Re: can, tcan4x5x: look to merge rpi support into rpi kernel tree

Torin Cooper-Bennun
2021-02-26T13:46:11Z

On Fri, Feb 26, 2021 at 02:39:36PM +0100, Marc Kleine-Budde wrote:
> > Am I correct in saying that rx-offload requires RX timestamps to be
> > available?
>
> Proper timestamps for RX and TX would be best, but you can use
> can_rx_offload_queue_tail() if you don't have any timestamps.
>
> > They can be enabled in M_CAN, but the v3.3 manual states that
> > the internal timestamp generation (apparently only option for tcan4x5x)
> > cannot be used for CAN-FD.
>
> Can you give me a reference to this?

Here's the manual for 3.3 (annoyingly, I can't find corresponding
documents for earlier M_CAN versions, and TCAN4550 uses 3.2...)

http://www.bosch-semiconductors.com/media/ip_modules/pdf_2/m_can/mcan_users_manual_v330.pdf

See Section 2.3.9, "Timestamp Counter Configuration (TSCC)". Quote:

Note: With CAN FD an external counter is required for timestamp
generation (TSS = “10”)

--
Regards,

Torin Cooper-Bennun
Software Engineer | maxiluxsystems.com