[U-Boot] [PATCHv3 2/3] driver/ddr/altera/: Add the sdram calibration portion

Wolfgang Denk
2015-05-25T13:23:58Z

Dear Pavel,

In message <20150525123750.GD9943@amd> you wrote:
>
> > + ** All global variables that are explicitly initialized (including **
> > + ** explicitly initialized to zero), are only initialized once, during **
> > + ** configuration time, and not again on reset. This means that they **
> > + ** preserve their current contents across resets, which is needed for some **
> > + ** special cases involving communication with external modules. In **
> > + ** addition, this avoids paying the price to have the memory initialized, **
> > + ** even for zeroed data, provided it is explicitly set to zero in the code, **
> > + ** and doesn't rely on implicit initialization. **
> > + ******************************************************************************
> > +
>
> Is this sane thing to do? How does it work for variables in other
> sources?

My concern is if this is actually true (and I asked this before, in an
earlier round ov reviews). I cannot make heads or tails of this
comment, as I don't understand what "configuration time" and "reset"
are supposed to mean in U-Boot context. In my understanding, after a
reset the memory content is uninitialized, i. e. random, and thus MUST
always be properly initialized.

Also, what are "external modules"?

Best regards,

Wolfgang Denk

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