Re: [PATCH v4 2/2] dt-binding:Documents of the mbigen bindings
From: Marc Zyngier
Date: Tue Sep 22 2015 - 10:41:27 EST
On Tue, 22 Sep 2015 19:35:38 +0800
"majun (F)" <majun258@xxxxxxxxxx> wrote:
> Hi Marc:
>
> å 2015/9/22 2:09, Marc Zyngier åé:
> > On Wed, 19 Aug 2015 03:55:20 +0100
> > MaJun <majun258@xxxxxxxxxx> wrote:
> >
> [...]
> >> +These nodes must have the following properties:
> >> +- msi-parent: This property has two cells.
> >> + The 1st cell specifies the ITS this device connected.
> >> + The 2nd cell specifies the device id.
> >> +- nr-interrupts:Specifies the total number of interrupt this device has.
> >> +- mbigen_node: Specifies the information of mbigen nodes this device
> >> + connected.Some devices with many interrupts maybe connects with several
> >> + mbigen nodes.
> >> +
> >> +Examples:
> >> +
> >> + mbigen_dsa: interrupt-controller@c0080000 {
> >> + compatible = "hisilicon,mbigen-v2";
> >> + interrupt-controller;
> >> + #interrupt-cells = <5>;
> >> + #mbigen-node-cells = <3>;
> >> + reg = <0xc0080000 0x10000>;
> >> +
> >> + mbigen_device_01 {
> >> + msi-parent = <&its 0x40b1c>;
> >> + nr-interrupts = <9>;
> >> + mbigen_node = <1 2 0>,
> >> + <3 2 4>,
> >> + <4 5 0>;
> >> + }
> >> +
> >> + mbigen_device_02 {
> >> + msi-parent = <&its 0x40b1d>;
> >> + nr-interrupts = <3>;
> >> + mbigen_node = <6 3 0>;
> >> + interrupt-controller;
> >> + }
> >> + };
> >> +
> >> +Device connect to mbigen required properties:
> >> +----------------------------------------------------
> >> +-interrupt-parent: Specifies the mbigen node which device connected.
> >> +-interrupts:specifies the interrupt source.The first cell is hwirq num, the
> >> + second number is trigger type.
> >> +
> >> +Examples:
> >> + smmu_dsa {
> >> + compatible = "arm,smmu-v3";
> >> + reg = <0x0 0xc0040000 0x0 0x20000>;
> >> + interrupt-parent = <&mbigen_dsa>;
> >> + interrupts = <0x40b20 6 78 1>,
> >> + <0x40b20 6 79 1>,
> >> + <0x40b20 6 80 1>;
> >> + };
> >> +
> >
> > I find the current split very confusing. In your example, the interrupt
> > controller is the mbigen block, which forces you to encode the DevID as
> > part of the interrupt specifier. This doesn't feel like an ideal
> > design, because you end up duplicating the DevID information at both
> > the "client" device and the mbi_device.
> >
> > I'd be more inclined to have the mbi_device itself be the interrupt
> > controller for the client device. This would eliminate information
> > duplication, and reflect the hardware (or what I understand of the
> > hardware) a bit more.
>
> Do you mean make the dts likes below?
>
>
> mbigen_dsa: interrupt-controller@c0080000 {
> compatible = "hisilicon,mbigen-v2";
> interrupt-controller;
> #interrupt-cells = <5>;
These two statements shouldn't be here...
> #mbigen-node-cells = <3>;
> reg = <0xc0080000 0x10000>;
>
> mbigen_client_device1 {
> msi-parent = <&its 0x40b1c>;
> nr-interrupts = <9>;
> interrupt-controller;
This is where #interrupt-cells should be.
> }
>
> mbigen_client_device2{
> msi-parent = <&its 0x40b1d>;
> nr-interrupts = <3>;
> interrupt-controller;
> }
> };
>
>
> client_device1 {
> compatible = "arm,smmu-v3";
> reg = <0x0 0xc0040000 0x0 0x20000>;
> interrupt-parent = <&mbigen_client_device1>;
> interrupts = <pin_offset 78 1>,
> <pin_offset 79 1>,
> <pin_offset 80 1>;
> };
>
>
But otherwise, this looks better.
Thanks,
M.
--
Jazz is not dead. It just smells funny.
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