SocketCAN timestamps

SocketCAN timestamps

[Stefan Tatschner]

Hi,

I did some google work to find out how to retrieve timestamps of
received messages. I have found this:

http://socket-can.996257.n3.nabble.com/PATCH-Add-timestamps-description-to-can-txt-td1430.html

It seems that this patch has never been applied to the kernel tree. Are
there any reasons (besides being forgotten) for this?

Stefan

Re: SocketCAN timestamps

[Marc Kleine-Budde]

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On 11/24/2015 02:07 PM, Stefan Tatschner wrote:
> I did some google work to find out how to retrieve timestamps of
> received messages. I have found this:
> 
> http://socket-can.996257.n3.nabble.com/PATCH-Add-timestamps-description-to-can-txt-td1430.html
> 
> It seems that this patch has never been applied to the kernel tree. Are
> there any reasons (besides being forgotten) for this?

Maybe it was the time when mainlining the first bits and pieces to linux
kernel. Can you port this patch against a current linux kernel?

Marc

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[PATCH] can-doc: Add hint about getting timestamps

[Stefan Tatschner]

This patch adds a hint about how to get timestamps of received
CAN frames with ioctl(2). This hint has been applied to the
former SocketCAN Documentation, but it got lost during mainlining
the first bits and pieces to linux kernel.

Signed-off-by: Stefan Tatschner <rumpelsepp@sevenbyte.org>
---
 Documentation/networking/can.txt | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt
index 05fd83b..6ab619f 100644
--- a/Documentation/networking/can.txt
+++ b/Documentation/networking/can.txt
@@ -372,6 +372,15 @@ solution for a couple of reasons:
     nbytes = sendto(s, &frame, sizeof(struct can_frame),
                     0, (struct sockaddr*)&addr, sizeof(addr));
 
+  An accurate timestamp can be obtained with an ioctl(2) call after reading
+  a message from the socket:
+
+    struct timeval tv;
+    ioctl(s, SIOCGSTAMP, &tv);
+
+  The timestamp has a resolution of one microsecond and is set automatically
+  at the reception of a CAN frame.
+
   Remark about CAN FD (flexible data rate) support:
 
   Generally the handling of CAN FD is very similar to the formerly described
-- 
2.6.2

Re: [PATCH] can-doc: Add hint about getting timestamps

[Stefan Tatschner]

On 24.11.2015 15:06, Stefan Tatschner wrote:
> This patch adds a hint about how to get timestamps of received
> CAN frames with ioctl(2). This hint has been applied to the
> former SocketCAN Documentation, but it got lost during mainlining
> the first bits and pieces to linux kernel.
> 
> Signed-off-by: Stefan Tatschner <rumpelsepp@sevenbyte.org>

Any comments on this patch?

Stefan

Re: [PATCH] can-doc: Add hint about getting timestamps

[Jonathan Corbet]

On Tue, 24 Nov 2015 15:06:29 +0100
Stefan Tatschner <rumpelsepp@sevenbyte.org> wrote:

> This patch adds a hint about how to get timestamps of received
> CAN frames with ioctl(2). This hint has been applied to the
> former SocketCAN Documentation, but it got lost during mainlining
> the first bits and pieces to linux kernel.

Applied to the docs tree, thanks.

jon