Messages in this thread | | | Subject | Re: Opinion on ordering of writel vs. stores to RAM | From | Benjamin Herrenschmidt <> | Date | Mon, 11 Sep 2006 11:04:04 +1000 |
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> If we go this route though, can I request that we don't introduce any > performance regressions in drivers currently using mmiowb()? I.e. > they'll be converted over to the new accessor routines when they become > available along with the new barrier macros?
There are few enough of them, I've grep'ed, so that should be doable. The segher mentioned in favor of his approach (option B -> ioremap flags) that doing a test in writeX/readX is very cheap compared to the cost of IOs in general and would make driver conversion easier: you don't have to change a single occurence of writel/readl : just add the necessary barriers and change the ioremap call. Thus I tend to agree that his approach makes it easier from a driver writer point of view.
Now, I don't have a strong preference myself, which is why I asked for a vote here. So far, I could your vote for A :)
Ben.
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