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Subject: Re: [PATCH v5 1/2] dt-bindings: dma: Add bindings for intel LGM SOC
To:     Rob Herring <robh@kernel.org>
Cc:     dmaengine@vger.kernel.org, vkoul@kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        andriy.shevchenko@intel.com, cheol.yong.kim@intel.com,
        qi-ming.wu@intel.com, chuanhua.lei@linux.intel.com,
        malliamireddy009@gmail.com
References: <cover.1597381889.git.mallikarjunax.reddy@linux.intel.com>
 <68c77fd2ffb477aa4a52a58f8a26bfb191d3c5d1.1597381889.git.mallikarjunax.reddy@linux.intel.com>
 <20200814203222.GA2674896@bogus>
From:   "Reddy, MallikarjunaX" <mallikarjunax.reddy@linux.intel.com>
Message-ID: <7cdc0587-8b4f-4360-a303-1541c9ad57b2@linux.intel.com>
Date:   Tue, 18 Aug 2020 15:00:44 +0800
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Hi Rob,
Thanks for your valuable comments. Please see my comments inline..

On 8/15/2020 4:32 AM, Rob Herring wrote:
> On Fri, Aug 14, 2020 at 01:26:09PM +0800, Amireddy Mallikarjuna reddy wrote:
>> Add DT bindings YAML schema for DMA controller driver
>> of Lightning Mountain(LGM) SoC.
>>
>> Signed-off-by: Amireddy Mallikarjuna reddy <mallikarjunax.reddy@linux.intel.com>
>> ---
>> v1:
>> - Initial version.
>>
>> v2:
>> - Fix bot errors.
>>
>> v3:
>> - No change.
>>
>> v4:
>> - Address Thomas langer comments
>>    - use node name pattern as dma-controller as in common binding.
>>    - Remove "_" (underscore) in instance name.
>>    - Remove "port-" and "chan-" in attribute name for both 'dma-ports' & 'dma-channels' child nodes.
>>
>> v5:
>> - Moved some of the attributes in 'dma-ports' & 'dma-channels' child nodes to dma client/consumer side as cells in 'dmas' properties.
>> ---
>>   .../devicetree/bindings/dma/intel,ldma.yaml        | 319 +++++++++++++++++++++
>>   1 file changed, 319 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/dma/intel,ldma.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/dma/intel,ldma.yaml b/Documentation/devicetree/bindings/dma/intel,ldma.yaml
>> new file mode 100644
>> index 000000000000..9beaf191a6de
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/dma/intel,ldma.yaml
>> @@ -0,0 +1,319 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/dma/intel,ldma.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Lightning Mountain centralized low speed DMA and high speed DMA controllers.
>> +
>> +maintainers:
>> +  - chuanhua.lei@intel.com
>> +  - mallikarjunax.reddy@intel.com
>> +
>> +allOf:
>> +  - $ref: "dma-controller.yaml#"
>> +
>> +properties:
>> + $nodename:
>> +   pattern: "^dma-controller(@.*)?$"
>> +
>> + "#dma-cells":
>> +   const: 1
> Example says 3.
OK, i will fix it.
>
>> +
>> + compatible:
>> +  anyOf:
>> +   - const: intel,lgm-cdma
>> +   - const: intel,lgm-dma2tx
>> +   - const: intel,lgm-dma1rx
>> +   - const: intel,lgm-dma1tx
>> +   - const: intel,lgm-dma0tx
>> +   - const: intel,lgm-dma3
>> +   - const: intel,lgm-toe-dma30
>> +   - const: intel,lgm-toe-dma31
> 'anyOf' doesn't make sense here. This should be a single 'enum'.
ok. I will update it.
>
>> +
>> + reg:
>> +  maxItems: 1
>> +
>> + clocks:
>> +  maxItems: 1
>> +
>> + resets:
>> +  maxItems: 1
>> +
>> + interrupts:
>> +  maxItems: 1
>> +
>> + intel,dma-poll-cnt:
>> +   $ref: /schemas/types.yaml#definitions/uint32
>> +   description:
>> +     DMA descriptor polling counter. It may need fine tune according
>> +     to the system application scenario.
>> +
>> + intel,dma-byte-en:
>> +   type: boolean
>> +   description:
>> +     DMA byte enable is only valid for DMA write(RX).
>> +     Byte enable(1) means DMA write will be based on the number of dwords
>> +     instead of the whole burst.
>> +
>> + intel,dma-drb:
>> +    type: boolean
>> +    description:
>> +      DMA descriptor read back to make sure data and desc synchronization.
>> +
>> + intel,dma-burst:
>> +    $ref: /schemas/types.yaml#definitions/uint32
>> +    description:
>> +       Specifiy the DMA burst size(in dwords), the valid value will be 8, 16, 32.
>> +       Default is 16 for data path dma, 32 is for memcopy DMA.
>> +
>> + intel,dma-polling-cnt:
>> +    $ref: /schemas/types.yaml#definitions/uint32
>> +    description:
>> +       DMA descriptor polling counter. It may need fine tune according to
>> +       the system application scenario.
>> +
>> + intel,dma-desc-in-sram:
>> +    type: boolean
>> +    description:
>> +       DMA descritpors in SRAM or not. Some old controllers descriptors
>> +       can be in DRAM or SRAM. The new ones are all in SRAM.
>> +
>> + intel,dma-orrc:
>> +    $ref: /schemas/types.yaml#definitions/uint32
>> +    description:
>> +       DMA outstanding read counter. The maximum value is 16, and it may
>> +       need fine tune according to the system application scenarios.
>> +
>> + intel,dma-dburst-wr:
>> +    type: boolean
>> +    description:
>> +       Enable RX dynamic burst write. It only applies to RX DMA and memcopy DMA.
>> +
>> +
>> + dma-ports:
>> +    type: object
>> +    description:
>> +       This sub-node must contain a sub-node for each DMA port.
>> +    properties:
>> +      '#address-cells':
>> +        const: 1
>> +      '#size-cells':
>> +        const: 0
>> +
>> +    patternProperties:
>> +      "^dma-ports@[0-9]+$":
>> +          type: object
>> +
>> +          properties:
>> +            reg:
>> +              items:
>> +                - enum: [0, 1, 2, 3, 4, 5]
>> +              description:
>> +                 Which port this node refers to.
>> +
>> +            intel,name:
>> +              $ref: /schemas/types.yaml#definitions/string-array
>> +              description:
>> +                 Port name of each DMA port.
> No other DMA controller needs this, why do you?
  Answered below. (*ABC)
>
>> +
>> +            intel,chans:
>> +              $ref: /schemas/types.yaml#/definitions/uint32-array
>> +              description:
>> +                 The channels included on this port. Format is channel start
>> +                 number and how many channels on this port.
> Why does this need to be in DT? This all seems like it can be in the dma
> cells for each client.
(*ABC)
Yes. We need this.
for dma0(lgm-cdma) old SOC supports 16 channels and the new SOC supports 
22 channels. and the logical channel mapping for the peripherals also 
differ b/w old and new SOCs.

