On Fri, 31 May 2019 at 18:11, Richard Cochran <richardcoch...@gmail.com> wrote: > > On Fri, May 31, 2019 at 05:27:15PM +0300, Vladimir Oltean wrote: > > On Fri, 31 May 2019 at 17:08, Richard Cochran <richardcoch...@gmail.com> > > wrote: > > > This can be done simply using a data structure in the driver with an > > > appropriate locking mechanism. Then you don't have to worry which > > > core the driver code runs on. > > > > > > > Actually you do. DSA is special because it is not the first net device > > in the RX path that processes the frames. Something needs to be done > > on the master port. > > Before you said, > > the switch in its great wisdom mangles bytes 01-1B-19-xx-xx-00 > of the DMAC to place the switch id and source port there (a > rudimentary tagging mechanism). > > So why not simply save each frame in a per-switch/port data structure? >
You mean to queue it and subvert DSA's own RX timestamping callback? Why would I do that? Just so as not to introduce my .can_timestamp callback? > Now I'm starting to understand your series. I think it can be done in > simpler way... > > sja1105_rcv_meta_state_machine - can and should be at the driver level > and not at the port level. > Can: yes. Should: why? > sja1105_port_rxtstamp_work - isn't needed at all. > > How about this? > > 1. When the driver receives a deferred PTP frame, save it into a > per-switch,port slot at the driver (not port) level. > > 2. When the driver receives a META frame, match it to the > per-switch,port slot. If there is a PTP frame in that slot, then > deliver it with the time stamp from the META frame. > One important aspect makes this need be a little bit more complicated: reconstructing these RX timestamps. You see, there is a mutex on the SPI bus, so in practice I do need the sja1105_port_rxtstamp_work for exactly this purpose - to read the timestamping clock over SPI. > Thanks, > Richard
