Date:   Fri, 20 Oct 2017 08:31:38 +0200
From:   Michal Simek <michal.simek@...inx.com>
To:     Kedareswara rao Appana <appana.durga.rao@...inx.com>,
        <vinod.koul@...el.com>, <dan.j.williams@...el.com>,
        <michal.simek@...inx.com>, <sr@...x.de>,
        <linus.walleij@...aro.org>, <dave.jiang@...el.com>
CC:     <dmaengine@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Kedareswara rao Appana <appanad@...inx.com>
Subject: Re: [PATCH] dmaengine: zynqmp_dma: Add runtime pm support

On 18.10.2017 09:02, Kedareswara rao Appana wrote:
> This patch adds runtime pm support in the driver.
> 
> Signed-off-by: Kedareswara rao Appana <appanad@...inx.com>
> ---
>  drivers/dma/xilinx/zynqmp_dma.c | 167 ++++++++++++++++++++++++++++++++--------
>  1 file changed, 135 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
> index 1ee1241..dd73831 100644
> --- a/drivers/dma/xilinx/zynqmp_dma.c
> +++ b/drivers/dma/xilinx/zynqmp_dma.c
> @@ -23,6 +23,7 @@
>  #include <linux/slab.h>
>  #include <linux/clk.h>
>  #include <linux/io-64-nonatomic-lo-hi.h>
> +#include <linux/pm_runtime.h>
>  
>  #include "../dmaengine.h"
>  
> @@ -138,6 +139,8 @@
>  #define ZYNQMP_DMA_BUS_WIDTH_64		64
>  #define ZYNQMP_DMA_BUS_WIDTH_128	128
>  
> +#define ZDMA_PM_TIMEOUT			100
> +
>  #define ZYNQMP_DMA_DESC_SIZE(chan)	(chan->desc_size)
>  
>  #define to_chan(chan)		container_of(chan, struct zynqmp_dma_chan, \
> @@ -211,8 +214,6 @@ struct zynqmp_dma_desc_sw {
>   * @bus_width: Bus width
>   * @src_burst_len: Source burst length
>   * @dst_burst_len: Dest burst length
> - * @clk_main: Pointer to main clock
> - * @clk_apb: Pointer to apb clock
>   */
>  struct zynqmp_dma_chan {
>  	struct zynqmp_dma_device *zdev;
> @@ -237,8 +238,6 @@ struct zynqmp_dma_chan {
>  	u32 bus_width;
>  	u32 src_burst_len;
>  	u32 dst_burst_len;
> -	struct clk *clk_main;
> -	struct clk *clk_apb;
>  };
>  
>  /**
> @@ -246,11 +245,15 @@ struct zynqmp_dma_chan {
>   * @dev: Device Structure
>   * @common: DMA device structure
>   * @chan: Driver specific DMA channel
> + * @clk_main: Pointer to main clock
> + * @clk_apb: Pointer to apb clock
>   */
>  struct zynqmp_dma_device {
>  	struct device *dev;
>  	struct dma_device common;
>  	struct zynqmp_dma_chan *chan;
> +	struct clk *clk_main;
> +	struct clk *clk_apb;
>  };
>  
>  static inline void zynqmp_dma_writeq(struct zynqmp_dma_chan *chan, u32 reg,
> @@ -461,7 +464,11 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
>  {
>  	struct zynqmp_dma_chan *chan = to_chan(dchan);
>  	struct zynqmp_dma_desc_sw *desc;
> -	int i;
> +	int i, ret;
> +
> +	ret = pm_runtime_get_sync(chan->dev);
> +	if (ret < 0)
> +		return ret;
>  
>  	chan->sw_desc_pool = kzalloc(sizeof(*desc) * ZYNQMP_DMA_NUM_DESCS,
>  				     GFP_KERNEL);
> @@ -664,6 +671,8 @@ static void zynqmp_dma_free_chan_resources(struct dma_chan *dchan)
>  		(2 * ZYNQMP_DMA_DESC_SIZE(chan) * ZYNQMP_DMA_NUM_DESCS),
