RE: [net-next 3/3] net: mscc: ocelot: support PTP Sync one-step timestamping

From: Y.b. Lu
Date: Tue Apr 20 2021 - 03:33:45 EST

Next message: Greg Kroah-Hartman: "Re: [PATCH 5.10 043/103] net: tipc: Fix spelling errors in net/tipc module"
Previous message: Keqian Zhu: "Re: [PATCH v3 02/12] iommu: Add iommu_split_block interface"
In reply to: Vladimir Oltean: "Re: [net-next 3/3] net: mscc: ocelot: support PTP Sync one-step timestamping"
Next in thread: Vladimir Oltean: "Re: [net-next 3/3] net: mscc: ocelot: support PTP Sync one-step timestamping"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hi Vladimir,

> -----Original Message-----
> From: Vladimir Oltean <olteanv@xxxxxxxxx>
> Sent: 2021年4月18日 17:46
> To: Y.b. Lu <yangbo.lu@xxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx; Richard Cochran <richardcochran@xxxxxxxxx>;
> Vladimir Oltean <vladimir.oltean@xxxxxxx>; David S . Miller
> <davem@xxxxxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Jonathan Corbet
> <corbet@xxxxxxx>; Kurt Kanzenbach <kurt@xxxxxxxxxxxxx>; Andrew Lunn
> <andrew@xxxxxxx>; Vivien Didelot <vivien.didelot@xxxxxxxxx>; Florian
> Fainelli <f.fainelli@xxxxxxxxx>; Claudiu Manoil <claudiu.manoil@xxxxxxx>;
> Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>;
> UNGLinuxDriver@xxxxxxxxxxxxx; linux-doc@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [net-next 3/3] net: mscc: ocelot: support PTP Sync one-step
> timestamping
>
> On Fri, Apr 16, 2021 at 08:36:55PM +0800, Yangbo Lu wrote:
> > Although HWTSTAMP_TX_ONESTEP_SYNC existed in ioctl for hardware
> > timestamp configuration, the PTP Sync one-step timestamping had never
> been supported.
> >
> > This patch is to truely support it.
>
> Actually the ocelot switchdev driver does support one-step timestamping, just
> the felix DSA driver does not.

Actually I don’t think ocelot support one-step timestamping properly.
Without one-step sync packet identification, the one-step timestamping is applying to all packets requiring timestamp.
The user space PTP stack won't work.

