[U-Boot-Users] U-Boot on MPC8280

[Wolfgang Denk]

Dear Matias,

in message <37FB7AA6F5F9814FB634A7BF4C35A6F501213D91 at ESEALNT442.al.sw.ericsson.se> you wrote:
> 
> Do you think that the Windriver equipment ( e.g. VisionPROBE ) is of low quality?

First of all I have to point out that I  don't  have  any  first-hand
experience  with  the  Vision*  tools.  My  statement is based on the
collected reports of users of these tools for  PPCBoot,  U-Boot,  and
Linux debugging.

If you search the mailing list you will find many reports from people
who ran into problems using the Vision* tools. With U-Boot there  are
two typical problems: getting the images loaded on the target system,
and debugging after relocation to RAM.

I don't think it is low quality. Actually I think the tools are  high
quality, but they are somewhat limited in operation.


> When looking at the demos, they have been looking a bit sharper
> than e.g. the BDI2000.

The main difference is that the BDI2000 is just  a  debug  interface,
and  the  quality  of  the total system depends on the quality of the
debugger frontend. If you are used  to  working  with  GDB  /  DDD  /
Insight etc. this is all you need.

The Vision* tools provide a complex solution, with some  restrictions
(please correct me if I'm wrong):

* The tools seem to have problems understanding and  loading  certain
  image  formats;  obviously  you cannot simply use a binary image to
  avoid all interpretation of internal data structures, and  the  ELF
  loader  loads  only  the  segments  it knows about (which may cause
  problems with certain Linux images),

* The tools are limited in the way how they support  the  MMU.  AFAIK
  only  a  static  mapping  is  supported, which is not sufficient to
  really debug a system like  Linux  where  you  have  to  deal  with
  dynamic  page tables, dynamically loaded device drivers and modules
  etc.

Maybe the BDI2000 is not as fancy to use, but  at  least  it  does  a
solid job in these areas, and simply works.

Other things to keep in mind:

* I have been told that the price for the Linux version of the  tools
  is  significantly  higher  (2  x  ?)  than the windoze version. The
  BDI2000 in contrast is not only cheaper, but also  OS  independend:
  it will run on any system where you find a GDB.

* Note that you can buy firmware versions of  the  BDI2000  for  most
  well-known debuggers, which might give you the same "sharp look" as
  Vision*  -  but  I  never used any such tools (because usually they
  will cost a lot of $$ and run only  under  Windoze  which  I  don;t
  touch).


Hope this helps.

Best regards,

Wolfgang Denk

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