RE: [ECOS] SA11x0 platform port problems

[Gary Thomas <gthomas@cambridge.redhat.com>]

 
On 26-Feb-2001 Nathan J Ickes wrote:
> I'm doing platform ports for two custom boards, one based on the
> SA1110 and one on the SA1100. Both are similar to the Assabet board,
> with the notable exception that they use SRAM (1MB) instead of
> Assabet's SDRAM. I'm having the same problem with RedBoot on both
> boards: on boot, both boards print the following:
> 
> +
> RedBoo
> 
> and then apparently die. Coincidentally (or not), that's a total of
> eight characters (two for the '\n', and not counting '+', which isn't
> part of the printf() call), exactly the length of the hardware
> transmit FIFO in the SA11x0. This makes me suspect I have an interrupt
> problem, except that RedBoot runs fine on my Assabet board, and I
> don't see what's different. It wouldn't surprise me if there was
> another hardcoded reference to the DRAM bank somewhere in there, but I
> haven't found anything. Anybody else seen this sort of problem?
> 

You might be able to determine more about this by putting a huge spin
loop inside of 'cyg_hal_plf_serial_putc()' (in hal/arm/sa11x0/var/current/hal_diag.c),
just to see if it is a timing issue.

BTW, what tools are you using?  Did you build the RedBoot that you
run on the Assabet?

> Where does that '+' character come from? I notice that the Assabet
> board also prints a character before the "\nRedBoot..." string, but on
> that board, the character is non-ASCII. Is this a garbage character
> that's due to the way the serial port is initialized, or is it
> intentional?
> 

The garbage is not intentional, but probably due to the clock switching
code in the startup.  The '+' character is being printed by the GDB stubs
initialization code, BTW.

> Also, I noticed that the ARM vectors.S appears to miscalculate the
> reset vector: the first eight instructions of the _platform_setup1
> macro are skipped. The easy solution is of course to add eight nop
> instructions to the start of the macro, and I notice that the Brutus
> platform port does exactly this. The nops are missing from the Assabet
> port, though, and this makes the board very flaky about booting up. Is
> this miscalculation a feature (if so, for what purpose?), or a bug?

I hadn't heard about this at all and I'm not convinced it may be a tools
problem.  However, I have recently revamped this setup which removes
these problems (no more funny pointers, at least for ROM applications).
I don't know if/when these changes will hit anon CVS though, so if you
need them right away, I might be able to provide them to you in private
email.