Hi Marc,

On 27/12/18 11:38 AM, Lokesh Vutla wrote:

TI AM65x SoC based on K3 architecture, introduced support for Events
which are message based interrupts with minimal latency. These events
are not compatible with regular interrupts and are valid only through
an event transport lane. An Interrupt Aggregator(INTA) is introduced
to convert these events to interrupts. INTA can also group 64 events
into a single interrupt. Now the SoC has many peripherals and a large
number of event sources (time sync or DMA), the use of events is
completely dependent on a user's specific application, which drives a
need for maximum flexibility in which event sources are used in the
system. It is also completely up to software control as to how the
events are serviced.

Because of the huge flexibility there are certain standard peripherals
(like GPIO etc)where all interrupts cannot be directly corrected to host
interrupt controller. For this purpose, Interrupt Router(INTR) is
introduced in the SoC. INTR just does a classic interrupt redirection.

So the SoC has 3 types of interrupt controllers:
- GIC500
- Interrupt Router
- Interrupt Aggregator

Below is a diagrammatic view of how SoC integration of these interrupt
controllers:(https://pastebin.ubuntu.com/p/9ngV3jdGj2/)

Device Index-x               Device Index-y
           |                         |
           |                         |
                      ....
            \                       /
             \                     /
              \  (global events)  /
          +---------------------------+   +---------+
          |                           |   |         |
          |             INTA          |   |  GPIO   |
          |                           |   |         |
          +---------------------------+   +---------+
                         |   (vint)            |
                         |                     |
                        \|/                    |
          +---------------------------+        |
          |                           |<-------+
          |           INTR            |
          |                           |
          +---------------------------+
                         |
                         |
                        \|/ (gic irq)
          +---------------------------+
          |                           |
          |             GIC           |
          |                           |
          +---------------------------+

Can you please take a look at the MSI changes and provide your feedback? There
are few places(mentioned in the respective patches) where I felt I am hacking
around. It would be really helpful if you give any direction for such hacks.

Thanks and regards,
Lokesh

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