See this in the documentation The returned virtual address is a current CPU mapping for the memory address given. It is only valid to use this function on addresses that have a kernel mapping
This function does not handle bus mappings for DMA transfers. In almost all conceivable cases a device driver should not be using this function Nobin On 7/11/07, Manu Abraham <[EMAIL PROTECTED]> wrote:
On 7/11/07, Nobin Mathew <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]> wrote: > > On 7/10/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> 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 > > >
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