>  		chan->desc_pool_v, chan->desc_pool_p);
>  	kfree(chan->sw_desc_pool);
> +	pm_runtime_mark_last_busy(chan->dev);
> +	pm_runtime_put_autosuspend(chan->dev);
>  }
>  
>  /**
> @@ -841,8 +850,6 @@ static void zynqmp_dma_chan_remove(struct zynqmp_dma_chan *chan)
>  	devm_free_irq(chan->zdev->dev, chan->irq, chan);
>  	tasklet_kill(&chan->tasklet);
>  	list_del(&chan->common.device_node);
> -	clk_disable_unprepare(chan->clk_apb);
> -	clk_disable_unprepare(chan->clk_main);
>  }
>  
>  /**
> @@ -907,30 +914,6 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
>  			       "zynqmp-dma", chan);
>  	if (err)
>  		return err;
> -	chan->clk_main = devm_clk_get(&pdev->dev, "clk_main");
> -	if (IS_ERR(chan->clk_main)) {
> -		dev_err(&pdev->dev, "main clock not found.\n");
> -		return PTR_ERR(chan->clk_main);
> -	}
> -
> -	chan->clk_apb = devm_clk_get(&pdev->dev, "clk_apb");
> -	if (IS_ERR(chan->clk_apb)) {
> -		dev_err(&pdev->dev, "apb clock not found.\n");
> -		return PTR_ERR(chan->clk_apb);
> -	}
> -
> -	err = clk_prepare_enable(chan->clk_main);
> -	if (err) {
> -		dev_err(&pdev->dev, "Unable to enable main clock.\n");
> -		return err;
> -	}
> -
> -	err = clk_prepare_enable(chan->clk_apb);
> -	if (err) {
> -		clk_disable_unprepare(chan->clk_main);
> -		dev_err(&pdev->dev, "Unable to enable apb clock.\n");
> -		return err;
> -	}
>  
>  	chan->desc_size = sizeof(struct zynqmp_dma_desc_ll);
>  	chan->idle = true;
> @@ -953,6 +936,87 @@ static struct dma_chan *of_zynqmp_dma_xlate(struct of_phandle_args *dma_spec,
>  }
>  
>  /**
> + * zynqmp_dma_suspend - Suspend method for the driver
> + * @dev:	Address of the device structure
> + *
> + * Put the driver into low power mode.
> + * Return: 0 on success and failure value on error
> + */
> +static int __maybe_unused zynqmp_dma_suspend(struct device *dev)
> +{
> +	if (!device_may_wakeup(dev))
> +		return pm_runtime_force_suspend(dev);
> +
> +	return 0;
> +}
> +
> +/**
> + * zynqmp_dma_resume - Resume from suspend
> + * @dev:	Address of the device structure
> + *
> + * Resume operation after suspend.
> + * Return: 0 on success and failure value on error
> + */
> +static int __maybe_unused zynqmp_dma_resume(struct device *dev)
> +{
> +	if (!device_may_wakeup(dev))
> +		return pm_runtime_force_resume(dev);
> +
> +	return 0;
> +}
> +
> +/**
> + * zynqmp_dma_runtime_suspend - Runtime suspend method for the driver
> + * @dev:	Address of the device structure
> + *
> + * Put the driver into low power mode.
> + * Return: 0 always
> + */
> +static int __maybe_unused zynqmp_dma_runtime_suspend(struct device *dev)
> +{
> +	struct zynqmp_dma_device *zdev = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(zdev->clk_main);
> +	clk_disable_unprepare(zdev->clk_apb);
> +
> +	return 0;
> +}
> +
> +/**
> + * zynqmp_dma_runtime_resume - Runtime suspend method for the driver
> + * @dev:	Address of the device structure
> + *
> + * Put the driver into low power mode.
