PPC beginner questions

Grant Likely grant.likely at secretlab.ca
Tue Aug 22 00:14:36 EST 2006

On 8/21/06, Wade Maxfield <wmaxfield at gmail.com> wrote:
>   We are using Xilinx with PPC built in.
>    The PPC has a memory management unit.  All of the IP we've added is
> mapped to physical addresses.
>    1. Can I access the memory the peripherasl are mapped to directly within
> the driver without going through functions?

No, you need to map them into virtual memory, then you can use the in*
out* functions to read/write.  (You can also directly use the virtual
addresses as pointers, but in*/out* is more portable)

>        if NOT, then Do I use
>           1. ioremap(),
>           2. request_mem_region(),
>           3. request_region()
>           4. something else?


>    2.  Are there any gotcha's with the ppc 405 that Xilinx uses that I
> should know about?

Yes, lots.  :)

Actually it's pretty straight forward.  Mainline Linux 2.6 contains
support for both the Virtex-II Pro and the Virtex 4, but not a lot of
device drivers.  The MontaVista 2.4 tree is supported by Xilinx with
drivers, but then you have to use linux 2.4.  :p

Also, it's a good idea to read the Xilinx errata.

have fun.

Grant Likely, B.Sc. P.Eng.
Secret Lab Technologies Ltd.
grant.likely at secretlab.ca
(403) 399-0195

More information about the Linuxppc-embedded mailing list