Message-ID: <C246CAC1457055469EF09E3A7AC4E11A4A4F43EC@XAP-PVEXMBX01.xlnx.xilinx.com>
Date:	Mon, 26 Oct 2015 06:11:39 +0000
From:	Appana Durga Kedareswara Rao <appana.durga.rao@...inx.com>
To:	Marc Kleine-Budde <mkl@...gutronix.de>,
	Anirudha Sarangi <anirudh@...inx.com>,
	"wg@...ndegger.com" <wg@...ndegger.com>,
	Michal Simek <michals@...inx.com>,
	Soren Brinkmann <sorenb@...inx.com>
CC:	"linux-can@...r.kernel.org" <linux-can@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v7] can: xilinx: Convert to runtime_pm

Hi Marc,

> -----Original Message-----
> From: Marc Kleine-Budde [mailto:mkl@...gutronix.de]
> Sent: Monday, October 26, 2015 1:54 AM
> To: Appana Durga Kedareswara Rao; Anirudha Sarangi; wg@...ndegger.com;
> Michal Simek; Soren Brinkmann
> Cc: linux-can@...r.kernel.org; netdev@...r.kernel.org; linux-arm-
> kernel@...ts.infradead.org; linux-kernel@...r.kernel.org; Appana Durga
> Kedareswara Rao
> Subject: Re: [PATCH v7] can: xilinx: Convert to runtime_pm
> 
> On 10/23/2015 07:23 AM, Kedareswara rao Appana wrote:
> > Instead of enabling/disabling clocks at several locations in the
> > driver, Use the runtime_pm framework. This consolidates the actions
> > for runtime PM In the appropriate callbacks and makes the driver more
> readable and mantainable.
> >
> > Signed-off-by: Kedareswara rao Appana <appanad@...inx.com>
> > ---
> > Changes for v7:
> >   - Removed the unnecessary clk_prepare/clk_unprepare calls
> >     From  the probe and remove as suggested by Soren.
> > Changes for v6:
> >  - Updated the driver with review comments as suggested by Marc.
> > Changes for v5:
> >  - Updated with the review comments.
> >    Updated the remove fuction to use runtime_pm.
> > Chnages for v4:
> >  - Updated with the review comments.
> > Changes for v3:
> >   - Converted the driver to use runtime_pm.
> > Changes for v2:
> >   - Removed the struct platform_device* from suspend/resume
> >     as suggest by Lothar.
> >
> >  drivers/net/can/xilinx_can.c | 177
> > +++++++++++++++++++++++++------------------
> >  1 file changed, 102 insertions(+), 75 deletions(-)
> >
> > diff --git a/drivers/net/can/xilinx_can.c
> > b/drivers/net/can/xilinx_can.c index fc55e8e..fcb584f 100644
> > --- a/drivers/net/can/xilinx_can.c
> > +++ b/drivers/net/can/xilinx_can.c
> > @@ -32,6 +32,7 @@
> >  #include <linux/can/dev.h>
> >  #include <linux/can/error.h>
> >  #include <linux/can/led.h>
> > +#include <linux/pm_runtime.h>
> >
> >  #define DRIVER_NAME	"xilinx_can"
> >
> > @@ -138,7 +139,7 @@ struct xcan_priv {
> >  	u32 (*read_reg)(const struct xcan_priv *priv, enum xcan_reg reg);
> >  	void (*write_reg)(const struct xcan_priv *priv, enum xcan_reg reg,
> >  			u32 val);
> > -	struct net_device *dev;
> > +	struct device *dev;
> >  	void __iomem *reg_base;
> >  	unsigned long irq_flags;
> >  	struct clk *bus_clk;
> > @@ -843,6 +844,13 @@ static int xcan_open(struct net_device *ndev)
> >  	struct xcan_priv *priv = netdev_priv(ndev);
> >  	int ret;
> >
> > +	ret = pm_runtime_get_sync(priv->dev);
> > +	if (ret < 0) {
> > +		netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
> > +				__func__, ret);
> > +		return ret;
> > +	}
> > +
> >  	ret = request_irq(ndev->irq, xcan_interrupt, priv->irq_flags,
> >  			ndev->name, ndev);
> >  	if (ret < 0) {
> > @@ -850,29 +858,17 @@ static int xcan_open(struct net_device *ndev)
> >  		goto err;
> >  	}
> >
> > -	ret = clk_prepare_enable(priv->can_clk);
> > -	if (ret) {
> > -		netdev_err(ndev, "unable to enable device clock\n");
> > -		goto err_irq;
> > -	}
> > -
> > -	ret = clk_prepare_enable(priv->bus_clk);
