diff options
Diffstat (limited to 'net/dsa/tag_sja1105.c')
| -rw-r--r-- | net/dsa/tag_sja1105.c | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/net/dsa/tag_sja1105.c b/net/dsa/tag_sja1105.c new file mode 100644 index 000000000..07876160e --- /dev/null +++ b/net/dsa/tag_sja1105.c @@ -0,0 +1,373 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com> + */ +#include <linux/if_vlan.h> +#include <linux/dsa/sja1105.h> +#include <linux/dsa/8021q.h> +#include <linux/packing.h> +#include "dsa_priv.h" + +/* Similar to is_link_local_ether_addr(hdr->h_dest) but also covers PTP */ +static inline bool sja1105_is_link_local(const struct sk_buff *skb) +{ + const struct ethhdr *hdr = eth_hdr(skb); + u64 dmac = ether_addr_to_u64(hdr->h_dest); + + if (ntohs(hdr->h_proto) == ETH_P_SJA1105_META) + return false; + if ((dmac & SJA1105_LINKLOCAL_FILTER_A_MASK) == + SJA1105_LINKLOCAL_FILTER_A) + return true; + if ((dmac & SJA1105_LINKLOCAL_FILTER_B_MASK) == + SJA1105_LINKLOCAL_FILTER_B) + return true; + return false; +} + +struct sja1105_meta { + u64 tstamp; + u64 dmac_byte_4; + u64 dmac_byte_3; + u64 source_port; + u64 switch_id; +}; + +static void sja1105_meta_unpack(const struct sk_buff *skb, + struct sja1105_meta *meta) +{ + u8 *buf = skb_mac_header(skb) + ETH_HLEN; + + /* UM10944.pdf section 4.2.17 AVB Parameters: + * Structure of the meta-data follow-up frame. + * It is in network byte order, so there are no quirks + * while unpacking the meta frame. + * + * Also SJA1105 E/T only populates bits 23:0 of the timestamp + * whereas P/Q/R/S does 32 bits. Since the structure is the + * same and the E/T puts zeroes in the high-order byte, use + * a unified unpacking command for both device series. + */ + packing(buf, &meta->tstamp, 31, 0, 4, UNPACK, 0); + packing(buf + 4, &meta->dmac_byte_3, 7, 0, 1, UNPACK, 0); + packing(buf + 5, &meta->dmac_byte_4, 7, 0, 1, UNPACK, 0); + packing(buf + 6, &meta->source_port, 7, 0, 1, UNPACK, 0); + packing(buf + 7, &meta->switch_id, 7, 0, 1, UNPACK, 0); +} + +static inline bool sja1105_is_meta_frame(const struct sk_buff *skb) +{ + const struct ethhdr *hdr = eth_hdr(skb); + u64 smac = ether_addr_to_u64(hdr->h_source); + u64 dmac = ether_addr_to_u64(hdr->h_dest); + + if (smac != SJA1105_META_SMAC) + return false; + if (dmac != SJA1105_META_DMAC) + return false; + if (ntohs(hdr->h_proto) != ETH_P_SJA1105_META) + return false; + return true; +} + +static bool sja1105_can_use_vlan_as_tags(const struct sk_buff *skb) +{ + struct vlan_ethhdr *hdr = vlan_eth_hdr(skb); + u16 vlan_tci; + + if (hdr->h_vlan_proto == htons(ETH_P_SJA1105)) + return true; + + if (hdr->h_vlan_proto != htons(ETH_P_8021Q) && + !skb_vlan_tag_present(skb)) + return false; + + if (skb_vlan_tag_present(skb)) + vlan_tci = skb_vlan_tag_get(skb); + else + vlan_tci = ntohs(hdr->h_vlan_TCI); + + return vid_is_dsa_8021q(vlan_tci & VLAN_VID_MASK); +} + +/* This is the first time the tagger sees the frame on RX. + * Figure out if we can decode it. + */ +static bool sja1105_filter(const struct sk_buff *skb, struct net_device *dev) +{ + if (sja1105_can_use_vlan_as_tags(skb)) + return true; + if (sja1105_is_link_local(skb)) + return true; + if (sja1105_is_meta_frame(skb)) + return true; + return false; +} + +/* Calls sja1105_port_deferred_xmit in sja1105_main.c */ +static struct sk_buff *sja1105_defer_xmit(struct sja1105_port *sp, + struct sk_buff *skb) +{ + /* Increase refcount so the kfree_skb in dsa_slave_xmit + * won't really free the packet. + */ + skb_queue_tail(&sp->xmit_queue, skb_get(skb)); + kthread_queue_work(sp->xmit_worker, &sp->xmit_work); + + return NULL; +} + +static u16 sja1105_xmit_tpid(struct sja1105_port *sp) +{ + return sp->xmit_tpid; +} + +static struct sk_buff *sja1105_xmit(struct sk_buff *skb, + struct net_device *netdev) +{ + struct dsa_port *dp = dsa_slave_to_port(netdev); + u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index); + u16 queue_mapping = skb_get_queue_mapping(skb); + u8 pcp = netdev_txq_to_tc(netdev, queue_mapping); + + /* Transmitting management traffic does not rely upon switch tagging, + * but instead SPI-installed management routes. Part 2 of this + * is the .port_deferred_xmit driver callback. + */ + if (unlikely(sja1105_is_link_local(skb))) + return sja1105_defer_xmit(dp->priv, skb); + + return dsa_8021q_xmit(skb, netdev, sja1105_xmit_tpid(dp->priv), + ((pcp << VLAN_PRIO_SHIFT) | tx_vid)); +} + +static void sja1105_transfer_meta(struct sk_buff *skb, + const struct sja1105_meta *meta) +{ + struct ethhdr *hdr = eth_hdr(skb); + + hdr->h_dest[3] = meta->dmac_byte_3; + hdr->h_dest[4] = meta->dmac_byte_4; + SJA1105_SKB_CB(skb)->meta_tstamp = meta->tstamp; +} + +/* This is a simple state machine which follows the hardware mechanism of + * generating RX timestamps: + * + * After each timestampable skb (all traffic for which send_meta1 and + * send_meta0 is true, aka all MAC-filtered link-local traffic) a meta frame + * containing a partial timestamp is immediately generated by the switch and + * sent as a follow-up to the link-local frame on the CPU port. + * + * The meta frames have no unique identifier (such as sequence number) by which + * one may pair them to the correct timestampable frame. + * Instead, the switch has internal logic that ensures no frames are sent on + * the CPU port between a link-local timestampable frame and its corresponding + * meta follow-up. It also ensures strict ordering between ports (lower ports + * have higher priority towards the CPU port). For this reason, a per-port + * data structure is not needed/desirable. + * + * This function pairs the link-local frame with its partial timestamp from the + * meta follow-up frame. The full timestamp will be reconstructed later in a + * work queue. + */ +static struct sk_buff +*sja1105_rcv_meta_state_machine(struct sk_buff *skb, + struct sja1105_meta *meta, + bool is_link_local, + bool is_meta) +{ + struct sja1105_port *sp; + struct dsa_port *dp; + + dp = dsa_slave_to_port(skb->dev); + sp = dp->priv; + + /* Step 1: A timestampable frame was received. + * Buffer it until we get its meta frame. + */ + if (is_link_local) { + if (!test_bit(SJA1105_HWTS_RX_EN, &sp->data->state)) + /* Do normal processing. */ + return skb; + + spin_lock(&sp->data->meta_lock); + /* Was this a link-local frame instead of the meta + * that we were expecting? + */ + if (sp->data->stampable_skb) { + dev_err_ratelimited(dp->ds->dev, + "Expected meta frame, is %12llx " + "in the DSA master multicast filter?\n", + SJA1105_META_DMAC); + kfree_skb(sp->data->stampable_skb); + } + + /* Hold a reference to avoid dsa_switch_rcv + * from freeing the skb. + */ + sp->data->stampable_skb = skb_get(skb); + spin_unlock(&sp->data->meta_lock); + + /* Tell DSA we got nothing */ + return NULL; + + /* Step 2: The meta frame arrived. + * Time to take the stampable skb out of the closet, annotate it + * with the partial timestamp, and pretend that we received it + * just now (basically masquerade the buffered frame as the meta + * frame, which serves no further purpose). + */ + } else if (is_meta) { + struct sk_buff *stampable_skb; + + /* Drop the meta frame if we're not in the right state + * to process it. + */ + if (!test_bit(SJA1105_HWTS_RX_EN, &sp->data->state)) + return NULL; + + spin_lock(&sp->data->meta_lock); + + stampable_skb = sp->data->stampable_skb; + sp->data->stampable_skb = NULL; + + /* Was this a meta frame instead of the link-local + * that we were expecting? + */ + if (!stampable_skb) { + dev_err_ratelimited(dp->ds->dev, + "Unexpected meta frame\n"); + spin_unlock(&sp->data->meta_lock); + return NULL; + } + + if (stampable_skb->dev != skb->dev) { + dev_err_ratelimited(dp->ds->dev, + "Meta frame on wrong port\n"); + spin_unlock(&sp->data->meta_lock); + return NULL; + } + + /* Free the meta frame and give DSA the buffered stampable_skb + * for further processing up the network stack. + */ + kfree_skb(skb); + skb = stampable_skb; + sja1105_transfer_meta(skb, meta); + + spin_unlock(&sp->data->meta_lock); + } + + return skb; +} + +static void sja1105_decode_subvlan(struct sk_buff *skb, u16 subvlan) +{ + struct dsa_port *dp = dsa_slave_to_port(skb->dev); + struct sja1105_port *sp = dp->priv; + u16 vid = sp->subvlan_map[subvlan]; + u16 vlan_tci; + + if (vid == VLAN_N_VID) + return; + + vlan_tci = (skb->priority << VLAN_PRIO_SHIFT) | vid; + __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), vlan_tci); +} + +static struct sk_buff *sja1105_rcv(struct sk_buff *skb, + struct net_device *netdev, + struct packet_type *pt) +{ + struct sja1105_meta meta = {0}; + int source_port, switch_id; + struct ethhdr *hdr; + u16 tpid, vid, tci; + bool is_link_local; + u16 subvlan = 0; + bool is_tagged; + bool is_meta; + + hdr = eth_hdr(skb); + tpid = ntohs(hdr->h_proto); + is_tagged = (tpid == ETH_P_SJA1105 || tpid == ETH_P_8021Q || + skb_vlan_tag_present(skb)); + is_link_local = sja1105_is_link_local(skb); + is_meta = sja1105_is_meta_frame(skb); + + skb->offload_fwd_mark = 1; + + if (is_tagged) { + /* Normal traffic path. */ + skb_push_rcsum(skb, ETH_HLEN); + if (skb_vlan_tag_present(skb)) { + tci = skb_vlan_tag_get(skb); + __vlan_hwaccel_clear_tag(skb); + } else { + __skb_vlan_pop(skb, &tci); + } + skb_pull_rcsum(skb, ETH_HLEN); + skb_reset_network_header(skb); + skb_reset_transport_header(skb); + + vid = tci & VLAN_VID_MASK; + source_port = dsa_8021q_rx_source_port(vid); + switch_id = dsa_8021q_rx_switch_id(vid); + skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT; + subvlan = dsa_8021q_rx_subvlan(vid); + } else if (is_link_local) { + /* Management traffic path. Switch embeds the switch ID and + * port ID into bytes of the destination MAC, courtesy of + * the incl_srcpt options. + */ + source_port = hdr->h_dest[3]; + switch_id = hdr->h_dest[4]; + /* Clear the DMAC bytes that were mangled by the switch */ + hdr->h_dest[3] = 0; + hdr->h_dest[4] = 0; + } else if (is_meta) { + sja1105_meta_unpack(skb, &meta); + source_port = meta.source_port; + switch_id = meta.switch_id; + } else { + return NULL; + } + + skb->dev = dsa_master_find_slave(netdev, switch_id, source_port); + if (!skb->dev) { + netdev_warn(netdev, "Couldn't decode source port\n"); + return NULL; + } + + if (subvlan) + sja1105_decode_subvlan(skb, subvlan); + + return sja1105_rcv_meta_state_machine(skb, &meta, is_link_local, + is_meta); +} + +static void sja1105_flow_dissect(const struct sk_buff *skb, __be16 *proto, + int *offset) +{ + /* No tag added for management frames, all ok */ + if (unlikely(sja1105_is_link_local(skb))) + return; + + dsa_tag_generic_flow_dissect(skb, proto, offset); +} + +static const struct dsa_device_ops sja1105_netdev_ops = { + .name = "sja1105", + .proto = DSA_TAG_PROTO_SJA1105, + .xmit = sja1105_xmit, + .rcv = sja1105_rcv, + .filter = sja1105_filter, + .overhead = VLAN_HLEN, + .flow_dissect = sja1105_flow_dissect, + .promisc_on_master = true, +}; + +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_SJA1105); + +module_dsa_tag_driver(sja1105_netdev_ops); |