lkml.org 
[lkml]   [2019]   [Feb]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH v2 01/14] dt-bindings: remoteproc: Add TI PRUSS bindings
    From
    Date
    On 2/14/19 9:48 AM, Roger Quadros wrote:
    > 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@ti.com> wrote:
    >>>>
    >>>>
    >>>> On 14/02/19 10:37, Linus Walleij wrote:
    >>>>> On Thu, Feb 14, 2019 at 4:13 AM Suman Anna <s-anna@ti.com> 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?
    >>

    Mark, Linus,

    So, I hope it is clear from Roger's responses that above assertions do
    not hold true to this INTC, and so want to confirm that we are good with
    the current non-hierarchical design.

    regards
    Suman

    \
     
     \ /
      Last update: 2019-02-15 02:00    [W:3.795 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site