linux-kernel - Re: [PATCH v2 06/12] dmaengine: sun6i: make gate bit in sun8i's DMA engines a common quirk

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Message-ID: <CAGb2v65Cic941D7ioDZvqBXTdCxxYQTp-QDe3zwPhnXaiYoOOw@mail.gmail.com>
Date:   Mon, 6 Mar 2017 11:50:52 +0800
From:   Chen-Yu Tsai <wens@...e.org>
To:     Icenowy Zheng <icenowy@...c.xyz>
Cc:     Vinod Koul <vinod.koul@...el.com>,
        Rob Herring <robh+dt@...nel.org>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Chen-Yu Tsai <wens@...e.org>, Mark Brown <broonie@...nel.org>,
        dmaengine@...r.kernel.org, devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Linux-ALSA <alsa-devel@...a-project.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>
Subject: Re: [PATCH v2 06/12] dmaengine: sun6i: make gate bit in sun8i's DMA
 engines a common quirk

On Sun, Mar 5, 2017 at 9:37 PM, Icenowy Zheng <icenowy@...c.xyz> wrote:
> Originally we enable a special gate bit when the compatible indicates
> A23/33.
>
> But according to BSP sources and user manuals, more SoCs will need this
> gate bit.
>
> So make it a common quirk configured in the config struct.
>
> The BSP source also indicates that A83T will need this gate bit (there's
> "SUN8IW6" in the #ifdef's), so also enable this gate bit for it.

This should be 2 patches, 1 making the option generic, and 1 setting it
for A83T. The DMA engine on A83T is unused in past releases, so no need
to CC stable.

Normally when you mention "also xxxx" in your commit message, it is a
good indicator you should split your patch, unless it is something really
trivial like an extra whitespace cleanup, or splitting the patch would
break the build.

Once split, please add

Acked-by: Chen-Yu Tsai <wens@...e.org>

to both patches.

Regards
ChenYu

> Signed-off-by: Icenowy Zheng <icenowy@...c.xyz>
> ---
>  drivers/dma/sun6i-dma.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
> index a2358780ab2c..889fb24023cd 100644
> --- a/drivers/dma/sun6i-dma.c
> +++ b/drivers/dma/sun6i-dma.c
> @@ -101,6 +101,7 @@ struct sun6i_dma_config {
>         u32 nr_max_channels;
>         u32 nr_max_requests;
>         u32 nr_max_vchans;
> +       bool gate_needed;
>  };
>
>  /*
> @@ -1009,12 +1010,14 @@ static struct sun6i_dma_config sun8i_a23_dma_cfg = {
>         .nr_max_channels = 8,
>         .nr_max_requests = 24,
>         .nr_max_vchans   = 37,
> +       .gate_needed     = true,
>  };
>
>  static struct sun6i_dma_config sun8i_a83t_dma_cfg = {
>         .nr_max_channels = 8,
>         .nr_max_requests = 28,
>         .nr_max_vchans   = 39,
> +       .gate_needed     = true,
>  };
>
>  /*
> @@ -1177,10 +1180,10 @@ static int sun6i_dma_probe(struct platform_device *pdev)
>         /*
>          * sun8i variant requires us to toggle a dma gating register,
>          * as seen in Allwinner's SDK. This register is not documented
> -        * in the A23 user manual.
> +        * in the A23 user manual, but documented at least in V3s user
> +        * manual.
>          */
> -       if (of_device_is_compatible(pdev->dev.of_node,
> -                                   "allwinner,sun8i-a23-dma"))
> +       if (sdc->cfg->gate_needed)
>                 writel(SUN8I_DMA_GATE_ENABLE, sdc->base + SUN8I_DMA_GATE);
>
>         return 0;
> --
> 2.11.1
>