| Message ID | 20220322210722.6405-3-gerhard@engleder-embedded.com (mailing list archive) |
|---|---|
| State | Deferred |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | ptp: Support hardware clocks with additional free running time | expand |
On Tue, Mar 22, 2022 at 10:07:18PM +0100, Gerhard Engleder wrote: > The free running time of physical clocks called cycles shall be used for > hardware timestamps to enable synchronisation. > > Introduce new flag SKBTX_HW_TSTAMP_USE_CYCLES, which signals driver to > provide a TX timestamp based on cycles if cycles are supported. > > Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com> > --- > include/linux/skbuff.h | 3 +++ > net/core/skbuff.c | 2 ++ > net/socket.c | 10 +++++++++- > 3 files changed, 14 insertions(+), 1 deletion(-) > > diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h > index 26538ceb4b01..f494ddbfc826 100644 > --- a/include/linux/skbuff.h > +++ b/include/linux/skbuff.h > @@ -578,6 +578,9 @@ enum { > /* device driver is going to provide hardware time stamp */ > SKBTX_IN_PROGRESS = 1 << 2, > > + /* generate hardware time stamp based on cycles if supported */ > + SKBTX_HW_TSTAMP_USE_CYCLES = 1 << 3, Bit 4 used, but 3 was unused... interesting! > /* generate wifi status information (where possible) */ > SKBTX_WIFI_STATUS = 1 << 4, > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index 10bde7c6db44..c0f8f1341c3f 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -4847,6 +4847,8 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb, > skb_shinfo(skb)->tx_flags |= skb_shinfo(orig_skb)->tx_flags & > SKBTX_ANY_TSTAMP; > skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey; > + } else { > + skb_shinfo(skb)->tx_flags &= ~SKBTX_HW_TSTAMP_USE_CYCLES; > } > > if (hwtstamps) > diff --git a/net/socket.c b/net/socket.c > index 982eecad464c..1acebcb19e8f 100644 > --- a/net/socket.c > +++ b/net/socket.c > @@ -683,9 +683,17 @@ void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags) > { > u8 flags = *tx_flags; > > - if (tsflags & SOF_TIMESTAMPING_TX_HARDWARE) > + if (tsflags & SOF_TIMESTAMPING_TX_HARDWARE) { > flags |= SKBTX_HW_TSTAMP; > > + /* PTP hardware clocks can provide a free running time called > + * cycles as base for virtual clocks. "PTP hardware clocks can provide a free running cycle counter as a time base for virtual clocks." Thanks, Richard
On Thu, Mar 24, 2022 at 06:49:34AM -0700, Richard Cochran wrote: > On Tue, Mar 22, 2022 at 10:07:18PM +0100, Gerhard Engleder wrote: > > --- a/include/linux/skbuff.h > > +++ b/include/linux/skbuff.h > > @@ -578,6 +578,9 @@ enum { > > /* device driver is going to provide hardware time stamp */ > > SKBTX_IN_PROGRESS = 1 << 2, > > > > + /* generate hardware time stamp based on cycles if supported */ > > + SKBTX_HW_TSTAMP_USE_CYCLES = 1 << 3, > > Bit 4 used, but 3 was unused... interesting! It seems the bit 3 and 5 were removed in commit 06b4feb37e64 ("net: group skb_shinfo zerocopy related bits together.").
> > @@ -683,9 +683,17 @@ void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags) > > { > > u8 flags = *tx_flags; > > > > - if (tsflags & SOF_TIMESTAMPING_TX_HARDWARE) > > + if (tsflags & SOF_TIMESTAMPING_TX_HARDWARE) { > > flags |= SKBTX_HW_TSTAMP; > > > > + /* PTP hardware clocks can provide a free running time called > > + * cycles as base for virtual clocks. > > "PTP hardware clocks can provide a free running cycle counter as a > time base for virtual clocks." I'll use your wording here. I'll also update other comments and commit messages with this wording. Thanks, Gerhard
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 26538ceb4b01..f494ddbfc826 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -578,6 +578,9 @@ enum { /* device driver is going to provide hardware time stamp */ SKBTX_IN_PROGRESS = 1 << 2, + /* generate hardware time stamp based on cycles if supported */ + SKBTX_HW_TSTAMP_USE_CYCLES = 1 << 3, + /* generate wifi status information (where possible) */ SKBTX_WIFI_STATUS = 1 << 4, diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 10bde7c6db44..c0f8f1341c3f 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4847,6 +4847,8 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb, skb_shinfo(skb)->tx_flags |= skb_shinfo(orig_skb)->tx_flags & SKBTX_ANY_TSTAMP; skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey; + } else { + skb_shinfo(skb)->tx_flags &= ~SKBTX_HW_TSTAMP_USE_CYCLES; } if (hwtstamps) diff --git a/net/socket.c b/net/socket.c index 982eecad464c..1acebcb19e8f 100644 --- a/net/socket.c +++ b/net/socket.c @@ -683,9 +683,17 @@ void __sock_tx_timestamp(__u16 tsflags, __u8 *tx_flags) { u8 flags = *tx_flags; - if (tsflags & SOF_TIMESTAMPING_TX_HARDWARE) + if (tsflags & SOF_TIMESTAMPING_TX_HARDWARE) { flags |= SKBTX_HW_TSTAMP; + /* PTP hardware clocks can provide a free running time called + * cycles as base for virtual clocks. Tell driver to use cycles + * for timestamp if socket is bound to virtual clock. + */ + if (tsflags & SOF_TIMESTAMPING_BIND_PHC) + flags |= SKBTX_HW_TSTAMP_USE_CYCLES; + } + if (tsflags & SOF_TIMESTAMPING_TX_SOFTWARE) flags |= SKBTX_SW_TSTAMP;
The free running time of physical clocks called cycles shall be used for hardware timestamps to enable synchronisation. Introduce new flag SKBTX_HW_TSTAMP_USE_CYCLES, which signals driver to provide a TX timestamp based on cycles if cycles are supported. Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com> --- include/linux/skbuff.h | 3 +++ net/core/skbuff.c | 2 ++ net/socket.c | 10 +++++++++- 3 files changed, 14 insertions(+), 1 deletion(-)