Thanks for your reply. Plz see inline On Tue, Jul 10, 2012 at 11:17 AM, Philipp Ittershagen < [email protected]> wrote:
> Hi Prabhu, > > On Tue, Jul 10, 2012 at 6:56 AM, Prabhu nath <[email protected]> > wrote: > > For E.g. I have a device whose physical address range is 0x80008000 to > > 0x80008FFF. > > Is it possible to map this device physical address to a > known > > virtual address range 0xF0008000 to 0xF0008FFF. > > I don't think this is possible, because these virtual address ranges > are handled by the kernel VMA system and are allocated dynamically, so > that is not just a bitmask or something to change. > > > My hardware configuration has 128 MB of system RAM which will have been > > MAPPED to the Kernel virtual address from 0xC0000000 to 0xC7FFFFFF > > > > Also is it possible to configure the vmalloc kernel virtual address > region > > to a fixed range of 128 MB from 0xC8000000 to 0xCFFFFFFF > > You could change PAGE_OFFSET. From [1]: > > > PHYS_OFFSET > Physical start address of the first bank of RAM. > > PAGE_OFFSET > Virtual start address of the first bank of RAM. During the kernel > boot phase, virtual address PAGE_OFFSET will be mapped to physical > address PHYS_OFFSET, along with any other mappings you supply. > This should be the same value as TASK_SIZE. > > > But I'm curious: Why do you want to change it? > Just wanted to have a constant mapping from PA to VA of devices and wanted to have a separate region for vmalloc. > > > Greetings, > > Philipp > > > [1]: http://www.kernelport.org/defines.html >
_______________________________________________ Kernelnewbies mailing list [email protected] http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
