2019-10-14 19:21:20 +03:00
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/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
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net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
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*/
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#ifndef _SJA1105_PTP_H
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#define _SJA1105_PTP_H
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net: dsa: sja1105: poll for extts events from a timer
The current poll interval is enough to ensure that rising and falling
edge events are not lost for a 1 PPS signal with 50% duty cycle.
But when we deliver the events to user space, it will try to infer if
they were corresponding to a rising or to a falling edge (the kernel
driver doesn't know that either). User space will try to make that
inference based on the time at which the PPS master had emitted the
pulse (i.e. if it's a .0 time, it's rising edge, if it's .5 time, it's
falling edge).
But there is no in-kernel API for retrieving the precise timestamp
corresponding to a PPS master (aka perout) pulse. So user space has to
guess even that. It will read the PTP time on the PPS master right after
we've delivered the extts event, and declare that the PPS master time
was just the closest integer second, based on 2 thresholds (lower than
.25, or higher than .75, and ignore anything else).
Except that, if we poll for extts events (and our hardware doesn't
really help us, by not providing an interrupt), then there is a risk
that the poll period (and therefore the time at which the event is
delivered) might confuse user space.
Because we are always scheduling the next extts poll at
SJA1105_EXTTS_INTERVAL "from now" (that's the only thing that the
schedule_delayed_work() API gives us), it means that the start time of
the next delayed workqueue will always be shifted to the right a little
bit (shifted with the SPI access duration of this workqueue run).
In turn, because user space sees extts events that are non-periodic
compared to the PPS master's time, this means that it might start making
wrong guesses about rising/falling edge.
To understand the effect, here is the output of ts2phc currently. Notice
the 'src' timestamps of the 'SKIP extts' events, and how they have a
large wander. They keep increasing until the upper limit for the ignore
threshold (.75 seconds), after which the application starts ignoring the
_other_ edge.
ts2phc[26.624]: /dev/ptp3 SKIP extts index 0 at 21.449898912 src 21.657784518
ts2phc[27.133]: adding tstamp 21.949894240 to clock /dev/ptp3
ts2phc[27.133]: adding tstamp 22.000000000 to clock /dev/ptp1
ts2phc[27.133]: /dev/ptp3 offset 640 s2 freq +5112
ts2phc[27.636]: /dev/ptp3 SKIP extts index 0 at 22.449889360 src 22.669398022
ts2phc[28.140]: adding tstamp 22.949884376 to clock /dev/ptp3
ts2phc[28.140]: adding tstamp 23.000000000 to clock /dev/ptp1
ts2phc[28.140]: /dev/ptp3 offset 96 s2 freq +4760
ts2phc[28.644]: /dev/ptp3 SKIP extts index 0 at 23.449879504 src 23.677420422
ts2phc[29.153]: adding tstamp 23.949874704 to clock /dev/ptp3
ts2phc[29.153]: adding tstamp 24.000000000 to clock /dev/ptp1
ts2phc[29.153]: /dev/ptp3 offset -264 s2 freq +4429
ts2phc[29.656]: /dev/ptp3 SKIP extts index 0 at 24.449870008 src 24.689407238
ts2phc[30.160]: adding tstamp 24.949865376 to clock /dev/ptp3
ts2phc[30.160]: adding tstamp 25.000000000 to clock /dev/ptp1
ts2phc[30.160]: /dev/ptp3 offset -280 s2 freq +4334
ts2phc[30.664]: /dev/ptp3 SKIP extts index 0 at 25.449860760 src 25.697449926
ts2phc[31.168]: adding tstamp 25.949856176 to clock /dev/ptp3
ts2phc[31.168]: adding tstamp 26.000000000 to clock /dev/ptp1
ts2phc[31.168]: /dev/ptp3 offset -176 s2 freq +4354
ts2phc[31.672]: /dev/ptp3 SKIP extts index 0 at 26.449851584 src 26.705433606
ts2phc[32.180]: adding tstamp 26.949846992 to clock /dev/ptp3
ts2phc[32.180]: adding tstamp 27.000000000 to clock /dev/ptp1
ts2phc[32.180]: /dev/ptp3 offset -80 s2 freq +4397
ts2phc[32.684]: /dev/ptp3 SKIP extts index 0 at 27.449842384 src 27.717415110
ts2phc[33.192]: adding tstamp 27.949837768 to clock /dev/ptp3
ts2phc[33.192]: adding tstamp 28.000000000 to clock /dev/ptp1
ts2phc[33.192]: /dev/ptp3 offset 0 s2 freq +4453
ts2phc[33.696]: /dev/ptp3 SKIP extts index 0 at 28.449833128 src 28.729412902
ts2phc[34.200]: adding tstamp 28.949828472 to clock /dev/ptp3
ts2phc[34.200]: adding tstamp 29.000000000 to clock /dev/ptp1
ts2phc[34.200]: /dev/ptp3 offset 8 s2 freq +4461
ts2phc[34.704]: /dev/ptp3 SKIP extts index 0 at 29.449823816 src 29.737416038
ts2phc[35.208]: adding tstamp 29.949819152 to clock /dev/ptp3
ts2phc[35.208]: adding tstamp 30.000000000 to clock /dev/ptp1
ts2phc[35.208]: /dev/ptp3 offset -8 s2 freq +4447
ts2phc[35.712]: /dev/ptp3 SKIP extts index 0 at 30.449814496 src 30.745554982
ts2phc[36.216]: adding tstamp 30.949809840 to clock /dev/ptp3
ts2phc[36.216]: adding tstamp 31.000000000 to clock /dev/ptp1
ts2phc[36.216]: /dev/ptp3 offset -8 s2 freq +4445
ts2phc[36.468]: /dev/ptp3 SKIP extts index 0 at 31.449805184 src 31.501109446
ts2phc[36.972]: adding tstamp 31.949800536 to clock /dev/ptp3
ts2phc[36.972]: adding tstamp 32.000000000 to clock /dev/ptp1
ts2phc[36.972]: /dev/ptp3 offset -8 s2 freq +4442
ts2phc[37.480]: /dev/ptp3 SKIP extts index 0 at 32.449795896 src 32.513320070
ts2phc[37.984]: adding tstamp 32.949791248 to clock /dev/ptp3
ts2phc[37.984]: adding tstamp 33.000000000 to clock /dev/ptp1
ts2phc[37.984]: /dev/ptp3 offset 0 s2 freq +4448
Fix that by taking the following measures:
- Schedule the poll from a timer. Because we are really scheduling the
timer periodically, the extts events delivered to user space are
periodic too, and don't suffer from the "shift-to-the-right" effect.
- Increase the poll period to 6 times a second. This imposes a smaller
upper bound to the shift that can occur to the delivery time of extts
events, and makes user space (ts2phc) to always interpret correctly
which events should be skipped and which shouldn't.
- Move the SPI readout itself to the main PTP kernel thread, instead of
the generic workqueue. This is because the timer runs in atomic
context, but is also better than before, because if needed, we can
chrt & taskset this kernel thread, to ensure it gets enough priority
under load.
