Re: how to support more than 512MB RAM for MIPS32 ?

[Kevin Hickey <khickey@netlogicmicro.com>]

We use HIGHMEM on the Au1300 to access any memory spaces >256 MB.  Our
I/O area starts at 256 MB.  We just map the extra DRAM to any area
outside the I/O space, enable highmem, and register it as BOOT_MEM_RAM
with add_memory_region.  Works great.

=Kevin
--
Kevin Hickey
Netlogic Microsystems


On Wed, 2009-11-25 at 14:34 +0800, figo zhang wrote:
> 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