lkml.org 
[lkml]   [2019]   [Jul]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 1/4] mailbox: arm_mhuv2: add device tree binding documentation
    Date
    From: Morten Borup Petersen <morten.petersen@arm.com>

    This patch adds device tree binding for Message Handling Unit
    controller version 2 from Arm.

    Signed-off-by: Morten Borup Petersen <morten.petersen@arm.com>
    Signed-off-by: Tushar Khandelwal <tushar.khandelwal@arm.com>
    Cc: robh+dt@kernel.org
    Cc: mark.rutland@arm.com
    Cc: devicetree@vger.kernel.org
    Cc: jassisinghbrar@gmail.com
    ---
    .../devicetree/bindings/mailbox/arm,mhuv2.txt | 108 ++++++++++++++++++
    1 file changed, 108 insertions(+)
    create mode 100644 Documentation/devicetree/bindings/mailbox/arm,mhuv2.txt

    diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhuv2.txt b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.txt
    new file mode 100644
    index 000000000000..3a05593414bc
    --- /dev/null
    +++ b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.txt
    @@ -0,0 +1,108 @@
    +Arm MHUv2 Mailbox Driver
    +========================
    +
    +The Arm Message-Handling-Unit (MHU) Version 2 is a mailbox controller that has
    +between 1 and 124 channel windows to provide unidirectional communication with
    +remote processor(s).
    +
    +Given the unidirectional nature of the device, an MHUv2 mailbox may only be
    +written to or read from. If a pair of MHU devices is implemented between two
    +processing elements to provide bidirectional communication, these must be
    +specified as two separate mailboxes.
    +
    +A device tree node for an Arm MHUv2 device must specify either a receiver frame
    +or a sender frame, indicating which end of the unidirectional MHU device which
    +the device node entry describes.
    +
    +An MHU device must be specified with a transport protocol. The transport
    +protocol of an MHU device determines the method of data transmission as well as
    +the number of provided mailboxes.
    +Following are the possible transport protocol types:
    +- Single-word: An MHU device implements as many mailboxes as it
    + provides channel windows. Data is transmitted through
    + the MHU registers.
    +- Multi-word: An MHU device implements a single mailbox. All channel windows
    + will be used during transmission. Data is transmitted through
    + the MHU registers.
    +- Doorbell: An MHU device implements as many mailboxes as there are flag
    + bits available in its channel windows. Optionally, data may
    + be transmitted through a shared memory region, wherein the MHU
    + is used strictly as an interrupt generation mechanism.
    +
    +Mailbox Device Node:
    +====================
    +
    +Required properties:
    +--------------------
    +- compatible: Shall be "arm,mhuv2" & "arm,primecell"
    +- reg: Contains the mailbox register address range (base
    + address and length)
    +- #mbox-cells Shall be 1 - the index of the channel needed.
    +- mhu-frame Frame type of the device.
    + Shall be either "sender" or "receiver"
    +- mhu-protocol Transport protocol of the device. Shall be one of the
    + following: "single-word", "multi-word", "doorbell"
    +
    +Required properties (receiver frame):
    +-------------------------------------
    +- interrupts: Contains the interrupt information corresponding to the
    + combined interrupt of the receiver frame
    +
    +Example:
    +--------
    +
    + mbox_mw_tx: mhu@10000000 {
    + compatible = "arm,mhuv2","arm,primecell";
    + reg = <0x10000000 0x1000>;
    + clocks = <&refclk100mhz>;
    + clock-names = "apb_pclk";
    + #mbox-cells = <1>;
    + mhu-protocol = "multi-word";
    + mhu-frame = "sender";
    + };
    +
    + mbox_sw_tx: mhu@10000000 {
    + compatible = "arm,mhuv2","arm,primecell";
    + reg = <0x11000000 0x1000>;
    + clocks = <&refclk100mhz>;
    + clock-names = "apb_pclk";
    + #mbox-cells = <1>;
    + mhu-protocol = "single-word";
    + mhu-frame = "sender";
    + };
    +
    + mbox_db_rx: mhu@10000000 {
    + compatible = "arm,mhuv2","arm,primecell";
    + reg = <0x12000000 0x1000>;
    + clocks = <&refclk100mhz>;
    + clock-names = "apb_pclk";
    + #mbox-cells = <1>;
    + interrupts = <0 45 4>;
    + interrupt-names = "mhu_rx";
    + mhu-protocol = "doorbell";
    + mhu-frame = "receiver";
    + };
    +
    + mhu_client: scb@2e000000 {
    + compatible = "fujitsu,mb86s70-scb-1.0";
    + reg = <0 0x2e000000 0x4000>;
    + mboxes =
    + // For multi-word frames, client may only instantiate a single
    + // mailbox for a mailbox controller
    + <&mbox_mw_tx 0>,
    +
    + // For single-word frames, client may instantiate as many
    + // mailboxes as there are channel windows in the MHU
    + <&mbox_sw_tx 0>,
    + <&mbox_sw_tx 1>,
    + <&mbox_sw_tx 2>,
    + <&mbox_sw_tx 3>,
    +
    + // For doorbell frames, client may instantiate as many mailboxes
    + // as there are bits available in the combined number of channel
    + // windows ((channel windows * 32) mailboxes)
    + <mbox_db_rx 0>,
    + <mbox_db_rx 1>,
    + ...
    + <mbox_db_rx 17>;
    + };
    \ No newline at end of file
    --
    2.17.1
    \
     
     \ /
      Last update: 2019-07-17 21:27    [W:3.216 / U:0.228 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site