Re: [PATCH v2 1/5] bus: mhi: core: Handle syserr during power_up

[Jeffrey Hugo]

On 4/13/2020 7:34 AM, Manivannan Sadhasivam wrote:
> On Fri, Apr 10, 2020 at 03:39:57PM -0600, Jeffrey Hugo wrote:
> > On 4/10/2020 2:37 PM, Bhaumik Vasav Bhatt wrote:
> > > Hi Jeff,
> > >
> > > We will always have the mhi_intvec_handler registered and trigger your
> > > wake_up state event when you write MHI RESET. BHI INTVEC IRQ using
> > > mhi_cntrl->irq[0] is _not_ unregistered once you enter AMSS EE.
> >
> > I understand it is not unregistered.  However mhi_cntrl->irq[0] may be
> > reserved for BHI, and thus only exercised by PBL EE.  Where as,
> > mhi_cntrl->irq[1..N] may be only exercised by AMSS EE. mhi_intvec_handler is
> > not called in response to mhi_cntrl->irq[1..N].
> >
> > Additionally, I re-reviewed the MHI spec, and I don't see where the spec
> > requires the device to issue an interrupt upon completion of the RESET
> > request.
> >
> > Under section 3.5, step 11 states -
> >
> > "The host must poll for the value of the RESET bit to detect the completion
> > of the reset procedure by the device (RESET is set to 0)."
>
> If this is the scenario then we need to change all of the wait_event_timeout()
> implementation for MHI RESET in current stack to polling.
>
> Or the interrupt generation is not defined in spec (sheet) but part of the
> existing implementation?

It probably could be considered part of the existing implementation, but 
I'd like to hear from Hemant/Bhaumik.  Wherever we end up, I'd like to 
have the spec match.

--
Jeffrey Hugo
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.