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From: <Eugen.Hristev@microchip.com>
To: <robh@kernel.org>
Cc: <vkoul@kernel.org>, <Tudor.Ambarus@microchip.com>,
	<Ludovic.Desroches@microchip.com>, <dmaengine@vger.kernel.org>,
	<devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <Nicolas.Ferre@microchip.com>
Subject: Re: [PATCH 6/7] dt-bindings: dmaengine: at_xdmac: add optional microchip,m2m property
Date: Fri, 16 Oct 2020 06:45:51 +0000	[thread overview]
Message-ID: <6f305564-e91c-794b-0025-de805f1d1a58@microchip.com> (raw)
In-Reply-To: <20200922233327.GA3474555@bogus>

On 23.09.2020 02:33, Rob Herring wrote:

> On Mon, Sep 14, 2020 at 05:09:55PM +0300, Eugen Hristev wrote:
>> Add optional microchip,m2m property that specifies if a controller is
>> dedicated to memory to memory operations only.
>>
>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
>> ---
>>   Documentation/devicetree/bindings/dma/atmel-xdma.txt | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/dma/atmel-xdma.txt b/Documentation/devicetree/bindings/dma/atmel-xdma.txt
>> index 510b7f25ba24..642da6b95a29 100644
>> --- a/Documentation/devicetree/bindings/dma/atmel-xdma.txt
>> +++ b/Documentation/devicetree/bindings/dma/atmel-xdma.txt
>> @@ -15,6 +15,12 @@ the dmas property of client devices.
>>       interface identifier,
>>       - bit 30-24: PERID, peripheral identifier.
>>
>> +Optional properties:
>> +- microchip,m2m: this controller is connected on AXI only to memory and it's
>> +     dedicated to memory to memory DMA operations. If this option is
>> +     missing, it's assumed that the DMA controller is connected to
>> +     peripherals, thus it's a per2mem and mem2per.
> 
> Wouldn't 'dma-requests = <0>' cover this case?
> 
> Rob
> 

Hi Rob,

I do not think so. With requests = 0, it means that actually the DMA 
controller is unusable ?
Since you suggest requests = 0, it means that it cannot take requests at 
all ?
I do not find another example in current DT with this property set to zero.

Eugen


  reply	other threads:[~2020-10-16  6:45 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-14 14:09 [PATCH 0/7] dmaengine: add support for sama7g5 based at_xdmac Eugen Hristev
2020-09-14 14:09 ` [PATCH 1/7] dmaengine: at_xdmac: separate register defines into header file Eugen Hristev
2020-09-23  5:07   ` Tudor.Ambarus
2020-09-14 14:09 ` [PATCH 2/7] MAINTAINERS: add dma/at_xdmac_regs.h to XDMAC driver entry Eugen Hristev
2020-09-23  5:12   ` Tudor.Ambarus
2020-09-14 14:09 ` [PATCH 3/7] dt-bindings: dmaengine: at_xdmac: add compatible with microchip,sama7g5 Eugen Hristev
2020-09-22 23:32   ` Rob Herring
2020-09-14 14:09 ` [PATCH 4/7] dmaengine: at_xdmac: adapt perid for mem2mem operations Eugen Hristev
2020-09-23  5:30   ` Tudor.Ambarus
2020-09-23  5:35     ` Tudor.Ambarus
2020-09-14 14:09 ` [PATCH 5/7] dmaengine: at_xdmac: add support for sama7g5 based at_xdmac Eugen Hristev
2020-09-23  7:08   ` Tudor.Ambarus
2020-10-16  6:52     ` Eugen.Hristev
2020-09-14 14:09 ` [PATCH 6/7] dt-bindings: dmaengine: at_xdmac: add optional microchip,m2m property Eugen Hristev
2020-09-22 23:33   ` Rob Herring
2020-10-16  6:45     ` Eugen.Hristev [this message]
2020-10-16  7:06       ` Vinod Koul
2020-10-16  7:09         ` Eugen.Hristev
2020-09-14 14:09 ` [PATCH 7/7] dmaengine: at_xdmac: add AXI priority support and recommended settings Eugen Hristev

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