RE: [PATCH v5 2/2] dt-bindings: mailbox: Add Xilinx IPI Mailbox

From: Jiaying Liang
Date: Tue Nov 13 2018 - 02:16:36 EST



> -----Original Message-----
> From: Rob Herring [mailto:robh@xxxxxxxxxx]
> Sent: Monday, November 12, 2018 9:56 AM
> To: Jiaying Liang <jliang@xxxxxxxxxx>
> Cc: jassisinghbrar@xxxxxxxxx; Michal Simek <michals@xxxxxxxxxx>;
> mark.rutland@xxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v5 2/2] dt-bindings: mailbox: Add Xilinx IPI Mailbox
>
> On Mon, Nov 05, 2018 at 02:37:01PM -0800, Wendy Liang wrote:
> > Xilinx ZynqMP IPI(Inter Processor Interrupt) is a hardware block in
> > ZynqMP SoC used for the communication between various processor
> > systems.
> >
> > Signed-off-by: Wendy Liang <wendy.liang@xxxxxxxxxx>
> > ---
> > .../bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt | 128
> +++++++++++++++++++++
> > 1 file changed, 128 insertions(+)
> > create mode 100644
> > Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
> >
> > diff --git
> > a/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.tx
> > t
> > b/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-
> mailbox.tx
> > t
> > new file mode 100644
> > index 0000000..18fd7b4
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-
> mailbo
> > +++ x.txt
> > @@ -0,0 +1,128 @@
> > +Xilinx IPI Mailbox Controller
> > +========================================
> > +
> > +The Xilinx IPI(Inter Processor Interrupt) mailbox controller is to
> > +manage messaging between two Xilinx Zynq UltraScale+ MPSoC IPI
> > +agents. Each IPI agent owns registers used for notification and buffers for
> message.
> > +
> > + +-------------------------------------+
> > + | Xilinx ZynqMP IPI Controller |
> > + +-------------------------------------+
> > + +--------------------------------------------------+
> > +ATF | |
> > + | |
> > + | |
> > + +--------------------------+ |
> > + | |
> > + | |
> > + +--------------------------------------------------+
> > + +------------------------------------------+
> > + | +----------------+ +----------------+ |
> > +Hardware | | IPI Agent | | IPI Buffers | |
> > + | | Registers | | | |
> > + | | | | | |
> > + | +----------------+ +----------------+ |
> > + | |
> > + | Xilinx IPI Agent Block |
> > + +------------------------------------------+
> > +
> > +
> > +Controller Device Node:
> > +===========================
> > +Required properties:
> > +--------------------
> > +IPI agent node:
> > +- compatible: Shall be: "xlnx,zynqmp-ipi-mailbox"
> > +- interrupt-parent: Phandle for the interrupt controller
> > +- interrupts: Interrupt information corresponding to the
> > + interrupt-names property.
> > +- xlnx,ipi-id: local Xilinx IPI agent ID
> > +- #address-cells: number of address cells of internal IPI mailbox nodes
> > +- #size-cells: number of size cells of internal IPI mailbox nodes
> > +
> > +Internal IPI mailbox node:
> > +- reg: IPI buffers address ranges
> > +- reg-names: Names of the reg resources. It should have:
> > + * local_request_region
> > + - IPI request msg buffer written by local and read
> > + by remote
> > + * local_response_region
> > + - IPI response msg buffer written by local and read
> > + by remote
> > + * remote_request_region
> > + - IPI request msg buffer written by remote and read
> > + by local
> > + * remote_response_region
> > + - IPI response msg buffer written by remote and
> read
> > + by local
> > +- #mbox-cells: Shall be 1. It contains:
> > + * tx(0) or rx(1) channel
> > +- xlnx,ipi-id: remote Xilinx IPI agent ID of which the mailbox is
> > + connected to.
> > +
> > +Optional properties:
> > +--------------------
> > +- method: The method of accessing the IPI agent registers.
> > + Permitted values are: "smc" and "hvc". Default is
> > + "smc".
> > +
> > +Client Device Node:
> > +===========================
> > +Required properties:
> > +--------------------
> > +- mboxes: Standard property to specify a mailbox
> > + (See ./mailbox.txt)
> > +- mbox-names: List of identifier strings for each mailbox
> > + channel.
> > +
> > +Example:
> > +===========================
> > + zynqmp_ipi {
> > + compatible = "xlnx,zynqmp-ipi-mailbox";
> > + interrupt-parent = <&gic>;
> > + interrupts = <0 29 4>;
> > + xlnx,ipi-id = <0>;
> > + #address-cells = <1>;
> > + #size-cells = <1>;
>
> Both the parent and children are mailbox providers?
[Wendy] children are mailbox providers.
As the mailbox providers shared the same interrupt
And the same local IPI agent ID, and thus, use
This parent/child structure
>
> > +
> > + /* APU<->RPU0 IPI mailbox controller */
> > + ipi_mailbox_rpu0: mailbox@ff90400 {
> > + compatible = "xlnx,zynqmp-ipi-mailbox";
>
> You can't have the same compatible in the parent and here.
[Wendy] Will remove the compatible in the child node.

>
> > + reg = <0xff990400 0x20>,
> > + <0xff990420 0x20>,
> > + <0xff990080 0x20>,
> > + <0xff9900a0 0x20>;
> > + reg-names = "local_request_region",
> > + "local_response_region",
> > + "remote_request_region",
> > + "remote_response_region";
> > + #mbox-cells = <1>;
> > + xlnx,ipi-id = <1>;
> > + };
> > + /* APU<->RPU1 IPI mailbox controller */
> > + ipi_mailbox_rpu1: mailbox@ff990440 {
> > + compatible = "xlnx,zynqmp-ipi-mailbox";
> > + reg = <0xff990440 0x20>,
> > + <0xff990460 0x20>,
> > + <0xff990280 0x20>,
> > + <0xff9902a0 0x20>;
> > + reg-names = "local_request_region",
> > + "local_response_region",
> > + "remote_request_region",
> > + "remote_response_region";
> > + #mbox-cells = <1>;
> > + xlnx,ipi-id = <2>;
> > + };
> > + };
> > + rpu0 {
> > + ...
> > + mboxes = <&ipi_mailbox_rpu0 0>,
> > + <&ipi_mailbox_rpu0 1>;
> > + mbox-names = "tx", "rx";
> > + };
> > + rpu1 {
> > + ...
> > + mboxes = <&ipi_mailbox_rpu1 0>,
> > + <&ipi_mailbox_rpu1 1>;
> > + mbox-names = "tx", "rx";
> > + };
> > --
> > 2.7.4
> >