On 18.07.2022 12:20:06, Pavel Pisa wrote: > Hello Marc, > > On Monday 18 of July 2022 10:33:12 Marc Kleine-Budde wrote: > > On 16.07.2022 14:04:09, Matej Vasilevski wrote: > > > This patch adds support for hardware RX timestamps from Xilinx Zynq CAN > > > controllers. The timestamp is calculated against a timepoint reference > > > stored when the first CAN message is received. > > > > > > When CAN bus traffic does not contain long idle pauses (so that > > > the clocks would drift by a multiple of the counter rollover time), > > > then the hardware timestamps provide precise relative time between > > > received messages. This can be used e.g. for latency testing. > > > > Please make use of the existing cyclecounter/timecounter framework. Is > > there a way to read the current time from a register? If so, please > > setup a worker that does that regularly. > > > > Have a look at the mcp251xfd driver as an example: > > Matej Vasilevski has looked at the example. But there is problem > that we know no method how to read actual counter value at least for > Xilinx Zynq 7000. May be we overlooked something or there > is hidden test register. I haven't found a documented register in the TRM. I've added Michal Simek into the loop, maybe Michal has some connection to the HW designers. Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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