MPIC Timer of U3

Benjamin Herrenschmidt benh at
Fri Jan 23 11:24:32 EST 2004

On Thu, 2004-01-22 at 21:41, Régis Odeyé wrote:
> Hi,
> I'm trying to use the MPIC Timer sub-module of the U3 (host bridge on JS20).

I don't recommend that. I can't tell more at this point, but this
resource may not be available in future revisions of the product.

(Actually, if js20 uses U3H, I'm not sure the timer is still there
at all in this revision even)

> First of all, I did not see any API in the kernel except or the
> definition of MPIC stucture in open_pic_defs.h, so I added a small
> module (dynamically loaded) remapping the mpic structure of the U3
> (through ioremap call).
> The mapping seems to be OK because I read the Vendor Id properly and I'm
> able to read/write to the interruptions part of the MPIC (Source part of
> the MPIC structure).
> But unfortunately, the Timer Frequency and the Timers seem not to be
> programmable (re-read always 0x0).
> Is there anybody who experimented such a behaviour with the MPIC Timer
> of the U3 ?

Hrm... It may just not exist in the U3H version of the cell.


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