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net: dsa: forward timestamping callbacks to switch drivers
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Forward the rx/tx timestamp machinery from the dsa infrastructure to the
switch driver.

On the rx side, defer delivery of skbs until we have an rx timestamp.
This mimicks the behavior of skb_defer_rx_timestamp.

On the tx side, identify PTP packets, clone them, and pass them to the
underlying switch driver before we transmit. This mimicks the behavior
of skb_tx_timestamp.

Adjusted txstamp API to keep the allocation and freeing of the clone
in the same central function by Richard Cochran

Signed-off-by: Brandon Streiff <brandon.streiff@ni.com>
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Brandon Streiff authored and David S. Miller committed Feb 14, 2018
1 parent 0336369 commit 90af105
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Showing 3 changed files with 71 additions and 0 deletions.
5 changes: 5 additions & 0 deletions include/net/dsa.h
Original file line number Diff line number Diff line change
Expand Up @@ -102,6 +102,7 @@ struct dsa_platform_data {
};

struct packet_type;
struct dsa_switch;

struct dsa_device_ops {
struct sk_buff *(*xmit)(struct sk_buff *skb, struct net_device *dev);
Expand Down Expand Up @@ -484,6 +485,10 @@ struct dsa_switch_ops {
struct ifreq *ifr);
int (*port_hwtstamp_set)(struct dsa_switch *ds, int port,
struct ifreq *ifr);
bool (*port_txtstamp)(struct dsa_switch *ds, int port,
struct sk_buff *clone, unsigned int type);
bool (*port_rxtstamp)(struct dsa_switch *ds, int port,
struct sk_buff *skb, unsigned int type);
};

struct dsa_switch_driver {
Expand Down
36 changes: 36 additions & 0 deletions net/dsa/dsa.c
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
#include <linux/netdevice.h>
#include <linux/sysfs.h>
#include <linux/phy_fixed.h>
#include <linux/ptp_classify.h>
#include <linux/gpio/consumer.h>
#include <linux/etherdevice.h>

Expand Down Expand Up @@ -122,6 +123,38 @@ struct net_device *dsa_dev_to_net_device(struct device *dev)
}
EXPORT_SYMBOL_GPL(dsa_dev_to_net_device);

/* Determine if we should defer delivery of skb until we have a rx timestamp.
*
* Called from dsa_switch_rcv. For now, this will only work if tagging is
* enabled on the switch. Normally the MAC driver would retrieve the hardware
* timestamp when it reads the packet out of the hardware. However in a DSA
* switch, the DSA driver owning the interface to which the packet is
* delivered is never notified unless we do so here.
*/
static bool dsa_skb_defer_rx_timestamp(struct dsa_slave_priv *p,
struct sk_buff *skb)
{
struct dsa_switch *ds = p->dp->ds;
unsigned int type;

if (skb_headroom(skb) < ETH_HLEN)
return false;

__skb_push(skb, ETH_HLEN);

type = ptp_classify_raw(skb);

__skb_pull(skb, ETH_HLEN);

if (type == PTP_CLASS_NONE)
return false;

if (likely(ds->ops->port_rxtstamp))
return ds->ops->port_rxtstamp(ds, p->dp->index, skb, type);

return false;
}

static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *unused)
{
Expand Down Expand Up @@ -157,6 +190,9 @@ static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
s->rx_bytes += skb->len;
u64_stats_update_end(&s->syncp);

if (dsa_skb_defer_rx_timestamp(p, skb))
return 0;

netif_receive_skb(skb);

return 0;
Expand Down
30 changes: 30 additions & 0 deletions net/dsa/slave.c
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
#include <net/tc_act/tc_mirred.h>
#include <linux/if_bridge.h>
#include <linux/netpoll.h>
#include <linux/ptp_classify.h>

#include "dsa_priv.h"

Expand Down Expand Up @@ -401,6 +402,30 @@ static inline netdev_tx_t dsa_slave_netpoll_send_skb(struct net_device *dev,
return NETDEV_TX_OK;
}

static void dsa_skb_tx_timestamp(struct dsa_slave_priv *p,
struct sk_buff *skb)
{
struct dsa_switch *ds = p->dp->ds;
struct sk_buff *clone;
unsigned int type;

type = ptp_classify_raw(skb);
if (type == PTP_CLASS_NONE)
return;

if (!ds->ops->port_txtstamp)
return;

clone = skb_clone_sk(skb);
if (!clone)
return;

if (ds->ops->port_txtstamp(ds, p->dp->index, clone, type))
return;

kfree_skb(clone);
}

static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct dsa_slave_priv *p = netdev_priv(dev);
Expand All @@ -413,6 +438,11 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
s->tx_bytes += skb->len;
u64_stats_update_end(&s->syncp);

/* Identify PTP protocol packets, clone them, and pass them to the
* switch driver
*/
dsa_skb_tx_timestamp(p, skb);

/* Transmit function may have to reallocate the original SKB,
* in which case it must have freed it. Only free it here on error.
*/
Expand Down

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