After this patch, one can notice that the wander is greatly reduced, and
that the latencies of one extts poll are not propagated to the next. The
'src' timestamp that is skipped is never larger than .65 seconds (which
means .15 seconds larger than the time at which the real event occurred
at, and .10 seconds smaller than the .75 upper threshold for ignoring
the falling edge):
ts2phc[40.076]: adding tstamp 34.949261296 to clock /dev/ptp3
ts2phc[40.076]: adding tstamp 35.000000000 to clock /dev/ptp1
ts2phc[40.076]: /dev/ptp3 offset 48 s2 freq +4631
ts2phc[40.568]: /dev/ptp3 SKIP extts index 0 at 35.449256496 src 35.595791078
ts2phc[41.064]: adding tstamp 35.949251744 to clock /dev/ptp3
ts2phc[41.064]: adding tstamp 36.000000000 to clock /dev/ptp1
ts2phc[41.064]: /dev/ptp3 offset -224 s2 freq +4374
ts2phc[41.552]: /dev/ptp3 SKIP extts index 0 at 36.449247088 src 36.579825574
ts2phc[42.044]: adding tstamp 36.949242456 to clock /dev/ptp3
ts2phc[42.044]: adding tstamp 37.000000000 to clock /dev/ptp1
ts2phc[42.044]: /dev/ptp3 offset -240 s2 freq +4290
ts2phc[42.536]: /dev/ptp3 SKIP extts index 0 at 37.449237848 src 37.563828774
ts2phc[43.028]: adding tstamp 37.949233264 to clock /dev/ptp3
ts2phc[43.028]: adding tstamp 38.000000000 to clock /dev/ptp1
ts2phc[43.028]: /dev/ptp3 offset -144 s2 freq +4314
ts2phc[43.520]: /dev/ptp3 SKIP extts index 0 at 38.449228656 src 38.547823238
ts2phc[44.012]: adding tstamp 38.949224048 to clock /dev/ptp3
ts2phc[44.012]: adding tstamp 39.000000000 to clock /dev/ptp1
ts2phc[44.012]: /dev/ptp3 offset -80 s2 freq +4335
ts2phc[44.508]: /dev/ptp3 SKIP extts index 0 at 39.449219432 src 39.535846118
ts2phc[44.996]: adding tstamp 39.949214816 to clock /dev/ptp3
ts2phc[44.996]: adding tstamp 40.000000000 to clock /dev/ptp1
ts2phc[44.996]: /dev/ptp3 offset -32 s2 freq +4359
ts2phc[45.488]: /dev/ptp3 SKIP extts index 0 at 40.449210192 src 40.515824678
ts2phc[45.980]: adding tstamp 40.949205568 to clock /dev/ptp3
ts2phc[45.980]: adding tstamp 41.000000000 to clock /dev/ptp1
ts2phc[45.980]: /dev/ptp3 offset 8 s2 freq +4390
ts2phc[46.636]: /dev/ptp3 SKIP extts index 0 at 41.449200928 src 41.664176902
ts2phc[47.132]: adding tstamp 41.949196288 to clock /dev/ptp3
ts2phc[47.132]: adding tstamp 42.000000000 to clock /dev/ptp1
ts2phc[47.132]: /dev/ptp3 offset 0 s2 freq +4384
ts2phc[47.620]: /dev/ptp3 SKIP extts index 0 at 42.449191656 src 42.648117190
ts2phc[48.112]: adding tstamp 42.949187016 to clock /dev/ptp3
ts2phc[48.112]: adding tstamp 43.000000000 to clock /dev/ptp1
ts2phc[48.112]: /dev/ptp3 offset 0 s2 freq +4384
ts2phc[48.604]: /dev/ptp3 SKIP extts index 0 at 43.449182384 src 43.632112582
ts2phc[49.100]: adding tstamp 43.949177736 to clock /dev/ptp3
ts2phc[49.100]: adding tstamp 44.000000000 to clock /dev/ptp1
ts2phc[49.100]: /dev/ptp3 offset -8 s2 freq +4376
ts2phc[49.588]: /dev/ptp3 SKIP extts index 0 at 44.449173096 src 44.616136774
ts2phc[50.080]: adding tstamp 44.949168464 to clock /dev/ptp3
ts2phc[50.080]: adding tstamp 45.000000000 to clock /dev/ptp1
ts2phc[50.080]: /dev/ptp3 offset 8 s2 freq +4390
ts2phc[50.572]: /dev/ptp3 SKIP extts index 0 at 45.449163816 src 45.600134662
ts2phc[51.064]: adding tstamp 45.949159160 to clock /dev/ptp3
ts2phc[51.064]: adding tstamp 46.000000000 to clock /dev/ptp1
ts2phc[51.064]: /dev/ptp3 offset -8 s2 freq +4376
ts2phc[51.556]: /dev/ptp3 SKIP extts index 0 at 46.449154528 src 46.584588550
ts2phc[52.048]: adding tstamp 46.949149896 to clock /dev/ptp3
ts2phc[52.048]: adding tstamp 47.000000000 to clock /dev/ptp1
ts2phc[52.048]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[52.540]: /dev/ptp3 SKIP extts index 0 at 47.449145256 src 47.568132198
ts2phc[53.032]: adding tstamp 47.949140616 to clock /dev/ptp3
ts2phc[53.032]: adding tstamp 48.000000000 to clock /dev/ptp1
ts2phc[53.032]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[53.524]: /dev/ptp3 SKIP extts index 0 at 48.449135968 src 48.552121446
ts2phc[54.016]: adding tstamp 48.949131320 to clock /dev/ptp3
ts2phc[54.016]: adding tstamp 49.000000000 to clock /dev/ptp1
ts2phc[54.016]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[54.512]: /dev/ptp3 SKIP extts index 0 at 49.449126680 src 49.540147014
ts2phc[55.000]: adding tstamp 49.949122040 to clock /dev/ptp3
ts2phc[55.000]: adding tstamp 50.000000000 to clock /dev/ptp1
ts2phc[55.000]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[55.492]: /dev/ptp3 SKIP extts index 0 at 50.449117400 src 50.520119078
ts2phc[55.988]: adding tstamp 50.949112768 to clock /dev/ptp3
ts2phc[55.988]: adding tstamp 51.000000000 to clock /dev/ptp1
ts2phc[55.988]: /dev/ptp3 offset 8 s2 freq +4390
ts2phc[56.476]: /dev/ptp3 SKIP extts index 0 at 51.449108120 src 51.504175910
ts2phc[57.132]: adding tstamp 51.949103480 to clock /dev/ptp3
ts2phc[57.132]: adding tstamp 52.000000000 to clock /dev/ptp1
ts2phc[57.132]: /dev/ptp3 offset 0 s2 freq +4384
ts2phc[57.624]: /dev/ptp3 SKIP extts index 0 at 52.449098840 src 52.651833574
ts2phc[58.116]: adding tstamp 52.949094200 to clock /dev/ptp3
ts2phc[58.116]: adding tstamp 53.000000000 to clock /dev/ptp1
ts2phc[58.116]: /dev/ptp3 offset 8 s2 freq +4392
ts2phc[58.612]: /dev/ptp3 SKIP extts index 0 at 53.449089560 src 53.639826918
ts2phc[59.100]: adding tstamp 53.949084920 to clock /dev/ptp3
ts2phc[59.100]: adding tstamp 54.000000000 to clock /dev/ptp1
ts2phc[59.100]: /dev/ptp3 offset 8 s2 freq +4394
ts2phc[59.592]: /dev/ptp3 SKIP extts index 0 at 54.449080272 src 54.619842278
ts2phc[60.084]: adding tstamp 54.949075624 to clock /dev/ptp3
ts2phc[60.084]: adding tstamp 55.000000000 to clock /dev/ptp1
ts2phc[60.084]: /dev/ptp3 offset 8 s2 freq +4397
ts2phc[60.576]: /dev/ptp3 SKIP extts index 0 at 55.449070968 src 55.603885542
ts2phc[61.068]: adding tstamp 55.949066312 to clock /dev/ptp3
ts2phc[61.068]: adding tstamp 56.000000000 to clock /dev/ptp1
ts2phc[61.068]: /dev/ptp3 offset 0 s2 freq +4391
ts2phc[61.560]: /dev/ptp3 SKIP extts index 0 at 56.449061680 src 56.587885798
ts2phc[62.052]: adding tstamp 56.949057032 to clock /dev/ptp3
ts2phc[62.052]: adding tstamp 57.000000000 to clock /dev/ptp1
ts2phc[62.052]: /dev/ptp3 offset -8 s2 freq +4383
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-03 20:51:58 +03:00
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#include <linux/timer.h>
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net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
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#if IS_ENABLED(CONFIG_NET_DSA_SJA1105_PTP)
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2021-12-10 02:34:45 +03:00
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/* Timestamps are in units of 8 ns clock ticks (equivalent to
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* a fixed 125 MHz clock).
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*/
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#define SJA1105_TICK_NS 8
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static inline s64 ns_to_sja1105_ticks(s64 ns)
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{
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return ns / SJA1105_TICK_NS;
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}
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static inline s64 sja1105_ticks_to_ns(s64 ticks)
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{
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return ticks * SJA1105_TICK_NS;
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}
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2020-03-24 01:59:22 +03:00
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/* Calculate the first base_time in the future that satisfies this
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* relationship:
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*
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* future_base_time = base_time + N x cycle_time >= now, or
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*
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* now - base_time
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* N >= ---------------
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* cycle_time
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*
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* Because N is an integer, the ceiling value of the above "a / b" ratio
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* is in fact precisely the floor value of "(a + b - 1) / b", which is
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* easier to calculate only having integer division tools.
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*/
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static inline s64 future_base_time(s64 base_time, s64 cycle_time, s64 now)
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{
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s64 a, b, n;
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if (base_time >= now)
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return base_time;
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a = now - base_time;
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b = cycle_time;
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n = div_s64(a + b - 1, b);
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return base_time + n * cycle_time;
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}
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net: dsa: sja1105: implement tc-gate using time-triggered virtual links
Restrict the TTEthernet hardware support on this switch to operate as
closely as possible to IEEE 802.1Qci as possible. This means that it can
perform PTP-time-based ingress admission control on streams identified
by {DMAC, VID, PCP}, which is useful when trying to ensure the
determinism of traffic scheduled via IEEE 802.1Qbv.
The oddity comes from the fact that in hardware (and in TTEthernet at
large), virtual links always need a full-blown action, including not
only the type of policing, but also the list of destination ports. So in
practice, a single tc-gate action will result in all packets getting
dropped. Additional actions (either "trap" or "redirect") need to be
specified in the same filter rule such that the conforming packets are
actually forwarded somewhere.
Apart from the VL Lookup, Policing and Forwarding tables which need to
be programmed for each flow (virtual link), the Schedule engine also
needs to be told to open/close the admission gates for each individual
virtual link. A fairly accurate (and detailed) description of how that
works is already present in sja1105_tas.c, since it is already used to
trigger the egress gates for the tc-taprio offload (IEEE 802.1Qbv). Key
point here, we remember that the schedule engine supports 8
"subschedules" (execution threads that iterate through the global
schedule in parallel, and that no 2 hardware threads must execute a
schedule entry at the same time). For tc-taprio, each egress port used
one of these 8 subschedules, leaving a total of 4 subschedules unused.
In principle we could have allocated 1 subschedule for the tc-gate
offload of each ingress port, but actually the schedules of all virtual
links installed on each ingress port would have needed to be merged
together, before they could have been programmed to hardware. So
simplify our life and just merge the entire tc-gate configuration, for
all virtual links on all ingress ports, into a single subschedule. Be
sure to check that against the usual hardware scheduling conflicts, and
program it to hardware alongside any tc-taprio subschedule that may be
present.
The following scenarios were tested:
1. Quantitative testing:
tc qdisc add dev swp2 clsact
tc filter add dev swp2 ingress flower skip_sw \
dst_mac 42:be:24:9b:76:20 \
action gate index 1 base-time 0 \
sched-entry OPEN 1200 -1 -1 \
sched-entry CLOSE 1200 -1 -1 \
action trap
ping 192.168.1.2 -f
PING 192.168.1.2 (192.168.1.2) 56(84) bytes of data.
.............................
--- 192.168.1.2 ping statistics ---
948 packets transmitted, 467 received, 50.7384% packet loss, time 9671ms
2. Qualitative testing (with a phase-aligned schedule - the clocks are
synchronized by ptp4l, not shown here):
Receiver (sja1105):
tc qdisc add dev swp2 clsact
now=$(phc_ctl /dev/ptp1 get | awk '/clock time is/ {print $5}') && \
sec=$(echo $now | awk -F. '{print $1}') && \
base_time="$(((sec + 2) * 1000000000))" && \
echo "base time ${base_time}"
tc filter add dev swp2 ingress flower skip_sw \
dst_mac 42:be:24:9b:76:20 \
action gate base-time ${base_time} \
sched-entry OPEN 60000 -1 -1 \
sched-entry CLOSE 40000 -1 -1 \
action trap
Sender (enetc):
now=$(phc_ctl /dev/ptp0 get | awk '/clock time is/ {print $5}') && \
sec=$(echo $now | awk -F. '{print $1}') && \
base_time="$(((sec + 2) * 1000000000))" && \
echo "base time ${base_time}"
tc qdisc add dev eno0 parent root taprio \
num_tc 8 \
map 0 1 2 3 4 5 6 7 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
base-time ${base_time} \
sched-entry S 01 50000 \
sched-entry S 00 50000 \
flags 2
ping -A 192.168.1.1
PING 192.168.1.1 (192.168.1.1): 56 data bytes
...
^C
--- 192.168.1.1 ping statistics ---
1425 packets transmitted, 1424 packets received, 0% packet loss
round-trip min/avg/max = 0.322/0.361/0.990 ms
And just for comparison, with the tc-taprio schedule deleted:
ping -A 192.168.1.1
PING 192.168.1.1 (192.168.1.1): 56 data bytes
...
^C
--- 192.168.1.1 ping statistics ---
33 packets transmitted, 19 packets received, 42% packet loss
round-trip min/avg/max = 0.336/0.464/0.597 ms
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-05 22:20:56 +03:00
|
|
|
/* This is not a preprocessor macro because the "ns" argument may or may not be
|
|
|
|
* s64 at caller side. This ensures it is properly type-cast before div_s64.
|
|
|
|
*/
|
|
|
|
static inline s64 ns_to_sja1105_delta(s64 ns)
|
|
|
|
{
|
|
|
|
return div_s64(ns, 200);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline s64 sja1105_delta_to_ns(s64 delta)
|
|
|
|
{
|
|
|
|
return delta * 200;
|
|
|
|
}
|
|
|
|
|
2019-10-12 02:18:16 +03:00
|
|
|
struct sja1105_ptp_cmd {
|
net: dsa: sja1105: configure the PTP_CLK pin as EXT_TS or PER_OUT
The SJA1105 switch family has a PTP_CLK pin which emits a signal with
fixed 50% duty cycle, but variable frequency and programmable start time.
On the second generation (P/Q/R/S) switches, this pin supports even more
functionality. The use case described by the hardware documents talks
about synchronization via oneshot pulses: given 2 sja1105 switches,
arbitrarily designated as a master and a slave, the master emits a
single pulse on PTP_CLK, while the slave is configured to timestamp this
pulse received on its PTP_CLK pin (which must obviously be configured as
input). The difference between the timestamps then exactly becomes the
slave offset to the master.
The only trouble with the above is that the hardware is very much tied
into this use case only, and not very generic beyond that:
- When emitting a oneshot pulse, instead of being told when to emit it,
the switch just does it "now" and tells you later what time it was,
via the PTPSYNCTS register. [ Incidentally, this is the same register
that the slave uses to collect the ext_ts timestamp from, too. ]
- On the sync slave, there is no interrupt mechanism on reception of a
new extts, and no FIFO to buffer them, because in the foreseen use
case, software is in control of both the master and the slave pins,
so it "knows" when there's something to collect.
These 2 problems mean that:
- We don't support (at least yet) the quirky oneshot mode exposed by
the hardware, just normal periodic output.
- We abuse the hardware a little bit when we expose generic extts.
Because there's no interrupt mechanism, we need to poll at double the
frequency we expect to receive a pulse. Currently that means a
non-configurable "twice a second".
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-24 01:59:24 +03:00
|
|
|
u64 startptpcp; /* start toggling PTP_CLK pin */
|
|
|
|
u64 stopptpcp; /* stop toggling PTP_CLK pin */
|
2019-11-12 03:11:54 +03:00
|
|
|
u64 ptpstrtsch; /* start schedule */
|
|
|
|
u64 ptpstopsch; /* stop schedule */
|
2019-10-12 02:18:16 +03:00
|
|
|
u64 resptp; /* reset */
|
2019-10-16 21:41:02 +03:00
|
|
|
u64 corrclk4ts; /* use the corrected clock for timestamps */
|
|
|
|
u64 ptpclkadd; /* enum sja1105_ptp_clk_mode */
|
2019-10-12 02:18:16 +03:00
|
|
|
};
|
|
|
|
|
2019-10-12 02:18:15 +03:00
|
|
|
struct sja1105_ptp_data {
|
net: dsa: sja1105: poll for extts events from a timer
The current poll interval is enough to ensure that rising and falling
edge events are not lost for a 1 PPS signal with 50% duty cycle.
But when we deliver the events to user space, it will try to infer if
they were corresponding to a rising or to a falling edge (the kernel
driver doesn't know that either). User space will try to make that
inference based on the time at which the PPS master had emitted the
pulse (i.e. if it's a .0 time, it's rising edge, if it's .5 time, it's
falling edge).
But there is no in-kernel API for retrieving the precise timestamp
corresponding to a PPS master (aka perout) pulse. So user space has to
guess even that. It will read the PTP time on the PPS master right after
we've delivered the extts event, and declare that the PPS master time
was just the closest integer second, based on 2 thresholds (lower than
.25, or higher than .75, and ignore anything else).
Except that, if we poll for extts events (and our hardware doesn't
really help us, by not providing an interrupt), then there is a risk
that the poll period (and therefore the time at which the event is
delivered) might confuse user space.
Because we are always scheduling the next extts poll at
SJA1105_EXTTS_INTERVAL "from now" (that's the only thing that the
schedule_delayed_work() API gives us), it means that the start time of
the next delayed workqueue will always be shifted to the right a little
bit (shifted with the SPI access duration of this workqueue run).
In turn, because user space sees extts events that are non-periodic
compared to the PPS master's time, this means that it might start making
wrong guesses about rising/falling edge.
