fixed DTML id. On 14/02/19 17:44, 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. > >> If these assertions do hold, then your design is typical of a >> hierarchy, for which we have countless examples in the tree (including >> for some TI HW). > > OK. > Suman, Andrew, Lokesh, thoughts? > -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
