diff options
Diffstat (limited to 'net/dsa/tag_lan9303.c')
| -rw-r--r-- | net/dsa/tag_lan9303.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/net/dsa/tag_lan9303.c b/net/dsa/tag_lan9303.c new file mode 100644 index 000000000..c25f55367 --- /dev/null +++ b/net/dsa/tag_lan9303.c @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de> + */ +#include <linux/dsa/lan9303.h> +#include <linux/etherdevice.h> +#include <linux/list.h> +#include <linux/slab.h> + +#include "tag.h" + +/* To define the outgoing port and to discover the incoming port a regular + * VLAN tag is used by the LAN9303. But its VID meaning is 'special': + * + * Dest MAC Src MAC TAG Type + * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |... + * |<------->| + * TAG: + * |<------------->| + * | 1 2 | 3 4 | + * TPID VID + * 0x8100 + * + * VID bit 3 indicates a request for an ALR lookup. + * + * If VID bit 3 is zero, then bits 0 and 1 specify the destination port + * (0, 1, 2) or broadcast (3) or the source port (1, 2). + * + * VID bit 4 is used to specify if the STP port state should be overridden. + * Required when no forwarding between the external ports should happen. + */ + +#define LAN9303_NAME "lan9303" + +#define LAN9303_TAG_LEN 4 +# define LAN9303_TAG_TX_USE_ALR BIT(3) +# define LAN9303_TAG_TX_STP_OVERRIDE BIT(4) +# define LAN9303_TAG_RX_IGMP BIT(3) +# define LAN9303_TAG_RX_STP BIT(4) +# define LAN9303_TAG_RX_TRAPPED_TO_CPU (LAN9303_TAG_RX_IGMP | \ + LAN9303_TAG_RX_STP) + +/* Decide whether to transmit using ALR lookup, or transmit directly to + * port using tag. ALR learning is performed only when using ALR lookup. + * If the two external ports are bridged and the frame is unicast, + * then use ALR lookup to allow ALR learning on CPU port. + * Otherwise transmit directly to port with STP state override. + * See also: lan9303_separate_ports() and lan9303.pdf 6.4.10.1 + */ +static int lan9303_xmit_use_arl(struct dsa_port *dp, u8 *dest_addr) +{ + struct lan9303 *chip = dp->ds->priv; + + return chip->is_bridged && !is_multicast_ether_addr(dest_addr); +} + +static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct dsa_port *dp = dsa_slave_to_port(dev); + __be16 *lan9303_tag; + u16 tag; + + /* provide 'LAN9303_TAG_LEN' bytes additional space */ + skb_push(skb, LAN9303_TAG_LEN); + + /* make room between MACs and Ether-Type */ + dsa_alloc_etype_header(skb, LAN9303_TAG_LEN); + + lan9303_tag = dsa_etype_header_pos_tx(skb); + + tag = lan9303_xmit_use_arl(dp, skb->data) ? + LAN9303_TAG_TX_USE_ALR : + dp->index | LAN9303_TAG_TX_STP_OVERRIDE; + lan9303_tag[0] = htons(ETH_P_8021Q); + lan9303_tag[1] = htons(tag); + + return skb; +} + +static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev) +{ + u16 lan9303_tag1; + unsigned int source_port; + + if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) { + dev_warn_ratelimited(&dev->dev, + "Dropping packet, cannot pull\n"); + return NULL; + } + + if (skb_vlan_tag_present(skb)) { + lan9303_tag1 = skb_vlan_tag_get(skb); + __vlan_hwaccel_clear_tag(skb); + } else { + skb_push_rcsum(skb, ETH_HLEN); + __skb_vlan_pop(skb, &lan9303_tag1); + skb_pull_rcsum(skb, ETH_HLEN); + } + + source_port = lan9303_tag1 & 0x3; + + skb->dev = dsa_master_find_slave(dev, 0, source_port); + if (!skb->dev) { + dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n"); + return NULL; + } + + if (!(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU)) + dsa_default_offload_fwd_mark(skb); + + return skb; +} + +static const struct dsa_device_ops lan9303_netdev_ops = { + .name = LAN9303_NAME, + .proto = DSA_TAG_PROTO_LAN9303, + .xmit = lan9303_xmit, + .rcv = lan9303_rcv, + .needed_headroom = LAN9303_TAG_LEN, +}; + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_LAN9303, LAN9303_NAME); + +module_dsa_tag_driver(lan9303_netdev_ops); |