summaryrefslogtreecommitdiffstats
path: root/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml')
-rw-r--r--Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml208
1 files changed, 208 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml
new file mode 100644
index 000000000..a4f1fe636
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml
@@ -0,0 +1,208 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/arm,mhuv2.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARM MHUv2 Mailbox Controller
+
+maintainers:
+ - Tushar Khandelwal <tushar.khandelwal@arm.com>
+ - Viresh Kumar <viresh.kumar@linaro.org>
+
+description: |
+ The Arm Message Handling Unit (MHU) Version 2 is a mailbox controller that has
+ between 1 and 124 channel windows (each 32-bit wide) to provide unidirectional
+ communication with remote processor(s), where the number of channel windows
+ are implementation dependent.
+
+ Given the unidirectional nature of the controller, an MHUv2 mailbox may only
+ be written to or read from. If a pair of MHU controllers is implemented
+ between two processing elements to provide bidirectional communication, these
+ must be specified as two separate mailboxes.
+
+ If the interrupts property is present in device tree node, then its treated as
+ a "receiver" mailbox, otherwise a "sender".
+
+ An MHU controller must be specified along with the supported transport
+ protocols. The transport protocols determine the method of data transmission
+ as well as the number of provided mailbox channels.
+
+ Following are the possible transport protocols.
+
+ - Data-transfer: Each transfer is made of one or more words, using one or more
+ channel windows.
+
+ - Doorbell: Each transfer is made up of single bit flag, using any one of the
+ bits in a channel window. A channel window can support up to 32 doorbells
+ and the entire window shall be used in doorbell protocol. Optionally, data
+ may be transmitted through a shared memory region, wherein the MHU is used
+ strictly as an interrupt generation mechanism but that is out of the scope
+ of these bindings.
+
+# We need a select here so we don't match all nodes with 'arm,primecell'
+select:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - arm,mhuv2-tx
+ - arm,mhuv2-rx
+ required:
+ - compatible
+
+properties:
+ compatible:
+ oneOf:
+ - description: Sender mode
+ items:
+ - const: arm,mhuv2-tx
+ - const: arm,primecell
+
+ - description: Receiver-mode
+ items:
+ - const: arm,mhuv2-rx
+ - const: arm,primecell
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ description: |
+ The MHUv2 controller always implements an interrupt in the "receiver"
+ mode, while the interrupt in the "sender" mode was not available in the
+ version MHUv2.0, but the later versions do have it.
+ maxItems: 1
+
+ clocks:
+ maxItems: 1
+
+ clock-names:
+ maxItems: 1
+
+ arm,mhuv2-protocols:
+ $ref: /schemas/types.yaml#/definitions/uint32-matrix
+ description: |
+ The MHUv2 controller may contain up to 124 channel windows (each 32-bit
+ wide). The hardware and the DT bindings allows any combination of those to
+ be used for various transport protocols.
+
+ This property allows a platform to describe how these channel windows are
+ used in various transport protocols. The entries in this property shall be
+ present as an array of tuples, where each tuple describes details about
+ one of the transport protocol being implemented over some channel
+ window(s).
+
+ The first field of a tuple signifies the transfer protocol, 0 is reserved
+ for doorbell protocol, and 1 is reserved for data-transfer protocol.
+ Using any other value in the first field of a tuple makes it invalid.
+
+ The second field of a tuple signifies the number of channel windows where
+ the protocol would be used and should be set to a non zero value. For
+ doorbell protocol this field signifies the number of 32-bit channel
+ windows that implement the doorbell protocol. For data-transfer protocol,
+ this field signifies the number of 32-bit channel windows that implement
+ the data-transfer protocol.
+
+ The total number of channel windows specified here shouldn't be more than
+ the ones implemented by the platform, though one can specify lesser number
+ of windows here than what the platform implements.
+
+ mhu: mailbox@2b1f0000 {
+ ...
