[U-Boot] [PATCH] arm: Kirkwood: Add memory barriers to kwgbe_send/recv

[Wolfgang Denk]

Dear Simon Kagstrom,

In message <20090702084702.3e4ecae4 at marrow.netinsight.se> you wrote:
> On Wed, 1 Jul 2009 09:57:10 -0700
> Prafulla Wadaskar <prafulla at marvell.com> wrote:
> > > kwgbe_send/recv both have loops waiting for the hardware to 
> > > set  a bit.
> > > GCC 4.3.3 cleverly optimizes this to ... a while(1); loop.
> > Struct used is defined as volatile here.
> > Is this not sufficient?
> 
> Right, but that was only for recv - send isn't volatile. I'll send a
> new patch with the required changes. The question is which :-):
> 
> 1. Make structure volatile in send as well
> 
> 2. Use readl() where needed
> 
> 3. Keep the memory barrier approach (and maybe add a mb() macro to arm
>    as well)
> 
> I'm happy to get suggestions!

There is a pretty clear policy in U-Boot now: please always use
accessor functions.

Best regards,

Wolfgang Denk

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