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