To understand the effect, here is the output of ts2phc currently. Notice
the 'src' timestamps of the 'SKIP extts' events, and how they have a
large wander. They keep increasing until the upper limit for the ignore
threshold (.75 seconds), after which the application starts ignoring the
_other_ edge.
ts2phc[26.624]: /dev/ptp3 SKIP extts index 0 at 21.449898912 src 21.657784518
ts2phc[27.133]: adding tstamp 21.949894240 to clock /dev/ptp3
ts2phc[27.133]: adding tstamp 22.000000000 to clock /dev/ptp1
ts2phc[27.133]: /dev/ptp3 offset 640 s2 freq +5112
ts2phc[27.636]: /dev/ptp3 SKIP extts index 0 at 22.449889360 src 22.669398022
ts2phc[28.140]: adding tstamp 22.949884376 to clock /dev/ptp3
ts2phc[28.140]: adding tstamp 23.000000000 to clock /dev/ptp1
ts2phc[28.140]: /dev/ptp3 offset 96 s2 freq +4760
ts2phc[28.644]: /dev/ptp3 SKIP extts index 0 at 23.449879504 src 23.677420422
ts2phc[29.153]: adding tstamp 23.949874704 to clock /dev/ptp3
ts2phc[29.153]: adding tstamp 24.000000000 to clock /dev/ptp1
ts2phc[29.153]: /dev/ptp3 offset -264 s2 freq +4429
ts2phc[29.656]: /dev/ptp3 SKIP extts index 0 at 24.449870008 src 24.689407238
ts2phc[30.160]: adding tstamp 24.949865376 to clock /dev/ptp3
ts2phc[30.160]: adding tstamp 25.000000000 to clock /dev/ptp1
ts2phc[30.160]: /dev/ptp3 offset -280 s2 freq +4334
ts2phc[30.664]: /dev/ptp3 SKIP extts index 0 at 25.449860760 src 25.697449926
ts2phc[31.168]: adding tstamp 25.949856176 to clock /dev/ptp3
ts2phc[31.168]: adding tstamp 26.000000000 to clock /dev/ptp1
ts2phc[31.168]: /dev/ptp3 offset -176 s2 freq +4354
ts2phc[31.672]: /dev/ptp3 SKIP extts index 0 at 26.449851584 src 26.705433606
ts2phc[32.180]: adding tstamp 26.949846992 to clock /dev/ptp3
ts2phc[32.180]: adding tstamp 27.000000000 to clock /dev/ptp1
ts2phc[32.180]: /dev/ptp3 offset -80 s2 freq +4397
ts2phc[32.684]: /dev/ptp3 SKIP extts index 0 at 27.449842384 src 27.717415110
ts2phc[33.192]: adding tstamp 27.949837768 to clock /dev/ptp3
ts2phc[33.192]: adding tstamp 28.000000000 to clock /dev/ptp1
ts2phc[33.192]: /dev/ptp3 offset 0 s2 freq +4453
ts2phc[33.696]: /dev/ptp3 SKIP extts index 0 at 28.449833128 src 28.729412902
ts2phc[34.200]: adding tstamp 28.949828472 to clock /dev/ptp3
ts2phc[34.200]: adding tstamp 29.000000000 to clock /dev/ptp1
ts2phc[34.200]: /dev/ptp3 offset 8 s2 freq +4461
ts2phc[34.704]: /dev/ptp3 SKIP extts index 0 at 29.449823816 src 29.737416038
ts2phc[35.208]: adding tstamp 29.949819152 to clock /dev/ptp3
ts2phc[35.208]: adding tstamp 30.000000000 to clock /dev/ptp1
ts2phc[35.208]: /dev/ptp3 offset -8 s2 freq +4447
ts2phc[35.712]: /dev/ptp3 SKIP extts index 0 at 30.449814496 src 30.745554982
ts2phc[36.216]: adding tstamp 30.949809840 to clock /dev/ptp3
ts2phc[36.216]: adding tstamp 31.000000000 to clock /dev/ptp1
ts2phc[36.216]: /dev/ptp3 offset -8 s2 freq +4445
ts2phc[36.468]: /dev/ptp3 SKIP extts index 0 at 31.449805184 src 31.501109446
ts2phc[36.972]: adding tstamp 31.949800536 to clock /dev/ptp3
ts2phc[36.972]: adding tstamp 32.000000000 to clock /dev/ptp1
ts2phc[36.972]: /dev/ptp3 offset -8 s2 freq +4442
ts2phc[37.480]: /dev/ptp3 SKIP extts index 0 at 32.449795896 src 32.513320070
ts2phc[37.984]: adding tstamp 32.949791248 to clock /dev/ptp3
ts2phc[37.984]: adding tstamp 33.000000000 to clock /dev/ptp1
ts2phc[37.984]: /dev/ptp3 offset 0 s2 freq +4448
Fix that by taking the following measures:
- Schedule the poll from a timer. Because we are really scheduling the
timer periodically, the extts events delivered to user space are
periodic too, and don't suffer from the "shift-to-the-right" effect.
- Increase the poll period to 6 times a second. This imposes a smaller
upper bound to the shift that can occur to the delivery time of extts
events, and makes user space (ts2phc) to always interpret correctly
which events should be skipped and which shouldn't.
- Move the SPI readout itself to the main PTP kernel thread, instead of
the generic workqueue. This is because the timer runs in atomic
context, but is also better than before, because if needed, we can
chrt & taskset this kernel thread, to ensure it gets enough priority
under load.
After this patch, one can notice that the wander is greatly reduced, and
that the latencies of one extts poll are not propagated to the next. The
'src' timestamp that is skipped is never larger than .65 seconds (which
means .15 seconds larger than the time at which the real event occurred
at, and .10 seconds smaller than the .75 upper threshold for ignoring
the falling edge):
ts2phc[40.076]: adding tstamp 34.949261296 to clock /dev/ptp3
ts2phc[40.076]: adding tstamp 35.000000000 to clock /dev/ptp1
ts2phc[40.076]: /dev/ptp3 offset 48 s2 freq +4631
ts2phc[40.568]: /dev/ptp3 SKIP extts index 0 at 35.449256496 src 35.595791078
ts2phc[41.064]: adding tstamp 35.949251744 to clock /dev/ptp3
ts2phc[41.064]: adding tstamp 36.000000000 to clock /dev/ptp1
ts2phc[41.064]: /dev/ptp3 offset -224 s2 freq +4374
ts2phc[41.552]: /dev/ptp3 SKIP extts index 0 at 36.449247088 src 36.579825574
ts2phc[42.044]: adding tstamp 36.949242456 to clock /dev/ptp3
ts2phc[42.044]: adding tstamp 37.000000000 to clock /dev/ptp1
ts2phc[42.044]: /dev/ptp3 offset -240 s2 freq +4290
ts2phc[42.536]: /dev/ptp3 SKIP extts index 0 at 37.449237848 src 37.563828774
ts2phc[43.028]: adding tstamp 37.949233264 to clock /dev/ptp3
ts2phc[43.028]: adding tstamp 38.000000000 to clock /dev/ptp1
ts2phc[43.028]: /dev/ptp3 offset -144 s2 freq +4314
ts2phc[43.520]: /dev/ptp3 SKIP extts index 0 at 38.449228656 src 38.547823238
ts2phc[44.012]: adding tstamp 38.949224048 to clock /dev/ptp3
ts2phc[44.012]: adding tstamp 39.000000000 to clock /dev/ptp1
ts2phc[44.012]: /dev/ptp3 offset -80 s2 freq +4335
ts2phc[44.508]: /dev/ptp3 SKIP extts index 0 at 39.449219432 src 39.535846118
ts2phc[44.996]: adding tstamp 39.949214816 to clock /dev/ptp3
ts2phc[44.996]: adding tstamp 40.000000000 to clock /dev/ptp1
ts2phc[44.996]: /dev/ptp3 offset -32 s2 freq +4359
ts2phc[45.488]: /dev/ptp3 SKIP extts index 0 at 40.449210192 src 40.515824678
ts2phc[45.980]: adding tstamp 40.949205568 to clock /dev/ptp3
ts2phc[45.980]: adding tstamp 41.000000000 to clock /dev/ptp1
ts2phc[45.980]: /dev/ptp3 offset 8 s2 freq +4390
ts2phc[46.636]: /dev/ptp3 SKIP extts index 0 at 41.449200928 src 41.664176902
ts2phc[47.132]: adding tstamp 41.949196288 to clock /dev/ptp3
ts2phc[47.132]: adding tstamp 42.000000000 to clock /dev/ptp1
ts2phc[47.132]: /dev/ptp3 offset 0 s2 freq +4384
ts2phc[47.620]: /dev/ptp3 SKIP extts index 0 at 42.449191656 src 42.648117190
ts2phc[48.112]: adding tstamp 42.949187016 to clock /dev/ptp3
ts2phc[48.112]: adding tstamp 43.000000000 to clock /dev/ptp1
ts2phc[48.112]: /dev/ptp3 offset 0 s2 freq +4384
ts2phc[48.604]: /dev/ptp3 SKIP extts index 0 at 43.449182384 src 43.632112582
ts2phc[49.100]: adding tstamp 43.949177736 to clock /dev/ptp3
ts2phc[49.100]: adding tstamp 44.000000000 to clock /dev/ptp1
ts2phc[49.100]: /dev/ptp3 offset -8 s2 freq +4376
ts2phc[49.588]: /dev/ptp3 SKIP extts index 0 at 44.449173096 src 44.616136774
ts2phc[50.080]: adding tstamp 44.949168464 to clock /dev/ptp3
ts2phc[50.080]: adding tstamp 45.000000000 to clock /dev/ptp1
ts2phc[50.080]: /dev/ptp3 offset 8 s2 freq +4390
ts2phc[50.572]: /dev/ptp3 SKIP extts index 0 at 45.449163816 src 45.600134662
ts2phc[51.064]: adding tstamp 45.949159160 to clock /dev/ptp3
ts2phc[51.064]: adding tstamp 46.000000000 to clock /dev/ptp1
ts2phc[51.064]: /dev/ptp3 offset -8 s2 freq +4376
ts2phc[51.556]: /dev/ptp3 SKIP extts index 0 at 46.449154528 src 46.584588550
