSZ9477_TAIL_TAG_OVERRIDE; 119 120 *tag = cpu_to_be16(*tag); 121 122 return nskb; 123 } 124 125 static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev, 126 struct packet_type *pt) 127 { 128 /* Tag decoding */ 129 u8 *tag = skb_tail_pointer(skb) - KSZ_EGRESS_TAG_LEN; 130 unsigned int port = tag[0] & 7; 131 unsigned int len = KSZ_EGRESS_TAG_LEN; 132 133 /* Extra 4-bytes PTP timestamp */ 134 if (tag[0] & KSZ9477_PTP_TAG_INDICATION) 135 len += KSZ9477_PTP_TAG_LEN; 136 137 return ksz_common_rcv(skb, dev, port, len); 138 } 139 140 const struct dsa_device_ops ksz9477_netdev_ops = { 141 .xmit = ksz9477_xmit, 142 .rcv = ksz9477_rcv, 143 .overhead = KSZ9477_INGRESS_TAG_LEN, 144 }; 145 146 #define KSZ9893_TAIL_TAG_OVERRIDE BIT(5) 147 #define KSZ9893_TAIL_TAG_LOOKUP BIT(6) 148 149 static struct sk_buff *ksz9893_xmit(struct sk_buff *skb, 150 struct net_device *dev) 151 { 152 struct dsa_port *dp = dsa_slave_to_port(dev); 153 struct sk_buff *nskb; 154 u8 *addr; 155 u8 *tag; 156 157 nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN); 158 if (!nskb) 159 return NULL; 160 161 /* Tag encoding */ 162 tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN); 163 addr = skb_mac_header(nskb); 164 165 *tag = BIT(dp->index); 166 167 if (is_link_local_ether_addr(addr)) 168 *tag |= KSZ9893_TAIL_TAG_OVERRIDE; 169 170 return nskb; 171 } 172 173 const struct dsa_device_ops ksz9893_netdev_ops = { 174 .xmit = ksz9893_xmit, 175 .rcv = ksz9477_rcv, 176 .overhead = KSZ_INGRESS_TAG_LEN, 177 }; 178