> > -	if (ret) {
> > -		netdev_err(ndev, "unable to enable bus clock\n");
> > -		goto err_can_clk;
> > -	}
> > -
> >  	/* Set chip into reset mode */
> >  	ret = set_reset_mode(ndev);
> >  	if (ret < 0) {
> >  		netdev_err(ndev, "mode resetting failed!\n");
> > -		goto err_bus_clk;
> > +		goto err_irq;
> >  	}
> >
> >  	/* Common open */
> >  	ret = open_candev(ndev);
> >  	if (ret)
> > -		goto err_bus_clk;
> > +		goto err_irq;
> >
> >  	ret = xcan_chip_start(ndev);
> >  	if (ret < 0) {
> > @@ -888,13 +884,11 @@ static int xcan_open(struct net_device *ndev)
> >
> >  err_candev:
> >  	close_candev(ndev);
> > -err_bus_clk:
> > -	clk_disable_unprepare(priv->bus_clk);
> > -err_can_clk:
> > -	clk_disable_unprepare(priv->can_clk);
> >  err_irq:
> >  	free_irq(ndev->irq, ndev);
> >  err:
> > +	pm_runtime_put(priv->dev);
> > +
> >  	return ret;
> >  }
> >
> > @@ -911,12 +905,11 @@ static int xcan_close(struct net_device *ndev)
> >  	netif_stop_queue(ndev);
> >  	napi_disable(&priv->napi);
> >  	xcan_chip_stop(ndev);
> > -	clk_disable_unprepare(priv->bus_clk);
> > -	clk_disable_unprepare(priv->can_clk);
> >  	free_irq(ndev->irq, ndev);
> >  	close_candev(ndev);
> >
> >  	can_led_event(ndev, CAN_LED_EVENT_STOP);
> > +	pm_runtime_put(priv->dev);
> >
> >  	return 0;
> >  }
> > @@ -935,27 +928,20 @@ static int xcan_get_berr_counter(const struct
> net_device *ndev,
> >  	struct xcan_priv *priv = netdev_priv(ndev);
> >  	int ret;
> >
> > -	ret = clk_prepare_enable(priv->can_clk);
> > -	if (ret)
> > -		goto err;
> > -
> > -	ret = clk_prepare_enable(priv->bus_clk);
> > -	if (ret)
> > -		goto err_clk;
> > +	ret = pm_runtime_get_sync(priv->dev);
> > +	if (ret < 0) {
> > +		netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
> > +				__func__, ret);
> > +		return ret;
> > +	}
> >
> >  	bec->txerr = priv->read_reg(priv, XCAN_ECR_OFFSET) &
> XCAN_ECR_TEC_MASK;
> >  	bec->rxerr = ((priv->read_reg(priv, XCAN_ECR_OFFSET) &
> >  			XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT);
> >
> > -	clk_disable_unprepare(priv->bus_clk);
> > -	clk_disable_unprepare(priv->can_clk);
> > +	pm_runtime_put(priv->dev);
> >
> >  	return 0;
> > -
> > -err_clk:
> > -	clk_disable_unprepare(priv->can_clk);
> > -err:
> > -	return ret;
> >  }
> >
> >
> > @@ -968,15 +954,45 @@ static const struct net_device_ops
> > xcan_netdev_ops = {
> >
> >  /**
> >   * xcan_suspend - Suspend method for the driver
> > - * @dev:	Address of the platform_device structure
> > + * @dev:	Address of the device structure
> >   *
> >   * Put the driver into low power mode.
> > - * Return: 0 always
> > + * Return: 0 on success and failure value on error
> >   */
> >  static int __maybe_unused xcan_suspend(struct device *dev)  {
> > -	struct platform_device *pdev = dev_get_drvdata(dev);
> > -	struct net_device *ndev = platform_get_drvdata(pdev);
> > +	if (!device_may_wakeup(dev))
> > +		return pm_runtime_force_suspend(dev);
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * xcan_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 xcan_resume(struct device *dev) {
> > +	if (!device_may_wakeup(dev))
> > +		return pm_runtime_force_resume(dev);
> > +
> > +	return 0;
> > +
> > +}
> > +
> > +/**
> > + * xcan_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 xcan_runtime_suspend(struct device *dev) {
> > +	struct net_device *ndev = dev_get_drvdata(dev);
> >  	struct xcan_priv *priv = netdev_priv(ndev);
> >
> >  	if (netif_running(ndev)) {
> > @@ -987,43 +1003,55 @@ static int __maybe_unused xcan_suspend(struct
> device *dev)
> >  	priv->write_reg(priv, XCAN_MSR_OFFSET, XCAN_MSR_SLEEP_MASK);
