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From: Vinod Koul <vkoul@kernel.org>
To: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: robh+dt@kernel.org, dmaengine@vger.kernel.org,
	linux-kernel@vger.kernel.org, dan.j.williams@intel.com,
	devicetree@vger.kernel.org
Subject: Re: [RFC 1/3] dt-bindings: dma: Add documentation for DMA domains
Date: Sun, 8 Sep 2019 17:40:58 +0530
Message-ID: <20190908121058.GL2672@vkoul-mobl> (raw)
In-Reply-To: <961d30ea-d707-1120-7ecf-f51c11c41891@ti.com>

On 08-09-19, 10:47, Peter Ujfalusi wrote:
> 
> 
> On 06/09/2019 17.18, Peter Ujfalusi wrote:
> > On systems where multiple DMA controllers available, none Slave (for example
> > memcpy operation) users can not be described in DT as there is no device
> > involved from the DMA controller's point of view, DMA binding is not usable.
> > However in these systems still a peripheral might need to be serviced by or
> > it is better to serviced by specific DMA controller.
> > When a memcpy is used to/from a memory mapped region for example a DMA in the
> > same domain can perform better.
> > For generic software modules doing mem 2 mem operations it also matter that
> > they will get a channel from a controller which is faster in DDR to DDR mode
> > rather then from the first controller happen to be loaded.
> > 
> > This property is inherited, so it may be specified in a device node or in any
> > of its parent nodes.
> > 
> > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> > ---
> >  .../devicetree/bindings/dma/dma-domain.yaml   | 59 +++++++++++++++++++
> >  1 file changed, 59 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/dma/dma-domain.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/dma/dma-domain.yaml b/Documentation/devicetree/bindings/dma/dma-domain.yaml
> > new file mode 100644
> > index 000000000000..c2f182f30081
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/dma/dma-domain.yaml
> > @@ -0,0 +1,59 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/dma/dma-controller.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: DMA Domain Controller Definition
> > +
> > +maintainers:
> > +  - Vinod Koul <vkoul@kernel.org>
> > +
> > +allOf:
> > +  - $ref: "dma-controller.yaml#"
> > +
> > +description:
> > +  On systems where multiple DMA controllers available, none Slave (for example
> > +  memcpy operation) users can not be described in DT as there is no device
> > +  involved from the DMA controller's point of view, DMA binding is not usable.
> > +  However in these systems still a peripheral might need to be serviced by or
> > +  it is better to serviced by specific DMA controller.
> > +  When a memcpy is used to/from a memory mapped region for example a DMA in the
> > +  same domain can perform better.
> > +  For generic software modules doing mem 2 mem operations it also matter that
> > +  they will get a channel from a controller which is faster in DDR to DDR mode
> > +  rather then from the first controller happen to be loaded.
> > +
> > +  This property is inherited, so it may be specified in a device node or in any
> > +  of its parent nodes.
> > +
> > +properties:
> > +  $dma-domain-controller:
> 
> or domain-dma-controller?

I feel dma-domain-controller sounds fine as we are defining domains for
dmaengine. Another thought which comes here is that why not extend this to
slave as well and define dma-domain-controller for them as use that for
filtering, that is what we really need along with slave id in case a
specific channel is to be used by a peripheral

Thoughts..?

-- 
~Vinod

  reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-06 14:18 [RFC 0/3] dmaengine: Support for DMA domain controllers Peter Ujfalusi
2019-09-06 14:18 ` [RFC 1/3] dt-bindings: dma: Add documentation for DMA domains Peter Ujfalusi
2019-09-08  7:47   ` Peter Ujfalusi
2019-09-08 12:10     ` Vinod Koul [this message]
2019-09-09  6:30       ` Peter Ujfalusi
2019-09-12 17:03         ` Vinod Koul
2019-09-13  7:21           ` Peter Ujfalusi
2019-09-13 10:36             ` Vinod Koul
2019-09-13 12:19               ` Peter Ujfalusi
2019-09-13 13:33                 ` Vinod Koul
2019-09-08 12:06   ` Vinod Koul
2019-09-09  6:00     ` Peter Ujfalusi
2019-09-06 14:18 ` [RFC 2/3] dmaengine: of_dma: Function to look up the DMA domain of a client Peter Ujfalusi
2019-09-08 12:12   ` Vinod Koul
2019-09-06 14:18 ` [RFC 3/3] dmaengine: Support for requesting channels preferring DMA domain controller Peter Ujfalusi
2019-09-08  7:46   ` Peter Ujfalusi
2019-09-08 12:15   ` Vinod Koul
2019-09-09  5:56     ` Peter Ujfalusi
2019-09-12 16:49       ` Vinod Koul
  -- strict thread matches above, loose matches on Subject: below --
2019-09-06 14:17 [RFC 0/3] dmaengine: Support for DMA domain controllers Peter Ujfalusi
2019-09-06 14:17 ` [RFC 1/3] dt-bindings: dma: Add documentation for DMA domains Peter Ujfalusi

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