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Subject: Re: [PATCH v5 05/10] dt-bindings: irqchip: Introduce TISCI Interrupt
 router bindings
To:     <marc.zyngier@arm.com>, Tony Lindgren <tony@atomide.com>,
        Nishanth Menon <nm@ti.com>,
        Santosh Shilimkar <ssantosh@kernel.org>,
        Rob Herring <robh+dt@kernel.org>, <tglx@linutronix.de>,
        <jason@lakedaemon.net>
CC:     Linux ARM Mailing List <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        Device Tree Mailing List <devicetree@vger.kernel.org>,
        Sekhar Nori <nsekhar@ti.com>, Tero Kristo <t-kristo@ti.com>,
        Peter Ujfalusi <peter.ujfalusi@ti.com>
References: <20190212074237.2875-1-lokeshvutla@ti.com>
 <20190212074237.2875-6-lokeshvutla@ti.com>
From:   Lokesh Vutla <lokeshvutla@ti.com>
Message-ID: <41a9780b-d971-2b20-1ecb-c55852292563@ti.com>
Date:   Sat, 16 Feb 2019 09:00:01 +0530
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Hi Rob,

On 2/12/2019 1:12 PM, Lokesh Vutla wrote:
> Add the DT binding documentation for Interrupt router driver.
> 
> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
> ---
> Changes since v4:
> - None
> 
>  .../interrupt-controller/ti,sci-intr.txt      | 85 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 86 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..4b0ca797fda1
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
> @@ -0,0 +1,85 @@
> +Texas Instruments K3 Interrupt Router
> +=====================================
> +
> +The Interrupt Router (INTR) module provides a mechanism to route 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  |  |----->|  IRQ  |
> +        | 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 Host 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 4.
> +			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.
> +			Fourth cell should be 1 if the irq is coming from
> +			interrupt aggregator else 0.
> +- ti,sci:		Phandle to TI-SCI compatible System controller node.
> +- ti,sci-dst-id:	TISCI device ID of the destination IRQ controller.

Please help me here. As said this is the TISCI device id for the host
interrupt controller. While sending message to the system co-processor
this ID needs to be specified so that the irq route gets discovered and
configured. Atleast with the current design device Ids are not
discoverable. Can you mention what can be improved here? Is there any
such example where a firmware supports querying the deivce ids?

Also do you have any further comments on this patch?

Thanks and regards,
Lokesh

> +- ti,sci-rm-range-girq:	Array of TISCI subtype ids representing the host irqs
> +			assigned to this interrupt router. Each subtype id
> +			corresponds to a range of host irqs.
> +
> +For more details on TISCI IRQ resource management refer:
> +http://downloads.ti.com/tisci/esd/latest/2_tisci_msgs/rm/rm_irq.html
> +
> +Example:
> +--------
> +The following example demonstrates both interrupt router node and the consumer
> +node(main gpio) on the AM654 SoC:
> +
> +main_intr: interrupt-controller0 {
> +	compatible = "ti,sci-intr";
> +	interrupt-controller;
> +	interrupt-parent = <&gic500>;
> +	#interrupt-cells = <4>;
> +	ti,sci = <&dmsc>;
> +	ti,sci-dst-id = <56>;
> +	ti,sci-rm-range-girq = <0x1>;
> +};
> +
> +main_gpio0: gpio@600000 {
> +	...
> +	interrupt-parent = <&main_intr>;
> +	interrupts = <57 256 IRQ_TYPE_EDGE_RISING 0>,
> +			<57 257 IRQ_TYPE_EDGE_RISING 0>,
> +			<57 258 IRQ_TYPE_EDGE_RISING 0>,
> +			<57 259 IRQ_TYPE_EDGE_RISING 0>,
> +			<57 260 IRQ_TYPE_EDGE_RISING 0>,
> +			<57 261 IRQ_TYPE_EDGE_RISING 0>;
> +	...
> +};
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 8c68de3cfd80..c918d9b2ee18 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -15064,6 +15064,7 @@ F:	Documentation/devicetree/bindings/reset/ti,sci-reset.txt
>  F:	Documentation/devicetree/bindings/clock/ti,sci-clk.txt
>  F:	drivers/clk/keystone/sci-clk.c
>  F:	drivers/reset/reset-ti-sci.c
> +F:	Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
>  
>  Texas Instruments ASoC drivers
>  M:	Peter Ujfalusi <peter.ujfalusi@ti.com>
>