On Wed, 24 Mar 2021 13:09:00 +0000 Stefan Chulski <stef...@marvell.com> wrote:
> > > > > > > > SGMII uses the same coding as 1000base-x, but the latter works only > > > > with one speed (1000mbps), while the former can also work in 10mbps > > > > and 100mbps (by repeating each byte 100 or 10 times, respectively). > > > > > > > > Then there is 2500base-x, which is the same as 1000base-x, but with > > > > the clock being at 2.5x the speed of 1000base-x clock. > > > > > > > > But there is no analogue of the SGMII protocol (i.e. the repearing > > > > of bytes in order to achieve lower speed) for the 2500base-x. > > > > > > > > So what I am confused about here is what is supposed to be the > > > > difference between > > > > PHY_INTERFACE_MODE_SGMII_2500 > > > > and > > > > PHY_INTERFACE_MODE_2500BASEX > > > > ? > > > > > > > > Marek > > > > I not sure what is correct naming for these mode. PHY_INTERFACE includes > > both MAC2PHY interfaces(MII, RGMII and etc), PHY2PHY interfaces(like > > BASEX) and SGMII(which is kind of both). > > For both 2500BASEX and SGMII_2500 Serdes lanes set to HS-SGMII in 3.125G > > speed, but MAC configured differently and autoneg cannot be supported. > > > > Regards, > > Stefan. > > Since we already has PHY_INTERFACE_MODE_SGMII and PHY_INTERFACE_MODE_QSGMII > (5G mode), maybe we should call > PHY_INTERFACE_MODE_HSGMII - High-Serial Gigabit Media Independent Interface > (HSGMII, 3.125Gbps). And we have now autonegotiation in this discussion. Just today I sent a question to Marvell about 2500base-x and why inband autonegotiation is not supported there, while it is for 1000base-x. So are you saying that 2500base-x mode is like 1000base-x, but at 2.5g speed, and without inband autonegotiation? And meanwhile HS-SGMII mode is like SGMII, but at 2.5g speed, and _WITH_ autonegotiation? And what does this autonegotiation support? Does is support only negotiation of Pause? Or does it support negotiation of duplexicity and speed as well? Thank you. Marek
