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

[Mulyadi Santosa]

On Sat, May 28, 2011 at 00:48, anish singh <anish198519851985 at gmail.com> wrote:
>
>
> 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?

Yeah, I agree too

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

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