On 15 April 2015 at 07:37, Ian Kent <ra...@themaw.net> wrote: > On Sun, 2015-04-12 at 19:01 +0200, Rafał Miłecki wrote: >> Newer revisions (5+) of BCM53011 and probably all revs of BCM53012 >> require overriding CPU port to work. So far we were handling it only for >> CPU port 8, but some devices may use e.g. port 5. In such case we need >> to use recently defined GMII_PORT registers. >> It was tested for regressions on BCM53011 revs 2 & 3. It was also >> confirmed to fix switch on some internal Broadcom board. > > CPU port as 5 also allows the switch on my R8000 (BCM53012) rev 5 device > to function. > > The puzzle is the the Vendor firmware uses port 8 as the cpu port (+ 5 > and 7 for some unknown purpose) for these higher rev switches. We > clearly don't know what the relationship is between ports 5, 7 and 8 and > I suspect there's more to it than just configuring the three ports > properly. But my code to set ports 5, 7 and 8 when cpu is 8 might not be > correct either, don't know yet.
I guess this is simply for performance reasons. Imagine there are two 1 Gbps devices connected to the router and that they want to "talk" with router system (for whatever reason). To achieve max speeds we need router system to Tx/Rx with 2 Gbps. This is impossible if switch is connected to CPU with a single 1 Gbps port. By combining 2/3 ports this should be possible (of course you're still limited by CPU performance). _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
