the concept of "remap" is to map again, thus, if u call ioremap() multiple times, u will just remove the previous mapping setup. This is implied in the source for ioremap() - delved down all the way to where the PTE is setup. the reason for this is because the MMU translation process is hardware-based - each page table can only map from one physical memory to another virtual memory, based on the PTE values. but it is possible to have same physical address mapping to the different virtual address - but definitely not for kernel virtual address, (which thus eliminate IO addresses) - the page tables have to be different. this is because all kernel virtual addresses share the same page table. more info: http://www.kernel.org/doc/gorman/html/understand/understand006.html On Fri, May 27, 2011 at 6:49 PM, sandeep kumar <coolsandyforyou@xxxxxxxxx> wrote: > Hi all, > Memory mapping is done so that CPU can access the devices, which it cant > unless. > > 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? > > Please give reply.. > > -- > With regards, > Sandeep Kumar Anantapalli, > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > -- Regards, Peter Teoh _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
