Message-ID: <bd4301c5-d79f-6ba5-a840-95b733d2d44e@starfivetech.com>
Date:   Fri, 24 Feb 2023 21:09:07 +0800
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Subject: Re: [PATCH v2 1/3] dt-bindings: dma: snps,dw-axi-dmac: Add reset
 items
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To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>,
        Vinod Koul <vkoul@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor@kernel.org>,
        "Palmer Dabbelt" <palmer@dabbelt.com>,
        Emil Renner Berthing <kernel@esmil.dk>,
        "Emil Renner Berthing" <emil.renner.berthing@canonical.com>
CC:     <dmaengine@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-riscv@lists.infradead.org>
References: <20230221140424.719-1-walker.chen@starfivetech.com>
 <20230221140424.719-2-walker.chen@starfivetech.com>
 <1467f7c5-07eb-97db-c6f2-573a4208cc28@linaro.org>
 <d0984638-3f7f-7e4e-fe3e-5e1f88375dca@starfivetech.com>
 <36188e04-332f-e944-9c58-f6f2b74987da@linaro.org>
From:   Walker Chen <walker.chen@starfivetech.com>
In-Reply-To: <36188e04-332f-e944-9c58-f6f2b74987da@linaro.org>
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On 2023/2/24 18:51, Krzysztof Kozlowski wrote:
> On 24/02/2023 11:14, Walker Chen wrote:
>>>>    resets:
>>>> -    maxItems: 1
>>>> +    maxItems: 2
>>>
>>> This breaks ABI and all other users. Test your changes before sending.
>> 
>> I think 'minItems' should be added here. So like this:
>> resets:
>>   minItems: 1
>>   maxItems: 2
>> 
>> Other platform/users will not be affected by this.
> 
> Which will allow two resets on all platforms. Is this correct for these
> platforms? Do they have two resets?
> 
In kernel 6.2, only two platforms use this DMA controller (see 'arch/arc/boot/dts/hsdk.dts' and 'arch/riscv/boot/dts/canaan/k210.dtsi').
There is one reset on k210, while there is no reset of DMA on hsdk at all.
If here minItems with value 1 is added and the value of maxItems is changed to 2, after my testing,
whether it is one reset or two resets, even no reset, there is no errors occur when doing dtbs_check,
the DMA initialization shall not be affected either on their platforms.