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 01:10:00 -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 4/4] ASoC: fsl_asrc_dma: Fix data copying speed
 issue with EDMA
Message-ID: <20200612081000.GD22422@Asurada-Nvidia>
References: <cover.1591947428.git.shengjiu.wang@nxp.com>
 <424ed6c249bafcbe30791c9de0352821c5ea67e2.1591947428.git.shengjiu.wang@nxp.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <424ed6c249bafcbe30791c9de0352821c5ea67e2.1591947428.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 03:37:51PM +0800, Shengjiu Wang wrote:
> With EDMA, there is two dma channels can be used for dev_to_dev,
> one is from ASRC, one is from another peripheral (ESAI or SAI).
> 
> If we select the dma channel of ASRC, there is an issue for ideal
> ratio case, the speed of copy data is faster than sample
> frequency, because ASRC output data is very fast in ideal ratio
> mode.
> 
> So it is reasonable to use the dma channel of Back-End peripheral.
> then copying speed of DMA is controlled by data consumption
> speed in the peripheral FIFO,
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>

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