ts2phc[52.048]: adding tstamp 46.949149896 to clock /dev/ptp3
ts2phc[52.048]: adding tstamp 47.000000000 to clock /dev/ptp1
ts2phc[52.048]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[52.540]: /dev/ptp3 SKIP extts index 0 at 47.449145256 src 47.568132198
ts2phc[53.032]: adding tstamp 47.949140616 to clock /dev/ptp3
ts2phc[53.032]: adding tstamp 48.000000000 to clock /dev/ptp1
ts2phc[53.032]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[53.524]: /dev/ptp3 SKIP extts index 0 at 48.449135968 src 48.552121446
ts2phc[54.016]: adding tstamp 48.949131320 to clock /dev/ptp3
ts2phc[54.016]: adding tstamp 49.000000000 to clock /dev/ptp1
ts2phc[54.016]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[54.512]: /dev/ptp3 SKIP extts index 0 at 49.449126680 src 49.540147014
ts2phc[55.000]: adding tstamp 49.949122040 to clock /dev/ptp3
ts2phc[55.000]: adding tstamp 50.000000000 to clock /dev/ptp1
ts2phc[55.000]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[55.492]: /dev/ptp3 SKIP extts index 0 at 50.449117400 src 50.520119078
ts2phc[55.988]: adding tstamp 50.949112768 to clock /dev/ptp3
ts2phc[55.988]: adding tstamp 51.000000000 to clock /dev/ptp1
ts2phc[55.988]: /dev/ptp3 offset 8 s2 freq +4390
ts2phc[56.476]: /dev/ptp3 SKIP extts index 0 at 51.449108120 src 51.504175910
ts2phc[57.132]: adding tstamp 51.949103480 to clock /dev/ptp3
ts2phc[57.132]: adding tstamp 52.000000000 to clock /dev/ptp1
ts2phc[57.132]: /dev/ptp3 offset 0 s2 freq +4384
ts2phc[57.624]: /dev/ptp3 SKIP extts index 0 at 52.449098840 src 52.651833574
ts2phc[58.116]: adding tstamp 52.949094200 to clock /dev/ptp3
ts2phc[58.116]: adding tstamp 53.000000000 to clock /dev/ptp1
ts2phc[58.116]: /dev/ptp3 offset 8 s2 freq +4392
ts2phc[58.612]: /dev/ptp3 SKIP extts index 0 at 53.449089560 src 53.639826918
ts2phc[59.100]: adding tstamp 53.949084920 to clock /dev/ptp3
ts2phc[59.100]: adding tstamp 54.000000000 to clock /dev/ptp1
ts2phc[59.100]: /dev/ptp3 offset 8 s2 freq +4394
ts2phc[59.592]: /dev/ptp3 SKIP extts index 0 at 54.449080272 src 54.619842278
ts2phc[60.084]: adding tstamp 54.949075624 to clock /dev/ptp3
ts2phc[60.084]: adding tstamp 55.000000000 to clock /dev/ptp1
ts2phc[60.084]: /dev/ptp3 offset 8 s2 freq +4397
ts2phc[60.576]: /dev/ptp3 SKIP extts index 0 at 55.449070968 src 55.603885542
ts2phc[61.068]: adding tstamp 55.949066312 to clock /dev/ptp3
ts2phc[61.068]: adding tstamp 56.000000000 to clock /dev/ptp1
ts2phc[61.068]: /dev/ptp3 offset 0 s2 freq +4391
ts2phc[61.560]: /dev/ptp3 SKIP extts index 0 at 56.449061680 src 56.587885798
ts2phc[62.052]: adding tstamp 56.949057032 to clock /dev/ptp3
ts2phc[62.052]: adding tstamp 57.000000000 to clock /dev/ptp1
ts2phc[62.052]: /dev/ptp3 offset -8 s2 freq +4383
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-03 20:51:58 +03:00
|
|
|
struct timer_list extts_timer;
|
net: dsa: sja1105: implement TX timestamping for SJA1110
The TX timestamping procedure for SJA1105 is a bit unconventional
because the transmit procedure itself is unconventional.
Control packets (and therefore PTP as well) are transmitted to a
specific port in SJA1105 using "management routes" which must be written
over SPI to the switch. These are one-shot rules that match by
destination MAC address on traffic coming from the CPU port, and select
the precise destination port for that packet. So to transmit a packet
from NET_TX softirq context, we actually need to defer to a process
context so that we can perform that SPI write before we send the packet.
The DSA master dev_queue_xmit() runs in process context, and we poll
until the switch confirms it took the TX timestamp, then we annotate the
skb clone with that TX timestamp. This is why the sja1105 driver does
not need an skb queue for TX timestamping.
But the SJA1110 is a bit (not much!) more conventional, and you can
request 2-step TX timestamping through the DSA header, as well as give
the switch a cookie (timestamp ID) which it will give back to you when
it has the timestamp. So now we do need a queue for keeping the skb
clones until their TX timestamps become available.
The interesting part is that the metadata frames from SJA1105 haven't
disappeared completely. On SJA1105 they were used as follow-ups which
contained RX timestamps, but on SJA1110 they are actually TX completion
packets, which contain a variable (up to 32) array of timestamps.
Why an array? Because:
- not only is the TX timestamp on the egress port being communicated,
but also the RX timestamp on the CPU port. Nice, but we don't care
about that, so we ignore it.
- because a packet could be multicast to multiple egress ports, each
port takes its own timestamp, and the TX completion packet contains
the individual timestamps on each port.
This is unconventional because switches typically have a timestamping
FIFO and raise an interrupt, but this one doesn't. So the tagger needs
to detect and parse meta frames, and call into the main switch driver,
which pairs the timestamps with the skbs in the TX timestamping queue
which are waiting for one.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-11 22:01:31 +03:00
|
|
|
/* Used only on SJA1105 to reconstruct partial timestamps */
|
2019-12-27 16:02:29 +03:00
|
|
|
struct sk_buff_head skb_rxtstamp_queue;
|
2021-12-10 02:34:45 +03:00
|
|
|
/* Used on SJA1110 where meta frames are generated only for
|
|
|
|
* 2-step TX timestamps
|
|
|
|
*/
|
|
|
|
struct sk_buff_head skb_txtstamp_queue;
|
2019-10-12 02:18:15 +03:00
|
|
|
struct ptp_clock_info caps;
|
|
|
|
struct ptp_clock *clock;
|
2019-10-12 02:18:16 +03:00
|
|
|
struct sja1105_ptp_cmd cmd;
|
2019-10-16 21:41:02 +03:00
|
|
|
/* Serializes all operations on the PTP hardware clock */
|
2019-10-12 02:18:15 +03:00
|
|
|
struct mutex lock;
|
net: dsa: sja1105: poll for extts events from a timer
The current poll interval is enough to ensure that rising and falling
edge events are not lost for a 1 PPS signal with 50% duty cycle.
But when we deliver the events to user space, it will try to infer if
they were corresponding to a rising or to a falling edge (the kernel
driver doesn't know that either). User space will try to make that
inference based on the time at which the PPS master had emitted the
pulse (i.e. if it's a .0 time, it's rising edge, if it's .5 time, it's
falling edge).
But there is no in-kernel API for retrieving the precise timestamp
corresponding to a PPS master (aka perout) pulse. So user space has to
guess even that. It will read the PTP time on the PPS master right after
we've delivered the extts event, and declare that the PPS master time
was just the closest integer second, based on 2 thresholds (lower than
.25, or higher than .75, and ignore anything else).
Except that, if we poll for extts events (and our hardware doesn't
really help us, by not providing an interrupt), then there is a risk
that the poll period (and therefore the time at which the event is
delivered) might confuse user space.
Because we are always scheduling the next extts poll at
SJA1105_EXTTS_INTERVAL "from now" (that's the only thing that the
schedule_delayed_work() API gives us), it means that the start time of
the next delayed workqueue will always be shifted to the right a little
bit (shifted with the SPI access duration of this workqueue run).
In turn, because user space sees extts events that are non-periodic
compared to the PPS master's time, this means that it might start making
wrong guesses about rising/falling edge.
