From: Pierre Yves MORDRET <pierre-yves.mordret@st.com>
To: Peter Ujfalusi <peter.ujfalusi@ti.com>,
Vinod Koul <vinod.koul@intel.com>
Cc: Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre TORGUE <alexandre.torgue@st.com>,
Russell King <linux@armlinux.org.uk>,
Dan Williams <dan.j.williams@intel.com>,
"M'boumba Cedric Madianga" <cedric.madianga@gmail.com>,
Fabrice GASNIER <fabrice.gasnier@st.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Fabien DESSENNE <fabien.dessenne@st.com>,
Amelie DELAUNAY <amelie.delaunay@st.com>,
"dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/5] dmaengine: Add STM32 DMAMUX driver
Date: Wed, 2 Aug 2017 16:28:40 +0200 [thread overview]
Message-ID: <0e16a519-3d60-f683-5517-12a520e0e521@st.com> (raw)
In-Reply-To: <47ceba83-1097-072e-bed6-d1964bce7a25@ti.com>
On 08/02/2017 04:09 PM, Peter Ujfalusi wrote:
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
> On 2017-08-02 16:11, Pierre Yves MORDRET wrote:
>> Our SoC works with or without DMAMUX. Both binding is allowed. Using only DMA a
>> ChannelId and request line is part of the binding.
>
> In our case the am335x's eDMA can work with or without the router, we
> only use the router node if we need none default event for a given DMA
> request line.
>
>> Using DMAMUx now the request
>> line is coming from dma_spec forwards to dma-master as well explained by Peter.
>> However ChannelID is now given by dma_get_any_slave_channel instead of bindings.
>> DMAMUX driver has to be aware of this ID to route request line to out DMA
>> channel. This channel id information is carried on until DMAMUX through
>> dmaengine_slave_config with a custom API.
>> Hope it clarifies the need.
>
> I see, this is not much different then what we face with our dra7
> devices. In theory we could use direct DMA binding to the DMA controller
> itself, but some requests would not be reachable, so we always use the
> router's node for DMA on dra7 family.
>
> Basically the router would manage the ChannelID and create
> 'st,stm32-dma' compatible dma_spec (the four parameters).
> Afaik you could have 3 parameters for the router and create a four
> parameter dma_spec, where the ChannelID is dynamically allocated.
Correct router needs 3 parameters and among those 2 are forwarded though out
dma_spec. But when you say "ChannelID is dynamically allocated" you mean
dma_get_any_slave_channel ? If yes I can use the already existing bindings to
carry the channelID to DMA. No changes need to peripheral...
> But you need to convert all peripherals to use the router's node for the
> DMA.
>
> - Péter
>
Py
next prev parent reply other threads:[~2017-08-02 14:29 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-06 12:20 [PATCH v3 0/5] Add STM32 DMAMUX support Pierre-Yves MORDRET
2017-07-06 12:20 ` [PATCH v3 1/5] dt-bindings: Document the STM32 DMAMUX bindings Pierre-Yves MORDRET
2017-07-10 3:56 ` Rob Herring
2017-07-06 12:20 ` [PATCH v3 2/5] dmaengine: Add STM32 DMAMUX driver Pierre-Yves MORDRET
2017-07-22 6:51 ` Vinod Koul
2017-07-24 13:55 ` Pierre Yves MORDRET
2017-07-26 5:29 ` Vinod Koul
2017-07-26 7:38 ` Pierre Yves MORDRET
2017-07-31 12:31 ` Vinod Koul
2017-08-01 9:32 ` Pierre Yves MORDRET
2017-08-02 4:55 ` Vinod Koul
2017-08-02 9:19 ` Peter Ujfalusi
2017-08-02 13:11 ` Pierre Yves MORDRET
2017-08-02 14:09 ` Peter Ujfalusi
2017-08-02 14:28 ` Pierre Yves MORDRET [this message]
2017-08-03 6:42 ` Peter Ujfalusi
2017-08-03 9:00 ` Pierre Yves MORDRET
2017-08-03 9:48 ` Peter Ujfalusi
2017-08-04 12:50 ` Pierre Yves MORDRET
2017-08-04 14:21 ` Peter Ujfalusi
2017-08-21 9:34 ` Pierre Yves MORDRET
2017-08-24 5:47 ` Peter Ujfalusi
2017-08-24 13:03 ` Pierre Yves MORDRET
2017-08-28 11:48 ` Peter Ujfalusi
2017-08-30 8:02 ` Pierre Yves MORDRET
2017-07-06 12:20 ` [PATCH v3 3/5] dt-bindings: stm32-dma: Add property to handle STM32 DMAMUX Pierre-Yves MORDRET
2017-07-10 3:57 ` Rob Herring
2017-07-06 12:20 ` [PATCH v3 4/5] dmaengine: stm32-dma: Add support for " Pierre-Yves MORDRET
2017-07-06 12:20 ` [PATCH v3 5/5] ARM: configs: stm32: Add DMAMUX support in STM32 defconfig Pierre-Yves MORDRET
2017-07-20 9:42 ` [PATCH v3 0/5] Add STM32 DMAMUX support Pierre Yves MORDRET
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