From: Vinod Koul <vkoul@kernel.org>
To: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: dmaengine@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/3] dmaengine: add peripheral configuration
Date: Mon, 12 Oct 2020 11:39:16 +0530 [thread overview]
Message-ID: <20201012060916.GI2968@vkoul-mobl> (raw)
In-Reply-To: <13fdee71-5060-83fc-d69d-8ec73f82fac4@ti.com>
On 09-10-20, 14:29, Peter Ujfalusi wrote:
>
>
> On 09/10/2020 14.15, Vinod Koul wrote:
> >>> If for any any reason subsequent txn is for different direction, I would
> >>> expect that parameters are set again before prep_ calls
> >>
> >> But in DEV_TO_DEV?
> >
> > Do we support that :D
> >
> >> If we have two peripherals, both needs config:
> >> p1_config and p2_config
> >>
> >> What and how would one use the single peripheral_config?
> >
> > Since the config is implementation specific, I do not think it limits.
> > You may create
> >
> > struct peter_config {
> > struct p1_config;
> > struct p2_config;
> > };
>
> The use case is:
> MEM -DMA-> P1 -DMA-> P2
> or
> P2 -DMA-> P1 -DMA-> MEM
> or
> MEM -DMA-> P2
> or
> P2 -DMA-> MEM
> or
> MEM -DMA-> P1 -DMA-> MEM
>
> How would the DMA guess what it should do? How would the independent P1
> and P2 would know how to set up the config?
As I said, we do not support DEV_TO_DEV yet :)
Question is how would p1<-->p2 look, will p1 initiate a DMA txn or p2..?
who will configure these..
Do you have a real world example in horizon...
--
~Vinod
next prev parent reply other threads:[~2020-10-12 6:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 12:31 [PATCH v4 0/3] dmaengine: Add support for QCOM GSI dma controller Vinod Koul
2020-10-08 12:31 ` [PATCH v4 1/3] dt-bindings: dmaengine: Document qcom,gpi dma binding Vinod Koul
2020-10-12 18:57 ` Rob Herring
2020-10-13 7:02 ` Vinod Koul
2020-10-08 12:31 ` [PATCH v4 2/3] dmaengine: add peripheral configuration Vinod Koul
2020-10-09 9:04 ` Peter Ujfalusi
2020-10-09 10:30 ` Vinod Koul
2020-10-09 10:45 ` Peter Ujfalusi
2020-10-09 11:15 ` Vinod Koul
2020-10-09 11:29 ` Peter Ujfalusi
2020-10-12 6:09 ` Vinod Koul [this message]
2020-10-12 12:05 ` Peter Ujfalusi
2020-10-08 12:31 ` [PATCH v4 3/3] dmaengine: qcom: Add GPI dma driver Vinod Koul
2020-10-09 9:00 ` Peter Ujfalusi
2020-10-09 10:31 ` Vinod Koul
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