net: mscc: ocelot: serialize access to the injection/extraction groups

As explained by Horatiu Vultur in commit 603ead96582d ("net: sparx5: Add
spinlock for frame transmission from CPU") which is for a similar
hardware design, multiple CPUs can simultaneously perform injection
or extraction. There are only 2 register groups for injection and 2
for extraction, and the driver only uses one of each. So we'd better
serialize access using spin locks, otherwise frame corruption is
possible.

Note that unlike in sparx5, FDMA in ocelot does not have this issue
because struct ocelot_fdma_tx_ring already contains an xmit_lock.

I guess this is mostly a problem for NXP LS1028A, as that is dual core.
I don't think VSC7514 is. So I'm blaming the commit where LS1028A (aka
the felix DSA driver) started using register-based packet injection and
extraction.

Fixes: 0a6f17c6ae21 ("net: dsa: tag_ocelot_8021q: add support for PTP timestamping")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 56 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 9301716e21d5..f4e027a6fe95 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1099,6 +1099,48 @@ void ocelot_ptp_rx_timestamp(struct ocelot *ocelot, struct sk_buff *skb,
 }
 EXPORT_SYMBOL(ocelot_ptp_rx_timestamp);
 
+void ocelot_lock_inj_grp(struct ocelot *ocelot, int grp)
+			 __acquires(&ocelot->inj_lock)
+{
+	spin_lock(&ocelot->inj_lock);
+}
+EXPORT_SYMBOL_GPL(ocelot_lock_inj_grp);
+
+void ocelot_unlock_inj_grp(struct ocelot *ocelot, int grp)
+			   __releases(&ocelot->inj_lock)
+{
+	spin_unlock(&ocelot->inj_lock);
+}
+EXPORT_SYMBOL_GPL(ocelot_unlock_inj_grp);
+
+void ocelot_lock_xtr_grp(struct ocelot *ocelot, int grp)
+			 __acquires(&ocelot->inj_lock)
+{
+	spin_lock(&ocelot->inj_lock);
+}
+EXPORT_SYMBOL_GPL(ocelot_lock_xtr_grp);
+
+void ocelot_unlock_xtr_grp(struct ocelot *ocelot, int grp)
+			   __releases(&ocelot->inj_lock)
+{
+	spin_unlock(&ocelot->inj_lock);
+}
+EXPORT_SYMBOL_GPL(ocelot_unlock_xtr_grp);
+
+void ocelot_lock_xtr_grp_bh(struct ocelot *ocelot, int grp)
+			    __acquires(&ocelot->xtr_lock)
+{
+	spin_lock_bh(&ocelot->xtr_lock);
+}
+EXPORT_SYMBOL_GPL(ocelot_lock_xtr_grp_bh);
+
+void ocelot_unlock_xtr_grp_bh(struct ocelot *ocelot, int grp)
+			      __releases(&ocelot->xtr_lock)
+{
+	spin_unlock_bh(&ocelot->xtr_lock);
+}
+EXPORT_SYMBOL_GPL(ocelot_unlock_xtr_grp_bh);
+
 int ocelot_xtr_poll_frame(struct ocelot *ocelot, int grp, struct sk_buff **nskb)
 {
 	u64 timestamp, src_port, len;
@@ -1109,6 +1151,8 @@ int ocelot_xtr_poll_frame(struct ocelot *ocelot, int grp, struct sk_buff **nskb)
 	u32 val, *buf;
 	int err;
 
+	lockdep_assert_held(&ocelot->xtr_lock);
+
 	err = ocelot_xtr_poll_xfh(ocelot, grp, xfh);
 	if (err)
 		return err;
@@ -1184,6 +1228,8 @@ bool ocelot_can_inject(struct ocelot *ocelot, int grp)
 {
 	u32 val = ocelot_read(ocelot, QS_INJ_STATUS);
 
+	lockdep_assert_held(&ocelot->inj_lock);
+
 	if (!(val & QS_INJ_STATUS_FIFO_RDY(BIT(grp))))
 		return false;
 	if (val & QS_INJ_STATUS_WMARK_REACHED(BIT(grp)))
@@ -1236,6 +1282,8 @@ void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
 	u32 ifh[OCELOT_TAG_LEN / 4];
 	unsigned int i, count, last;
 
+	lockdep_assert_held(&ocelot->inj_lock);
+
 	ocelot_write_rix(ocelot, QS_INJ_CTRL_GAP_SIZE(1) |
 			 QS_INJ_CTRL_SOF, QS_INJ_CTRL, grp);
 
@@ -1272,6 +1320,8 @@ EXPORT_SYMBOL(ocelot_port_inject_frame);
 
 void ocelot_drain_cpu_queue(struct ocelot *ocelot, int grp)
 {
+	lockdep_assert_held(&ocelot->xtr_lock);
+
 	while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp))
 		ocelot_read_rix(ocelot, QS_XTR_RD, grp);
 }
@@ -2954,6 +3004,8 @@ int ocelot_init(struct ocelot *ocelot)
 	mutex_init(&ocelot->fwd_domain_lock);
 	spin_lock_init(&ocelot->ptp_clock_lock);
 	spin_lock_init(&ocelot->ts_id_lock);
+	spin_lock_init(&ocelot->inj_lock);
+	spin_lock_init(&ocelot->xtr_lock);
 
 	ocelot->owq = alloc_ordered_workqueue("ocelot-owq", 0);
 	if (!ocelot->owq)
diff --git a/drivers/net/ethernet/mscc/ocelot_vsc7514.c b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
index 993212c3a7da..c09dd2e3343c 100644
--- a/drivers/net/ethernet/mscc/ocelot_vsc7514.c
+++ b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
@@ -51,6 +51,8 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 	struct ocelot *ocelot = arg;
 	int grp = 0, err;
 
+	ocelot_lock_xtr_grp(ocelot, grp);
+
 	while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp)) {
 		struct sk_buff *skb;
 
@@ -69,6 +71,8 @@ out:
 	if (err < 0)
 		ocelot_drain_cpu_queue(ocelot, 0);
 
+	ocelot_unlock_xtr_grp(ocelot, grp);
+
 	return IRQ_HANDLED;
 }