+
+ arm,mhuv2-protocols = <0 2>, <1 1>, <1 5>, <1 7>;
+ }
+
+ The above example defines the protocols of an ARM MHUv2 mailbox
+ controller, where a total of 15 channel windows are used. The first two
+ windows are used in doorbell protocol (64 doorbells), followed by 1, 5 and
+ 7 windows (separately) used in data-transfer protocol.
+
+ minItems: 1
+ maxItems: 124
+ items:
+ items:
+ - enum: [ 0, 1 ]
+ - minimum: 0
+ maximum: 124
+
+
+ '#mbox-cells':
+ description: |
+ It is always set to 2. The first argument in the consumers 'mboxes'
+ property represents the channel window group, which may be used in
+ doorbell, or data-transfer protocol, and the second argument (only
+ relevant in doorbell protocol, should be 0 otherwise) represents the
+ doorbell number within the 32 bit wide channel window.
+
+ From the example given above for arm,mhuv2-protocols, here is how a client
+ node can reference them.
+
+ mboxes = <&mhu 0 5>; // Channel Window Group 0, doorbell 5.
+ mboxes = <&mhu 1 7>; // Channel Window Group 1, doorbell 7.
+ mboxes = <&mhu 2 0>; // Channel Window Group 2, data transfer protocol with 1 window.
+ mboxes = <&mhu 3 0>; // Channel Window Group 3, data transfer protocol with 5 windows.
+ mboxes = <&mhu 4 0>; // Channel Window Group 4, data transfer protocol with 7 windows.
+
+ const: 2
+
+if:
+ # Interrupt is compulsory for receiver
+ properties:
+ compatible:
+ contains:
+ const: arm,mhuv2-rx
+then:
+ required:
+ - interrupts
+
+required:
+ - compatible
+ - reg
+ - '#mbox-cells'
+ - arm,mhuv2-protocols
+
+additionalProperties: false
+
+examples:
+ # Multiple transport protocols implemented by the mailbox controllers
+ - |
+ soc {
+ #address-cells = <2>;
+ #size-cells = <2>;
+
+ mhu_tx: mailbox@2b1f0000 {
+ #mbox-cells = <2>;
+ compatible = "arm,mhuv2-tx", "arm,primecell";
+ reg = <0 0x2b1f0000 0 0x1000>;
+ clocks = <&clock 0>;
+ clock-names = "apb_pclk";
+ interrupts = <0 45 4>;
+ arm,mhuv2-protocols = <1 5>, <1 2>, <1 5>, <1 7>, <0 2>;
+ };
+
+ mhu_rx: mailbox@2b1f1000 {
+ #mbox-cells = <2>;
+ compatible = "arm,mhuv2-rx", "arm,primecell";
+ reg = <0 0x2b1f1000 0 0x1000>;
+ clocks = <&clock 0>;
+ clock-names = "apb_pclk";
+ interrupts = <0 46 4>;
+ arm,mhuv2-protocols = <1 1>, <1 7>, <0 2>;
+ };
+
+ mhu_client: dsp@596e8000 {
+ compatible = "fsl,imx8qxp-dsp";
+ reg = <0 0x596e8000 0 0x88000>;
+ clocks = <&adma_lpcg 0>, <&adma_lpcg 1>, <&adma_lpcg 2>;
+ clock-names = "ipg", "ocram", "core";
+ power-domains = <&pd 0>, <&pd 1>, <&pd 2>, <&pd 3>;
+ mbox-names = "txdb0", "txdb1", "rxdb0", "rxdb1";
+ mboxes = <&mhu_tx 2 0>, //data-transfer protocol with 5 windows, mhu-tx
+ <&mhu_tx 3 0>, //data-transfer protocol with 7 windows, mhu-tx
+ <&mhu_rx 2 27>, //doorbell protocol channel 2, doorbell 27, mhu-rx
+ <&mhu_rx 0 0>; //data-transfer protocol with 1 window, mhu-rx
+ memory-region = <&dsp_reserved>;
+ };
+ };