Re: [PATCH v5 1/3] dt-bindings: dmaengine: Add dmamux for CV18XX/SG200X series SoC

From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Inochi Amaoto <inochiama@outlook.com>,
	Vinod Koul <vkoul@kernel.org>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Chen Wang <unicorn_wang@outlook.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>
Cc: Jisheng Zhang <jszhang@kernel.org>,
	Liu Gui <kenneth.liu@sophgo.com>,
	Jingbao Qiu <qiujingbao.dlmu@gmail.com>,
	dlan@gentoo.org, dmaengine@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org
Subject: Re: [PATCH v5 1/3] dt-bindings: dmaengine: Add dmamux for CV18XX/SG200X series SoC
Date: Tue, 26 Mar 2024 12:50:33 +0100	[thread overview]
Message-ID: <1525c377-af73-4204-8a2b-983c6d99316c@linaro.org> (raw)
In-Reply-To: <IA1PR20MB4953EA589A0FF36DC6FCF0E8BB352@IA1PR20MB4953.namprd20.prod.outlook.com>

On 26/03/2024 12:41, Inochi Amaoto wrote:
>>>
>>> The driver does use this file.
>>
>> I checked and could not find. Please point me to specific parts of the code.
>>
> 
> In cv1800_dmamux_route_allocate.
>> +	regmap_set_bits(dmamux->regmap,
>> +			DMAMUX_CH_REG(chid),
>> +			DMAMUX_CH_SET(chid, devid));
>> +
>> +	regmap_update_bits(dmamux->regmap, CV1800_SDMA_DMA_INT_MUX,
>> +			   DMAMUX_INT_CH_MASK(chid, cpuid),
>> +			   DMAMUX_INT_CH_BIT(chid, cpuid));
> 
> I think this is.

So where exactly? I don't see any define being used here.
CV1800_SDMA_DMA_INT_MUX is not in your header. DMAMUX_ is not in your
header. So what are you pointing?

I don't understand this communication. Are you mocking me here or what?
It's waste of my time.

> 
>>>
>>>>> And considering the limitation of this dmamux, maybe only devices that 
>>>>> require dma as a must can have the dma assigned. 
>>>>> Due to the fact, I think it may be a long time to wait for this header
>>>>> to be used as the binding header.
>>>>
>>>> I don't understand. You did not provide a single reason why this is a
>>>> binding. Reason is: mapping IDs between DTS and driver. Where is this
>>>> reason?
>>>>
>>>
>>> It seems like that I misunderstood something. This file provides one-one
>>> mapping between the dma device id and cpuid, which is both used in the
>>> dts and driver. For dts, it provides device id and cpu id mapping. And
>>> for driver, it is used as the directive to tell how to write the mapping
>>> register.
>>
>> So where is it? I looked for DMA_TDM0_RX - nothing. Then DMA_I2C1_RX -
>> nothing. Then any "DMA_" - also looks nothing.
>>
> 
> It is just the value writed, so I say it is just a one-one mapping.
> Maybe I misunderstand the binding meaning? Is the binding a mapping 
> between the dts and something defind in the driver (not the real 
> device)?

Binding headers contains IDs which are used by the driver and DTS code.
Hardware constants are not bindings. Register values, addresses,
whatever hardware is using is not a binding.

Best regards,
Krzysztof