Paul> Linus Torvalds <torvalds@transmeta.com> wrote:
>> readl() is for things that want to look like PCI (ie subsets of PCI
>> like ISA and ISA PnP, or "look-alikes" of PCI like MCA).
Paul> OK, that's indeed useful to know, thanks.
Paul> In your opinion, should there be a guarantee that accesses
Paul> initiated by readl/writel/etc. will not be reordered?
Paul> Alternatively, should device driver writers be required to put
Paul> in an explicit statement (mb() or something similar) when they
Paul> use readl/writel/etc. and want to prevent the accesses being
Paul> reordered?
Now that you bring this up here it might be a good idea to mention
that we (you and I both included) have just been discussing this in a
different forum and there is disagreement between the Alpha and PPC
camps on this one.
My point is that the current implementation expects no protection
against reordering and many current device drivers already deal with
this correctly (I checked the aic7xxx this this morning and I noticed
that it deals with this explicitly, even on the PPC).
Jes
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/