Re: [PATCH v4 10/11] drivers: perf: hisi: Handle counter overflow IRQ in MN PMU

[Anurup M]

On Friday 24 February 2017 08:34 AM, Anurup M wrote:
> > > > > +static int hisi_mn_init_irqs_fdt(struct device *dev,
> > > > > +                struct hisi_pmu *mn_pmu)
> > > > > +{
> > > > > +    struct hisi_mn_data *mn_data = mn_pmu->hwmod_data;
> > > > > +    struct hisi_djtag_client *client = mn_data->client;
> > > > > +    int irq = -1, num_irqs, i;
> > > > > +
> > > > > +    num_irqs = of_irq_count(dev->of_node);
> > > > Surely we expect a specific number of interrupts?
> > > >
> > > > > +    for (i = 0; i < num_irqs; i++) {
> > > > > +        irq = of_irq_get(dev->of_node, i);
> > > > > +        if (irq < 0)
> > > > > +            dev_info(dev, "No IRQ resource!\n");
> > > > > +    }
> > > > Why are we throwing these away?
> > > >
> > > > > +
> > > > > +    if (irq < 0)
> > > > > +        return 0;
> > > > > +
> > > > > +    /* The last entry in the IRQ list to be chosen
> > > > > +     * This is as per mbigen-v2 IRQ mapping
> > > > > +     */
> > > > > +    return hisi_mn_init_irq(irq, mn_pmu, client);
> > > > I don't understand this comment.
> > > >
> > > > Why do we only use the list IRQ?
> > > >
> > > > What does this have to do with the mbigen?
> > > >
> > > > No ordering requirement was described in the DT binding.
> > > There is a defect in the mbigen hardware to handle the IRQ mapping
> > > for MN.
> > > Due to this the IRQ property
> > > of MN is made as a list and we read all IRQs and use only the last one.
> > > I shall mention it in the comment and also add note in the DT bindings.
> > You'll need to elaborate on that a bit further; I don't understand.
> >
> > If the interrupts aren't usable, there's arguably not much point listing
> > them in the DT.
> >
> > Regardless, the order of the list *must* be specified in the DT binding.
>
> I'm sorry for creating this confusion. It was a wrong workaround due 
> to my misunderstanding of the
> IRQ mapping.
> The MN will use a single IRQ for overflow in HiP07. I shall update it 
> and resend.
> But in HiP05/06 there is no support for this IRQ, So I shall modify to 
> use polling when IRQ is not available.

On further tests it is confirmed that the MN interrupt line is broken in 
hardware. so the driver
will only use poll method. I shall remove the IRQ support and resubmit 
adding poll method.

Thanks,
Anurup

> Thanks,
> Anurup
>
> > Thanks,
> > Mark.