Re: Boot loader woes

VG wrote:

A new boot loader that I built off a legacy code that I inherited is
giving me a lot of trouble. The BSP, code base has been in use for
production for several years. Recently there was a requirement to
upgrade RAM in one of our products. All these years it was 16 MB; now
it is 32 MB. That's the only change in hardware.

Tornado: 2.0.2
VxWorks: 5.4
Processor: MPC8241

This is my first brush with PowerPC architecture. And none of the
engineers who actually wrote/ported the BSP is with the company any
more. I just opened the project/workspace in Tornado, changed the
memory size macro and the RAM high address in config.h and project
parameters, that's it. The boot loader just does not start at all.
There is no activity on the serial console the moment I power my board
on. These are the old and new memory macros' values:

LOCAL_MEM_LOCAL_ADRS: 0x0 (no change)
LOCAL_MEM_SIZE: 0x1000000 (changed to 0x2000000)
RAM_LOW_ADRS: 0xA00000 (no change)
RAM_HIGH_ADRS: 0xE00000 (changed to 0x1F00000)
RAM_DST_ADRS: 0xA00000 (no change)
RAM_DATA_ADRS: 0xD00000 (no change)

First, I wonder if it's okay to have RAM_DATA_ADRS different from
RAM_HIGH_ADRS! Is this acceptable? Ours is a compressed boot loader.
Seems the boot loader has problem with the memory size. If I change
the LOCAL_MEM_SIZE back to 0x1000000, even with new RAM_HIGH_ADRS, if
works perfectly fine.

Could someone please provide me any clue as to what could be
happening? Has it anything to do with all those PPC's MMU, cache, etc?
Should I start looking at the romInit.s code and see how things are
being done there and probably change something there? Thanks.

I see a couple of things that may be causing your problems.

First, the value of RAM_HIGH_ADRS must be defined identically in both
the BSP's config.h and Makfile files and you didn't include Makefile
in the list of files you changed.

The second is that LOCAL_MEM_SIZE - RAM_HIGH_ADRS used to be 0x200000
and now it is 0x100000. This may not be enough room for the boot
loader image in RAM.

--
========================================================================
Michael Kesti | "And like, one and one don't make
| two, one and one make one."
mrkesti at hotmail dot com | - The Who, Bargain
.

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