[PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[Mahesh Bandewar]

add support for TS sandwich of the user preferred timebase. The options
supported are PTP_TS_REAL (CLOCK_REALTIME), PTP_TS_MONO (CLOCK_MONOTONIC),
and PTP_TS_RAW (CLOCK_MONOTONIC_RAW)

Option of PTP_TS_REAL is equivalent of using ptp_gettimex64().

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
CC: Richard Cochran <richardcochran@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
---
 include/linux/ptp_clock_kernel.h | 51 ++++++++++++++++++++++++++++++++
 include/uapi/linux/ptp_clock.h   |  7 +++++
 2 files changed, 58 insertions(+)

diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 1ef4e0f9bd2a..fd7be98e7bba 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -102,6 +102,15 @@ struct ptp_system_timestamp {
  *               reading the lowest bits of the PHC timestamp and the second
  *               reading immediately follows that.
  *
+ * @gettimex64any:  Reads the current time from the hardware clock and
+                 optionally also any of the MONO, MONO_RAW, or SYS clock.
+ *               parameter ts: Holds the PHC timestamp.
+ *               parameter sts: If not NULL, it holds a pair of timestamps from
+ *               the clock of choice. The first reading is made right before
+ *               reading the lowest bits of the PHC timestamp and the second
+ *               reading immediately follows that.
+ *               parameter type: any one of the TS opt from ptp_timestamp_types.
+ *
  * @getcrosststamp:  Reads the current time from the hardware clock and
  *                   system clock simultaneously.
  *                   parameter cts: Contains timestamp (device,system) pair,
@@ -180,6 +189,9 @@ struct ptp_clock_info {
 	int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
 	int (*gettimex64)(struct ptp_clock_info *ptp, struct timespec64 *ts,
 			  struct ptp_system_timestamp *sts);
+	int (*gettimex64any)(struct ptp_clock_info *ptp, struct timespec64 *ts,
+			     struct ptp_system_timestamp *sts,
+			     enum ptp_ts_types type);
 	int (*getcrosststamp)(struct ptp_clock_info *ptp,
 			      struct system_device_crosststamp *cts);
 	int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts);
@@ -464,4 +476,43 @@ static inline void ptp_read_system_postts(struct ptp_system_timestamp *sts)
 		ktime_get_real_ts64(&sts->post_ts);
 }
 
+static inline void ptp_read_any_prets(struct ptp_system_timestamp *sts,
+				      enum ptp_ts_types type)
+{
+	if (sts) {
+		switch (type) {
+		case PTP_TS_REAL:
+			ktime_get_real_ts64(&sts->pre_ts);
+			break;
+		case PTP_TS_MONO:
+			ktime_get_ts64(&sts->pre_ts);
+			break;
+		case PTP_TS_RAW:
+			ktime_get_raw_ts64(&sts->pre_ts);
+			break;
+		default:
+			break;
+		}
+	}
+}
+
+static inline void ptp_read_any_postts(struct ptp_system_timestamp *sts,
+				       enum ptp_ts_types type)
+{
+	if (sts) {
+		switch (type) {
+		case PTP_TS_REAL:
+			ktime_get_real_ts64(&sts->post_ts);
+			break;
+		case PTP_TS_MONO:
+			ktime_get_ts64(&sts->post_ts);
+			break;
+		case PTP_TS_RAW:
+			ktime_get_raw_ts64(&sts->post_ts);
+			break;
+		default:
+			break;
+		}
+	}
+}
 #endif
diff --git a/include/uapi/linux/ptp_clock.h b/include/uapi/linux/ptp_clock.h
index 05cc35fc94ac..dc44e34f8146 100644
--- a/include/uapi/linux/ptp_clock.h
+++ b/include/uapi/linux/ptp_clock.h
@@ -69,6 +69,13 @@
  */
 #define PTP_PEROUT_V1_VALID_FLAGS	(0)
 
