[PATCH 3/9] powerpc/ppc32: Update mpc52xx_psc structure with B revision changes

[Raquel Velasco and Bill Buck]

Sylvain, thanks.

http://bbrv.blogspot.com/2007/05/not-waiting-for-world-to-change-ii.html

Read through the post.  Your effort is being applied to good use.

R&B

On May 14, 2007, at 12:27 AM, Sylvain Munaut wrote:

> Matt Sealey wrote:
>> Would a note next to these new fields be worth it? "5200B only" or
>> "reserved on 5200" or even create a new PSC structure for the old
>> processor and recast it in drivers that really want to support both
>> revisions of the CPU?
>>
> A comment next to them yes, that looks a good idea.
> A new structure certainly not.
>> Real nitpick:
>>
>> Setting the CCR on the MPC5200 (not B) now means you need to left
>> shift your required CCR values by 16 bits before applying them into
>> the field for the desired effect.
>>
>> If you were being lazy and just wanted to set some low-order bits
>> in the CCR on the 5200, with the old structure that's fine. With
>> the new structure, it will be writing into previously reserved
>> space on the 5200. The 5200B might work fine, unless it's a driver
>> someone missed, and is programming a value that should be in the
>> upper 16 bits of the new CCR, in which case now you have to left
>> shift by 16 bits.. :)
> I know about the ccr that's annoying.
> I guess I could make ccr a union and have it contains ccr16 and ccr32.
>
> Note that old driver will still work ... then most likely do
> out_be16(&psc->ccr, ...) and the &psc->ccr address didn't change. They
> will just have a warning because ccr is a u32 so &psc->ccr is a  
> u32* and
> they give it to out_be16 ...
>
>
>     Sylvain
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev at ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev

Raquel and Bill
http://bbrv.blogspot.com