linux-kernel - Re: [PATCH 4/6] dma:imx-sdma:Use devm_clk_get

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Message-ID: <20240823130835.00003495@Huawei.com>
Date: Fri, 23 Aug 2024 13:08:35 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Liao Yuanhong <liaoyuanhong@...o.com>
CC: <vkoul@...nel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<dmaengine@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/6] dma:imx-sdma:Use devm_clk_get_enabled() helpers

On Fri, 23 Aug 2024 18:19:31 +0800
Liao Yuanhong <liaoyuanhong@...o.com> wrote:

> Use devm_clk_get_enabled() instead of clk functions in imx-sdma.
> 
> Signed-off-by: Liao Yuanhong <liaoyuanhong@...o.com>
No.
Consider why the clocks are adjusted where they are in existing code
before 'cleaning' it up.

> ---
>  drivers/dma/imx-sdma.c | 57 ++++--------------------------------------
>  1 file changed, 5 insertions(+), 52 deletions(-)
> 
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index 72299a08af44..af972a4b6ce1 100644
> --- a/drivers/dma/imx-sdma.c
> +++ b/drivers/dma/imx-sdma.c
> @@ -1493,24 +1493,11 @@ static int sdma_alloc_chan_resources(struct dma_chan *chan)
>  	sdmac->event_id0 = data->dma_request;
>  	sdmac->event_id1 = data->dma_request2;
>  
> -	ret = clk_enable(sdmac->sdma->clk_ipg);
> -	if (ret)
> -		return ret;
> -	ret = clk_enable(sdmac->sdma->clk_ahb);
> -	if (ret)
> -		goto disable_clk_ipg;
> -
>  	ret = sdma_set_channel_priority(sdmac, prio);
>  	if (ret)
> -		goto disable_clk_ahb;
> +		return ret;
>  
>  	return 0;
> -
> -disable_clk_ahb:
> -	clk_disable(sdmac->sdma->clk_ahb);
> -disable_clk_ipg:
> -	clk_disable(sdmac->sdma->clk_ipg);
> -	return ret;
>  }
>  
>  static void sdma_free_chan_resources(struct dma_chan *chan)
> @@ -1530,9 +1517,6 @@ static void sdma_free_chan_resources(struct dma_chan *chan)
>  	sdmac->event_id1 = 0;
>  
>  	sdma_set_channel_priority(sdmac, 0);
> -
> -	clk_disable(sdma->clk_ipg);
> -	clk_disable(sdma->clk_ahb);
>  }
>  
>  static struct sdma_desc *sdma_transfer_init(struct sdma_channel *sdmac,
> @@ -2015,14 +1999,10 @@ static void sdma_load_firmware(const struct firmware *fw, void *context)
>  	addr = (void *)header + header->script_addrs_start;
>  	ram_code = (void *)header + header->ram_code_start;
>  
> -	clk_enable(sdma->clk_ipg);
> -	clk_enable(sdma->clk_ahb);
>  	/* download the RAM image for SDMA */
>  	sdma_load_script(sdma, ram_code,
>  			 header->ram_code_size,
>  			 addr->ram_code_start_addr);
> -	clk_disable(sdma->clk_ipg);
> -	clk_disable(sdma->clk_ahb);
Why do you think it is suddenly fine to leave the locks on here and it
wasn't before?

Check all the paths.

>  
>  	sdma_add_scripts(sdma, addr);
>  
> @@ -2119,13 +2099,6 @@ static int sdma_init(struct sdma_engine *sdma)
>  	dma_addr_t ccb_phys;
>  	int ccbsize;
>  
> -	ret = clk_enable(sdma->clk_ipg);
> -	if (ret)
> -		return ret;
> -	ret = clk_enable(sdma->clk_ahb);
> -	if (ret)
> -		goto disable_clk_ipg;
> -
>  	if (sdma->drvdata->check_ratio &&
>  	    (clk_get_rate(sdma->clk_ahb) == clk_get_rate(sdma->clk_ipg)))
>  		sdma->clk_ratio = 1;
> @@ -2180,15 +2153,9 @@ static int sdma_init(struct sdma_engine *sdma)
>  	/* Initializes channel's priorities */
>  	sdma_set_channel_priority(&sdma->channel[0], 7);
>  
> -	clk_disable(sdma->clk_ipg);
> -	clk_disable(sdma->clk_ahb);
> -
>  	return 0;
>  
>  err_dma_alloc:
> -	clk_disable(sdma->clk_ahb);
> -disable_clk_ipg:
> -	clk_disable(sdma->clk_ipg);
>  	dev_err(sdma->dev, "initialisation failed with %d\n", ret);
>  	return ret;
>  }
> @@ -2266,33 +2233,25 @@ static int sdma_probe(struct platform_device *pdev)
>  	if (IS_ERR(sdma->regs))
>  		return PTR_ERR(sdma->regs);
>  
> -	sdma->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
> +	sdma->clk_ipg = devm_clk_get_enabled(&pdev->dev, "ipg");
>  	if (IS_ERR(sdma->clk_ipg))
>  		return PTR_ERR(sdma->clk_ipg);
>  
> -	sdma->clk_ahb = devm_clk_get(&pdev->dev, "ahb");
> +	sdma->clk_ahb = devm_clk_get_enabled(&pdev->dev, "ahb");
>  	if (IS_ERR(sdma->clk_ahb))
>  		return PTR_ERR(sdma->clk_ahb);
>  
> -	ret = clk_prepare(sdma->clk_ipg);
> -	if (ret)
> -		return ret;
> -
> -	ret = clk_prepare(sdma->clk_ahb);
> -	if (ret)
> -		goto err_clk;
> -
>  	ret = devm_request_irq(&pdev->dev, irq, sdma_int_handler, 0,
>  				dev_name(&pdev->dev), sdma);
>  	if (ret)
> -		goto err_irq;
> +		return ret;
>  
>  	sdma->irq = irq;
>  
>  	sdma->script_addrs = kzalloc(sizeof(*sdma->script_addrs), GFP_KERNEL);
>  	if (!sdma->script_addrs) {
>  		ret = -ENOMEM;
> -		goto err_irq;
> +		return ret;
>  	}
>  
>  	/* initially no scripts available */
> @@ -2407,10 +2366,6 @@ static int sdma_probe(struct platform_device *pdev)
>  	dma_async_device_unregister(&sdma->dma_device);
>  err_init:
>  	kfree(sdma->script_addrs);
> -err_irq:
> -	clk_unprepare(sdma->clk_ahb);
> -err_clk:
> -	clk_unprepare(sdma->clk_ipg);
>  	return ret;
>  }
>  
> @@ -2422,8 +2377,6 @@ static void sdma_remove(struct platform_device *pdev)
>  	devm_free_irq(&pdev->dev, sdma->irq, sdma);
>  	dma_async_device_unregister(&sdma->dma_device);
>  	kfree(sdma->script_addrs);
> -	clk_unprepare(sdma->clk_ahb);
> -	clk_unprepare(sdma->clk_ipg);
>  	/* Kill the tasklet */
>  	for (i = 0; i < MAX_DMA_CHANNELS; i++) {
>  		struct sdma_channel *sdmac = &sdma->channel[i];