> > > Make mdiobus_scan() to try harder to look for any PHY that only > talks C45. > > If you are not using Device Tree or ACPI, and you are letting the MDIO > > bus be scanned, it sounds like there should be a way for you to > > provide a hint as to which addresses should be scanned (that's > > mii_bus::phy_mask) and possibly enhance that with a mask of possible > > C45 devices? > > Yes, i don't like this unconditional c45 scanning. A lot of MDIO bus > drivers don't look for the MII_ADDR_C45. They are going to do a C22 > transfer, and maybe not mask out the MII_ADDR_C45 from reg, causing an > invalid register write. Bad things can then happen. > > With DT and ACPI, we have an explicit indication that C45 should be used, > so we know on this platform C45 is safe to use. We need something > similar when not using DT or ACPI. > > Andrew
Florian and Andrew, The mdio c22 is using the start-of-frame ST=01 while mdio c45 is using ST=00 as identifier. So mdio c22 device will not response to mdio c45 protocol. As in IEEE 802.1ae-2002 Annex 45A.3 mention that: " Even though the Clause 45 MDIO frames using the ST=00 frame code will also be driven on to the Clause 22 MII Management interface, the Clause 22 PHYs will ignore the frames. " Hence, I am not seeing any concern that the c45 scanning will mess up with c22 devices. Weifeng
