On 14/02/19 17:51, Marc Zyngier wrote: > On 14/02/2019 15:44, Roger Quadros wrote: >> On 14/02/19 14:52, Marc Zyngier wrote: >>> On Thu, 14 Feb 2019 10:55:10 +0000, >>> Roger Quadros <rogerq@xxxxxx> wrote: >>>> >>>> >>>> On 14/02/19 10:37, Linus Walleij wrote: >>>>> On Thu, Feb 14, 2019 at 4:13 AM Suman Anna <s-anna@xxxxxx> wrote: >>>>>> [Me] >>>>> >>>>>>> To be able to use hierarchical interrupt domain in the kernel, the top >>>>>>> interrupt controller must use the hierarchical (v2) irqdomain, so >>>>>>> if this is anything else than the ARM GIC it will be an interesting >>>>>>> undertaking to handle this. >>>>>> >>>>>> These are interrupt lines coming towards the host processor running >>>>>> Linux and are directly connected to the ARM GIC. This INTC module is >>>>>> actually an PRUSS internal interrupt controller that can take in 64 (on >>>>>> most SoCs) external events/interrupt sources and multiplexing them >>>>>> through two layers of many-to-one events-to-intr channels & >>>>>> intr-channels-to-host interrupts. Couple of the host interrupts go to >>>>>> the PRU cores themselves while the remaining ones come out of the IP to >>>>>> connect to other GICs in the SoC. >>>>> >>>>> If the muxing is static (like set up once at probe) so that while >>>>> the system is running, there is one and one only event mapped to >>>>> the GIC from the component below it, then it is hierarchical. >>>> >>>> This is how it looks. >>>> >>>> [GIC]<---8---[INTC]<---64---[events from peripherals] >>>> >>>> The 8 interrupt lines from INTC to the GIC are 1:1 mapped and fixed >>>> per SoC. The muxing between 64 inputs to INTC and its 8 outputs are >>>> programmable and might not necessarily be static per boot/probe as >>>> it depends on what firmware is loaded on the PRU. >>> >>> But the point is that at any given time, there are at most 8 out of 64 >>> inputs that are used, right? You *never* end-up with two (or more) of >>> these "events" being multiplexed on a single output line. >>> >> >> Since the INTC's internal logic allows assigning more than one event each outputs, >> at most all 64 events can be assigned to one output or distributed among the 8 outputs. > > OK. Do you get individual masking and status bits for each input? Yes, we have individual enable/disable and status bits for each of the 64 events. In addition to that it is possible to determine priority if multiple events come to the same output by reading a register specific to that output. -- cheers, -roger Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
