On Fri, Nov 28, 2014 at 12:15 PM, Jonas Gorski <j...@openwrt.org> wrote:
> On Fri, Nov 28, 2014 at 11:06 AM, Heiner Kallweit <hkallwe...@gmail.com> > wrote: > > In my tests with AR8327 this callback was never called with an addr != 0. > > Seems logical to me as it's called for the PHY attached to the net device > > only. > > > > In most cases this is addr 0, just for AR8316 with port4_phy being set > this > > could be 4. > > > > This leads to two questions: > > > > 1. The current version of this function checks for "addr == 0" always, > I'd > > assume this is not correct for AR8316 and port4_phy being set. > > > > 2. As it seems to be called for the attached PHY addr only and in exactly > > this case we do nothing: Can we simply replace this callback with a dummy > > "return 0" ? > > Port4_phy being set means the switch operates in dual-mii mode. > > Most Atheros switches (including AR8327) support a dual-phy mode, > where port 5 / phy 4 is split out from the rest of the switch and used > as a single phy for a second ethernet mac. In these cases phy 4 is > used like a standard phy, and the kernel needs to be able to configure > autonegotiation or other features. > > Consequently you will only see the callback being called for addr != 0 > if the switch is in this mode and there is a second ethernet mac as > the single wan port. I'm not sure if there are any OpenWrt supported > devices with this setup with AR8327, but there are several examples > for AR8316, e.g. the RouterStation Pro [1]. > > The switch driver claiming phy 0 is technically wrong, as the > connection to the switch isn't using phy 0, but uses a fixed (R)(G)MII > connection that does not support autonegotiation. But there also is no > other phy address on the MDIO bus which represents the cpu port, so we > need this workaround for autodetection/-attachment. > > From the switch perspective port 0 / cpu port. Phy 0 actually belongs > to the external port 1, therefore we stub it out for addr == 0. > > > Jonas Thanks a lot for the comprehensive explanation! Heiner
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