On 17/09/2019 12:24, Jianyong Wu wrote:
> A number of PTP drivers (such as ptp-kvm) are assuming what the
> current clock source is, which could lead to interesting effects on
> systems where the clocksource can change depending on external events.
>
> For this purpose, add a new API that retrives both the current
> monotonic clock as well as its counter value.
>
> Signed-off-by: Marc Zyngier <m...@kernel.org>
> Signed-off-by: Jianyong Wu <jianyong...@arm.com>
There must be something wrong with the way you've taken this patch in
your tree. My authorship is gone (not that I deeply care about it, but
it is good practice to keep attributions), and the subject line has been
rewritten.
I'd appreciate it if you could fix this in a future revision of this
series. For reference, the original patch is here[1].
> ---
> include/linux/timekeeping.h | 3 +++
> kernel/time/timekeeping.c | 13 +++++++++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
> index a8ab0f143ac4..a5389adaa8bc 100644
> --- a/include/linux/timekeeping.h
> +++ b/include/linux/timekeeping.h
> @@ -247,6 +247,9 @@ extern int get_device_system_crosststamp(
> struct system_time_snapshot *history,
> struct system_device_crosststamp *xtstamp);
>
> +/* Obtain current monotonic clock and its counter value */
> +extern void get_current_counterval(struct system_counterval_t *sc);
> +
> /*
> * Simultaneously snapshot realtime and monotonic raw clocks
> */
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
> index 44b726bab4bd..07a0969625b1 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -1098,6 +1098,19 @@ static bool cycle_between(u64 before, u64 test, u64
> after)
> return false;
> }
>
> +/**
> + * get_current_counterval - Snapshot the current clocksource and counter
> value
> + * @sc: Pointer to a struct containing the current clocksource and its
> value
> + */
> +void get_current_counterval(struct system_counterval_t *sc)
> +{
> + struct timekeeper *tk = &tk_core.timekeeper;
> +
> + sc->cs = READ_ONCE(tk->tkr_mono.clock);
> + sc->cycles = sc->cs->read(sc->cs);
> +}
> +EXPORT_SYMBOL_GPL(get_current_counterval);
This export wasn't in my original patch. I guess you need it because
your ptp driver builds as a module? It'd be good to mention it in the
commit log.
> +
> /**
> * get_device_system_crosststamp - Synchronously capture system/device
> timestamp
> * @get_time_fn: Callback to get simultaneous device time and
>
Thanks,
M.
[1]
https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=timer/counterval&id=a6e8abce025691b6a55e1c195878d7f76bfeb9d1
--
Jazz is not dead, it just smells funny...
