[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: HELP:(VIPER BOARD)AC'97 controller driver for rtlinux(rtlinux core driver)

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


--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive:       http://mail.nl.linux.org/kernelnewbies/
FAQ:           http://kernelnewbies.org/faq/