[PATCH v3 08/10] ARM: mxs: add ocotp read function
jamie at jamieiles.com
Wed Jan 5 12:25:01 EST 2011
On Wed, Jan 05, 2011 at 05:44:09PM +0100, Uwe Kleine-König wrote:
> Hello Jamie,
> On Wed, Jan 05, 2011 at 04:16:46PM +0000, Jamie Iles wrote:
> > On Wed, Jan 05, 2011 at 10:07:35PM +0800, Shawn Guo wrote:
> > > + /* check both BUSY and ERROR cleared */
> > > + while ((__raw_readl(ocotp_base) &
> > > + (BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR)) && --timeout)
> > > + /* nothing */;
> > Is it worth using cpu_relax() in these polling loops?
> I don't know what cpu_relax does for other platforms, but on ARM it's
> just a memory barrier which AFAICT doesn't help here at all (which
> doesn't need to be correct). Why do you think it would be better?
Well I don't see that there's anything broken without cpu_relax() but
using cpu_relax() seems to be the most common way of doing busy polling
loops that I've seen. It's also a bit easier to read than a comment and
semi-colon. Perhaps it's just personal preference.
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