Re: [PATCH v3 1/3] dt-bindings: remoteproc: k3-m4f: Add bindings for K3 AM64x SoCs

Krzysztof Kozlowski
2023-03-03T08:06:39Z

On 02/03/2023 18:14, Martyn Welch wrote:
> From: Hari Nagalla <hnagalla@ti.com>

Subject: drop second/last, redundant "bindings for". The "dt-bindings"
prefix is already stating that these are bindings.

>
> K3 AM64x SoC has a Cortex M4F subsystem in the MCU voltage domain.
> The remote processor's life cycle management and IPC mechanisms are
> similar across the R5F and M4F cores from remote processor driver
> point of view. However, there are subtle differences in image loading
> and starting the M4F subsystems.
>
> The YAML binding document provides the various node properties to be
> configured by the consumers of the M4F subsystem.
>
> Signed-off-by: Hari Nagalla <hnagalla@ti.com>
> [Martyn Welch: Amended as per review comments and to pass DT tests]
> Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
> ---
>
> Changes since v1:
> - Spelling corrections
> - Corrected to pass DT checks
>
> Changes since v2:
> - Missed spelling correction to commit message
>
> Note: The only review comment that I don't see directly addressed is the
> lack of description of `ti,sci`, `ti,sci-dev-id` and
> `ti,sci-proc-ids`. A reference has been added to
> `/schemas/arm/keystone/ti,k3-sci-common.yaml#` where they are
> described. I believe this is the correct approach, please advise if
> that is not the case.
>
> .../bindings/remoteproc/ti,k3-m4f-rproc.yaml | 158 ++++++++++++++++++
> 1 file changed, 158 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/remoteproc/ti,k3-m4f-rproc.yaml
>
> diff --git a/Documentation/devicetree/bindings/remoteproc/ti,k3-m4f-rproc.yaml b/Documentation/devicetree/bindings/remoteproc/ti,k3-m4f-rproc.yaml
> new file mode 100644
> index 000000000000..1b38df0be2e6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/remoteproc/ti,k3-m4f-rproc.yaml
> @@ -0,0 +1,158 @@
> +# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/remoteproc/ti,k3-m4f-rproc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: TI K3 M4F processor subsystems
> +
> +maintainers:
> + - Hari Nagalla <hnagalla@ti.com>
> +
> +description: |
> + Some K3 family SoCs have Arm Cortex M4F cores. AM64x is a SoC in K3
> + family with a M4F core. Typically safety oriented applications may use
> + the M4F core in isolation without an IPC. Where as some industrial and
> + home automation applications, may use the M4F core as a remote processor
> + with IPC communications.
> +
> +$ref: /schemas/arm/keystone/ti,k3-sci-common.yaml#
> +
> +properties:
> + $nodename:
> + pattern: "^m4fss(@.*)?"

Drop. It's not a generic name. Also we do not enforce names in device
schemas.

> +
> + compatible:
> + enum:
> + - ti,am64-m4fss
> +
> + power-domains:
> + description: |
> + Should contain a phandle to a PM domain provider node and an args
> + specifier containing the M4FSS device id value.

Drop description, especially that the args depend on provider, not consumer.

> + maxItems: 1
> +
> + "#address-cells":
> + const: 2
> +
> + "#size-cells":
> + const: 2
> +
> + reg:
> + items:
> + - description: Address and Size of the IRAM internal memory region

Just "IRAM internal memory region"

> + - description: Address and Size of the DRAM internal memory region
> +
> + reg-names:
> + items:
> + - const: iram
> + - const: dram
> +
> + resets:
> + description: |
> + Should contain the phandle to the reset controller node managing the
> + local resets for this device, and a reset specifier.

Drop description.

> + maxItems: 1
> +
> + firmware-name:
> + description: |
> + Should contain the name of the default firmware image
> + file located on the firmware search path

This description is basically duplicating the name... say something
useful or shorten it (e.g. "Should contain" is really redundant). You
also need $ref because we do not have the type defined anywhere.

> +
> + mboxes:
> + description: |
> + OMAP Mailbox specifier denoting the sub-mailbox, to be used for

OMAP?

> + communication with the remote processor. This property should match
> + with the sub-mailbox node used in the firmware image.
> + maxItems: 1
> +
> + memory-region:
> + description: |
> + phandle to the reserved memory nodes to be associated with the
> + remoteproc device. There should be at least two reserved memory nodes
> + defined.

Don't repeat constraints in free form text.

> The reserved memory nodes should be carveout nodes, and
> + should be defined with a "no-map" property as per the bindings in
> + Documentation/devicetree/bindings/reserved-memory/reserved-memory.yaml
> + minItems: 2
> + maxItems: 8
> + items:
> + - description: region used for dynamic DMA allocations like vrings and
> + vring buffers
> + - description: region reserved for firmware image sections
> + additionalItems: true

And what is the purpose of the rest of reserved nodes?

> +
> +required:
> + - compatible
> + - reg
> + - reg-names
> + - ti,sci
> + - ti,sci-dev-id
> + - ti,sci-proc-ids
> + - resets
> + - firmware-name
> + - mboxes
> + - memory-region
> +
> +unevaluatedProperties: false
> +
> +examples:
> + - |
> + reserved-memory {
> + #address-cells = <2>;
> + #size-cells = <2>;
> +
> + mcu_m4fss_dma_memory_region: m4f-dma-memory@9cb00000 {
> + compatible = "shared-dma-pool";
> + reg = <0x00 0x9cb00000 0x00 0x100000>;
> + no-map;
> + };
> +
> + mcu_m4fss_memory_region: m4f-memory@9cc00000 {
> + compatible = "shared-dma-pool";
> + reg = <0x00 0x9cc00000 0x00 0xe00000>;
> + no-map;
> + };
> + };
> +
> + soc {
> + #address-cells = <2>;
> + #size-cells = <2>;
> +
> + mailbox0_cluster0: mailbox-0 {
> + #mbox-cells = <1>;
> +
> + mbox_m4_0: mbox-m4-0 {
> + ti,mbox-rx = <0 0 0>;
> + ti,mbox-tx = <1 0 0>;
> + };
> + };

Does not look related to this binding... or is it somehow very specific
and needs showing?

> +
> + bus@f0000 {
> + compatible = "simple-bus";
> + #address-cells = <2>;
> + #size-cells = <2>;
> + ranges = <0x00 0x04000000 0x00 0x04000000 0x00 0x01ff1400>;

Why another bus? You already have soc in example, why more nodes?

> +
> + bus@4000000 {

And one more bus?

> + compatible = "simple-bus";
> + #address-cells = <2>;
> + #size-cells = <2>;
> + ranges = <0x00 0x04000000 0x00 0x04000000 0x00 0x01ff1400>;
> +
> + mcu_m4fss: m4fss@5000000 {

Generic node name. Qualcomm uses remoteproc.

> + compatible = "ti,am64-m4fss";
> + reg = <0x00 0x5000000 0x00 0x30000>,
> + <0x00 0x5040000 0x00 0x10000>;
> + reg-names = "iram", "dram";
> + ti,sci = <&dmsc>;
> + ti,sci-dev-id = <9>;
> + ti,sci-proc-ids = <0x18 0xff>;
> + resets = <&k3_reset 9 1>;
> + firmware-name = "am62-mcu-m4f0_0-fw";
> + mboxes = <&mailbox0_cluster0 &mbox_m4_0>;
> + memory-region = <&mcu_m4fss_dma_memory_region>,
> + <&mcu_m4fss_memory_region>;
> + };
> + };
> + };
> + };

Best regards,
Krzysztof