[ECOS] Redboot ROM image using RAM?

[Don Osburn]

Greetings, and I hope this is the correct group this time...

We have a new custom board we are attempting to bring up and are having some
difficulty with Redboot.  Our design is intel IXP425 reference with the
following exceptions.  We are using an IXP420 with an LXT971A PHY attached
to ethernet 0 only.  (The ref design has LXT972A attached to ethernet 0 and
ethernet1 on an IXP425.)

We have successfully burned redboot into flash and can boot.  The problem is
we can not understand where / how to load the snapgear images into flash to
boot linux.

I am using the NPE-enabled binaries for Redboot v2.01.  I use the
redboot_ROM.bin file from the ixdp425 directory and burn it into Intel
strata_flash.  It boots with a warning about NPE A.  Not sure about that
warning, but I can do an fconfig and fis init and everything looks fine.
(The warning may be do to the PHY difference.)

At this point I do a
RedBoot> load -r -v -b 0x01600000 zImage
and it works.  However, when I attempt a
RedBoot> load -r -v -b 0x00800000 ramdisk.gz

The processor hangs.  After poking around in memory for a while, we are
pretty confident that what is happening is redboot is using memory around
0x00800000 to run itself.  So, when we attempt to write to that area in RAM,
we are stomping on the bootloader. (?)  Why is that?  Our understanding was
if you loaded the ROM image, it should not use RAM?

We are having great difficulty understanding the documentation on this.
What is the difference between the ROM and the RAM images?  Also, when we
attempted to burn / load the RAM image, it doesn't work at all.

I have been loading images into an Avila eval board for some time with no
issues, so I am familiar with the process.  However, I have not done any
customization to RedBoot on that board.

Can someone please explain the difference between the ROM and RAM images for
the IXDP425 reference, and hopefully provide some more information on how we
should be using this?  Our hope was to use the IXDP425 reference bootloader
for initial startup, and then customize it later (to reduce memory, etc).
FYI, we have read/reviewed all the Intel app notes, and the RedBoot
websites.  Any help would be appreciated.

Don Osburn
Lead Engineer
Isco International
847-391-9481


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