Because of this hardware limitation we are trying to configure the total 
channels and port-channel mapping dynamically from device tree.

based on port name we are trying to configure the default values for 
different peripherals(ports).
Example: burst length is not same for all ports, so using port name to 
do default configurations.
>
>> +
>> +          required:
>> +            - reg
>> +            - intel,name
>> +            - intel,chans
>> +
>> +
>> + ldma-channels:
>> +    type: object
>> +    description:
>> +       This sub-node must contain a sub-node for each DMA channel.
>> +    properties:
>> +      '#address-cells':
>> +        const: 1
>> +      '#size-cells':
>> +        const: 0
>> +
>> +    patternProperties:
>> +      "^ldma-channels@[0-15]+$":
>> +          type: object
>> +
>> +          properties:
>> +            reg:
>> +              items:
>> +                - enum: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
>> +              description:
>> +                 Which channel this node refers to.
>> +
>> +            intel,desc_num:
>> +              $ref: /schemas/types.yaml#/definitions/uint32
>> +              description:
>> +                 Per channel maximum descriptor number. The max value is 255.
>> +
>> +            intel,hdr-mode:
>> +              $ref: /schemas/types.yaml#/definitions/uint32-array
>> +              description:
>> +                 The first parameter is header mode size, the second
>> +                 parameter is checksum enable or disable. If enabled,
>> +                 header mode size is ignored. If disabled, header mode
>> +                 size must be provided.
>> +
>> +            intel,hw-desc:
>> +              $ref: /schemas/types.yaml#/definitions/uint32-array
>> +              description:
>> +                 Per channel dma hardware descriptor configuration.
>> +                 The first parameter is descriptor physical address and the
>> +                 second parameter hardware descriptor number.
> Again, this all seems like per client information for dma cells.
  Ok, if we move all these attributes to 'dmas' then 'dma-channels' 
child node is not needed in dtsi.
#dma-cells number i am already using 7. If we move all these attributes 
to 'dmas' then integer cells will increase.

Is there any limitation in using a number of integer cells & as 
determined by the #dma-cells property?

>
>> +
>> +          required:
>> +            - reg
>> +
>> +required:
>> + - compatible
>> + - reg
>> + - '#dma-cells'
> Add:
>
> additionalProperties: false
Sure i will update it in the next patch..

