On 02/06/2022 07:21, Tinghan Shen wrote:

Hi Krzysztof,

On Wed, 2022-06-01 at 13:50 +0200, Krzysztof Kozlowski wrote:

quoted

On 01/06/2022 13:21, Tinghan Shen wrote:

quoted

The SCP co-processor is a dual-core RISC-V MCU on MT8195.

Add a new property to identify each core and helps to find drivers
through device tree API to cooperate with each other, e.g. boot flow and
watchdog timeout flow.

Add a new compatile for the driver of SCP 2nd core.

Signed-off-by: Tinghan Shen <redacted>
---
 .../devicetree/bindings/remoteproc/mtk,scp.yaml      | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/remoteproc/mtk,scp.yaml

b/Documentation/devicetree/bindings/remoteproc/mtk,scp.yaml
index eec3b9c4c713..b181786d9575 100644

--- a/Documentation/devicetree/bindings/remoteproc/mtk,scp.yaml
+++ b/Documentation/devicetree/bindings/remoteproc/mtk,scp.yaml

@@ -20,6 +20,7 @@ properties:
       - mediatek,mt8186-scp
       - mediatek,mt8192-scp
       - mediatek,mt8195-scp
+      - mediatek,mt8195-scp-dual
 
   reg:
     description:

@@ -57,6 +58,16 @@ properties:
   memory-region:
     maxItems: 1
 
+  mediatek,scp-core:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description:
+      The property value is a list with 2 items, a core id and a phandle

uint32, not phandle.

quoted

+      to the sibling SCP node. 

Skip this. First part is obvious from the schema, second part should be
described via items.

The core id represents the id of the dts node contains

quoted

+      this property. The valid values of core id are 0 and 1 for dual-core SCP.
+      The phandle of sibling SCP node is used to find the register settings,
+      trigger core dependent callback, and invoke rproc API.

Entire description did not help me to understand what's this. So far it
looks like it is not a hardware property but some programming help, so
it does not look like properly described in bindings.

quoted

+    maxItems: 1

In description you said - two items.

You need allOf:if:then disallowing this property for other variants.

quoted

+
 required:
   - compatible
   - reg

@@ -115,6 +126,7 @@ examples:
         reg-names = "sram", "cfg", "l1tcm";
         clocks = <&infracfg CLK_INFRA_SCPSYS>;
         clock-names = "main";
+        mediatek,scp-core = <0 &scp_dual>;

This looks like phandle, so wrong type.

quoted

 
         cros_ec {
             mediatek,rpmsg-name = "cros-ec-rpmsg";

Thanks for your feedback.
After looking for a comparable uses case, I find out a different approach.

  mediatek,scp-core:
    $ref: "/schemas/types.yaml#/definitions/phandle-array"
    description:
      Enable the dual-core support in scp driver.

You describe desired functional behavior, not the hardware. What is the
property about? If you just want to indicate this is two-core processor,
then it could be:
	mediatek,cores = <2>; /* number of cores */


However it seems you want to achieve here something different and as I
raised last time - it does not look like DT property.

Or maybe this is for first core and you want to indicate the sibling?
Something like that was mentioned in previous description.

    items:
      - items:
          - description: Assign a core id for current scp node.
            enum: [0, 1]
          - description:
              Phandle of another SCP node. This helps to find
              the scp driver of another core to trigger core
              dependent callback, invoke rproc subdevice API, etc.

Items should be rather reversed, as [0,1] being the argument to phandle
for a provider (see examples with syscon)...

Best regards,
Krzysztof

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