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References: <20220516005412.4844-1-chiawei_wang@aspeedtech.com> <20220516005412.4844-2-chiawei_wang@aspeedtech.com>
In-Reply-To: <20220516005412.4844-2-chiawei_wang@aspeedtech.com>
From:   Patrick Rudolph <patrick.rudolph@9elements.com>
Date:   Wed, 18 May 2022 08:18:10 +0200
Message-ID: <CALNFmy1pM4ZQ0BLDwHykxDCpR=Dv3sVaYq5QLLA_w0L+mzq7iQ@mail.gmail.com>
Subject: Re: [PATCH v5 1/4] dt-bindings: aspeed: Add eSPI controller
To:     Chia-Wei Wang <chiawei_wang@aspeedtech.com>
Cc:     robh+dt@kernel.org, joel@jms.id.au, andrew@aj.id.au,
        jk@codeconstruct.com.au, a.kartashev@yadro.com,
        dphadke@linux.microsoft.com, linux-aspeed@lists.ozlabs.org,
        openbmc@lists.ozlabs.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        ryan_chen@aspeedtech.com
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On Mon, May 16, 2022 at 2:55 AM Chia-Wei Wang
<chiawei_wang@aspeedtech.com> wrote:
>
> Add dt-bindings for Aspeed eSPI controller
>
> Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
> ---
>  .../devicetree/bindings/soc/aspeed/espi.yaml  | 162 ++++++++++++++++++
>  1 file changed, 162 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/soc/aspeed/espi.yaml
>
> diff --git a/Documentation/devicetree/bindings/soc/aspeed/espi.yaml b/Documentation/devicetree/bindings/soc/aspeed/espi.yaml
> new file mode 100644
> index 000000000000..aa91ec8caf6a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/soc/aspeed/espi.yaml
> @@ -0,0 +1,162 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# # Copyright (c) 2021 Aspeed Technology Inc.
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/soc/aspeed/espi.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Aspeed eSPI Controller
> +
> +maintainers:
> +  - Chia-Wei Wang <chiawei_wang@aspeedtech.com>
> +  - Ryan Chen <ryan_chen@aspeedtech.com>
> +
> +description:
> +  Aspeed eSPI controller implements a slave side eSPI endpoint device
> +  supporting the four eSPI channels, namely peripheral, virtual wire,
> +  out-of-band, and flash.
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - aspeed,ast2500-espi
> +          - aspeed,ast2600-espi
> +      - const: simple-mfd
> +      - const: syscon
> +
> +  reg:
> +    maxItems: 1
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 1
> +
> +  ranges: true
> +
> +patternProperties:
> +  "^espi-ctrl@[0-9a-f]+$":
> +    type: object
> +
> +    description: Control of the four basic eSPI channels
> +
> +    properties:
> +      compatible:
> +        items:
> +          - enum:
> +              - aspeed,ast2500-espi-ctrl
> +              - aspeed,ast2600-espi-ctrl
> +
> +      interrupts:
> +        maxItems: 1
> +
> +      clocks:
> +        maxItems: 1
> +
> +      perif,memcyc-enable:
> +        type: boolean
> +        description: Enable memory cycle over eSPI peripheral channel
> +
> +      perif,memcyc-src-addr:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description: The Host side address to be decoded into the memory cycle over eSPI peripheral channel
> +
> +      perif,memcyc-size:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        description: The size of the memory region allocated for the memory cycle over eSPI peripheral channel
> +        minimum: 65536
> +
> +      perif,dma-mode:
> +        type: boolean
> +        description: Enable DMA support for eSPI peripheral channel
> +
> +      oob,dma-mode:
> +        type: boolean
> +        description: Enable DMA support for eSPI out-of-band channel
> +
> +      oob,dma-tx-desc-num:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        minimum: 2
> +        maximum: 1023
> +        description: The number of TX descriptors available for eSPI OOB DMA engine
> +
> +      oob,dma-rx-desc-num:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        minimum: 2
> +        maximum: 1023
> +        description: The number of RX descriptors available for eSPI OOB DMA engine
> +
> +      flash,dma-mode:
> +        type: boolean
> +        description: Enable DMA support for eSPI flash channel
> +
In my tests using this driver the FIFO mode didn't work, but the DMA
mode worked fine.
IMHO you should always use DMA mode to reduce CPU load and get rid of
this property.

> +      flash,safs-mode:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        enum: [ 0, 1, 2 ]
> +        default: 0
> +        description: Slave-Attached-Sharing-Flash mode, 0->Mix, 1->SW, 2->HW
> +
On the AST2500 the HW mode is not supported, is it?

> +    dependencies:
> +      perif,memcyc-src-addr: [ "perif,memcyc-enable" ]
> +      perif,memcyc-size: [ "perif,memcyc-enable" ]
> +      oob,dma-tx-desc-num: [ "oob,dma-mode" ]
> +      oob,dma-rx-desc-num: [ "oob,dma-mode" ]
> +
> +    required:
> +      - compatible
> +      - interrupts
> +      - clocks
> +
> +  "^espi-mmbi@[0-9a-f]+$":
> +    type: object
> +
> +    description: Control of the PCH-BMC data exchange over eSPI peripheral memory cycle
> +
> +    properties:
> +      compatible:
> +        const: aspeed,ast2600-espi-mmbi
> +
> +      interrupts:
> +        maxItems: 1
> +
> +    required:
> +      - compatible
> +      - interrupts
> +
> +required:
> +  - compatible
> +  - reg
> +  - "#address-cells"
> +  - "#size-cells"
> +  - ranges
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/clock/ast2600-clock.h>
> +
> +    espi: espi@1e6ee000 {
> +        compatible = "aspeed,ast2600-espi", "simple-mfd", "syscon";
> +        reg = <0x1e6ee000 0x1000>;
> +
> +        #address-cells = <1>;
> +        #size-cells = <1>;
> +        ranges = <0x0 0x1e6ee000 0x1000>;
> +
> +        espi_ctrl: espi-ctrl@0 {
> +            compatible = "aspeed,ast2600-espi-ctrl";
> +            reg = <0x0 0x800>;
> +            interrupts = <GIC_SPI 42 IRQ_TYPE_LEVEL_HIGH>;
> +            clocks = <&syscon ASPEED_CLK_GATE_ESPICLK>;
> +        };
> +
> +        espi_mmbi: espi-mmbi@800 {
> +            compatible = "aspeed,ast2600-espi-mmbi";
> +            reg = <0x800 0x50>;
> +            interrupts = <GIC_SPI 108 IRQ_TYPE_LEVEL_HIGH>;
> +        };
> +    };
> --
> 2.25.1
>

Regards,
Patrick