In principle, ioremap() will return 0x00000000 if the physical address passed is of memory. I just want you to double check the address you have passed to ioremap(). In my experiment on x86 Desktop machine with 2GB RAM. I passed a physical address 0x63ACD000. As expected it returned 0x00000000. I am running linux version 3.5.1.
Regards, Prabhunath G Linux Trainer Bangalore On Fri, Mar 1, 2013 at 5:57 PM, sandeep kumar <[email protected]>wrote: > >Looks like you are trying to pass the address of physical memory to this > function as a parameter and it is screwing up. > Yes, i intentionally gave some physical address which is part of system > memory. > My problem infact is, it is not screwing up. It is allowing me to do that. > Its not 'panic'ing > > > On Fri, Mar 1, 2013 at 4:58 PM, Prabhu nath <[email protected]> wrote: > >> >> >> On Fri, Mar 1, 2013 at 4:48 PM, sandeep kumar >> <[email protected]>wrote: >> >>> Hi All >>> I am using ARM based board. >>> In mine, >>> i did the following... >>> >>> void __iomem *tcpm_base = ioremap_nocache(0x03B00000, 10*SZ_3MB); >>> >>> Actually i didnt reserve the 30MB memory @ 0x3B00000. But still the call >>> is succesful and i am able to read the memory. >>> >>> In the logs it is just showing a warning, to fix my driver as i am >>> calling ioremap() on system memory. >>> >>> However if i try to write something on that memory, then only it is >>> calling panic().. >>> >>> Don't you think it should throw panic()while calling the ioremap() >>> itself. Because this sounds like a serious violation... >>> >>> What say? >>> >> >> To my knowledge, ioremap is used only to map the device related physical >> address to kernel virtual address. i.e. this function will only map either >> device registers or device memory to kernel virtual address. >> >> Looks like you are trying to pass the address of physical memory to this >> function as a parameter and it is screwing up. >> >> Please verify. >> >> Regards, >> Prabhu >> >> -- >>> With regards, >>> Sandeep Kumar Anantapalli, >>> >>> _______________________________________________ >>> Kernelnewbies mailing list >>> [email protected] >>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >>> >>> >> > > > -- > With regards, > Sandeep Kumar Anantapalli, >
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