Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 12 Jun 2020 01:08:17 -0700
From:   Nicolin Chen <nicoleotsuka@gmail.com>
To:     Shengjiu Wang <shengjiu.wang@nxp.com>
Cc:     lars@metafoo.de, perex@perex.cz, tiwai@suse.com,
        lgirdwood@gmail.com, broonie@kernel.org, timur@kernel.org,
        Xiubo.Lee@gmail.com, festevam@gmail.com,
        alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC PATCH v3 3/4] ASoC: fsl_asrc_dma: Reuse the dma channel if
 available in Back-End
Message-ID: <20200612080817.GC22422@Asurada-Nvidia>
References: <cover.1591947428.git.shengjiu.wang@nxp.com>
 <3a79f0442cb4930c633cf72145cfe95a45b9c78e.1591947428.git.shengjiu.wang@nxp.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <3a79f0442cb4930c633cf72145cfe95a45b9c78e.1591947428.git.shengjiu.wang@nxp.com>
User-Agent: Mutt/1.9.4 (2018-02-28)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Jun 12, 2020 at 03:37:50PM +0800, Shengjiu Wang wrote:
> The dma channel has been requested by Back-End cpu dai driver already.
> If fsl_asrc_dma requests dma chan with same dma:tx symlink, then
> there will be below warning with SDMA.
> 
> [   48.174236] fsl-esai-dai 2024000.esai: Cannot create DMA dma:tx symlink
> 
> So if we can reuse the dma channel of Back-End, then the issue can be
> fixed.
> 
> In order to get the dma channel which is already requested in Back-End.
> we use the exported two functions (snd_soc_lookup_component_nolocked
> and soc_component_to_pcm). If we can get the dma channel, then reuse it,
> if can't, then request a new one.
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>

Reviewed-by: Nicolin Chen <nicoleotsuka@gmail.com>