Can we map a device address to two different memory locations?

[anish singh]

On Fri, May 27, 2011 at 10:54 PM, Mulyadi Santosa <mulyadi.santosa at gmail.com
> wrote:

> Hi...
>
> On Fri, May 27, 2011 at 17:49, sandeep kumar <coolsandyforyou at gmail.com>
> wrote:
> > Now the question is can we memory map a one device resource(say some
> > iomemory) to two different memory locations?
> > the other way of seeing at this question is,
> > Will ioremap() gives different 'virtual addresses' when called multiple
> > times?
>
> I agree with Daniel, but I suggest you to think about it: in reading
> operation, maybe it's ok, no concurrency issues need to be taken
> care...but how about writing? unless we're sure they are atomically or
> uninterruptible, i see a chance that race condition might happen here.
>
> Actually it's similar when you map a file into two different VMA and
> write into it, correct?
>
Don't you think it would also be reducing the memory map space in RAM
which is a critical resource and many other drivers would be denied
the mapping of there IO resources?
--
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

>
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