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net: dsa: tag_ocelot: single out PTP-related transmit tag processing

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There is one place where we cannot avoid accessing driver data, and that
is 2-step PTP TX timestamping, since the switch wants us to provide a
timestamp request ID through the injection header, which naturally must
come from a sequence number kept by the driver (it is generated by the
.port_txtstamp method prior to the tagger's xmit).

However, since other drivers like dsa_loop do not claim PTP support
anyway, the DSA_SKB_CB(skb)->clone will always be NULL anyway, so if we
move all PTP-related dereferences of struct ocelot and struct ocelot_port
into a separate function, we can effectively ensure that this is dead
code when the ocelot tagger is attached to non-ocelot switches, and the
stateful portion of the tagger is more self-contained.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vladimir Oltean 2021-02-14 00:37:57 +02:00 committed by David S. Miller
parent 40d3f295b5
commit 62bf5fde5e
1 changed files with 21 additions and 11 deletions
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32
net/dsa/tag_ocelot.c
View File

@ -5,6 +5,25 @@
#include <soc/mscc/ocelot.h>
#include "dsa_priv.h"
static void ocelot_xmit_ptp(struct dsa_port *dp, void *injection,
struct sk_buff *clone)
{
struct ocelot *ocelot = dp->ds->priv;
struct ocelot_port *ocelot_port;
u64 rew_op;
ocelot_port = ocelot->ports[dp->index];
rew_op = ocelot_port->ptp_cmd;
/* Retrieve timestamp ID populated inside skb->cb[0] of the
* clone by ocelot_port_add_txtstamp_skb
*/
if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
rew_op |= clone->cb[0] << 3;
ocelot_ifh_set_rew_op(injection, rew_op);
}
static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
struct net_device *netdev)
{
@ -29,17 +48,8 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
ocelot_ifh_set_qos_class(injection, skb->priority);
/* TX timestamping was requested */
if (clone) {
u64 rew_op = ocelot_port->ptp_cmd;
/* Retrieve timestamp ID populated inside skb->cb[0] of the
* clone by ocelot_port_add_txtstamp_skb
*/
if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
rew_op |= clone->cb[0] << 3;
ocelot_ifh_set_rew_op(injection, rew_op);
}
if (clone)
ocelot_xmit_ptp(dp, injection, clone);
return skb;
}