Dear friends,
I am trying to develop a codec driver (rtlinux driver)
from scratch.
In Viper board (PXA255) physical memory range
0x40000000-0x43FFFFFF is used by the PXA255
peripherals.In that address range
0x40500000-0x405005FC is needed for AC'97 controller
registers. Is this memory range is already mapped to
virtual address space, else How to map this to virtual
address space.
When i tried ioremap() it is giving same virtual
address with different physical address(i tried
ioremap with another driver(same board)with different
physical memory address)
Or if this driver already available for RTLinux Please
sent me.
Nobin Mathew
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Hi,
>
> I am trying to develop a codec driver (rtlinux
> driver) from scratch. In Viper board (PXA255)
> physical memory range 0x40000000-0x43FFFFFF is used
> by the PXA255 peripherals.In that address range
> 0x40500000-0x405005FC is needed for AC'97 controller
> registers. Is this memory range is already mapped to
> virtual address space, else How to map this to
> virtual address space.
>
You have to map this address range using "ioremap()". Data at address returned by ioremap can be accessed by calling readl(), writel() et al
>
> When i tried ioremap() it is giving same virtual
> address with different physical address(i tried
> ioremap with another driver(same board)with different
> physical memory address)
>
Same virtual address can point to different physical addresses depending upon how it is mapped.
Nitin