Hello, I'm still fairly new to Ethernet drivers and there are a lot of interesting pieces. What I need help with is understanding MDIO --> (R)MII vs direct I/O to the MAC (e.g., via ioread32, iowrite32). Why is there not always a struct mii_bus to talk to this hardware? Is it because the PHY and/or MAC hardware sometimes attached via an MDIO device and sometimes directly to the I/O bus? Or does some type of "indirect access" need to be enabled for that to work?
I might be trying to do something that's unnecessary however, I'm not sure yet. I need to add functionality to change a port's auto-negotiate, duplex, etc. I'm adding it to the swconfig first and then will look at adding it for DSA afterwards. When I run "swconfig dev switch0 port 0 show", the current mt7530 / mt7620 driver is querying the MAC status register (at base + 0x3008 + 0x100 * port, described on pages 323-324 of the MT7620 Programming Guide), so I implemented the "set" functionality by modifying the MAC's control register (offset 0x3000 on page 321), but it doesn't seem to change anything. So I figured maybe I need to modify the MII interface's control register for the port (page 350), but upon debugging I can see that the struct mii_bus *bus member is NULL. So should I be able to change it via the MAC's control register and something else is wrong? Why is there no struct mii_bus? Can I talk to the MII hardware in some other way? Thanks, Daniel https://download.villagetelco.org/hardware/MT7620/MT7620_ProgrammingGuide.pdf
