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Message-ID: <df4fdecb-6ca7-d96b-bcad-02cefb52ce4e@linaro.org>
Date: Fri, 13 Jan 2023 08:52:08 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Tanmay Shah <tanmay.shah@....com>, robh+dt@...nel.org,
krzysztof.kozlowski+dt@...aro.org
Cc: devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-remoteproc@...r.kernel.org
Subject: Re: [PATCH] dt-bindings: sram: Tightly Coupled Memory (TCM) bindings
On 13/01/2023 08:30, Tanmay Shah wrote:
> This patch introduces bindings for TCM memory address space on AMD-xilinx
> platforms. As of now TCM addresses are hardcoded in xilinx remoteproc
> driver. This bindings will help in defining TCM in device-tree and
> make it's access platform agnostic and data-driven from the driver.
>
> Signed-off-by: Tanmay Shah <tanmay.shah@....com>
> ---
> .../devicetree/bindings/sram/xlnx,tcm.yaml | 137 ++++++++++++++++++
> 1 file changed, 137 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/sram/xlnx,tcm.yaml
>
> diff --git a/Documentation/devicetree/bindings/sram/xlnx,tcm.yaml b/Documentation/devicetree/bindings/sram/xlnx,tcm.yaml
> new file mode 100644
> index 000000000000..02d17026fb1f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sram/xlnx,tcm.yaml
> @@ -0,0 +1,137 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/sram/xlnx,tcm.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Tightly Coupled Memory (TCM)
> +
> +maintainers:
> + - Tanmay Shah <tanmay.shah@....com>
> +
> +description: |
> + Tightly Coupled Memory(TCM) is available on AMD-Xilinx paltforms for ARM
> + cortex remote processors to use. It is low-latency memory that provide
> + predictable instruction execution and predictable data load/store timing.
> + TCM can be configured in lockstep mode or split mode. In split mode
> + configuration each RPU core has its own set of ATCM and BTCM memories and in
> + lockstep mode redundant processor's TCM become available to lockstep
> + processor. So In lockstep mode ATCM and BTCM size is increased.
> +
> +properties:
> + $nodename:
> + pattern: "sram-[0-9a-f]+$"
Drop node name requirement.
Why do you need sram node at all?
> +
> +patternProperties:
> + "^tcm-[a-z]+@[0-9a-f]+$":
> + type: object
> + description: |
> + During the split mode, each RPU core has its own set of ATCM and BTCM memory
> +
> + During the lock-step operation, the TCMs that are associated with the
> + redundant processor become available to the lock-step processor.
> + For example if each individual processor has 64KB ATCM, then in lockstep mode
> + The size of ATCM become 128KB. Same for BTCM. tcm-lockstep node represents
> + TCM address space in lockstep mode. tcm-core@x node specfies each core's
> + TCM address space in split mode.
> +
> + properties:
> + compatible:
> + oneOf:
This is not oneOf.
> + - items:
and you do not have more than one item.
> + - enum:
> + - xlnx,tcm-lockstep
> + - xlnx,tcm-split
compatible describes hardware, not configuration. What you encode here
does not fit compatible.
> +
> + "#address-cells":
Use consistent quotes, either " or '
> + const: 1
> +
> + "#size-cells":
> + const: 1
> +
> + reg:
> + items:
> + - description: |
> + ATCM Memory address space. An ATCM typically holds interrupt or
> + exception code that must be accessed at high speed, without any
> + potential delay resulting from a cache miss.
> + RPU on AMD-Xilinx platform can also fetch data from ATCM
> + - description: |
> + BTCM Memory address space. A BTCM typically holds a block of data
> + for intensive processing, such as audio or video processing. RPU on
> + AMD-Xilinx Platforms can also fetch Code (Instructions) from BTCM
> +
> + reg-names:
> + items:
> + - const: atcm
> + - const: btcm
> +
> + ranges: true
> +
> + power-domains:
> + maxItems: 8
> + items:
> + - description: list of ATCM Power domains
> + - description: list of BTCM Power domains
> + additionalItems: true
And what are the rest?
> +
> + required:
> + - compatible
> + - '#address-cells'
> + - '#size-cells'
> + - reg
> + - ranges
> + - power-domains
> + unevaluatedProperties: false
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/power/xlnx-zynqmp-power.h>
> +
> + amba {
Drop.
> + sram@...00000 {
This does not match your bindings.
> + tcm-lockstep@...00000 {
> + compatible = "xlnx,tcm-lockstep";
> +
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + reg = <0xffe00000 0x20000>, <0xffe20000 0x20000>;
> + reg-names = "atcm", "btcm";
> + ranges = <0x0 0xffe00000 0x20000>, <0x20000 0xffe20000 0x20000>;
> + power-domains = <&zynqmp_firmware PD_R5_0_ATCM>,
> + <&zynqmp_firmware PD_R5_1_ATCM>,
This is BTCM domain according to your binding. Your binding here is
probably wrong and does not match real DTS.
> + <&zynqmp_firmware PD_R5_0_BTCM>,
> + <&zynqmp_firmware PD_R5_1_BTCM>;
> + };
> +
> + tcm-core@0 {
> + compatible = "xlnx,tcm-split";
> +
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + reg = <0xffe00000 0x10000>, <0xffe20000 0x10000>;
> + reg-names = "atcm", "btcm";
> + ranges = <0x0 0xffe00000 0x10000>, <0x20000 0xffe20000 0x10000>;
> + power-domains = <&zynqmp_firmware PD_R5_0_ATCM>,
> + <&zynqmp_firmware PD_R5_0_BTCM>;
> + };
> +
> + tcm-core@1 {
> + compatible = "xlnx,tcm-split";
> +
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + reg = <0xffe90000 0x10000>, <0xffeb0000 0x10000>;
> + reg-names = "atcm", "btcm";
> + ranges = <0x0 0xffe90000 0x10000>, <0x20000 0xffeb0000 0x10000>;
> + power-domains = <&zynqmp_firmware PD_R5_1_ATCM>,
> + <&zynqmp_firmware PD_R5_1_BTCM>;
> + };
> + };
> + };
> +...
>
> base-commit: 6b31ffe9c8b9947d6d3552d6e10752fd96d0f80f
Best regards,
Krzysztof
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