+enum ptp_ts_types {
+	PTP_TS_REAL = 0,
+	PTP_TS_MONO,
+	PTP_TS_RAW,
+	PTP_TS_MAX,
+};
+
 /*
  * struct ptp_clock_time - represents a time value
  *
-- 
2.42.0.582.g8ccd20d70d-goog

Re: [PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[Simon Horman]

On Mon, Oct 02, 2023 at 09:17:01PM -0700, Mahesh Bandewar wrote:
> add support for TS sandwich of the user preferred timebase. The options
> supported are PTP_TS_REAL (CLOCK_REALTIME), PTP_TS_MONO (CLOCK_MONOTONIC),
> and PTP_TS_RAW (CLOCK_MONOTONIC_RAW)
> 
> Option of PTP_TS_REAL is equivalent of using ptp_gettimex64().
> 
> Signed-off-by: Mahesh Bandewar <maheshb@google.com>
> CC: Richard Cochran <richardcochran@gmail.com>
> CC: "David S. Miller" <davem@davemloft.net>
> CC: netdev@vger.kernel.org
> ---
>  include/linux/ptp_clock_kernel.h | 51 ++++++++++++++++++++++++++++++++
>  include/uapi/linux/ptp_clock.h   |  7 +++++
>  2 files changed, 58 insertions(+)
> 
> diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
> index 1ef4e0f9bd2a..fd7be98e7bba 100644
> --- a/include/linux/ptp_clock_kernel.h
> +++ b/include/linux/ptp_clock_kernel.h
> @@ -102,6 +102,15 @@ struct ptp_system_timestamp {
>   *               reading the lowest bits of the PHC timestamp and the second
>   *               reading immediately follows that.
>   *
> + * @gettimex64any:  Reads the current time from the hardware clock and
> +                 optionally also any of the MONO, MONO_RAW, or SYS clock.

nit: I think a '*' is needed on the line above.

> + *               parameter ts: Holds the PHC timestamp.
> + *               parameter sts: If not NULL, it holds a pair of timestamps from
> + *               the clock of choice. The first reading is made right before
> + *               reading the lowest bits of the PHC timestamp and the second
> + *               reading immediately follows that.
> + *               parameter type: any one of the TS opt from ptp_timestamp_types.
> + *
>   * @getcrosststamp:  Reads the current time from the hardware clock and
>   *                   system clock simultaneously.
>   *                   parameter cts: Contains timestamp (device,system) pair,

...

Re: [PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[Richard Cochran]

On Mon, Oct 02, 2023 at 09:17:01PM -0700, Mahesh Bandewar wrote:
> add support for TS sandwich of the user preferred timebase. The options
> supported are PTP_TS_REAL (CLOCK_REALTIME), PTP_TS_MONO (CLOCK_MONOTONIC),
> and PTP_TS_RAW (CLOCK_MONOTONIC_RAW)
> 
> Option of PTP_TS_REAL is equivalent of using ptp_gettimex64().

NAK

Don't just ignore feedback and repost.

Re: [PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[Richard Cochran]

On Mon, Oct 02, 2023 at 09:17:01PM -0700, Mahesh Bandewar wrote:
> add support for TS sandwich of the user preferred timebase. The options
> supported are PTP_TS_REAL (CLOCK_REALTIME), PTP_TS_MONO (CLOCK_MONOTONIC),
> and PTP_TS_RAW (CLOCK_MONOTONIC_RAW)
> 
> Option of PTP_TS_REAL is equivalent of using ptp_gettimex64().

This change log is horrible.

Please write a proper explanation, and be sure to cover the following
three points.

1. context
2. problem
3. solution

Every change log must have those three items.

In addition, this series needs a cover letter that clearly justifies
the need for this change.

Thanks,
Richard

Re: [PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[Mahesh Bandewar (महेश बंडेवार)]

On Tue, Oct 3, 2023 at 9:29 PM Richard Cochran <richardcochran@gmail.com> wrote:
>
> On Mon, Oct 02, 2023 at 09:17:01PM -0700, Mahesh Bandewar wrote:
> > add support for TS sandwich of the user preferred timebase. The options
> > supported are PTP_TS_REAL (CLOCK_REALTIME), PTP_TS_MONO (CLOCK_MONOTONIC),
> > and PTP_TS_RAW (CLOCK_MONOTONIC_RAW)
> >
> > Option of PTP_TS_REAL is equivalent of using ptp_gettimex64().
>
> NAK
>
> Don't just ignore feedback and repost.