To understand the effect, here is the output of ts2phc currently. Notice
the 'src' timestamps of the 'SKIP extts' events, and how they have a
large wander. They keep increasing until the upper limit for the ignore
threshold (.75 seconds), after which the application starts ignoring the
_other_ edge.
ts2phc[26.624]: /dev/ptp3 SKIP extts index 0 at 21.449898912 src 21.657784518
ts2phc[27.133]: adding tstamp 21.949894240 to clock /dev/ptp3
ts2phc[27.133]: adding tstamp 22.000000000 to clock /dev/ptp1
ts2phc[27.133]: /dev/ptp3 offset 640 s2 freq +5112
ts2phc[27.636]: /dev/ptp3 SKIP extts index 0 at 22.449889360 src 22.669398022
ts2phc[28.140]: adding tstamp 22.949884376 to clock /dev/ptp3
ts2phc[28.140]: adding tstamp 23.000000000 to clock /dev/ptp1
ts2phc[28.140]: /dev/ptp3 offset 96 s2 freq +4760
ts2phc[28.644]: /dev/ptp3 SKIP extts index 0 at 23.449879504 src 23.677420422
ts2phc[29.153]: adding tstamp 23.949874704 to clock /dev/ptp3
ts2phc[29.153]: adding tstamp 24.000000000 to clock /dev/ptp1
ts2phc[29.153]: /dev/ptp3 offset -264 s2 freq +4429
ts2phc[29.656]: /dev/ptp3 SKIP extts index 0 at 24.449870008 src 24.689407238
ts2phc[30.160]: adding tstamp 24.949865376 to clock /dev/ptp3
ts2phc[30.160]: adding tstamp 25.000000000 to clock /dev/ptp1
ts2phc[30.160]: /dev/ptp3 offset -280 s2 freq +4334
ts2phc[30.664]: /dev/ptp3 SKIP extts index 0 at 25.449860760 src 25.697449926
ts2phc[31.168]: adding tstamp 25.949856176 to clock /dev/ptp3
ts2phc[31.168]: adding tstamp 26.000000000 to clock /dev/ptp1
ts2phc[31.168]: /dev/ptp3 offset -176 s2 freq +4354
ts2phc[31.672]: /dev/ptp3 SKIP extts index 0 at 26.449851584 src 26.705433606
ts2phc[32.180]: adding tstamp 26.949846992 to clock /dev/ptp3
ts2phc[32.180]: adding tstamp 27.000000000 to clock /dev/ptp1
ts2phc[32.180]: /dev/ptp3 offset -80 s2 freq +4397
ts2phc[32.684]: /dev/ptp3 SKIP extts index 0 at 27.449842384 src 27.717415110
ts2phc[33.192]: adding tstamp 27.949837768 to clock /dev/ptp3
ts2phc[33.192]: adding tstamp 28.000000000 to clock /dev/ptp1
ts2phc[33.192]: /dev/ptp3 offset 0 s2 freq +4453
ts2phc[33.696]: /dev/ptp3 SKIP extts index 0 at 28.449833128 src 28.729412902
ts2phc[34.200]: adding tstamp 28.949828472 to clock /dev/ptp3
ts2phc[34.200]: adding tstamp 29.000000000 to clock /dev/ptp1
ts2phc[34.200]: /dev/ptp3 offset 8 s2 freq +4461
ts2phc[34.704]: /dev/ptp3 SKIP extts index 0 at 29.449823816 src 29.737416038
ts2phc[35.208]: adding tstamp 29.949819152 to clock /dev/ptp3
ts2phc[35.208]: adding tstamp 30.000000000 to clock /dev/ptp1
ts2phc[35.208]: /dev/ptp3 offset -8 s2 freq +4447
ts2phc[35.712]: /dev/ptp3 SKIP extts index 0 at 30.449814496 src 30.745554982
ts2phc[36.216]: adding tstamp 30.949809840 to clock /dev/ptp3
ts2phc[36.216]: adding tstamp 31.000000000 to clock /dev/ptp1
ts2phc[36.216]: /dev/ptp3 offset -8 s2 freq +4445
ts2phc[36.468]: /dev/ptp3 SKIP extts index 0 at 31.449805184 src 31.501109446
ts2phc[36.972]: adding tstamp 31.949800536 to clock /dev/ptp3
ts2phc[36.972]: adding tstamp 32.000000000 to clock /dev/ptp1
ts2phc[36.972]: /dev/ptp3 offset -8 s2 freq +4442
ts2phc[37.480]: /dev/ptp3 SKIP extts index 0 at 32.449795896 src 32.513320070
ts2phc[37.984]: adding tstamp 32.949791248 to clock /dev/ptp3
ts2phc[37.984]: adding tstamp 33.000000000 to clock /dev/ptp1
ts2phc[37.984]: /dev/ptp3 offset 0 s2 freq +4448
Fix that by taking the following measures:
- Schedule the poll from a timer. Because we are really scheduling the
timer periodically, the extts events delivered to user space are
periodic too, and don't suffer from the "shift-to-the-right" effect.
- Increase the poll period to 6 times a second. This imposes a smaller
upper bound to the shift that can occur to the delivery time of extts
events, and makes user space (ts2phc) to always interpret correctly
which events should be skipped and which shouldn't.
- Move the SPI readout itself to the main PTP kernel thread, instead of
the generic workqueue. This is because the timer runs in atomic
context, but is also better than before, because if needed, we can
chrt & taskset this kernel thread, to ensure it gets enough priority
under load.
After this patch, one can notice that the wander is greatly reduced, and
that the latencies of one extts poll are not propagated to the next. The
'src' timestamp that is skipped is never larger than .65 seconds (which
means .15 seconds larger than the time at which the real event occurred
at, and .10 seconds smaller than the .75 upper threshold for ignoring
the falling edge):
ts2phc[40.076]: adding tstamp 34.949261296 to clock /dev/ptp3
ts2phc[40.076]: adding tstamp 35.000000000 to clock /dev/ptp1
ts2phc[40.076]: /dev/ptp3 offset 48 s2 freq +4631
ts2phc[40.568]: /dev/ptp3 SKIP extts index 0 at 35.449256496 src 35.595791078
ts2phc[41.064]: adding tstamp 35.949251744 to clock /dev/ptp3
ts2phc[41.064]: adding tstamp 36.000000000 to clock /dev/ptp1
ts2phc[41.064]: /dev/ptp3 offset -224 s2 freq +4374
ts2phc[41.552]: /dev/ptp3 SKIP extts index 0 at 36.449247088 src 36.579825574
ts2phc[42.044]: adding tstamp 36.949242456 to clock /dev/ptp3
ts2phc[42.044]: adding tstamp 37.000000000 to clock /dev/ptp1
ts2phc[42.044]: /dev/ptp3 offset -240 s2 freq +4290
ts2phc[42.536]: /dev/ptp3 SKIP extts index 0 at 37.449237848 src 37.563828774
ts2phc[43.028]: adding tstamp 37.949233264 to clock /dev/ptp3
ts2phc[43.028]: adding tstamp 38.000000000 to clock /dev/ptp1
ts2phc[43.028]: /dev/ptp3 offset -144 s2 freq +4314
ts2phc[43.520]: /dev/ptp3 SKIP extts index 0 at 38.449228656 src 38.547823238
ts2phc[44.012]: adding tstamp 38.949224048 to clock /dev/ptp3
ts2phc[44.012]: adding tstamp 39.000000000 to clock /dev/ptp1
ts2phc[44.012]: /dev/ptp3 offset -80 s2 freq +4335
ts2phc[44.508]: /dev/ptp3 SKIP extts index 0 at 39.449219432 src 39.535846118
ts2phc[44.996]: adding tstamp 39.949214816 to clock /dev/ptp3
ts2phc[44.996]: adding tstamp 40.000000000 to clock /dev/ptp1
ts2phc[44.996]: /dev/ptp3 offset -32 s2 freq +4359
ts2phc[45.488]: /dev/ptp3 SKIP extts index 0 at 40.449210192 src 40.515824678
ts2phc[45.980]: adding tstamp 40.949205568 to clock /dev/ptp3
ts2phc[45.980]: adding tstamp 41.000000000 to clock /dev/ptp1
ts2phc[45.980]: /dev/ptp3 offset 8 s2 freq +4390
ts2phc[46.636]: /dev/ptp3 SKIP extts index 0 at 41.449200928 src 41.664176902
ts2phc[47.132]: adding tstamp 41.949196288 to clock /dev/ptp3
ts2phc[47.132]: adding tstamp 42.000000000 to clock /dev/ptp1
ts2phc[47.132]: /dev/ptp3 offset 0 s2 freq +4384
ts2phc[47.620]: /dev/ptp3 SKIP extts index 0 at 42.449191656 src 42.648117190
ts2phc[48.112]: adding tstamp 42.949187016 to clock /dev/ptp3
ts2phc[48.112]: adding tstamp 43.000000000 to clock /dev/ptp1
ts2phc[48.112]: /dev/ptp3 offset 0 s2 freq +4384
ts2phc[48.604]: /dev/ptp3 SKIP extts index 0 at 43.449182384 src 43.632112582
ts2phc[49.100]: adding tstamp 43.949177736 to clock /dev/ptp3
ts2phc[49.100]: adding tstamp 44.000000000 to clock /dev/ptp1
ts2phc[49.100]: /dev/ptp3 offset -8 s2 freq +4376
ts2phc[49.588]: /dev/ptp3 SKIP extts index 0 at 44.449173096 src 44.616136774
ts2phc[50.080]: adding tstamp 44.949168464 to clock /dev/ptp3
ts2phc[50.080]: adding tstamp 45.000000000 to clock /dev/ptp1
ts2phc[50.080]: /dev/ptp3 offset 8 s2 freq +4390
ts2phc[50.572]: /dev/ptp3 SKIP extts index 0 at 45.449163816 src 45.600134662
