Re: [PATCH 6/7] net: dsa: b53: Add logic for TX timestamping

[Martin Kaistra]

Am 06.11.21 um 03:50 schrieb Florian Fainelli:
> On 11/4/2021 6:32 AM, Martin Kaistra wrote:
> > In order to get the switch to generate a timestamp for a transmitted
> > packet, we need to set the TS bit in the BRCM tag. The switch will then
> > create a status frame, which gets send back to the cpu.
> > In b53_port_txtstamp() we put the skb into a waiting position.
> >
> > When a status frame is received, we extract the timestamp and put the 
> > time
> > according to our timecounter into the waiting skb. When
> > TX_TSTAMP_TIMEOUT is reached and we have no means to correctly get back
> > a full timestamp, we cancel the process.
> >
> > As the status frame doesn't contain a reference to the original packet,
> > only one packet with timestamp request can be sent at a time.
> >
> > Signed-off-by: Martin Kaistra <martin.kaistra@xxxxxxxxxxxxx>
> > ---
>
> [snip]
>
> > +static long b53_hwtstamp_work(struct ptp_clock_info *ptp)
> > +{
> > +    struct b53_device *dev =
> > +        container_of(ptp, struct b53_device, ptp_clock_info);
> > +    struct dsa_switch *ds = dev->ds;
> > +    int i;
> > +
> > +    for (i = 0; i < ds->num_ports; i++) {
> > +        struct b53_port_hwtstamp *ps;
> > +
> > +        if (!dsa_is_user_port(ds, i))
> > +            continue;
>
> Can you also check on !dsa_port_is_unused()?
After the currently implemented check, dp->type should be 
DSA_PORT_TYPE_USER, so it can't be DSA_PORT_TYPE_UNUSED, right?


Thanks,
Martin