On Sat, Jan 11, 2014 at 7:48 AM, Beniamino Galvani <b.galv...@gmail.com> wrote: > On Mon, Jan 06, 2014 at 02:12:27PM +0800, Stefan Hajnoczi wrote: >> > >> More a comment for net in general, but I think sooner or later we need >> > >> to move towards a split between phy and mac on the device level. >> > >> continuing the phy-within-mac philosophy is going to make the >> > >> socification efforts awkward. Are MII and friends a busses (as in >> > >> TYPE_BUS) in their own right, and connection of mac and phy has to >> > >> happen on the board level? >> > > >> > > I see PHY and MAC split as advantageous because it allows code reuse and >> > > better testing. The main thing I'd like to see is PHY device tests >> > > using tests/libqtest.h. >> > > >> > > If someone wants to implement it, great. It would make it easier to add >> > > more NIC models in the future. >> > > >> > > Regarding SOCification and busses, I'm not sure. Is it okay to just say >> > > a NIC has-a PHY (i.e. composition)? >> > > >> > >> > Generally speaking, in the (ARM) SoCification the MAC is part of the >> > SoC which in the latest styling guidelines is a composite device. This >> > composite is supposed to reflect the self contained SoC product which >> > the PHY is usually not a part of. So we have two opposing compositions >> > here: >> > >> > NIC = MAC + PHY >> > SOC = CPUs + MAC + ... >> > >> > MAC can't be in both. So for SoCs the NIC concept needs to abandoned. >> > After all the expansion of NIC as "Network Interface Card" is a little >> > bit PCish. Your average SoC networking solution has no such "card". >> > Just an on chip MAC (same pacakge/die as CPU etc) connecting to a PHY >> > via PCB traces. >> > >> > So I think long term, MII has to be a TYPE_BUS that is visible on the >> > top level SoC device. Self contained NICs (as we know them today) are >> > then also implementable as container devices (of MAC and PHY) that use >> > this bus internally (in much the same way the SoC boards would attach >> > external PHY to SoC). >> >> Okay, that makes sense. Given the amount of emulated hardware in QEMU >> today, I think it would be okay to simply add new MAC/PHYs while still >> supporting the NICs of old. If someone is enthusiastic about >> refactoring and testing existing NICs then great. But I think it's more >> pragmatic to simply start working with a split MAC/PHY where that is >> beneficial. > > Regarding the patch, can I resubmit it with MAC and PHY modeled as a > single device? Or it's better to start thinking on how to implement > proper MAC/PHY split? >
Resubmit as a single. Don't wait on the proposed fifo cleanups either. I'm not going to block. Regards, Peter > Beniamino >
