[PATCH 5.14 148/151] net: mscc: ocelot: deny TX timestamping of non-PTP packets

Greg Kroah-Hartman
2021-10-18T14:03:54Z

From: Vladimir Oltean <vladimir.oltean@nxp.com>

commit fba01283d85a09e0e2ef552c6e764b903111d90a upstream.

It appears that Ocelot switches cannot timestamp non-PTP frames,
I tested this using the isochron program at:
https://github.com/vladimiroltean/tsn-scripts

with the result that the driver increments the ocelot_port->ts_id
counter as expected, puts it in the REW_OP, but the hardware seems to
not timestamp these packets at all, since no IRQ is emitted.

Therefore check whether we are sending PTP frames, and refuse to
populate REW_OP otherwise.

Fixes: 4e3b0468e6d7 ("net: mscc: PTP Hardware Clock (PHC) support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/mscc/ocelot.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -585,16 +585,12 @@ u32 ocelot_ptp_rew_op(struct sk_buff *sk
}
EXPORT_SYMBOL(ocelot_ptp_rew_op);

-static bool ocelot_ptp_is_onestep_sync(struct sk_buff *skb)
+static bool ocelot_ptp_is_onestep_sync(struct sk_buff *skb,
+ unsigned int ptp_class)
{
struct ptp_header *hdr;
- unsigned int ptp_class;
u8 msgtype, twostep;

- ptp_class = ptp_classify_raw(skb);
- if (ptp_class == PTP_CLASS_NONE)
- return false;
-
hdr = ptp_parse_header(skb, ptp_class);
if (!hdr)
return false;
@@ -614,11 +610,20 @@ int ocelot_port_txtstamp_request(struct
{
struct ocelot_port *ocelot_port = ocelot->ports[port];
u8 ptp_cmd = ocelot_port->ptp_cmd;
+ unsigned int ptp_class;
int err;

+ /* Don't do anything if PTP timestamping not enabled */
+ if (!ptp_cmd)
+ return 0;
+
+ ptp_class = ptp_classify_raw(skb);
+ if (ptp_class == PTP_CLASS_NONE)
+ return -EINVAL;
+
/* Store ptp_cmd in OCELOT_SKB_CB(skb)->ptp_cmd */
if (ptp_cmd == IFH_REW_OP_ORIGIN_PTP) {
- if (ocelot_ptp_is_onestep_sync(skb)) {
+ if (ocelot_ptp_is_onestep_sync(skb, ptp_class)) {
OCELOT_SKB_CB(skb)->ptp_cmd = ptp_cmd;
return 0;
}