Hi people, I am porting my (not linux) OS to the 5200. I went all the way understanding how the SDMA works and programming what I needed for it so things are now pretty stable in terms of disk I/O and system memory -> PCI (offscreen window buffers -> PCI display framebuffer).
And I wanted to make use of the Ethernet ("FEC", as they have it), hoping it would take me a few days (not my first one). I am out of luck - it is practically undocumented. There is some talk of receive buffers which the FEC should see empty etc., how on earth is that supposed to happen when it has no bus master capability at all? It relies on the SDMA for its bus activity - but in what format does it expect to get these buffer related data? Or (more likely, at least hopefully so) this talk in the MPC5200BUM (and MPC5200UM, for that) is just nonsense and the FEC simply puts in the FIFO incoming packets, writing as a last .l the receive frame status word? If so, I could easily handle that with the SDMA. Same question about transmitting. I can only hope/assume that the FEC will just send what it is handed through the FIFO by the SDMA, the very first .l being the frame control word, and ending when the TFD from the data drd1a or whatever makes it through? If the above assumptions are correct, I could manage it in a reasonably short time. I know this is an "untypicall" question, but people who have wrestled the FEC & SDMA may have enough observations to confirm or reject my assumptions and perhaps provide some more insight. Thanks for any input, Dimiter ------------------------------------------------------ Dimiter Popoff Transgalactic Instruments http://www.tgi-sci.com ------------------------------------------------------ http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/ _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev