On 2020-07-08 08:04, Grzegorz Jaszczyk wrote:
On Sun, 5 Jul 2020 at 22:45, Marc Zyngier <maz@xxxxxxxxxx> wrote:
On 2020-07-05 14:26, Grzegorz Jaszczyk wrote:
> On Sat, 4 Jul 2020 at 11:39, Marc Zyngier <maz@xxxxxxxxxx> wrote:
>>
>> On 2020-07-03 15:28, Grzegorz Jaszczyk wrote:
[...]
>> It still begs the question: if the HW can support both edge and level
>> triggered interrupts, why isn't the driver supporting this diversity?
>> I appreciate that your HW may only have level interrupts so far, but
>> what guarantees that this will forever be true? It would imply a
>> change
>> in the DT binding, which isn't desirable.
>
> Ok, I've got your point. I will try to come up with something later
> on. Probably extending interrupt-cells by one and passing interrupt
> type will be enough for now. Extending this driver to actually support
> it can be handled later if needed. Hope it works for you.
Writing a set_type callback to deal with this should be pretty easy.
Don't delay doing the right thing.
Ok.
[...]
>> >> > + hwirq = hipir & GENMASK(9, 0);
>> >> > + virq = irq_linear_revmap(intc->domain, hwirq);
>> >>
>> >> And this is where I worry. You seems to have a single irqdomain
>> >> for all the muxes. Are you guaranteed that you will have no
>> >> overlap between muxes? And please use irq_find_mapping(), as
>> >> I have top-secret plans to kill irq_linear_revmap().
>> >
>> > Regarding irq_find_mapping - sure.
>> >
>> > Regarding irqdomains:
>> > It is a single irqdomain since the hwirq (system event) can be mapped
>> > to different irq_host (muxes). Patch #6
>> > https://lkml.org/lkml/2020/7/2/616 implements and describes how input
>> > events can be mapped to some output host interrupts through 2 levels
>> > of many-to-one mapping i.e. events to channel mapping and channels to
>> > host interrupts. Mentioned implementation ensures that specific system
>> > event (hwirq) can be mapped through PRUSS specific channel into a
>> > single host interrupt.
>>
>> Patch #6 is a nightmare of its own, and I haven't fully groked it yet.
>> Also, this driver seems to totally ignore the 2-level routing. Where
>> is it set up? map/unmap in this driver do exactly *nothing*, so
>> something somewhere must set it up.
>
> The map/unmap is updated in patch #6 and it deals with those 2-level
> routing setup. Map is responsible for programming the Channel Map
> Registers (CMRx) and Host-Interrupt Map Registers (HMRx) basing on
> provided configuration from the one parsed in the xlate function.
> Unmap undo whatever was done on the map. More details can be found in
> patch #6.
>
> Maybe it would be better to squash patch #6 with this one so it would
> be less confusing. What is your advice?
So am I right in understanding that without patch #6, this driver does
exactly nothing? If so, it has been a waste of review time.
Please split patch #6 so that this driver does something useful
for Linux, without any of the PRU interrupt routing stuff. I want
to see a Linux-only driver that works and doesn't rely on any other
exotic feature.
Patch #6 provides PRU specific 2-level routing setup. This step is
required and it is part of the entire patch-set. Theoretically routing
setup could be done by other platform driver (not irq one) or e.g. by
PRU firmware. In such case this driver would be functional without
patch #6 but I do not think it would be proper.
Then this whole driver is non-functional until the last patch that
comes with the PRU-specific "value-add".
[...]
I am open to any suggestion if there is a better way of handling
2-level routing. I will also appreciate if you could elaborate about
issues that you see with patch #6.
The two level routing has to be part of this (or another) irqchip
driver (specially given that it appears to me like another set of
crossbar). There should only be a *single* binding for all interrupts,
including those targeting the PRU (you seem to have two).
And the non-CPU interrupt code has to be in its own patch, because
it is pretty borderline anyway (I'm still not completely convinced
this is Linux's job).
N,
--
Jazz is not dead. It just smells funny...
