Hi Rob, DT maintainers,
On Saturday 06 October 2018 09:59 PM, Nishanth Menon wrote:
On 12:58-20181006, Lokesh Vutla wrote:
Add the DT binding documentation for Interrupt router driver.
Signed-off-by: Lokesh Vutla <lokeshvutla@xxxxxx>
---
.../interrupt-controller/ti,sci-intr.txt | 83 +++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 84 insertions(+)
create mode 100644 Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
diff --git a/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt b/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
new file mode 100644
index 000000000000..681ca53cc5fb
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
@@ -0,0 +1,83 @@
+Texas Instruments K3 Interrupt Router
+=====================================
+
+The Interrupt Router (INTR) module provides a mechanism to mux M
+interrupt inputs to N interrupt outputs, where all M inputs are selectable
+to be driven per N output. There is one register per output (MUXCNTL_N) that
+controls the selection.
+
+
+ Interrupt Router
+ +----------------------+
+ | Inputs Outputs |
+ +-------+ | +------+ |
+ | GPIO |----------->| | irq0 | | Host IRQ
+ +-------+ | +------+ | controller
+ | . +-----+ | +-------+
+ +-------+ | . | 0 | |----->| GIC |
+ | INTA |----------->| . +-----+ | +-------+
+ +-------+ | . . |
+ | +------+ . |
+ | | irqM | +-----+ |
+ | +------+ | N | |
+ | +-----+ |
+ +----------------------+
+
+Configuration of these MUXCNTL_N registers is done by a system controller
+(like the Device Memory and Security Controller on K3 AM654 SoC). System
+controller will keep track of the used and unused registers within the Router.
+Driver should request the system controller to get the range of GIC IRQs
+assigned to the requesting hosts. It is the drivers responsibility to keep
+track of GIC IRQs.
+
+Communication between the host processor running an OS and the system
+controller happens through a protocol called TI System Control Interface
+(TISCI protocol). For more details refer:
+Documentation/devicetree/bindings/arm/keystone/ti,sci.txt
+
+TISCI Interrupt Router Node:
+----------------------------
+- compatible: Must be "ti,sci-intr".
+- interrupt-controller: Identifies the node as an interrupt controller
+- #interrupt-cells: Specifies the number of cells needed to encode an
+ interrupt source. The value should be 3.
+ First cell should contain the TISCI device ID of source
+ Second cell should contain the interrupt source offset
+ within the device
+ Third cell specifies the trigger type as defined
+ in interrupts.txt in this directory.
+- interrupt-parent: phandle of irq parent for TISCI intr. The parent must
+ use the same interrupt-cells format as GIC.
+- ti,sci: Phandle to TI-SCI compatible System controller node.
+- ti,sci-dst-id: TISCI device ID of the destination IRQ controller.
+- ti,sci-rm-range-girq: Tuple corresponding to unique TISCI resource type that
+ defines the dst host irq ranges assigned to this
+ interrupt router from this host context.
+ Tuple should be of format <type subtype>.
+
Rob, DT maintainers,
I'd like a feedback from DT maintainers on this 'range' topic.
TISCI Firmware [1] currently seems to define a type corresponding to a
device ID[2]. in AM6 device, for example, this is different, however
have a 1 to 1 correspondence. However, there is expectation that type will
end up as device ID in a future SoC.
While this is subject to much debate internally, I'd like some feedback if this
is OK from Device tree representation - it is true that Firmware does
look at it as type, however in some future SoC, it could be that the
values themselves may correspond one to one with a device id -> The
original wish was that types might be something reusable across SoCs,
but that is turning out to be more of a theoretical wish than any thing
practical.
[1]http://software-dl.ti.com/tisci/esd/latest/5_soc_doc/am6x/resasg_types.html
[2]http://software-dl.ti.com/tisci/esd/latest/5_soc_doc/am6x/devices.html
Any help on this topic?
Thanks and regards,
Lokesh
