Driver / PCI address remapping.

Hi - I am trying to write a new driver for a DT303. I have a PCI query
that I hope someone can give me a relatively quick answer and save me
some time.

The driver does not use any interrupts and communicates via the PCI
address space. In common with other drivers I use pci_resource_start()
to get the phys_io_base. (Incidentally this gives a value of 0xf700 0000
which matches the base obtained from cat /proc/pci). Usually the ioremap
function is used after this to get a remapped address - Why is this? for
example the remapped address is 0xf884 5000. Why use the remapped
address when the card thinks its at the physical base? I've used
pcitweak to examine the PCI settings and the base address register 0 is
set to the physical address.

I'm currently trying to get basic DIO functionality working and the
messages are not getting through so I'm obviously using the wrong
mapping.

Any ideas appreciated.

Regards

John Openshaw



-- 
John Openshaw

Received on 2004-01-05Z14:15:23