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Subject: Re: [PATCH v4 2/3] dmaengine: add peripheral configuration
To:     Vinod Koul <vkoul@kernel.org>, <dmaengine@vger.kernel.org>
CC:     Rob Herring <robh+dt@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        <linux-arm-msm@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <20201008123151.764238-1-vkoul@kernel.org>
 <20201008123151.764238-3-vkoul@kernel.org>
From:   Peter Ujfalusi <peter.ujfalusi@ti.com>
Message-ID: <e2c0323b-4f41-1926-5930-c63624fe1dd1@ti.com>
Date:   Fri, 9 Oct 2020 12:04:24 +0300
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On 08/10/2020 15.31, Vinod Koul wrote:
> Some complex dmaengine controllers have capability to program the
> peripheral device, so pass on the peripheral configuration as part of
> dma_slave_config
>
> Signed-off-by: Vinod Koul <vkoul@kernel.org>
> ---
>  include/linux/dmaengine.h | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 6fbd5c99e30c..a15dc2960f6d 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -418,6 +418,9 @@ enum dma_slave_buswidth {
>   * @slave_id: Slave requester id. Only valid for slave channels. The dma
>   * slave peripheral will have unique id as dma requester which need to be
>   * pass as slave config.
> + * @peripheral_config: peripheral configuration for programming peripheral
> + * for dmaengine transfer
> + * @peripheral_size: peripheral configuration buffer size
>   *
>   * This struct is passed in as configuration data to a DMA engine
>   * in order to set up a certain channel for DMA transport at runtime.
> @@ -443,6 +446,8 @@ struct dma_slave_config {
>  	u32 dst_port_window_size;
>  	bool device_fc;
>  	unsigned int slave_id;
> +	void *peripheral_config;
> +	size_t peripheral_size;

Do you foresee a need of src/dst pair of these?
If we do DEV_TO_DEV with different type of peripherals it is going to
cause issues.

AASRC to McASP and McASP to AASRC for example.

>  };
>  
>  /**
> 

- Péter

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