Subject: Question concerning memory configuration

From: Jeff Harrell <[email-masked]>
Date: Fri, 28 Jan 2000 15:32:22 -0700

I have question concerning the memory configuration variables in the
MIPS/Linux
codebase.  I am working on a board that has 64Mbytes (0x400 0000) of
SDRAM.  We
are using an R4000 core and have the memory map setup so that KSEG0 &
KSEG1 both
map to address 0x0 in physical memory.  On our embedded system we are
going to hard
code the variable mips_memory_upper (This eventually is stored in
memory_end).  My
question is what I should initialize the value to?  Do I treat the top
of memory as KSEG1
+ 64Mbytes? (i.e., 0xA400 0000) or do I initialize it realative to 0?
If anybody has any
insights in this area, any information would be greatly appreciated.

Thanks,
Jeff

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jeff Harrell                    Work:  (801) 619-6104
Broadband Access group/TI
[email-masked]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

---

From: Ralf Baechle <[email-masked]>
Date: Sat, 29 Jan 2000 03:52:33 +0100

On Fri, Jan 28, 2000 at 03:32:22PM -0700, Jeff Harrell wrote:

> MIPS/Linux codebase.  I am working on a board that has 64Mbytes
> (0x400 0000) of SDRAM.  We are using an R4000 core and have the memory
> map setup so that KSEG0 & KSEG1 both map to address 0x0 in physical
> memory.  On our embedded system we are going to hard code the variable
> mips_memory_upper (This eventually is stored in memory_end).  My
> of memory as KSEG1 + 64Mbytes? (i.e., 0xA400 0000) or do I initialize it
> realative to 0?  If anybody has any insights in this area, any
> information would be greatly appreciated.

I killed mips_memory_upper in 2.3.27.  Now the kernel uses the same
bootmem functions as the other machines to implement that functionality.
I suggest you take a look at arch/mips64/sgi-ip27/ip27-memory.c for
a simple example how to use this interface.

  Ralf