> + * Return: 0 always
> + */
> +static int __maybe_unused zynqmp_dma_runtime_resume(struct device *dev)
> +{
> +	struct zynqmp_dma_device *zdev = dev_get_drvdata(dev);
> +	int err;
> +
> +	err = clk_prepare_enable(zdev->clk_main);
> +	if (err) {
> +		dev_err(dev, "Unable to enable main clock.\n");
> +		return err;
> +	}
> +
> +	err = clk_prepare_enable(zdev->clk_apb);
> +	if (err) {
> +		dev_err(dev, "Unable to enable apb clock.\n");
> +		clk_disable_unprepare(zdev->clk_main);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops zynqmp_dma_dev_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(zynqmp_dma_suspend, zynqmp_dma_resume)
> +	SET_RUNTIME_PM_OPS(zynqmp_dma_runtime_suspend,
> +			   zynqmp_dma_runtime_resume, NULL)
> +};
> +
> +/**
>   * zynqmp_dma_probe - Driver probe function
>   * @pdev: Pointer to the platform_device structure
>   *
> @@ -984,12 +1048,39 @@ static int zynqmp_dma_probe(struct platform_device *pdev)
>  	p->device_config = zynqmp_dma_device_config;
>  	p->dev = &pdev->dev;
>  
> +	zdev->clk_main = devm_clk_get(&pdev->dev, "clk_main");
> +	if (IS_ERR(zdev->clk_main)) {
> +		dev_err(&pdev->dev, "main clock not found.\n");
> +		return PTR_ERR(zdev->clk_main);
> +	}
> +
> +	zdev->clk_apb = devm_clk_get(&pdev->dev, "clk_apb");
> +	if (IS_ERR(zdev->clk_apb)) {
> +		dev_err(&pdev->dev, "apb clock not found.\n");
> +		return PTR_ERR(zdev->clk_apb);
> +	}
> +
> +	ret = clk_prepare_enable(zdev->clk_main);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Unable to enable main clock.\n");
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(zdev->clk_apb);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Unable to enable apb clock.\n");
> +		goto err_disable_clk;
> +	}
> +
>  	platform_set_drvdata(pdev, zdev);
> +	pm_runtime_set_autosuspend_delay(zdev->dev, ZDMA_PM_TIMEOUT);
> +	pm_runtime_use_autosuspend(zdev->dev);
> +	pm_runtime_enable(zdev->dev);
>  
>  	ret = zynqmp_dma_chan_probe(zdev, pdev);
>  	if (ret) {
>  		dev_err(&pdev->dev, "Probing channel failed\n");
> -		goto free_chan_resources;
> +		goto err_disable_pm;
>  	}
>  
>  	p->dst_addr_widths = BIT(zdev->chan->bus_width / 8);
> @@ -1005,10 +1096,18 @@ static int zynqmp_dma_probe(struct platform_device *pdev)
>  		goto free_chan_resources;
>  	}
>  
> +	pm_runtime_mark_last_busy(zdev->dev);
> +	pm_runtime_put_sync_autosuspend(zdev->dev);
> +
>  	dev_info(&pdev->dev, "ZynqMP DMA driver Probe success\n");
>  
>  	return 0;
>  
> +err_disable_clk:
> +	clk_disable_unprepare(zdev->clk_main);
> +err_disable_pm:
> +	clk_disable_unprepare(zdev->clk_apb);
> +	pm_runtime_disable(zdev->dev);
>  free_chan_resources:
>  	zynqmp_dma_chan_remove(zdev->chan);
>  	return ret;
> @@ -1028,6 +1127,9 @@ static int zynqmp_dma_remove(struct platform_device *pdev)
>  	dma_async_device_unregister(&zdev->common);
>  
>  	zynqmp_dma_chan_remove(zdev->chan);
> +	pm_runtime_disable(zdev->dev);
> +	clk_disable_unprepare(zdev->clk_apb);
> +	clk_disable_unprepare(zdev->clk_main);
>  
>  	return 0;
>  }
> @@ -1042,6 +1144,7 @@ static struct platform_driver zynqmp_dma_driver = {
>  	.driver = {
>  		.name = "xilinx-zynqmp-dma",
>  		.of_match_table = zynqmp_dma_of_match,
> +		.pm = &zynqmp_dma_dev_pm_ops,
>  	},
>  	.probe = zynqmp_dma_probe,
>  	.remove = zynqmp_dma_remove,
> 

CR number?

M

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