Discussion:
[Linuxptp-users] PTP implementation on AM335x
Hardik Gohil
2016-11-21 06:20:46 UTC
Permalink
Hello,

I am working on AM335x running on linux -3.2.0

I want to implement PTP and I have done the following configuration

1. Select PPS Support - Device Drivers ---> PPS Support ---> <*> PPS
Support
2. Select PTP Clock Support - Device Drivers ---> PTP Clock Support --->
<*> PTP Clock Support
3. Select TI CPTS PTP Clock - Device Drivers ---> PTP Clock Support --->
<*> TI CPTS as PTP clock

As per my study AM335x supports Hardware time stamping at MAC layer.

In order to confirm this I am using ethtool.

***@phyCORE-AM335x:~ ./ethtool -T eth0
Time stamping parameters for eth0:
Cannot get device time stamping settings: Operation not supported

starting from which kernel version support is there ?
how to confirm HW time stamping feature ?

Regards,
Hardik A Gohil
Richard Cochran
2016-11-21 13:30:24 UTC
Permalink
Post by Hardik Gohil
starting from which kernel version support is there ?
Check out the driver support matrix at:

http://linuxptp.sourceforge.net

There you will find:

| cpts | Texas Instruments am335x | 3.8 |

This information is also in the README.org file.
Post by Hardik Gohil
how to confirm HW time stamping feature ?
ethtool -T is a good start.

HTH,
Richard

------------------------------------------------------------------------------
Hardik Gohil
2016-11-21 14:13:32 UTC
Permalink
Post by Richard Cochran
Post by Hardik Gohil
starting from which kernel version support is there ?
http://linuxptp.sourceforge.net
| cpts | Texas Instruments am335x | 3.8 |
Does this means support is there from kernel 3.8
Post by Richard Cochran
This information is also in the README.org file.
Post by Hardik Gohil
how to confirm HW time stamping feature ?
ethtool -T is a good start.
Yes I have tried this method and posted the problem in previous message.
Post by Richard Cochran
HTH,
Richard
Richard Cochran
2016-11-21 18:18:51 UTC
Permalink
Post by Hardik Gohil
Does this means support is there from kernel 3.8
Yes.
Post by Hardik Gohil
Yes I have tried this method and posted the problem in previous message.
You said you were running kernel 3.2. That won't work. Use kernel
3.8 or later.

BTW, the '-T' ethtool option only works on kernel 3.5 or later.

HTH,
Richard


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Hardik Gohil
2016-11-22 06:21:07 UTC
Permalink
Hello,

Thank you.

so for HW time stamping at CPTS core I need to change kernel to 3.8 or
later.

what is the accuracy of time sync ??





Regards,
Hardik A Gohil
Post by Richard Cochran
Post by Hardik Gohil
Does this means support is there from kernel 3.8
Yes.
Post by Hardik Gohil
Yes I have tried this method and posted the problem in previous message.
You said you were running kernel 3.2. That won't work. Use kernel
3.8 or later.
BTW, the '-T' ethtool option only works on kernel 3.5 or later.
HTH,
Richard
Richard Cochran
2016-11-22 08:18:42 UTC
Permalink
Post by Hardik Gohil
what is the accuracy of time sync ??
It depends.

Cheers,
Richard

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Hardik Gohil
2016-11-22 08:28:51 UTC
Permalink
Hello,

How can get details on this ?

I will be using HW time stamping at MAC layer at CPTS core for TI Chip.

and linuxptp to synchronize clock between system clock and PTP hardware
clock.

Master clock is GPS receiver



Regards,
Hardik A Gohil
Post by Richard Cochran
Post by Hardik Gohil
what is the accuracy of time sync ??
It depends.
Cheers,
Richard
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