[U-Boot] [PATCH v2] mpc83xx: update LCRR register handling

[Detlev Zundel <dzu@denx.de>]

Hi Kim,

> o LCRR_PDYP, granted dangerous in your case, is obviously a writeable
> bit (not read-only), and documented as such in later documentation.  In
> fact, there are no non-writeable bits in LCRR.

Well, "reserved" != "non-writable" (usually there is a comment that
writing reserved bits produces undefined behaviour) so I agree with
Heiko that as long the documentation that we have access to, designates
bits as reserved, it makes sense to have such a mask.

> o the user loses visibility into what is going on if they
> decide to drop/add sensitive bits such as LCRR_DBYP in their board's
> CONFIG_SYS_LCRR settings, and there's a mask lurking in the background.
>
> o let's be practical here - in a board port, LCRR settings have to be
> paid attention to, no matter what hidden behaviours or new bits there
> are lying underneath - perhaps the form of 'protection' you seek is in
> the form of a comment in the code?

So what is it that you propose?  That Heiko uses a LCRR in his board
config (over-)writing reserved bits?

Cheers
  Detlev

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