linux-kernel - Re: [PATCH v2 2/3] dmaengine: imx-sdma: Only check ratio on parts that support 1:1

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Date:   Thu, 18 Apr 2019 08:54:07 +0000
From:   Robin Gong <yibin.gong@....com>
To:     Angus Ainslie <angus.ainslie@...i.sm>,
        "angus@...ea.ca" <angus@...ea.ca>
CC:     dl-linux-imx <linux-imx@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "ccaione@...libre.com" <ccaione@...libre.com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "festevam@...il.com" <festevam@...il.com>,
        "agx@...xcpu.org" <agx@...xcpu.org>,
        "dan.j.williams@...el.com" <dan.j.williams@...el.com>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "dmaengine@...r.kernel.org" <dmaengine@...r.kernel.org>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "vkoul@...nel.org" <vkoul@...nel.org>,
        Daniel Baluta <daniel.baluta@....com>,
        "l.stach@...gutronix.de" <l.stach@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>
Subject: Re: [PATCH v2 2/3] dmaengine: imx-sdma: Only check ratio on parts
 that support 1:1

Acked-by: Robin Gong <yibin.gong@....com>
On 2019-03-29 at 15:21 +0000, Angus Ainslie (Purism) wrote:
> On imx8mq B0 chip, AHB/SDMA clock ratio 2:1 can't be supported,
> since SDMA clock ratio has to be increased to 250Mhz, AHB can't reach
> to 500Mhz, so use 1:1 instead.
> 
> To limit this change to the imx8mq for now this patch also adds an
> im8mq-sdma compatible string.
> 
> Signed-off-by: Angus Ainslie (Purism) <angus@...ea.ca>
> ---
>  drivers/dma/imx-sdma.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index 5f3c1378b90e..99d9f431ae2c 100644
> --- a/drivers/dma/imx-sdma.c
> +++ b/drivers/dma/imx-sdma.c
> @@ -419,6 +419,7 @@ struct sdma_driver_data {
>  	int chnenbl0;
>  	int num_events;
>  	struct sdma_script_start_addrs	*script_addrs;
> +	bool check_ratio;
>  };
>  
>  struct sdma_engine {
> @@ -557,6 +558,13 @@ static struct sdma_driver_data sdma_imx7d = {
>  	.script_addrs = &sdma_script_imx7d,
>  };
>  
> +static struct sdma_driver_data sdma_imx8mq = {
> +	.chnenbl0 = SDMA_CHNENBL0_IMX35,
> +	.num_events = 48,
> +	.script_addrs = &sdma_script_imx7d,
> +	.check_ratio = 1,
> +};
> +
>  static const struct platform_device_id sdma_devtypes[] = {
>  	{
>  		.name = "imx25-sdma",
> @@ -579,6 +587,9 @@ static const struct platform_device_id
> sdma_devtypes[] = {
>  	}, {
>  		.name = "imx7d-sdma",
>  		.driver_data = (unsigned long)&sdma_imx7d,
> +	}, {
> +		.name = "imx8mq-sdma",
> +		.driver_data = (unsigned long)&sdma_imx8mq,
>  	}, {
>  		/* sentinel */
>  	}
> @@ -593,6 +604,7 @@ static const struct of_device_id sdma_dt_ids[] =
> {
>  	{ .compatible = "fsl,imx31-sdma", .data = &sdma_imx31, },
>  	{ .compatible = "fsl,imx25-sdma", .data = &sdma_imx25, },
>  	{ .compatible = "fsl,imx7d-sdma", .data = &sdma_imx7d, },
> +	{ .compatible = "fsl,imx8mq-sdma", .data = &sdma_imx8mq, },
>  	{ /* sentinel */ }
>  };
>  MODULE_DEVICE_TABLE(of, sdma_dt_ids);
> @@ -1852,7 +1864,8 @@ static int sdma_init(struct sdma_engine *sdma)
>  	if (ret)
>  		goto disable_clk_ipg;
>  
> -	if (clk_get_rate(sdma->clk_ahb) == clk_get_rate(sdma-
> >clk_ipg))
> +	if (sdma->drvdata->check_ratio &&
> +	    (clk_get_rate(sdma->clk_ahb) == clk_get_rate(sdma-
> >clk_ipg)))
>  		sdma->clk_ratio = 1;
>  
>  	/* Be sure SDMA has not started yet */