[U-Boot-Users] U-boot - odd errors in memsetup

[Wolfgang Denk]

Dear David,

in message <3551A602-F519-11D8-84C7-000393C7979E at student.unsw.edu.au> you wrote:
> 
> > What has the disassembly to do with the values read by the processor?
> > It may be what you _want_ to be read by the  CPU,  but  what  do  you
> > actually see on your data bus?
> 
> The disassembly is derived from the code which was read from the flash. 
> (e.g. Multi-ICE downloads the data from flash, runs it through a 
> disassembler, and displays it as you step through). In order to get the 
> correct disassembly, the correct code has to be in flash.

But again, this is just what the Multi-ICE is telling you. And I  bet
it  accesses  the  flash memory in a different way than the processor
when fetching instructions.

> > Timing, for example. Also it may use bursts to fetch  the  data  into
> > cache. Depends on your configuration and system setup which you don't
> > bother to share with us.
> 
> This is all before the flash timings have been configured, so its using 
> the PXA255's reset values, which are all the slowest as I understand it 
> (and non-burst). I am using two Intel 28F320B3 (Advanced boot block 
> flash memory) chips configured as a single 32-bit wide bank.

Well, attach a logic analyzer and verify which data are actually seen
on the bus.

> > And do you really expect that we check this without  any  explanation
> > what  it  wwas  derived  from,  what  you  changed and why, what your
> > hardware is looking like etc.?
> 
> > I stopped looking when I saw that your changes  violate  the  Codiing
> > Style requirements as specified in the README.
> >
> > You're sending 40kB of trash to the list, and expect that we solve  a
> > problem for you without being given any relevant data?
> 
> > Sorry, this is not the way it works.
> 
> You've asked for two contradicting qualities -- a small email along 
> with all the possible relevant data. I provided what I thought was the 
> relevant data, and specifically asked if I had got it right (which I 
> guess I didn't).

No. The data you sent was not relevant, and not usable.

If you think that the memset code was critical, you could have simply
referred to a known version and provided a diff against the  file  in
the  CVS  tree.  No need to send 500 lines of source when 22 lines of
diff will do as well.

> Thankyou for your thoughts. I'll try to do it better next time. If 
> you've got any ideas regarding the problem, it would be much 
> appreciated. Is it possible that the PXA could be reading the flash in 
> burst-mode at startup?

See above. Attach a logic analyzer and check what's going on  on  the
bus.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Knowledge, sir, should be free to all!
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