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Date:	Fri, 26 Jun 2009 08:26:46 -0700
From:	David Daney <ddaney@caviumnetworks.com>
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To:	joe seb <joe.seb8@gmail.com>
CC:	linux-mips@linux-mips.org
Subject: Re: linux porting - doubts
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joe seb wrote:
> Hi,
> 
> We are trying to port linux to our new platform based on MIPS32 24Kc.
> 
> In our platform we have physical RAM of 256M mapped from 0x90000000
> to 0xa0000000( KSEG0 - cached) and 0xb0000000 to 0xc0000000(KSEG1- 
> uncached).
> 
> We made the following changes for our platform,
> 
> CAC_BASE to  0x90000000 in spaces.h
> KSEG0 to 0x90000000 and KSEG1 to 0xb0000000 in addrspace.h
> CKSEG0 to 0x90000000 and CKSEG1 to 0xb0000000 in addrspace.h
> loadaddr to 0x90000000 in the Makefile under arch/mips folder.
> 
> Are these changes sufficient??
> Is there any other platform port with such variations which we can refer to
> make sure about the changes made.
> 

That seems mostly wrong.

The CAC_BASE, KSEG0, and CKSEG0 should probably be left unchanged.  You 
the load-y in arch/mips/Makefile for your target to the load address of 
the kernel.  Then when registering memory call  add_memory_region() only 
for the physical memory that you want the kernel to use.  In your case 
physical addresses from 0 to fffffff would seem to have no RAM, so you 
would do something like:

  add_memory_region(0x10000000, 0x10000000, BOOT_MEM_RAM);

David Daney