[U-Boot] SPL Dfu update

[Otavio Salvador]

Hello Michael,

On Wed, Oct 30, 2013 at 6:35 PM, Michael Trimarchi
<michael at amarulasolutions.com> wrote:
> On Wed, Oct 30, 2013 at 9:11 PM, Wolfgang Denk <wd at denx.de> wrote:
>> Dear Michael Trimarchi,
>>
>> In message <CAOf5uw=hCkwPaqogCO3KvM1erhS-dvC5BRT4USU3uqKETtTQ7A at mail.gmail.com> you wrote:
>>>
>>> > This does not answer Stefano's question: why do it in SPL, what's
>>> > wrong with loading the real U-Boot for this purpose?
>>>
>>> Because it's not possible, internal memory size of some cpus. You need
>>> to have a way to load the second stage and I'm discussing a general
>>> way to do.
>>
>> I'm not sure that there are many use cases where you have sufficient
>> room for all that is needed for DFU (including I/O buffers); and if
>> you move to RAM early, you have other options as well.
>>
>
> No because you need anyway to have a way to load it and dfu is a way.
>
>>> What is your alternative way?
>>
>> Depending on your hardware there is a zillion ways to do this.  For
>> low to medium volumes good old JTAG is still a very powerful tool; for
>> high volumes you will probably just fit pre-programmed NAND on your
>> board.  And of course there is the growing number of systems that can
>> just boot and install from a SDCard or USB MSD.
>>
>
> I accept the lesson even I don't thing that I need a lesson on it. We
> are talking that we have only otg.

I see your user-case and I think I agree with you.

> BTW Forget about it.

Please don't. I think it is a valuable contribution and I think it is
good to have a mechanism which work for your user-case in U-Boot; it
is easy to maintain long term and avoid duplication of work in case
users has some problem.

I got a little bit lost when Tom gave an example where he 'loads' MLO
and U-Boot image from OTG; just clarify it for me as it is not clear
if it works for you or does not.