[U-Boot] [PATCH v3] dfu: Introduction of the "dfu_hash_algo" env variable for checksum method setting

Wolfgang Denk
2014-05-15T14:07:50Z

Dear Lukasz,

In message <20140515154334.626923b4@amdc2363> you wrote:
>
> > This reinforces my speculation that you are actually addressing the
> > wrong problem. Instead of adding new code and environment variables
> > and making the system even more complex, we should just leave
> > everything as is,
>
> During working on this patch I've replaced the crc32() method with the
> call to hash_method(), which IMHO is welcome.

Yes, indeed this is highly welcome. Thanks a lot for that!

> I also don't personally like the crc32, hence I like the choice which
> this patch gives me to use other algorithm (for which I've got HW
> support on my platform - e.g. MD5).

Well, is this really useful? dfu-utils provides only CRC caculation,
so where would you get the reference value for any other checksum metod
from?

> > and you should try to find out why the CRC
> > calculation is so low for you. Checking if caches are enabled is
> > probably among the things that should be done first.
>
> L1 is enabled. L2 has been disabled on purpose (power consumption
> reduction).

This certainly contributes to slow code execution.

> Please note that the last revision of DFU is from 2004. I've contacted
> Greg KH (one of the original authors) and he replied that no new attempt
> to revise the standard was made.

This may just mean that users were just happy with the current
situation. It's definitely better than if changed had been proposed
but rejected.

> The best however, would be to revise the standard to include such
> functionality to it. In the same time I'm fully aware that this is
> very unlikely to happen.

Why do you think it is unlikely? Of course, it would require that
someone comes up with such a proposal in the first place. But you
sound as if you were certain a proposal had no chance for being
considered. I may be naive, but should we not at least try before
giving up?

Best regards,

Wolfgang Denk

--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
God may be subtle, but He isn't plain mean. - Albert Einstein