>
> > The hardware timestamp request type is stored in DSA_SKB_CB_PRIV first
> > byte per skb, so that corresponding configuration could be done during
> > transmitting. Non-onestep-Sync packet with one-step timestamp request
> > should fall back to use two-step timestamp.
> >
> > Signed-off-by: Yangbo Lu <yangbo.lu@xxxxxxx>
> > ---
> > drivers/net/ethernet/mscc/ocelot.c | 57
> ++++++++++++++++++++++++++
> > drivers/net/ethernet/mscc/ocelot_net.c | 5 +--
> > include/soc/mscc/ocelot.h | 1 +
> > net/dsa/tag_ocelot.c | 25 ++---------
> > net/dsa/tag_ocelot_8021q.c | 39 +++++-------------
> > 5 files changed, 72 insertions(+), 55 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/mscc/ocelot.c
> > b/drivers/net/ethernet/mscc/ocelot.c
> > index 541d3b4076be..69d36b6241ff 100644
> > --- a/drivers/net/ethernet/mscc/ocelot.c
> > +++ b/drivers/net/ethernet/mscc/ocelot.c
> > @@ -6,6 +6,7 @@
> > */
> > #include <linux/dsa/ocelot.h>
> > #include <linux/if_bridge.h>
> > +#include <linux/ptp_classify.h>
> > #include <soc/mscc/ocelot_vcap.h>
> > #include "ocelot.h"
> > #include "ocelot_vcap.h"
> > @@ -546,6 +547,50 @@ static void ocelot_port_add_txtstamp_skb(struct
> ocelot *ocelot, int port,
> > spin_unlock(&ocelot_port->ts_id_lock);
> > }
> >
> > +bool ocelot_ptp_rew_op(struct sk_buff *skb, struct sk_buff *clone,
> > +u32 *rew_op) {
> > + /* For two-step timestamp, retrieve ptp_cmd in DSA_SKB_CB_PRIV
> > + * and timestamp ID in clone->cb[0].
> > + * For one-step timestamp, retrieve ptp_cmd in DSA_SKB_CB_PRIV.
> > + */
> > + u8 *ptp_cmd = DSA_SKB_CB_PRIV(skb);
>
> This is fine in the sense that it works, but please consider creating something
> similar to sja1105:
>
> struct ocelot_skb_cb {
> u8 ptp_cmd; /* For both one-step and two-step timestamping */
> u8 ts_id; /* Only for two-step timestamping */ };
>
> #define OCELOT_SKB_CB(skb) \
> ((struct ocelot_skb_cb *)DSA_SKB_CB_PRIV(skb))
>
> And then access as OCELOT_SKB_CB(skb)->ptp_cmd,
> OCELOT_SKB_CB(clone)->ts_id.
>
> and put a comment to explain that this is done in order to have common code
> between Felix DSA and Ocelot switchdev. Basically Ocelot will not use the first
> 8 bytes of skb->cb, but there's enough space for this to not make any
> difference. The original skb will hold only ptp_cmd, the clone will only hold
> ts_id, but it helps to have the same structure in place.
>
> If you create this ocelot_skb_cb structure, I expect the comment above to be
> fairly redundant, you can consider removing it.
>

You're right to define the structure.
Considering patch #1, move skb cloning to drivers, and populate DSA_SKB_CB(skb)->clone if needs to do so (per suggestion).
Can we totally drop dsa_skb_cb in dsa core? The only usage of it is holding a skb clone pointer, for only felix and sja1105.
Actually we can move such pointer in <device>_skb_cb, instead of reserving the space of skb for any drivers.

Do you think so?

> > +
> > + if (clone) {
> > + *rew_op = *ptp_cmd;
> > + *rew_op |= clone->cb[0] << 3;
> > + } else if (*ptp_cmd) {
> > + *rew_op = *ptp_cmd;
> > + } else {
> > + return false;
> > + }
> > +
> > + return true;
>
> Just make this function return an u32. If the packet isn't PTP, the rew_op will
> be 0.

Ok. Thanks.

>
> > +}
> > +EXPORT_SYMBOL(ocelot_ptp_rew_op);
> > +
> > +static bool ocelot_ptp_is_onestep_sync(struct sk_buff *skb) {
> > + 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;
> > +
> > + msgtype = ptp_get_msgtype(hdr, ptp_class);
> > + twostep = hdr->flag_field[0] & 0x2;
> > +
> > + if (msgtype == PTP_MSGTYPE_SYNC && twostep == 0)
> > + return true;
> > +
> > + return false;
> > +}
> > +
>
> This is generic, but if you were to move it to net/core/ptp_classifier.c, I think
> you would have to pass the output of ptp_classify_raw() as an "unsigned int
> type" argument. So I think I would leave it the way it is for now - inside of
> ocelot - until somebody else needs something similar, and we see what is the
> required prototype.

Yes. This is indeed generic, and useful. I'd like to leave it the way it is for now.
I may make another patch-set for this in future.

