[PATCH V2 2/5] arm: mvebu: Added initial support for power managmement service unit

Will Deacon will.deacon at arm.com
Wed Nov 14 20:46:40 EST 2012


On Wed, Nov 14, 2012 at 12:07:36AM +0000, Russell King - ARM Linux wrote:
> On Mon, Nov 05, 2012 at 02:05:58PM +0000, Will Deacon wrote:
> > On Mon, Oct 29, 2012 at 09:11:45PM +0000, Gregory CLEMENT wrote:
> > > +	/* Make sure value hits memory before reset */
> > > +	dsb();
> > 
> > writel has barrier semantics -- you shouldn't need this dsb.
> 
> writel has a barrier before the write (to ensure that DMA agents see data
> that was written to memory when they are enabled by the write).  There
> isn't a barrier after the write.

Indeed, but there's a following write to actually do the reset, so the dsb
should come from there.

Will



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