ts2phc[51.064]: adding tstamp 45.949159160 to clock /dev/ptp3
ts2phc[51.064]: adding tstamp 46.000000000 to clock /dev/ptp1
ts2phc[51.064]: /dev/ptp3 offset -8 s2 freq +4376
ts2phc[51.556]: /dev/ptp3 SKIP extts index 0 at 46.449154528 src 46.584588550
ts2phc[52.048]: adding tstamp 46.949149896 to clock /dev/ptp3
ts2phc[52.048]: adding tstamp 47.000000000 to clock /dev/ptp1
ts2phc[52.048]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[52.540]: /dev/ptp3 SKIP extts index 0 at 47.449145256 src 47.568132198
ts2phc[53.032]: adding tstamp 47.949140616 to clock /dev/ptp3
ts2phc[53.032]: adding tstamp 48.000000000 to clock /dev/ptp1
ts2phc[53.032]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[53.524]: /dev/ptp3 SKIP extts index 0 at 48.449135968 src 48.552121446
ts2phc[54.016]: adding tstamp 48.949131320 to clock /dev/ptp3
ts2phc[54.016]: adding tstamp 49.000000000 to clock /dev/ptp1
ts2phc[54.016]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[54.512]: /dev/ptp3 SKIP extts index 0 at 49.449126680 src 49.540147014
ts2phc[55.000]: adding tstamp 49.949122040 to clock /dev/ptp3
ts2phc[55.000]: adding tstamp 50.000000000 to clock /dev/ptp1
ts2phc[55.000]: /dev/ptp3 offset 0 s2 freq +4382
ts2phc[55.492]: /dev/ptp3 SKIP extts index 0 at 50.449117400 src 50.520119078
ts2phc[55.988]: adding tstamp 50.949112768 to clock /dev/ptp3
ts2phc[55.988]: adding tstamp 51.000000000 to clock /dev/ptp1
ts2phc[55.988]: /dev/ptp3 offset 8 s2 freq +4390
ts2phc[56.476]: /dev/ptp3 SKIP extts index 0 at 51.449108120 src 51.504175910
ts2phc[57.132]: adding tstamp 51.949103480 to clock /dev/ptp3
ts2phc[57.132]: adding tstamp 52.000000000 to clock /dev/ptp1
ts2phc[57.132]: /dev/ptp3 offset 0 s2 freq +4384
ts2phc[57.624]: /dev/ptp3 SKIP extts index 0 at 52.449098840 src 52.651833574
ts2phc[58.116]: adding tstamp 52.949094200 to clock /dev/ptp3
ts2phc[58.116]: adding tstamp 53.000000000 to clock /dev/ptp1
ts2phc[58.116]: /dev/ptp3 offset 8 s2 freq +4392
ts2phc[58.612]: /dev/ptp3 SKIP extts index 0 at 53.449089560 src 53.639826918
ts2phc[59.100]: adding tstamp 53.949084920 to clock /dev/ptp3
ts2phc[59.100]: adding tstamp 54.000000000 to clock /dev/ptp1
ts2phc[59.100]: /dev/ptp3 offset 8 s2 freq +4394
ts2phc[59.592]: /dev/ptp3 SKIP extts index 0 at 54.449080272 src 54.619842278
ts2phc[60.084]: adding tstamp 54.949075624 to clock /dev/ptp3
ts2phc[60.084]: adding tstamp 55.000000000 to clock /dev/ptp1
ts2phc[60.084]: /dev/ptp3 offset 8 s2 freq +4397
ts2phc[60.576]: /dev/ptp3 SKIP extts index 0 at 55.449070968 src 55.603885542
ts2phc[61.068]: adding tstamp 55.949066312 to clock /dev/ptp3
ts2phc[61.068]: adding tstamp 56.000000000 to clock /dev/ptp1
ts2phc[61.068]: /dev/ptp3 offset 0 s2 freq +4391
ts2phc[61.560]: /dev/ptp3 SKIP extts index 0 at 56.449061680 src 56.587885798
ts2phc[62.052]: adding tstamp 56.949057032 to clock /dev/ptp3
ts2phc[62.052]: adding tstamp 57.000000000 to clock /dev/ptp1
ts2phc[62.052]: /dev/ptp3 offset -8 s2 freq +4383
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-03 20:51:58 +03:00
|
|
|
bool extts_enabled;
|
net: dsa: sja1105: configure the PTP_CLK pin as EXT_TS or PER_OUT
The SJA1105 switch family has a PTP_CLK pin which emits a signal with
fixed 50% duty cycle, but variable frequency and programmable start time.
On the second generation (P/Q/R/S) switches, this pin supports even more
functionality. The use case described by the hardware documents talks
about synchronization via oneshot pulses: given 2 sja1105 switches,
arbitrarily designated as a master and a slave, the master emits a
single pulse on PTP_CLK, while the slave is configured to timestamp this
pulse received on its PTP_CLK pin (which must obviously be configured as
input). The difference between the timestamps then exactly becomes the
slave offset to the master.
The only trouble with the above is that the hardware is very much tied
into this use case only, and not very generic beyond that:
- When emitting a oneshot pulse, instead of being told when to emit it,
the switch just does it "now" and tells you later what time it was,
via the PTPSYNCTS register. [ Incidentally, this is the same register
that the slave uses to collect the ext_ts timestamp from, too. ]
- On the sync slave, there is no interrupt mechanism on reception of a
new extts, and no FIFO to buffer them, because in the foreseen use
case, software is in control of both the master and the slave pins,
so it "knows" when there's something to collect.
These 2 problems mean that:
- We don't support (at least yet) the quirky oneshot mode exposed by
the hardware, just normal periodic output.
- We abuse the hardware a little bit when we expose generic extts.
Because there's no interrupt mechanism, we need to poll at double the
frequency we expect to receive a pulse. Currently that means a
non-configurable "twice a second".
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-24 01:59:24 +03:00
|
|
|
u64 ptpsyncts;
|
2019-10-12 02:18:15 +03:00
|
|
|
};
|
|
|
|
|
2019-10-12 02:18:14 +03:00
|
|
|
int sja1105_ptp_clock_register(struct dsa_switch *ds);
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
|
2019-10-12 02:18:14 +03:00
|
|
|
void sja1105_ptp_clock_unregister(struct dsa_switch *ds);
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
|
2019-11-12 03:11:53 +03:00
|
|
|
void sja1105et_ptp_cmd_packing(u8 *buf, struct sja1105_ptp_cmd *cmd,
|
|
|
|
enum packing_op op);
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
|
2019-11-12 03:11:53 +03:00
|
|
|
void sja1105pqrs_ptp_cmd_packing(u8 *buf, struct sja1105_ptp_cmd *cmd,
|
|
|
|
enum packing_op op);
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
|
|
|
|
int sja1105_get_ts_info(struct dsa_switch *ds, int port,
|
|
|
|
struct ethtool_ts_info *ts);
|
|
|
|
|
2019-10-12 02:18:15 +03:00
|
|
|
void sja1105_ptp_txtstamp_skb(struct dsa_switch *ds, int slot,
|
|
|
|
struct sk_buff *clone);
|
2019-06-08 15:04:35 +03:00
|
|
|
|
2019-10-12 02:18:15 +03:00
|
|
|
bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
|
|
|
|
struct sk_buff *skb, unsigned int type);
|
|
|
|
|
2021-04-27 07:21:59 +03:00
|
|
|
void sja1105_port_txtstamp(struct dsa_switch *ds, int port,
|
2021-04-27 07:21:58 +03:00
|
|
|
struct sk_buff *skb);
|
2019-10-12 02:18:15 +03:00
|
|
|
|
|
|
|
int sja1105_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr);
|
|
|
|
|
|
|
|
int sja1105_hwtstamp_set(struct dsa_switch *ds, int port, struct ifreq *ifr);
|
|
|
|
|
2019-11-09 14:32:23 +03:00
|
|
|
int __sja1105_ptp_gettimex(struct dsa_switch *ds, u64 *ns,
|
|
|
|
struct ptp_system_timestamp *sts);
|
|
|
|
|
|
|
|
int __sja1105_ptp_settime(struct dsa_switch *ds, u64 ns,
|
|
|
|
struct ptp_system_timestamp *ptp_sts);
|
|
|
|
|
|
|
|
int __sja1105_ptp_adjtime(struct dsa_switch *ds, s64 delta);
|
|
|
|
|
2019-11-12 03:11:54 +03:00
|
|
|
int sja1105_ptp_commit(struct dsa_switch *ds, struct sja1105_ptp_cmd *cmd,
|
|
|
|
sja1105_spi_rw_mode_t rw);
|
|
|
|
|
2021-06-11 22:01:30 +03:00
|
|
|
bool sja1105_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb);
|
|
|
|
bool sja1110_rxtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb);
|
net: dsa: sja1105: implement TX timestamping for SJA1110
The TX timestamping procedure for SJA1105 is a bit unconventional
because the transmit procedure itself is unconventional.
