Commit 52849bcf authored by Vladimir Oltean's avatar Vladimir Oltean Committed by Jakub Kicinski
Browse files

net: mscc: ocelot: avoid overflowing the PTP timestamp FIFO 



PTP packets with 2-step TX timestamp requests are matched to packets
based on the egress port number and a 6-bit timestamp identifier.
All PTP timestamps are held in a common FIFO that is 128 entry deep.

This patch ensures that back-to-back timestamping requests cannot exceed
the hardware FIFO capacity. If that happens, simply send the packets
without requesting a TX timestamp to be taken (in the case of felix,
since the DSA API has a void return code in ds->ops->port_txtstamp) or
drop them (in the case of ocelot).

I've moved the ts_id_lock from a per-port basis to a per-switch basis,
because we need separate accounting for both numbers of PTP frames in
flight. And since we need locking to inc/dec the per-switch counter,
that also offers protection for the per-port counter and hence there is
no reason to have a per-port counter anymore.

Fixes: 4e3b0468 ("net: mscc: PTP Hardware Clock (PHC) support")
Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c57fe003

drivers/net/dsa/ocelot/felix.c

+5 −1
Original line number Diff line number Diff line
@@ -1291,8 +1291,12 @@ static void felix_txtstamp(struct dsa_switch *ds, int port, 
	if (!ocelot->ptp)

		return;



	if (ocelot_port_txtstamp_request(ocelot, port, skb, &clone))

	if (ocelot_port_txtstamp_request(ocelot, port, skb, &clone)) {

		dev_err_ratelimited(ds->dev,

				    "port %d delivering skb without TX timestamp\n",

				    port);

		return;

	}



	if (clone)

		OCELOT_SKB_CB(skb)->clone = clone;

drivers/net/ethernet/mscc/ocelot.c

+30 −7
Original line number Diff line number Diff line
@@ -569,22 +569,36 @@ void ocelot_phylink_mac_link_up(struct ocelot *ocelot, int port, 
}

EXPORT_SYMBOL_GPL(ocelot_phylink_mac_link_up);



static void ocelot_port_add_txtstamp_skb(struct ocelot *ocelot, int port,

static int ocelot_port_add_txtstamp_skb(struct ocelot *ocelot, int port,

					struct sk_buff *clone)

{

	struct ocelot_port *ocelot_port = ocelot->ports[port];

	unsigned long flags;



	spin_lock_irqsave(&ocelot->ts_id_lock, flags);



	spin_lock(&ocelot_port->ts_id_lock);

	if (ocelot_port->ptp_skbs_in_flight == OCELOT_MAX_PTP_ID ||

	    ocelot->ptp_skbs_in_flight == OCELOT_PTP_FIFO_SIZE) {

		spin_unlock_irqrestore(&ocelot->ts_id_lock, flags);

		return -EBUSY;

	}



	skb_shinfo(clone)->tx_flags |= SKBTX_IN_PROGRESS;

	/* Store timestamp ID in OCELOT_SKB_CB(clone)->ts_id */

	OCELOT_SKB_CB(clone)->ts_id = ocelot_port->ts_id;



	ocelot_port->ts_id++;

	if (ocelot_port->ts_id == OCELOT_MAX_PTP_ID)

		ocelot_port->ts_id = 0;



	ocelot_port->ptp_skbs_in_flight++;

	ocelot->ptp_skbs_in_flight++;



	skb_queue_tail(&ocelot_port->tx_skbs, clone);



	spin_unlock(&ocelot_port->ts_id_lock);

	spin_unlock_irqrestore(&ocelot->ts_id_lock, flags);



	return 0;

}



u32 ocelot_ptp_rew_op(struct sk_buff *skb)
@@ -633,6 +647,7 @@ int ocelot_port_txtstamp_request(struct ocelot *ocelot, int port, 
{

	struct ocelot_port *ocelot_port = ocelot->ports[port];

	u8 ptp_cmd = ocelot_port->ptp_cmd;

	int err;



	/* Store ptp_cmd in OCELOT_SKB_CB(skb)->ptp_cmd */

	if (ptp_cmd == IFH_REW_OP_ORIGIN_PTP) {
@@ -650,7 +665,10 @@ int ocelot_port_txtstamp_request(struct ocelot *ocelot, int port, 
		if (!(*clone))

			return -ENOMEM;



		ocelot_port_add_txtstamp_skb(ocelot, port, *clone);

		err = ocelot_port_add_txtstamp_skb(ocelot, port, *clone);

		if (err)

			return err;



		OCELOT_SKB_CB(skb)->ptp_cmd = ptp_cmd;

	}
@@ -709,9 +727,14 @@ void ocelot_get_txtstamp(struct ocelot *ocelot) 
		id = SYS_PTP_STATUS_PTP_MESS_ID_X(val);

		txport = SYS_PTP_STATUS_PTP_MESS_TXPORT_X(val);



		/* Retrieve its associated skb */

		port = ocelot->ports[txport];



		spin_lock(&ocelot->ts_id_lock);

		port->ptp_skbs_in_flight--;

		ocelot->ptp_skbs_in_flight--;

		spin_unlock(&ocelot->ts_id_lock);



		/* Retrieve its associated skb */

		spin_lock_irqsave(&port->tx_skbs.lock, flags);



		skb_queue_walk_safe(&port->tx_skbs, skb, skb_tmp) {
@@ -1950,7 +1973,6 @@ void ocelot_init_port(struct ocelot *ocelot, int port) 
	struct ocelot_port *ocelot_port = ocelot->ports[port];



	skb_queue_head_init(&ocelot_port->tx_skbs);

	spin_lock_init(&ocelot_port->ts_id_lock);



	/* Basic L2 initialization */
@@ -2083,6 +2105,7 @@ int ocelot_init(struct ocelot *ocelot) 
	mutex_init(&ocelot->stats_lock);

	mutex_init(&ocelot->ptp_lock);

	spin_lock_init(&ocelot->ptp_clock_lock);

	spin_lock_init(&ocelot->ts_id_lock);

	snprintf(queue_name, sizeof(queue_name), "%s-stats",

		 dev_name(ocelot->dev));

	ocelot->stats_queue = create_singlethread_workqueue(queue_name);

include/soc/mscc/ocelot.h

+4 −1
Original line number Diff line number Diff line
@@ -603,10 +603,10 @@ struct ocelot_port { 
	/* The VLAN ID that will be transmitted as untagged, on egress */

	struct ocelot_vlan		native_vlan;



	unsigned int			ptp_skbs_in_flight;

	u8				ptp_cmd;

	struct sk_buff_head		tx_skbs;

	u8				ts_id;

	spinlock_t			ts_id_lock;



	phy_interface_t			phy_mode;
@@ -680,6 +680,9 @@ struct ocelot { 
	struct ptp_clock		*ptp_clock;

	struct ptp_clock_info		ptp_info;

	struct hwtstamp_config		hwtstamp_config;

	unsigned int			ptp_skbs_in_flight;

	/* Protects the 2-step TX timestamp ID logic */

	spinlock_t			ts_id_lock;

	/* Protects the PTP interface state */

	struct mutex			ptp_lock;

	/* Protects the PTP clock */

include/soc/mscc/ocelot_ptp.h

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <soc/mscc/ocelot.h>



#define OCELOT_MAX_PTP_ID		63

#define OCELOT_PTP_FIFO_SIZE		128



#define PTP_PIN_CFG_RSZ			0x20

#define PTP_PIN_TOD_SEC_MSB_RSZ		PTP_PIN_CFG_RSZ