C67x00 USB Host

Hello,
I am currently trying to use the C67x00 driver in the vanilla branch of
Linux. I use it in coprocessor hpi mode (GPIO30 and GPIO31 =0) There is
something that I do not understand in the code.
In the probe() function there is a call to the function hpi_reg_init(). In
this function the interrupts are no more routed from HPI.
Then, in the probe function, the ll_reset() is called, there is a send in
the mailbox, and the response should be an interupt. But I do not receveive
any interrupt. I think it is normal because as I said they are no more
routed from the HPI. So I think I miss something.
Someone could tell me where the interrupt are routed towards HPI ?
Thanks by advance
Adrien