> >  	priv->can.state = CAN_STATE_SLEEPING;
> >
> > -	clk_disable(priv->bus_clk);
> > -	clk_disable(priv->can_clk);
> > +	clk_disable_unprepare(priv->bus_clk);
> > +	clk_disable_unprepare(priv->can_clk);
> >
> >  	return 0;
> >  }
> >
> >  /**
> > - * xcan_resume - Resume from suspend
> > - * @dev:	Address of the platformdevice structure
> > + * xcan_runtime_resume - Runtime 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 xcan_resume(struct device *dev)
> > +static int __maybe_unused xcan_runtime_resume(struct device *dev)
> >  {
> > -	struct platform_device *pdev = dev_get_drvdata(dev);
> > -	struct net_device *ndev = platform_get_drvdata(pdev);
> > +	struct net_device *ndev = dev_get_drvdata(dev);
> >  	struct xcan_priv *priv = netdev_priv(ndev);
> >  	int ret;
> > +	u32 isr, status;
> >
> > -	ret = clk_enable(priv->bus_clk);
> > +	ret = clk_prepare_enable(priv->bus_clk);
> >  	if (ret) {
> >  		dev_err(dev, "Cannot enable clock.\n");
> >  		return ret;
> >  	}
> > -	ret = clk_enable(priv->can_clk);
> > +	ret = clk_prepare_enable(priv->can_clk);
> >  	if (ret) {
> >  		dev_err(dev, "Cannot enable clock.\n");
> >  		clk_disable_unprepare(priv->bus_clk);
> >  		return ret;
> >  	}
> >
> > -	priv->write_reg(priv, XCAN_MSR_OFFSET, 0);
> > -	priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_CEN_MASK);
> > -	priv->can.state = CAN_STATE_ERROR_ACTIVE;
> > +	priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_RESET_MASK);
> > +	isr = priv->read_reg(priv, XCAN_ISR_OFFSET);
> > +	status = priv->read_reg(priv, XCAN_SR_OFFSET);
> >
> >  	if (netif_running(ndev)) {
> > +		if (isr & XCAN_IXR_BSOFF_MASK) {
> > +			priv->can.state = CAN_STATE_BUS_OFF;
> > +			priv->write_reg(priv, XCAN_SRR_OFFSET,
> > +					XCAN_SRR_RESET_MASK);
> > +		} else if ((status & XCAN_SR_ESTAT_MASK) ==
> > +					XCAN_SR_ESTAT_MASK) {
> > +			priv->can.state = CAN_STATE_ERROR_PASSIVE;
> > +		} else if (status & XCAN_SR_ERRWRN_MASK) {
> > +			priv->can.state = CAN_STATE_ERROR_WARNING;
> > +		} else {
> > +			priv->can.state = CAN_STATE_ERROR_ACTIVE;
> > +		}
> >  		netif_device_attach(ndev);
> >  		netif_start_queue(ndev);
> >  	}
> > @@ -1031,7 +1059,10 @@ static int __maybe_unused xcan_resume(struct
> device *dev)
> >  	return 0;
> >  }
> >
> > -static SIMPLE_DEV_PM_OPS(xcan_dev_pm_ops, xcan_suspend,
> xcan_resume);
> > +static const struct dev_pm_ops xcan_dev_pm_ops = {
> > +	SET_SYSTEM_SLEEP_PM_OPS(xcan_suspend, xcan_resume)
> > +	SET_RUNTIME_PM_OPS(xcan_runtime_suspend, xcan_runtime_resume,
> NULL)
> > +};
> >
> >  /**
> >   * xcan_probe - Platform registration call @@ -1072,7 +1103,7 @@
> > static int xcan_probe(struct platform_device *pdev)
> >  		return -ENOMEM;
> >
> >  	priv = netdev_priv(ndev);
> > -	priv->dev = ndev;
> > +	priv->dev = &pdev->dev;
> >  	priv->can.bittiming_const = &xcan_bittiming_const;
> >  	priv->can.do_set_mode = xcan_do_set_mode;
> >  	priv->can.do_get_berr_counter = xcan_get_berr_counter; @@ -
> 1114,21
> > +1145,18 @@ static int xcan_probe(struct platform_device *pdev)
> >  		}
> >  	}
> >
> > -	ret = clk_prepare_enable(priv->can_clk);
> > -	if (ret) {
> > -		dev_err(&pdev->dev, "unable to enable device clock\n");
> > -		goto err_free;
> > -	}
> > -
> > -	ret = clk_prepare_enable(priv->bus_clk);
> > -	if (ret) {
> > -		dev_err(&pdev->dev, "unable to enable bus clock\n");
> > -		goto err_unprepare_disable_dev;
> > -	}
> > -
> >  	priv->write_reg = xcan_write_reg_le;
> >  	priv->read_reg = xcan_read_reg_le;
> >
> > +	pm_runtime_irq_safe(&pdev->dev);
> 
> Have you tested the patch with lockdep enabled? 

