Re: PPC beginner questions

On 8/21/06, Wade Maxfield [off-list ref] 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?

ioremap

   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.
g.

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