There are 2 distinct code paths (listed below) in the source code which
set up an injection header for Ocelot(-like) switches. Code path (2)
lacks the QoS class and source port being set correctly. Especially the
improper QoS classification is a problem for the "ocelot-8021q"
alternative DSA tagging protocol, because we support tc-taprio and each
packet needs to be scheduled precisely through its time slot. This
includes PTP, which is normally assigned to a traffic class other than
0, but would be sent through TC 0 nonetheless.
The code paths are:
(1) ocelot_xmit_common() from net/dsa/tag_ocelot.c - called only by the
standard "ocelot" DSA tagging protocol which uses NPI-based
injection - sets up bit fields in the tag manually to account for
a small difference (destination port offset) between Ocelot and
Seville. Namely, ocelot_ifh_set_dest() is omitted out of
ocelot_xmit_common(), because there's also seville_ifh_set_dest().
(2) ocelot_ifh_set_basic(), called by:
- ocelot_fdma_prepare_skb() for FDMA transmission of the ocelot
switchdev driver
- ocelot_port_xmit() -> ocelot_port_inject_frame() for
register-based transmission of the ocelot switchdev driver
- felix_port_deferred_xmit() -> ocelot_port_inject_frame() for the
DSA tagger ocelot-8021q when it must transmit PTP frames (also
through register-based injection).
sets the bit fields according to its own logic.
The problem is that (2) doesn't call ocelot_ifh_set_qos_class().
Copying that logic from ocelot_xmit_common() fixes that.
Unfortunately, although desirable, it is not easily possible to
de-duplicate code paths (1) and (2), and make net/dsa/tag_ocelot.c
directly call ocelot_ifh_set_basic()), because of the ocelot/seville
difference. This is the "minimal" fix with some logic duplicated (but
at least more consolidated).
Fixes: 0a6f17c6ae21 ("net: dsa: tag_ocelot_8021q: add support for PTP timestamping")
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
---
drivers/net/ethernet/mscc/ocelot.c | 10 +++++++++-
drivers/net/ethernet/mscc/ocelot_fdma.c | 1 -
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 69a4e5a90475..9301716e21d5 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1208,13 +1208,21 @@ void ocelot_ifh_set_basic(void *ifh, struct ocelot *ocelot, int port,
u32 rew_op, struct sk_buff *skb)
{
struct ocelot_port *ocelot_port = ocelot->ports[port];
+ struct net_device *dev = skb->dev;
u64 vlan_tci, tag_type;
+ int qos_class;
ocelot_xmit_get_vlan_info(skb, ocelot_port->bridge, &vlan_tci,
&tag_type);
+ qos_class = netdev_get_num_tc(dev) ?
+ netdev_get_prio_tc_map(dev, skb->priority) : skb->priority;
+
+ memset(ifh, 0, OCELOT_TAG_LEN);
ocelot_ifh_set_bypass(ifh, 1);
+ ocelot_ifh_set_src(ifh, BIT_ULL(ocelot->num_phys_ports));
ocelot_ifh_set_dest(ifh, BIT_ULL(port));
+ ocelot_ifh_set_qos_class(ifh, qos_class);
ocelot_ifh_set_tag_type(ifh, tag_type);
ocelot_ifh_set_vlan_tci(ifh, vlan_tci);
if (rew_op)
@@ -1225,7 +1233,7 @@ EXPORT_SYMBOL(ocelot_ifh_set_basic);
void ocelot_port_inject_frame(struct ocelot *ocelot, int port, int grp,
u32 rew_op, struct sk_buff *skb)
{
- u32 ifh[OCELOT_TAG_LEN / 4] = {0};
+ u32 ifh[OCELOT_TAG_LEN / 4];
unsigned int i, count, last;
ocelot_write_rix(ocelot, QS_INJ_CTRL_GAP_SIZE(1) |
diff --git a/drivers/net/ethernet/mscc/ocelot_fdma.c b/drivers/net/ethernet/mscc/ocelot_fdma.c
index 87b59cc5e441..00326ae8c708 100644
--- a/drivers/net/ethernet/mscc/ocelot_fdma.c
+++ b/drivers/net/ethernet/mscc/ocelot_fdma.c
@@ -665,7 +665,6 @@ static int ocelot_fdma_prepare_skb(struct ocelot *ocelot, int port, u32 rew_op,
ifh = skb_push(skb, OCELOT_TAG_LEN);
skb_put(skb, ETH_FCS_LEN);
- memset(ifh, 0, OCELOT_TAG_LEN);
ocelot_ifh_set_basic(ifh, ocelot, port, rew_op, skb);
return 0;
--
2.34.1
