Hi Phil,
Philip Mason wrote:
I am having trouble accessing the upper half of the RAM connected to my 5272
Coldfire using the 2006/08/03 kernel.
What is the target board?
> I had it working fine by taking the default settings for the
processor and adding the things I needed (like NFS and the various
busybox commands) but when I added enough stuff that the free memory
dropped below 8MB (the chip is 16MB) telnet connectivity would be lost
and I would have to reboot the processor.
I would say from the symptoms it probably wasn't working, you just
hadn't used enough memory to hit the problem yet.
Suspecting that the problem was related the attempting to access the top half
of the memory I wrote a program that output the contents of the memory at
0x20000 which was the start of the kernel binary as expected. I then modified
the program to look at 0x820000 (exactly 8MB later) and discovered that this
showed exactly the same data.
This really sounds like your DRAM setup registers are wrong.
The uClinux kernel does not set these (*), they are setup by
your boot loader. What boot loader do you use?
(*) Exception is if you are running a kernel directly boot/run
from ROM/Flash - but most people don't do this.
Running 'free' showed the total amount of memory to be (16 minus image_size)MB
as I expected and I checked the address lines to the chip (the bank select
lines specifically) which seem to be changing as I would expect (thought I have
not totally ruled out a timing error at this point). I have tried changing the
RAM size (from AUTO to 16) and RAM bus width (from AUTO to 32) but neither of
these worked.
The RAM size config setting just sets the limits of RAM that
the kernel will use - it doesn't setup the DRAM registers.
Therefore I ask if anybody knows of any settings in the kernel that could lead
to the behaviour I am seeing?
You need to check your RAM setup in your boot loader.
Regards
Greg
------------------------------------------------------------------------
Greg Ungerer -- Chief Software Dude EMAIL: [EMAIL PROTECTED]
SnapGear -- a Secure Computing Company PHONE: +61 7 3435 2888
825 Stanley St, FAX: +61 7 3891 3630
Woolloongabba, QLD, 4102, Australia WEB: http://www.SnapGear.com
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