I replied to all your earlier comments, which one do you think I had ignored?

Re: [PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[Mahesh Bandewar (महेश बंडेवार)]

On Tue, Oct 3, 2023 at 9:38 PM Richard Cochran <richardcochran@gmail.com> wrote:
>
> On Mon, Oct 02, 2023 at 09:17:01PM -0700, Mahesh Bandewar wrote:
> > add support for TS sandwich of the user preferred timebase. The options
> > supported are PTP_TS_REAL (CLOCK_REALTIME), PTP_TS_MONO (CLOCK_MONOTONIC),
> > and PTP_TS_RAW (CLOCK_MONOTONIC_RAW)
> >
> > Option of PTP_TS_REAL is equivalent of using ptp_gettimex64().
>
> This change log is horrible.
>
> Please write a proper explanation, and be sure to cover the following
> three points.
>
> 1. context
> 2. problem
> 3. solution
>
> Every change log must have those three items.
>
> In addition, this series needs a cover letter that clearly justifies
> the need for this change.
>
Fair point and the series does have a cover letter  which you can
access it at https://lore.kernel.org/lkml/20231003041657.1745487-1-maheshb@google.com/
Probably it's fault of my mailer-script which finds the reviewers for
individual patches by running scripts/get_maintainer.pl but then
coverletter is just sent to the mailing-list


> Thanks,
> Richard
>

Re: [PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[Richard Cochran]

On Thu, Oct 05, 2023 at 04:12:44PM -0700, Mahesh Bandewar (महेश बंडेवार) wrote:

> I replied to all your earlier comments, which one do you think I had ignored?

new enums -- go back and read my reply again!

Thanks,
Richard

Re: [PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[Richard Cochran]

On Thu, Oct 05, 2023 at 04:12:44PM -0700, Mahesh Bandewar (महेश बंडेवार) wrote:
> I replied to all your earlier comments

Actually, you didn't.

(no) Thanks,
Richard

Re: [PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[Richard Cochran]

On Thu, Oct 05, 2023 at 04:23:27PM -0700, Mahesh Bandewar (महेश बंडेवार) wrote:

> Probably it's fault of my mailer-script which finds the reviewers for
> individual patches by running scripts/get_maintainer.pl but then
> coverletter is just sent to the mailing-list

No, it is your responsibility to ensure CC list is correct.

Thanks,
Richard

Re: [PATCHv2 next 1/3] ptp: add ptp_gettimex64any() support

[John Stultz]

On Mon, Oct 2, 2023 at 9:17 PM Mahesh Bandewar <maheshb@google.com> wrote:
>
> add support for TS sandwich of the user preferred timebase. The options
> supported are PTP_TS_REAL (CLOCK_REALTIME), PTP_TS_MONO (CLOCK_MONOTONIC),
> and PTP_TS_RAW (CLOCK_MONOTONIC_RAW)
>
> Option of PTP_TS_REAL is equivalent of using ptp_gettimex64().
>
> Signed-off-by: Mahesh Bandewar <maheshb@google.com>
> CC: Richard Cochran <richardcochran@gmail.com>
> CC: "David S. Miller" <davem@davemloft.net>
> CC: netdev@vger.kernel.org
> ---
>  include/linux/ptp_clock_kernel.h | 51 ++++++++++++++++++++++++++++++++
>  include/uapi/linux/ptp_clock.h   |  7 +++++
>  2 files changed, 58 insertions(+)

Hey Mahesh,
  Thanks for sending this out!  I've got a few thoughts below.


> diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
> index 1ef4e0f9bd2a..fd7be98e7bba 100644
> --- a/include/linux/ptp_clock_kernel.h
> +++ b/include/linux/ptp_clock_kernel.h
> @@ -102,6 +102,15 @@ struct ptp_system_timestamp {
>   *               reading the lowest bits of the PHC timestamp and the second
>   *               reading immediately follows that.
>   *
> + * @gettimex64any:  Reads the current time from the hardware clock and
> +                 optionally also any of the MONO, MONO_RAW, or SYS clock.
> + *               parameter ts: Holds the PHC timestamp.
> + *               parameter sts: If not NULL, it holds a pair of timestamps from
> + *               the clock of choice. The first reading is made right before
> + *               reading the lowest bits of the PHC timestamp and the second
> + *               reading immediately follows that.
> + *               parameter type: any one of the TS opt from ptp_timestamp_types.
> + *
>   * @getcrosststamp:  Reads the current time from the hardware clock and
>   *                   system clock simultaneously.
>   *                   parameter cts: Contains timestamp (device,system) pair,
> @@ -180,6 +189,9 @@ struct ptp_clock_info {
>         int (*gettime64)(struct ptp_clock_info *ptp, struct timespec64 *ts);
>         int (*gettimex64)(struct ptp_clock_info *ptp, struct timespec64 *ts,
>                           struct ptp_system_timestamp *sts);
> +       int (*gettimex64any)(struct ptp_clock_info *ptp, struct timespec64 *ts,
> +                            struct ptp_system_timestamp *sts,
> +                            enum ptp_ts_types type);
>         int (*getcrosststamp)(struct ptp_clock_info *ptp,
>                               struct system_device_crosststamp *cts);
>         int (*settime64)(struct ptp_clock_info *p, const struct timespec64 *ts);

So I don't see anything in this series that wires into this hook. Did
a patch go missing? Or am I maybe looking in the wrong place?


> @@ -464,4 +476,43 @@ static inline void ptp_read_system_postts(struct ptp_system_timestamp *sts)
>                 ktime_get_real_ts64(&sts->post_ts);
>  }
>
> +static inline void ptp_read_any_prets(struct ptp_system_timestamp *sts,
> +                                     enum ptp_ts_types type)
> +{
> +       if (sts) {
> +               switch (type) {
> +               case PTP_TS_REAL:
> +                       ktime_get_real_ts64(&sts->pre_ts);
> +                       break;
> +               case PTP_TS_MONO:
> +                       ktime_get_ts64(&sts->pre_ts);
> +                       break;
> +               case PTP_TS_RAW:
> +                       ktime_get_raw_ts64(&sts->pre_ts);
> +                       break;
> +               default:
> +                       break;
> +               }
> +       }
> +}
> +
> +static inline void ptp_read_any_postts(struct ptp_system_timestamp *sts,
> +                                      enum ptp_ts_types type)
> +{
> +       if (sts) {
> +               switch (type) {
> +               case PTP_TS_REAL:
> +                       ktime_get_real_ts64(&sts->post_ts);
> +                       break;
> +               case PTP_TS_MONO:
> +                       ktime_get_ts64(&sts->post_ts);
> +                       break;
> +               case PTP_TS_RAW:
> +                       ktime_get_raw_ts64(&sts->post_ts);
> +                       break;
> +               default:
> +                       break;
> +               }
> +       }
> +}

Similarly, I'm a little confused as to who the users of these two
functions are? I don't see them in this patch series.

Additionally it seems like instead of two functions, you could maybe
have one ptp_read_any_ts(enum ptp_ts_types type, struct timespec64
*ts) function that the caller passes the sts->pre_ts or sts->post_ts
to?

And finally, I'm not sure if it makes sense, but other logic in the
kernel that does similar clockid multiplexing includes
timens_add_monotonic() or timens_add_boottime() (though the latter
doesn't apply here) for namespace offsets.
I was never excited about time namespaces (hard enough to keep one
sense of time :), but there are some good reasons, and I suspect we
might want to avoid cases where clock_gettime() returns potentially
different values compared to this interface.

thanks again!
-john