Re: Reading a physical memory location

From: Manu Abraham
Date: Wed Jul 11 2007 - 04:25:46 EST


On 7/11/07, Nobin Mathew <nobin.mathew@xxxxxxxxx> wrote:
Which is your platform ?

Which processor?

If you want to use physical address directly, then disable MMU. That
is not possible in linux.

ioremap does map io memory using phys_to_virt
I thought phys_to_virt was enough to remap physical memory to virtual
http://mirror.linux.org.au/linux.conf.au/2005/cdrom-beta-1/linux-mandocs-2.6.12.6/phys_to_virt.html




Nobin

On 7/11/07, Manu Abraham <abraham.manu@xxxxxxxxx> wrote:
> On 7/10/07, vraghavan3@xxxxxxxxxxxxxxx <vraghavan3@xxxxxxxxxxxxxxx> wrote:
> >
> > Thanks for the quick reply. But I was wondering as to why I would have to map
> > the physical address to the virtual address when I know that the string is
> > permanently in the physical memory because its loaded into flash. Is there a way
> > to directly read from the physical memory location? Also, do the functions
> > ioremap() and readl(va) work when called from within a kernel module?
> >
>
> Of course, if you look at almost any of the memory mapped device
> drivers, you will find that ioremap/readl/writel is the backbone of
> your infrastructure.
>
>
> Manu
>

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/