[ARM_LINUX] ioremap() allowing to map system memory...

Prabhu nath gprabhunath at gmail.com
Fri Mar 1 06:28:19 EST 2013


On Fri, Mar 1, 2013 at 4:48 PM, sandeep kumar <coolsandyforyou at gmail.com>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,
>
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