ppc_sys.c with platform device model or create opb bus?

ppc_sys.c with platform device model or create opb bus?

[Yasushi SHOJI]

Hi all,

I've been reading some posts regarding to the transition of OCP to
platform device mode while searching for a good way to implement a
device driver for our fpga base platform. And now I have one question
regarding to ppc_sys.c

  should I use ppc_sys_*() for platform like fpga?

since I'm working on FPGA base platform, ppc_sys_spec seems to be too
static. that is, IMHO, having static array of device list isn't ideal
for a dynamic system like fpga.

I feel that the ppc_sys_spec is for SoC, which doesn't dynamically
change the peripherals it has.  otoh, fpga based platform can have
arbitrary number of devices if you configured so.

I usually implement a device with PLB or OPB.  for those bus, should I
use platform device model or create new buses for each?

regards,
--
        yashi

Re: ppc_sys.c with platform device model or create opb bus?

[Matt Porter]

On Sun, Jul 17, 2005 at 03:26:21PM +0900, Yasushi SHOJI wrote:
> Hi all,
> 
> I've been reading some posts regarding to the transition of OCP to
> platform device mode while searching for a good way to implement a
> device driver for our fpga base platform. And now I have one question
> regarding to ppc_sys.c
> 
>   should I use ppc_sys_*() for platform like fpga?
> 
> since I'm working on FPGA base platform, ppc_sys_spec seems to be too
> static. that is, IMHO, having static array of device list isn't ideal
> for a dynamic system like fpga.
> 
> I feel that the ppc_sys_spec is for SoC, which doesn't dynamically
> change the peripherals it has.  otoh, fpga based platform can have
> arbitrary number of devices if you configured so.
> 
> I usually implement a device with PLB or OPB.  for those bus, should I
> use platform device model or create new buses for each?

Use the platform model.  When you run into a case that can't be
handled properly then the platform model should be expanded to handle
it. If you instantiate a "platform device" by configuring the FPGA
from userspace then that's a hotplug event.  The platform model
should be extended to handle hotplug for these kind of cases since
they are pretty common.

-Matt

Re: ppc_sys.c with platform device model or create opb bus?

[Grant Likely]

On 7/17/05, Yasushi SHOJI <yashi@atmark-techno.com> wrote:
> I feel that the ppc_sys_spec is for SoC, which doesn't dynamically
> change the peripherals it has.  otoh, fpga based platform can have
> arbitrary number of devices if you configured so.
>=20
> I usually implement a device with PLB or OPB.  for those bus, should I
> use platform device model or create new buses for each?
ppc_sys is just a convenient wrapper around the platform device model.
 You can safely ignore ppc_sys if your board setup code calls
platform_device_register() for all of your devices directly.

Besides, as ppc moves to the flattened device tree for initializing
the platform bus, the whole ppc_sys stuff will be going away and the
device tree parsing code will call platform_device_* directly.

Cheers,
g.

Need SEC 1.0 Descriptor programmer's guide

[Vikas Aggarwal]

Hi All,
  I am porting a driver for SEC 1.0 on mpc8248(kernel 2.6.10 denx linux)
  Can anyone share with me the link/document on "SEC 1.0 Descriptor's
Programmer guide".

  On freescale's website, I could "ONLY" find the "SEC 2.0 Descriptor's
  programmer guide" at this URL.
  http://www.freescale.com/files/32bit/doc/app_note/AN2755.pdf


-vikas
MS CS Student
SUNY Albany