[PATCH 1/3] Docs: dt: add generic MSI bindings

David Daney
2015-07-23T18:26:11Z

On 07/23/2015 09:52 AM, Mark Rutland wrote:
[...]
> +MSI clients
> +===========
> +
> +MSI clients are devices which generate MSIs. For each MSI they wish to
> +generate, the doorbell and payload may be configured, though sideband
> +information may not be configurable.
> +
> +Required properties:
> +--------------------
> +
> +- msi-parent: A list of phandle + msi-specifier pairs, one for each MSI
> + controller which the device is capable of using.
> +

We say here that "msi-parent" consists of pairs ...

> + This property is unordered, and MSIs may be allocated from any combination of
> + MSI controllers listed in the msi-parent property.
> +
> + If a device has restrictions on the allocation of MSIs, these restrictions
> + must be described with additional properties.
> +
> + When #msi-cells is non-zero, busses with an msi-parent will require
> + additional properties to describe the relationship between devices on the bus
> + and the set of MSIs they can potentially generate.
> +
> +
> +Example
> +=======
> +
> +/ {
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + msi_a: msi-controller at a {
> + reg = <0xa 0xf00>;
> + compatible = "vendor-a,some-controller";
> + msi-controller;
> + /* No sideband data, so #msi-cells omitted */
> + };
> +
> + msi_b: msi-controller at b {
> + reg = <0xb 0xf00>;
> + compatible = "vendor-b,another-controller";
> + msi-controller;
> + /* Each device has some unique ID */
> + #msi-cells = <1>;
> + };
> +
> + msi_c: msi-controller at c {
> + reg = <0xb 0xf00>;
> + compatible = "vendor-b,another-controller";
> + msi-controller;
> + /* Each device has some unique ID */
> + #msi-cells = <1>;
> + };
> +
> + dev at 0 {
> + reg = <0x0 0xf00>;
> + compatible = "vendor-c,some-device";
> +
> + /* Can only generate MSIs to msi_a */
> + msi-parent = <&msi_a>;

My device-tree syntax foo is a little rusty, but doesn't "msi-parent"
need a pair of elements? This has only the phandle.

> + };
> +
> + dev at 1 {
> + reg = <0x1 0xf00>;
> + compatible = "vendor-c,some-device";
> +
> + /*
> + * Can generate MSIs to either A or B.
> + */
> + msi-parent = <&msi_a>, <&msi_b 0x17>;

... same here, ...

> + };
> +
> + dev at 2 {
> + reg = <0x2 0xf00>;
> + compatible = "vendor-c,some-device";
> + /*
> + * Has different IDs at each MSI controller.
> + * Can generate MSIs to all of the MSI controllers.
> + */
> + msi-parent = <&msi_a>, <&msi_b 0x17>, <&msi_c 0x53>;

... and here

> + };
> +};
>