Messages in this thread | | | Date | Fri, 9 Dec 2022 17:06:34 +0200 | From | Vladimir Oltean <> | Subject | Re: [Patch net-next v3 07/13] net: dsa: microchip: ptp: add packet reception timestamping |
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On Fri, Dec 09, 2022 at 12:54:31PM +0530, Arun Ramadoss wrote: > From: Christian Eggers <ceggers@arri.de> > > Rx Timestamping is done through 4 additional bytes in tail tag. > Whenever the ptp packet is received, the 4 byte hardware time stamped > value is added before 1 byte tail tag. Also, bit 7 in tail tag indicates > it as PTP frame. This 4 byte value is extracted from the tail tag and > reconstructed to absolute time and assigned to skb hwtstamp. > If the packet received in PDelay_Resp, then partial ingress timestamp > is subtracted from the correction field. Since user space tools expects > to be done in hardware. > > Signed-off-by: Christian Eggers <ceggers@arri.de> > Co-developed-by: Arun Ramadoss <arun.ramadoss@microchip.com> > Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com> > > ---
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
> +bool ksz_port_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb, > + unsigned int type) > +{ > + struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb); > + struct ksz_device *dev = ds->priv; > + struct ptp_header *ptp_hdr; > + u8 ptp_msg_type; > + ktime_t tstamp; > + s64 correction; > + > + tstamp = KSZ_SKB_CB(skb)->tstamp; > + memset(hwtstamps, 0, sizeof(*hwtstamps)); > + hwtstamps->hwtstamp = ksz_tstamp_reconstruct(dev, tstamp); > + > + ptp_hdr = ptp_parse_header(skb, type); > + if (!ptp_hdr) > + goto out; > + > + ptp_msg_type = ptp_get_msgtype(ptp_hdr, type); > + if (ptp_msg_type != PTP_MSGTYPE_PDELAY_REQ) > + goto out; > + > + /* Only subtract the partial time stamp from the correction field. When > + * the hardware adds the egress time stamp to the correction field of > + * the PDelay_Resp message on tx, also only the partial time stamp will > + * be added. > + */ > + correction = (s64)get_unaligned_be64(&ptp_hdr->correction); > + correction -= ktime_to_ns(tstamp) << 16; > + > + ptp_header_update_correction(skb, type, ptp_hdr, correction); > + > +out: > + return 0;
Nitpick: port_rxtstamp() returns "bool" as in "should reception of this packet be deferred until the full RX timestamp is available?". The answer of 0 is coincidentally correct, but should have been "false".
> +} > + > static int _ksz_ptp_gettime(struct ksz_device *dev, struct timespec64 *ts) > { > u32 nanoseconds;
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