Re: [RFC PATCH v3 10/12] dt-bindings: arm: Add virtio transport for SCMI
From: Rob Herring <robh@kernel.org>
Date: 2021-05-17 21:39:23
Also in:
linux-arm-kernel, linux-devicetree, lkml
On Tue, May 11, 2021 at 02:20:38AM +0200, Peter Hilber wrote:
From: Igor Skalkin <redacted> Document the properties for arm,scmi-virtio compatible nodes. The backing virtio SCMI device is described in patch [1]. [1] https://lists.oasis-open.org/archives/virtio-comment/202005/msg00096.html Signed-off-by: Igor Skalkin <redacted> [ Peter: Adapted patch for submission to upstream. ] Co-developed-by: Peter Hilber <redacted> Signed-off-by: Peter Hilber <redacted> --- .../devicetree/bindings/arm/arm,scmi.txt | 35 +++++++++++++++++-- 1 file changed, 33 insertions(+), 2 deletions(-)
Seems like it may not be perfectly clear what properties apply or not for the different transports. Can you convert this to DT schema first.
quoted hunk
diff --git a/Documentation/devicetree/bindings/arm/arm,scmi.txt b/Documentation/devicetree/bindings/arm/arm,scmi.txt index 667d58e0a659..5d209ba666f6 100644 --- a/Documentation/devicetree/bindings/arm/arm,scmi.txt +++ b/Documentation/devicetree/bindings/arm/arm,scmi.txt@@ -13,6 +13,9 @@ the device tree. Required properties: The scmi node with the following properties shall be under the /firmware/ node. +Some properties are specific to a transport type. + +shmem-based transports (mailbox, smc/hvc): - compatible : shall be "arm,scmi" or "arm,scmi-smc" for smc/hvc transports - mboxes: List of phandle and mailbox channel specifiers. It should contain@@ -21,6 +24,15 @@ The scmi node with the following properties shall be under the /firmware/ node. supported. - shmem : List of phandle pointing to the shared memory(SHM) area as per generic mailbox client binding. + +Virtio transport: + +- compatible : shall be "arm,scmi-virtio". + +The virtio transport only supports a single device. + +Additional required properties: + - #address-cells : should be '1' if the device has sub-nodes, maps to protocol identifier for a given sub-node. - #size-cells : should be '0' as 'reg' property doesn't have any size@@ -50,7 +62,8 @@ Each protocol supported shall have a sub-node with corresponding compatible as described in the following sections. If the platform supports dedicated communication channel for a particular protocol, the 3 properties namely: mboxes, mbox-names and shmem shall be present in the sub-node corresponding -to that protocol. +to that protocol. The virtio transport does not support dedicated communication +channels. Clock/Performance bindings for the clocks/OPPs based on SCMI Message Protocol ------------------------------------------------------------@@ -129,7 +142,8 @@ Required sub-node properties: [5] Documentation/devicetree/bindings/reset/reset.txt [6] Documentation/devicetree/bindings/regulator/regulator.yaml -Example: +Example (mailbox transport): +---------------------------- sram@50000000 { compatible = "mmio-sram";@@ -237,3 +251,20 @@ thermal-zones { ... }; }; + +Example (virtio transport): +--------------------------- + +virtio_mmio@4b001000 { + compatible = "virtio,mmio"; + ... +}; + +firmware { + ... + scmi { + compatible = "arm,scmi-virtio"; + ... + +The rest is similar to the mailbox transport example, when omitting the +mailbox/shmem-specific properties.-- 2.25.1
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