linux-kernel - Re: [PATCH 5/5] ASoC: rsnd: dma: use extended audio dmac registers when available

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Date:   13 Mar 2019 15:23:58 +0900
From:   Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
To:     Jiada Wang <jiada_wang@...tor.com>
Cc:     <horms@...ge.net.au>, <magnus.damm@...il.com>,
        <robh+dt@...nel.org>, <mark.rutland@....com>,
        <lgirdwood@...il.com>, <broonie@...nel.org>, <perex@...ex.cz>,
        <tiwai@...e.com>, <geert@...ux-m68k.org>,
        <linux-renesas-soc@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <alsa-devel@...a-project.org>
Subject: Re: [PATCH 5/5] ASoC: rsnd: dma: use extended audio dmac registers when available


Hi Jiada

> Some of SoCs have both basic and extended dmac registers set
> basic set only supports busif0 ~ busif3, in order to use
> busif4 ~ busif7, extended audio dmac registers need to be used.
> 
> This patch changes to use extended dmac registers set when it is
> available in device-tree.
> 
> Signed-off-by: Jiada Wang <jiada_wang@...tor.com>
> ---

1st of all, if you want to post this kind of patch-set,
you *should* post driver side patch 1st, and if it was accepted,
you need to post SoC side patch. Then, you need to indicate
to SoC maintainer which branch/commit should be based.
Otherwise, it will 100% breaks git-bisect.

2nd, in my understanding, our conclusion at Renesas-ML
is that we don't need to think about basic/extend DMAC register.
Because extend area is 100% covering basic area.
In other words, it is compatible.
Driver side don't need to think about it.

> --- a/sound/soc/sh/rcar/dma.c
> +++ b/sound/soc/sh/rcar/dma.c
> @@ -830,7 +830,10 @@ int rsnd_dma_probe(struct rsnd_priv *priv)
>  	/*
>  	 * for Gen2 or later
>  	 */
> -	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "audmapp");
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "extaudmapp");
> +	if (!res)
> +		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +						   "audmapp");
>  	dmac = devm_kzalloc(dev, sizeof(*dmac), GFP_KERNEL);
>  	if (!dmac || !res) {
>  		dev_err(dev, "dma allocate failed\n");
> -- 
> 2.19.2
>