OpenWrt support for Linksys MX8500

[lytr]

@robimarko

Ok, so lets try and figure out what they are doing:

• 0x401ec430 0xc0ef
  1E.C430 is Global LED Provisioning 1
• 0x401ec431 0xc0e0
  1E.C431 is Global LED Provisioning 2
• 0x40070010 0x91e1
  7.1 is Autonegotiation Standard Status 1.
  No idea what they are trying to set here as most bits are RO or duplicates from another register, only reserved bits are RW
• 0x40070000 0x3200
  7.0 is Autonegotiation Standard Control 1.
  They are restarting autonegotation here, required after FW is loaded.
• 0x4004c441 0x8
  4.C441 XAUI RX Reserved Vendor Provisioning 2.
  They are enabling USXGMII MAC Autoneg, this is also a standard thing.

The only one that I dont have any docs on is:
0x401e2680 0x1
But given that 1E.2681 is Global Common POR control 2 and it only does resetting my bet is that its another reset register.

I checked and after loading the firmware from NVMEM (without using the u-boot function), I have the following values:

root@OpenWrt:/# mdio 9* mmd 8:30 0x2680
0x0000
root@OpenWrt:/# mdio 9* mmd 8:30 0xC430
0x000f
root@OpenWrt:/# mdio 9* mmd 8:30 0xC431
0xc060
root@OpenWrt:/# mdio 9* mmd 8:7 0x0010
0x9d81
root@OpenWrt:/# mdio 9* mmd 8:7 0x0000
0x3000
root@OpenWrt:/# mdio 9* mmd 8:4 0xC441
0x0008