how to support more than 512MB RAM for MIPS32 ?

[figo zhang <figo1802@xxxxxxxxx>]

hi all,

I am using 24KEC SOC, i want to support larger more than 512MB RAM. The mips32 architure  in Kseg0/Kseg1,
such as:
0x8000,0000 ~ 0x92c0,0000  # 300MB for RAM
0x92c0,0000 ~ 0xa000,0000  # 212 for I/O register

so, mips32 only support 300MB memory, i dont how to support more than 512MB in linux-mips kernel , such as 2GB memory? it is using HIGHMEM strategy
for kernel(ZONE_HIGHMEM)?

Best,
Figo.zhang