From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/4] dt-bindings: Document the STM32 DMA bindings
Date: Thu, 08 Oct 2015 21:26:07 +0200 [thread overview]
Message-ID: <15651913.U8kb3JZ9vO@wuerfel> (raw)
In-Reply-To: <CAOAejn0y+6uFbho3iv37xh6=zKevnp_6MxOEw4e9Oc4U2x_csQ@mail.gmail.com>
On Thursday 08 October 2015 18:01:23 M'boumba Cedric Madianga wrote:
> Hi Arnd,
>
> 2015-10-08 17:43 GMT+02:00 Arnd Bergmann <arnd@arndb.de>:
> > On Thursday 08 October 2015 17:20:09 M'boumba Cedric Madianga wrote:
> >> +Each dmas request consists of 5 cells:
> >> +1. A phandle pointing to the STM32 DMA controller
> >> +2. The channel id
> >> +3. The request line number
> >> +4. A 32bit mask specifying the DMA channel configuration
> >>
> >
> > It's fairly unusual to encode the channel id here, rather than
> > letting the driver pick one. Is that actually required here?
>
> Yes it is required as in STM32 platform the channel/request DMA
> mapping is done by hardware lines.
> So, if one client wants to use DMA, he has to choose the correct
> channel/request values according to the DMA mapping of his STM32
> platform.
Interesting. So you have seven channels ans seven request lines,
with a random but fixed mapping between them?
How do you know which channels are available for memory-to-memory
transfers?
Arnd
next prev parent reply other threads:[~2015-10-08 19:26 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-08 15:20 [PATCH 0/4] Add support for STM32 DMA M'boumba Cedric Madianga
2015-10-08 15:20 ` [PATCH 1/4] dt-bindings: Document the STM32 DMA bindings M'boumba Cedric Madianga
2015-10-08 15:43 ` Arnd Bergmann
2015-10-08 16:01 ` M'boumba Cedric Madianga
2015-10-08 19:26 ` Arnd Bergmann [this message]
2015-10-08 20:25 ` M'boumba Cedric Madianga
2015-10-08 20:40 ` Arnd Bergmann
2015-10-12 19:16 ` Maxime Coquelin
2015-10-08 15:20 ` [PATCH 2/4] dmaengine: Add STM32 DMA driver M'boumba Cedric Madianga
2015-10-12 20:09 ` Maxime Coquelin
2015-10-13 11:25 ` M'boumba Cedric Madianga
2015-10-13 11:50 ` M'boumba Cedric Madianga
2015-10-08 15:20 ` [PATCH 3/4] ARM: dts: Add STM32 DMA support for STM32F429 MCU M'boumba Cedric Madianga
2015-10-08 15:20 ` [PATCH 4/4] ARM: configs: Add STM32 DMA support in STM32 defconfig M'boumba Cedric Madianga
2015-10-12 20:11 ` Maxime Coquelin
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