>
>> +
>> +examples:
>> + - |
>> +   dma0: dma-controller@e0e00000 {
>> +     compatible = "intel,lgm-cdma";
>> +     reg = <0xe0e00000 0x1000>;
>> +     #dma-cells = <3>;
>> +     interrupt-parent = <&ioapic1>;
>> +     interrupts = <82 1>;
>> +     resets = <&rcu0 0x30 0>;
>> +     reset-names = "ctrl";
> Not documented.
ok. will Document in the next patch.
>
>> +     clocks = <&cgu0 80>;
>> +     intel,dma-poll-cnt = <4>;
>> +     intel,dma-byte-en;
>> +     intel,dma-drb;
>> +     dma-ports {
>> +       #address-cells = <1>;
>> +       #size-cells = <0>;
>> +
>> +       dma-ports@0 {
>> +           reg = <0>;
>> +           intel,name = "SPI0";
>> +           intel,chans = <0 2>;
>> +       };
>> +       dma-ports@1 {
>> +           reg = <1>;
>> +           intel,name = "SPI1";
>> +           intel,chans = <2 2>;
>> +       };
>> +       dma-ports@2 {
>> +           reg = <2>;
>> +           intel,name = "SPI2";
>> +           intel,chans = <4 2>;
>> +       };
>> +       dma-ports@3 {
>> +           reg = <3>;
>> +           intel,name = "SPI3";
>> +           intel,chans = <6 2>;
>> +       };
>> +       dma-ports@4 {
>> +           reg = <4>;
>> +           intel,name = "HSNAND";
>> +           intel,chans = <8 2>;
>> +       };
>> +       dma-ports@5 {
>> +           reg = <5>;
>> +           intel,name = "PCM";
>> +           intel,chans = <10 6>;
>> +       };
>> +     };
>> +     ldma-channels {
>> +       #address-cells = <1>;
>> +       #size-cells = <0>;
>> +
>> +       ldma-channels@0 {
>> +           reg = <0>;
>> +           intel,desc_num = <1>;
>> +       };
>> +       ldma-channels@1 {
>> +           reg = <1>;
>> +           intel,desc_num = <1>;
>> +       };
>> +       ldma-channels@2 {
>> +           reg = <2>;
>> +           intel,desc_num = <1>;
>> +       };
>> +       ldma-channels@3 {
>> +           reg = <3>;
>> +           intel,desc_num = <1>;
>> +       };
>> +       ldma-channels@4 {
>> +           reg = <4>;
>> +           intel,desc_num = <1>;
>> +       };
>> +       ldma-channels@5 {
>> +           reg = <5>;
>> +           intel,desc_num = <1>;
>> +       };
>> +       ldma-channels@6 {
>> +           reg = <6>;
>> +           intel,desc_num = <1>;
>> +       };
>> +       ldma-channels@7 {
>> +           reg = <7>;
>> +           intel,desc_num = <1>;
>> +       };
>> +       ldma-channels@8 {
>> +           reg = <8>;
>> +       };
>> +       ldma-channels@9 {
>> +           reg = <9>;
>> +       };
>> +       ldma-channels@10 {
>> +           reg = <10>;
>> +       };
>> +       ldma-channels@11 {
>> +           reg = <11>;
>> +       };
>> +       ldma-channels@12 {
>> +           reg = <12>;
>> +       };
>> +       ldma-channels@13 {
>> +           reg = <13>;
>> +       };
>> +       ldma-channels@14 {
>> +           reg = <14>;
>> +       };
>> +       ldma-channels@15 {
>> +           reg = <15>;
>> +       };
>> +     };
>> +   };
>> + - |
>> +   dma3: dma-controller@ec800000 {
>> +     compatible = "intel,lgm-dma3";
>> +     reg = <0xec800000 0x1000>;
>> +     clocks = <&cgu0 71>;
>> +     resets = <&rcu0 0x10 9>;
>> +     #dma-cells = <7>;
>> +     intel,dma-burst = <32>;
>> +     intel,dma-polling-cnt = <16>;
>> +     intel,dma-desc-in-sram;
>> +     intel,dma-orrc = <16>;
>> +     intel,dma-byte-en;
>> +     intel,dma-dburst-wr;
>> +     ldma-channels {
>> +         #address-cells = <1>;
>> +         #size-cells = <0>;
>> +
>> +         ldma-channels@12 {
>> +             reg = <12>;
>> +             intel,hdr-mode = <128 0>;
>> +             intel,hw-desc = <0x20000000 8>;
>> +         };
>> +         ldma-channels@13 {
>> +             reg = <13>;
>> +             intel,hdr-mode = <128 0>;
>> +         };
>> +     };
>> +   };
>> -- 
>> 2.11.0
>>