[Skiboot] [PATCH V2 5/7] hmi: Rework HMI event handling of FIR read failure

[Russell Currey]

On Mon, 2016-03-21 at 12:29 +1100, Andrew Donnellan wrote:
> On 21/03/16 12:00, Russell Currey wrote:
> > 
> > If reading the FIR with XSCOM failed, the existing code would not raise
> > a HMI under the assumption that the CPU was asleep and nothing is
> > wrong.
> > Now that it is possible to check whether or not the CPU was asleep,
> > raise an unrecoverable HMI if the read failed for other reasons, and
> > skip the CPU if it was asleep.
> > 
> > If the CPU is asleep when it's not meant to be and that is the cause of
> > the HMI, an unrecoverable "catchall" HMI will be raised since no other
> > components will claim responsibility for it.
> > 
> > Signed-off-by: Russell Currey <ruscur at russell.cc>
> > ---
> > V2: Raise HMI on XSCOM fail for non-sleep reasons, completely reword
> > ---
> >   core/hmi.c | 19 +++++++++++++++++--
> >   1 file changed, 17 insertions(+), 2 deletions(-)
> > 
> > diff --git a/core/hmi.c b/core/hmi.c
> > index 127686f..71fdf48 100644
> > --- a/core/hmi.c
> > +++ b/core/hmi.c
> > @@ -299,6 +299,7 @@ static bool decode_core_fir(struct cpu_thread *cpu,
> >   	uint32_t core_id;
> >   	int i;
> >   	bool found = false;
> > +	int64_t ret;
> As per comment on patch 1, should this just be "int" to match the 
> declaration of xscom_read()?
> 
I used int64_t since xscom_read is an OPAL call, and since it returns OPAL
return codes which are defined as int64_t.  I do agree since it's being
used as an internal API even though it's external too, I can change it if I
spin up a v3.  I don't think it's a big deal though.
> > 
> > 
> >   	/* Sanity check */
> >   	if (!cpu || !hmi_evt)
> > @@ -307,9 +308,23 @@ static bool decode_core_fir(struct cpu_thread
> > *cpu,
> >   	core_id = pir_to_core_id(cpu->pir);
> > 
> >   	/* Get CORE FIR register value. */
> > -	if (xscom_read(cpu->chip_id, XSCOM_ADDR_P8_EX(core_id,
> > CORE_FIR),
> > -							&core_fir) !=
> > 0) {
> > +	ret = xscom_read(cpu->chip_id, XSCOM_ADDR_P8_EX(core_id,
> > CORE_FIR),
> > +			 &core_fir);
> > +
> > +	if (ret == OPAL_HARDWARE) {
> >   		prerror("HMI: XSCOM error reading CORE FIR\n");
> > +		/* If the FIR can't be read, we should checkstop. */
> > +		return true;
> > +	} else if (ret == OPAL_WRONG_STATE) {
> > +		/*
> > +		 * CPU is asleep, so it probably didn't cause the
> > checkstop.
> > +		 * If no other HMI cause is found a "catchall"
> > checkstop
> > +		 * will be raised, so if this CPU should've been awake
> > the
> > +		 * error will be handled appropriately.
> > +		 */
> > +		prlog(PR_DEBUG,
> > +		      "HMI: FIR read failed, chip %d core %d
> > asleep\n",
> > +		      cpu->chip_id, core_id);
> >   		return false;
> >   	}
> > 
> > 
> Rest doesn't look bad.
>