>
> > int ocelot_port_txtstamp_request(struct ocelot *ocelot, int port,
> > struct sk_buff *skb,
> > struct sk_buff **clone)
> > @@ -553,12 +598,24 @@ int ocelot_port_txtstamp_request(struct ocelot
> *ocelot, int port,
> > struct ocelot_port *ocelot_port = ocelot->ports[port];
> > u8 ptp_cmd = ocelot_port->ptp_cmd;
> >
> > + /* Store ptp_cmd in first byte of DSA_SKB_CB_PRIV per skb */
> > + if (ptp_cmd == IFH_REW_OP_ORIGIN_PTP) {
> > + if (ocelot_ptp_is_onestep_sync(skb)) {
> > + *(u8 *)DSA_SKB_CB_PRIV(skb) = ptp_cmd;
> > + return 0;
> > + }
> > +
> > + /* Fall back to two-step timestamping */
> > + ptp_cmd = IFH_REW_OP_TWO_STEP_PTP;
> > + }
> > +
> > if (ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
> > *clone = skb_clone_sk(skb);
> > if (!(*clone))
> > return -ENOMEM;
> >
> > ocelot_port_add_txtstamp_skb(ocelot, port, *clone);
> > + *(u8 *)DSA_SKB_CB_PRIV(skb) = ptp_cmd;
> > }
> >
> > return 0;
> > diff --git a/drivers/net/ethernet/mscc/ocelot_net.c
> > b/drivers/net/ethernet/mscc/ocelot_net.c
> > index 8293152a6dc1..eb3d525731da 100644
> > --- a/drivers/net/ethernet/mscc/ocelot_net.c
> > +++ b/drivers/net/ethernet/mscc/ocelot_net.c
> > @@ -514,10 +514,7 @@ static netdev_tx_t ocelot_port_xmit(struct sk_buff
> *skb, struct net_device *dev)
> > return NETDEV_TX_OK;
> > }
> >
> > - if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
> > - rew_op = ocelot_port->ptp_cmd;
> > - rew_op |= clone->cb[0] << 3;
> > - }
> > + ocelot_ptp_rew_op(skb, clone, &rew_op);
> > }
> >
> > ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb); diff --git
> > a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h index
> > 9cdaf1d9199f..19413532db0b 100644
> > --- a/include/soc/mscc/ocelot.h
> > +++ b/include/soc/mscc/ocelot.h
> > @@ -820,6 +820,7 @@ int ocelot_vlan_add(struct ocelot *ocelot, int
> > port, u16 vid, bool pvid, int ocelot_vlan_del(struct ocelot *ocelot,
> > int port, u16 vid); int ocelot_hwstamp_get(struct ocelot *ocelot, int
> > port, struct ifreq *ifr); int ocelot_hwstamp_set(struct ocelot
> > *ocelot, int port, struct ifreq *ifr);
> > +bool ocelot_ptp_rew_op(struct sk_buff *skb, struct sk_buff *clone,
> > +u32 *rew_op);
> > int ocelot_port_txtstamp_request(struct ocelot *ocelot, int port,
> > struct sk_buff *skb,
> > struct sk_buff **clone);
> > diff --git a/net/dsa/tag_ocelot.c b/net/dsa/tag_ocelot.c index
> > f9df9cac81c5..d5c73b36f0c1 100644
> > --- a/net/dsa/tag_ocelot.c
> > +++ b/net/dsa/tag_ocelot.c
> > @@ -5,25 +5,6 @@
> > #include <soc/mscc/ocelot.h>
> > #include "dsa_priv.h"
> >
> > -static void ocelot_xmit_ptp(struct dsa_port *dp, void *injection,
> > - struct sk_buff *clone)
> > -{
> > - struct ocelot *ocelot = dp->ds->priv;
> > - struct ocelot_port *ocelot_port;
> > - u64 rew_op;
> > -
> > - ocelot_port = ocelot->ports[dp->index];
> > - rew_op = ocelot_port->ptp_cmd;
> > -
> > - /* Retrieve timestamp ID populated inside skb->cb[0] of the
> > - * clone by ocelot_port_add_txtstamp_skb
> > - */
> > - if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
> > - rew_op |= clone->cb[0] << 3;
> > -
> > - ocelot_ifh_set_rew_op(injection, rew_op);
> > -}
> > -
> > static void ocelot_xmit_common(struct sk_buff *skb, struct net_device
> *netdev,
