linux-kernel - Re: [PATCH] ASoC: tegra: use dmaengine based dma driver

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Date:	Mon, 2 Jul 2012 13:55:58 +0530
From:	Laxman Dewangan <ldewangan@...dia.com>
To:	Stephen Warren <swarren@...dotorg.org>
CC:	"tiwai@...e.de" <tiwai@...e.de>, "perex@...ex.cz" <perex@...ex.cz>,
	Stephen Warren <swarren@...dia.com>,
	"broonie@...nsource.wolfsonmicro.com" 
	<broonie@...nsource.wolfsonmicro.com>, "lrg@...com" <lrg@...com>,
	"alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH] ASoC: tegra: use dmaengine based dma driver

On Saturday 30 June 2012 08:38 PM, Laxman Dewangan wrote:
> On Friday 29 June 2012 10:32 PM, Stephen Warren wrote:
>> On 06/29/2012 05:34 AM, Laxman Dewangan wrote:
>>> Use the dmaengine based Tegra APB DMA driver for
>>> data transfer between SPI fifo and memory in
>>> place of legacy Tegra APB DMA.
>>>
>>> Because generic soc-dmaengine-pcm uses the DMAs API
>>> based on dmaengine, using the exported APIs provided
>>> by this generic driver.
>>>
>>> The new driver is selected if legacy driver is not
>>> selected and new dma driver is enabled through config
>>> file.
>> This works just fine with the existing non-dmaengine DMA driver enabled.
>>
>> However, I can't get it to work with dmaengine:
>>
>>> # aplay ~/abba-dq-48000-stereo.wav
>>> [  151.613476] tegra20-i2s tegra20-i2s.0: dmaengine pcm open failed with err -6
>>> [  151.620557] tegra20-i2s tegra20-i2s.0: can't open platform tegra20-i2s.0: -6
>>> aplay: main:654: audio open error: No such device or address
> With the error, it seems that dmachannel is not getting allocated.
>
>> I do have the following in my local tree:
>> 68a67b8 ARM: tegra: add device tree AUXDATA for APBDMA
>> 0db7a96 ARM: tegra: dma: rename driver name for clock to "tegra-apbdma"
>>
> Some dma changes which I sent and already on linux-next are also require
> with the above change.
> Alsong with that I have local change like to rename the dma driver to
> compatible with dts files (remove -new from driver).
>
> I think I should send that patches so that you can test it by:
> - Taking already applied dma driver change in linux-next.
> - Apply my new patches which I am going to send.
>
> And do local change in the tegra_defconfig to disable SYSTEM_DMA and
> enable dmaengine based dma driver.
>
>
The new dma patches are:

  dma: tegra: fix residual calculation for cyclic case
  dma: tegra: rename driver and compatible to match with dts

You require dma changes which is already in linux-next:

  dma: tegra: set DMA_CYCLIC capability
  dma: tegra: do not set transfer desc flag to DMA_CTRL_ACK in cyclic mode
  dma: tegra: add clk_prepare/clk_unprepare
  dma: tegra: use sg_dma_address() for getting dma buffer address
  dma: tegra: add dmaengine based dma driver



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