Yes I tested with the lockdep enabled and it is working fine.

clk_prepare_enable() can sleep
> and pm_runtime_irq_safe() says that's it's ok to call the code from atomic
> context. Either remove the pm_runtime_irq_safe() or only call the clk_enable(),
> clk_disable in the RM runtime handlers.

Ok removed the pm_runtime_irq_safe call and tested it is working fine.
Will send the next version of the path.

Regards,
Kedar.

> 
> > +	pm_runtime_enable(&pdev->dev);
> > +	ret = pm_runtime_get_sync(&pdev->dev);
> > +	if (ret < 0) {
> > +		netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n",
> > +			__func__, ret);
> > +		goto err_pmdisable;
> > +	}
> > +
> >  	if (priv->read_reg(priv, XCAN_SR_OFFSET) != XCAN_SR_CONFIG_MASK) {
> >  		priv->write_reg = xcan_write_reg_be;
> >  		priv->read_reg = xcan_read_reg_be;
> > @@ -1141,22 +1169,23 @@ static int xcan_probe(struct platform_device
> *pdev)
> >  	ret = register_candev(ndev);
> >  	if (ret) {
> >  		dev_err(&pdev->dev, "fail to register failed (err=%d)\n", ret);
> > -		goto err_unprepare_disable_busclk;
> > +		goto err_disableclks;
> >  	}
> >
> >  	devm_can_led_init(ndev);
> > -	clk_disable_unprepare(priv->bus_clk);
> > -	clk_disable_unprepare(priv->can_clk);
> > +
> > +	pm_runtime_put(&pdev->dev);
> > +
> >  	netdev_dbg(ndev, "reg_base=0x%p irq=%d clock=%d, tx fifo
> depth:%d\n",
> >  			priv->reg_base, ndev->irq, priv->can.clock.freq,
> >  			priv->tx_max);
> >
> >  	return 0;
> >
> > -err_unprepare_disable_busclk:
> > -	clk_disable_unprepare(priv->bus_clk);
> > -err_unprepare_disable_dev:
> > -	clk_disable_unprepare(priv->can_clk);
> > +err_disableclks:
> > +	pm_runtime_put(priv->dev);
> > +err_pmdisable:
> > +	pm_runtime_disable(&pdev->dev);
> >  err_free:
> >  	free_candev(ndev);
> >  err:
> > @@ -1175,10 +1204,8 @@ static int xcan_remove(struct platform_device
> *pdev)
> >  	struct net_device *ndev = platform_get_drvdata(pdev);
> >  	struct xcan_priv *priv = netdev_priv(ndev);
> >
> > -	if (set_reset_mode(ndev) < 0)
> > -		netdev_err(ndev, "mode resetting failed!\n");
> > -
> >  	unregister_candev(ndev);
> > +	pm_runtime_disable(&pdev->dev);
> >  	netif_napi_del(&priv->napi);
> >  	free_candev(ndev);
> >
> >
> 
> Marc
> 
> --
> Pengutronix e.K.                  | Marc Kleine-Budde           |
> Industrial Linux Solutions        | Phone: +49-231-2826-924     |
> Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
> Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

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