> > __be32 ifh_prefix, void **ifh) { @@ -32,6 +13,7 @@
> static
> > void ocelot_xmit_common(struct sk_buff *skb, struct net_device *netdev,
> > struct dsa_switch *ds = dp->ds;
> > void *injection;
> > __be32 *prefix;
> > + u32 rew_op = 0;
> >
> > injection = skb_push(skb, OCELOT_TAG_LEN);
> > prefix = skb_push(skb, OCELOT_SHORT_PREFIX_LEN); @@ -42,9 +24,8
> @@
> > static void ocelot_xmit_common(struct sk_buff *skb, struct net_device
> *netdev,
> > ocelot_ifh_set_src(injection, ds->num_ports);
> > ocelot_ifh_set_qos_class(injection, skb->priority);
> >
> > - /* TX timestamping was requested */
> > - if (clone)
> > - ocelot_xmit_ptp(dp, injection, clone);
> > + if (ocelot_ptp_rew_op(skb, clone, &rew_op))
> > + ocelot_ifh_set_rew_op(injection, rew_op);
> >
> > *ifh = injection;
> > }
> > diff --git a/net/dsa/tag_ocelot_8021q.c b/net/dsa/tag_ocelot_8021q.c
> > index 5f3e8e124a82..bf32649a5a7b 100644
> > --- a/net/dsa/tag_ocelot_8021q.c
> > +++ b/net/dsa/tag_ocelot_8021q.c
> > @@ -13,32 +13,6 @@
> > #include <soc/mscc/ocelot_ptp.h>
> > #include "dsa_priv.h"
> >
> > -static struct sk_buff *ocelot_xmit_ptp(struct dsa_port *dp,
> > - struct sk_buff *skb,
> > - struct sk_buff *clone)
> > -{
> > - struct ocelot *ocelot = dp->ds->priv;
> > - struct ocelot_port *ocelot_port;
> > - int port = dp->index;
> > - u32 rew_op;
> > -
> > - if (!ocelot_can_inject(ocelot, 0))
> > - return NULL;
> > -
> > - ocelot_port = ocelot->ports[port];
> > - rew_op = ocelot_port->ptp_cmd;
> > -
> > - /* Retrieve timestamp ID populated inside skb->cb[0] of the
> > - * clone by ocelot_port_add_txtstamp_skb
> > - */
> > - if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
> > - rew_op |= clone->cb[0] << 3;
> > -
> > - ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
> > -
> > - return NULL;
> > -}
> > -
> > static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
> > struct net_device *netdev)
> > {
> > @@ -47,10 +21,17 @@ static struct sk_buff *ocelot_xmit(struct sk_buff
> *skb,
> > u16 queue_mapping = skb_get_queue_mapping(skb);
> > u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
> > struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
> > + struct ocelot *ocelot = dp->ds->priv;
> > + int port = dp->index;
> > + u32 rew_op = 0;
> > +
> > + if (ocelot_ptp_rew_op(skb, clone, &rew_op)) {
> > + if (!ocelot_can_inject(ocelot, 0))
> > + return NULL;
> >
> > - /* TX timestamping was requested, so inject through MMIO */
> > - if (clone)
> > - return ocelot_xmit_ptp(dp, skb, clone);
> > + ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
> > + return NULL;
> > + }
> >
> > return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,
> > ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
> > --
> > 2.25.1
> >

Next message: Greg Kroah-Hartman: "Re: [PATCH 5.10 043/103] net: tipc: Fix spelling errors in net/tipc module"
Previous message: Keqian Zhu: "Re: [PATCH v3 02/12] iommu: Add iommu_split_block interface"
In reply to: Vladimir Oltean: "Re: [net-next 3/3] net: mscc: ocelot: support PTP Sync one-step timestamping"
Next in thread: Vladimir Oltean: "Re: [net-next 3/3] net: mscc: ocelot: support PTP Sync one-step timestamping"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]