Control packets (and therefore PTP as well) are transmitted to a
specific port in SJA1105 using "management routes" which must be written
over SPI to the switch. These are one-shot rules that match by
destination MAC address on traffic coming from the CPU port, and select
the precise destination port for that packet. So to transmit a packet
from NET_TX softirq context, we actually need to defer to a process
context so that we can perform that SPI write before we send the packet.
The DSA master dev_queue_xmit() runs in process context, and we poll
until the switch confirms it took the TX timestamp, then we annotate the
skb clone with that TX timestamp. This is why the sja1105 driver does
not need an skb queue for TX timestamping.
But the SJA1110 is a bit (not much!) more conventional, and you can
request 2-step TX timestamping through the DSA header, as well as give
the switch a cookie (timestamp ID) which it will give back to you when
it has the timestamp. So now we do need a queue for keeping the skb
clones until their TX timestamps become available.
The interesting part is that the metadata frames from SJA1105 haven't
disappeared completely. On SJA1105 they were used as follow-ups which
contained RX timestamps, but on SJA1110 they are actually TX completion
packets, which contain a variable (up to 32) array of timestamps.
Why an array? Because:
- not only is the TX timestamp on the egress port being communicated,
but also the RX timestamp on the CPU port. Nice, but we don't care
about that, so we ignore it.
- because a packet could be multicast to multiple egress ports, each
port takes its own timestamp, and the TX completion packet contains
the individual timestamps on each port.
This is unconventional because switches typically have a timestamping
FIFO and raise an interrupt, but this one doesn't. So the tagger needs
to detect and parse meta frames, and call into the main switch driver,
which pairs the timestamps with the skbs in the TX timestamping queue
which are waiting for one.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-11 22:01:31 +03:00
|
|
|
void sja1110_txtstamp(struct dsa_switch *ds, int port, struct sk_buff *skb);
|
2021-06-11 22:01:30 +03:00
|
|
|
|
2021-12-10 02:34:45 +03:00
|
|
|
void sja1110_process_meta_tstamp(struct dsa_switch *ds, int port, u8 ts_id,
|
|
|
|
enum sja1110_meta_tstamp dir, u64 tstamp);
|
|
|
|
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
#else
|
|
|
|
|
2019-10-12 02:18:16 +03:00
|
|
|
struct sja1105_ptp_cmd;
|
|
|
|
|
2019-10-12 02:18:15 +03:00
|
|
|
/* Structures cannot be empty in C. Bah!
|
|
|
|
* Keep the mutex as the only element, which is a bit more difficult to
|
|
|
|
* refactor out of sja1105_main.c anyway.
|
|
|
|
*/
|
|
|
|
struct sja1105_ptp_data {
|
|
|
|
struct mutex lock;
|
|
|
|
};
|
|
|
|
|
2019-10-12 02:18:14 +03:00
|
|
|
static inline int sja1105_ptp_clock_register(struct dsa_switch *ds)
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2019-10-12 02:18:14 +03:00
|
|
|
static inline void sja1105_ptp_clock_unregister(struct dsa_switch *ds) { }
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
|
2019-10-12 02:18:15 +03:00
|
|
|
static inline void sja1105_ptp_txtstamp_skb(struct dsa_switch *ds, int slot,
|
|
|
|
struct sk_buff *clone)
|
2019-06-08 15:04:35 +03:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2019-11-09 14:32:23 +03:00
|
|
|
static inline int __sja1105_ptp_gettimex(struct dsa_switch *ds, u64 *ns,
|
|
|
|
struct ptp_system_timestamp *sts)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int __sja1105_ptp_settime(struct dsa_switch *ds, u64 ns,
|
|
|
|
struct ptp_system_timestamp *ptp_sts)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int __sja1105_ptp_adjtime(struct dsa_switch *ds, s64 delta)
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2019-11-12 03:11:54 +03:00
|
|
|
static inline int sja1105_ptp_commit(struct dsa_switch *ds,
|
|
|
|
struct sja1105_ptp_cmd *cmd,
|
|
|
|
sja1105_spi_rw_mode_t rw)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2019-11-12 03:11:53 +03:00
|
|
|
#define sja1105et_ptp_cmd_packing NULL
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
|
2019-11-12 03:11:53 +03:00
|
|
|
#define sja1105pqrs_ptp_cmd_packing NULL
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
|
|
|
|
#define sja1105_get_ts_info NULL
|
|
|
|
|
2019-10-12 02:18:15 +03:00
|
|
|
#define sja1105_port_rxtstamp NULL
|
|
|
|
|
|
|
|
#define sja1105_port_txtstamp NULL
|
|
|
|
|
|
|
|
#define sja1105_hwtstamp_get NULL
|
|
|
|
|
|
|
|
#define sja1105_hwtstamp_set NULL
|
|
|
|
|
2021-06-11 22:01:30 +03:00
|
|
|
#define sja1105_rxtstamp NULL
|
|
|
|
#define sja1110_rxtstamp NULL
|
net: dsa: sja1105: implement TX timestamping for SJA1110
The TX timestamping procedure for SJA1105 is a bit unconventional
because the transmit procedure itself is unconventional.
Control packets (and therefore PTP as well) are transmitted to a
specific port in SJA1105 using "management routes" which must be written
over SPI to the switch. These are one-shot rules that match by
destination MAC address on traffic coming from the CPU port, and select
the precise destination port for that packet. So to transmit a packet
from NET_TX softirq context, we actually need to defer to a process
context so that we can perform that SPI write before we send the packet.
The DSA master dev_queue_xmit() runs in process context, and we poll
until the switch confirms it took the TX timestamp, then we annotate the
skb clone with that TX timestamp. This is why the sja1105 driver does
not need an skb queue for TX timestamping.
But the SJA1110 is a bit (not much!) more conventional, and you can
request 2-step TX timestamping through the DSA header, as well as give
the switch a cookie (timestamp ID) which it will give back to you when
it has the timestamp. So now we do need a queue for keeping the skb
clones until their TX timestamps become available.
The interesting part is that the metadata frames from SJA1105 haven't
disappeared completely. On SJA1105 they were used as follow-ups which
contained RX timestamps, but on SJA1110 they are actually TX completion
packets, which contain a variable (up to 32) array of timestamps.
Why an array? Because:
- not only is the TX timestamp on the egress port being communicated,
but also the RX timestamp on the CPU port. Nice, but we don't care
about that, so we ignore it.
- because a packet could be multicast to multiple egress ports, each
port takes its own timestamp, and the TX completion packet contains
the individual timestamps on each port.
This is unconventional because switches typically have a timestamping
FIFO and raise an interrupt, but this one doesn't. So the tagger needs
to detect and parse meta frames, and call into the main switch driver,
which pairs the timestamps with the skbs in the TX timestamping queue
which are waiting for one.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-11 22:01:31 +03:00
|
|
|
#define sja1110_txtstamp NULL
|
2021-06-11 22:01:30 +03:00
|
|
|
|
2021-12-10 02:34:45 +03:00
|
|
|
#define sja1110_process_meta_tstamp NULL
|
|
|
|
|
net: dsa: sja1105: Add support for the PTP clock
The design of this PHC driver is influenced by the switch's behavior
w.r.t. timestamping. It exposes two PTP counters, one free-running
(PTPTSCLK) and the other offset- and frequency-corrected in hardware
through PTPCLKVAL, PTPCLKADD and PTPCLKRATE. The MACs can sample either
of these for frame timestamps.
However, the user manual warns that taking timestamps based on the
corrected clock is less than useful, as the switch can deliver corrupted
timestamps in a variety of circumstances.
Therefore, this PHC uses the free-running PTPTSCLK together with a
timecounter/cyclecounter structure that translates it into a software
time domain. Thus, the settime/adjtime and adjfine callbacks are
hardware no-ops.
The timestamps (introduced in a further patch) will also be translated
to the correct time domain before being handed over to the userspace PTP
stack.
The introduction of a second set of PHC operations that operate on the
hardware PTPCLKVAL/PTPCLKADD/PTPCLKRATE in the future is somewhat
unavoidable, as the TTEthernet core uses the corrected PTP time domain.
However, the free-running counter + timecounter structure combination
will suffice for now, as the resulting timestamps yield a sub-50 ns
synchronization offset in steady state using linuxptp.
For this patch, in absence of frame timestamping, the operations of the
switch PHC were tested by syncing it to the system time as a local slave
clock with:
phc2sys -s CLOCK_REALTIME -c swp2 -O 0 -m -S 0.01
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-08 15:04:34 +03:00
|
|
|
#endif /* IS_ENABLED(CONFIG_NET_DSA_SJA1105_PTP) */
|
|
|
|
|
|
|
|
#endif /* _SJA1105_PTP_H */
|