Date:   Thu, 14 Feb 2019 09:57:02 +0000
From:   Joakim Zhang <qiangqing.zhang@....com>
To:     "mkl@...gutronix.de" <mkl@...gutronix.de>,
        "linux-can@...r.kernel.org" <linux-can@...r.kernel.org>
CC:     "wg@...ndegger.com" <wg@...ndegger.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>,
        Aisheng Dong <aisheng.dong@....com>
Subject: RE: [PATCH V4] can: flexcan: implement can Runtime PM


Kindly Ping...

Best Regards,
Joakim Zhang

> -----Original Message-----
> From: Joakim Zhang
> Sent: 2019年1月17日 14:23
> To: mkl@...gutronix.de; linux-can@...r.kernel.org
> Cc: wg@...ndegger.com; netdev@...r.kernel.org;
> linux-kernel@...r.kernel.org; dl-linux-imx <linux-imx@....com>; Aisheng
> Dong <aisheng.dong@....com>
> Subject: RE: [PATCH V4] can: flexcan: implement can Runtime PM
> 
> 
> Kindly Ping...
> 
> Best Regards,
> Joakim Zhang
> 
> > -----Original Message-----
> > From: Joakim Zhang
> > Sent: 2018年11月30日 16:53
> > To: mkl@...gutronix.de; linux-can@...r.kernel.org
> > Cc: wg@...ndegger.com; netdev@...r.kernel.org;
> > linux-kernel@...r.kernel.org; dl-linux-imx <linux-imx@....com>;
> > Aisheng DONG <aisheng.dong@....com>; Joakim Zhang
> > <qiangqing.zhang@....com>
> > Subject: [PATCH V4] can: flexcan: implement can Runtime PM
> >
> > From: Aisheng Dong <aisheng.dong@....com>
> >
> > Flexcan will be disabled during suspend if no wakeup function required
> > and enabled after resume accordingly. During this period, we could
> > explicitly disable clocks.
> > Since PM is optional, the clock is enabled at probe to guarante the
> > clock is running when PM is not enabled in the kernel.
> >
> > Implement Runtime PM which will:
> > 1) Without CONFIG_PM, clock is running whether Flexcan up or down.
> > 2) With CONFIG_PM, clock enabled while Flexcan up and disabled when
> >    Flexcan down.
> > 3) Disable clock when do system suspend and enable clock while system
> >    resume.
> > 4) Make Power Domain framework be able to shutdown the corresponding
> >    power domain of this device.
> >
> > Signed-off-by: Aisheng Dong <aisheng.dong@....com>
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@....com>
> > ---
> > ChangeLog:
> > V1->V2:
> > 	*rebased on patch "can: flexcan: add self wakeup support".
> > V2->V3:
> > 	*fix device fails to probe without CONFIG_PM.
> > V3->V4:
> > 	*runtime pm enable should ahead of registering device.
> > 	*disable device even if keeping the clocks on.
> > ---
> >  drivers/net/can/flexcan.c | 111
> > +++++++++++++++++++++++++-------------
> >  1 file changed, 73 insertions(+), 38 deletions(-)
> >
> > diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> > index
> > 0f36eafe3ac1..cad42f20cfe5 100644
> > --- a/drivers/net/can/flexcan.c
> > +++ b/drivers/net/can/flexcan.c
> > @@ -24,6 +24,7 @@
> >  #include <linux/of.h>
> >  #include <linux/of_device.h>
> >  #include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> >  #include <linux/regulator/consumer.h>  #include <linux/regmap.h>
> >
> > @@ -277,6 +278,7 @@ struct flexcan_priv {
> >  	u32 reg_imask1_default;
> >  	u32 reg_imask2_default;
> >
> > +	struct device *dev;
> >  	struct clk *clk_ipg;
> >  	struct clk *clk_per;
> >  	const struct flexcan_devtype_data *devtype_data; @@ -444,6 +446,27
> > @@ static inline void flexcan_error_irq_disable(const struct flexcan_priv
> *priv)
> >  	priv->write(reg_ctrl, &regs->ctrl);
> >  }
> >
> > +static int flexcan_clks_enable(const struct flexcan_priv *priv) {
> > +	int err;
> > +
> > +	err = clk_prepare_enable(priv->clk_ipg);
> > +	if (err)
> > +		return err;
> > +
> > +	err = clk_prepare_enable(priv->clk_per);
> > +	if (err)
> > +		clk_disable_unprepare(priv->clk_ipg);
> > +
> > +	return err;
> > +}
> > +
> > +static void flexcan_clks_disable(const struct flexcan_priv *priv) {
> > +	clk_disable_unprepare(priv->clk_ipg);
> > +	clk_disable_unprepare(priv->clk_per);
> > +}
> > +
> >  static inline int flexcan_transceiver_enable(const struct flexcan_priv *priv)
> {
> >  	if (!priv->reg_xceiver)
> > @@ -570,19 +593,13 @@ static int flexcan_get_berr_counter(const struct
> > net_device *dev,
> >  	const struct flexcan_priv *priv = netdev_priv(dev);
> >  	int err;
> >
> > -	err = clk_prepare_enable(priv->clk_ipg);
> > -	if (err)
> > +	err = pm_runtime_get_sync(priv->dev);
> > +	if (err < 0)
> >  		return err;
> >
> > -	err = clk_prepare_enable(priv->clk_per);
> > -	if (err)
> > -		goto out_disable_ipg;
> > -
> >  	err = __flexcan_get_berr_counter(dev, bec);
> >
> > -	clk_disable_unprepare(priv->clk_per);
> > - out_disable_ipg:
> > -	clk_disable_unprepare(priv->clk_ipg);
> > +	pm_runtime_put(priv->dev);
> >
> >  	return err;
> >  }
> > @@ -1215,17 +1232,13 @@ static int flexcan_open(struct net_device *dev)
> >  	struct flexcan_priv *priv = netdev_priv(dev);
> >  	int err;
> >
> > -	err = clk_prepare_enable(priv->clk_ipg);
> > -	if (err)
> > +	err = pm_runtime_get_sync(priv->dev);
> > +	if (err < 0)
> >  		return err;
> >
> > -	err = clk_prepare_enable(priv->clk_per);
> > -	if (err)
> > -		goto out_disable_ipg;
> > -
> >  	err = open_candev(dev);
> >  	if (err)
> > -		goto out_disable_per;
> > +		goto out_disable_clks;
> >
> >  	err = request_irq(dev->irq, flexcan_irq, IRQF_SHARED, dev->name, dev);
> >  	if (err)
> > @@ -1288,10 +1301,8 @@ static int flexcan_open(struct net_device *dev)
> >  	free_irq(dev->irq, dev);
> >   out_close:
> >  	close_candev(dev);
> > - out_disable_per:
> > -	clk_disable_unprepare(priv->clk_per);
> > - out_disable_ipg:
> > -	clk_disable_unprepare(priv->clk_ipg);
> > + out_disable_clks:
> > +	pm_runtime_put(priv->dev);
> >
> >  	return err;
> >  }
> > @@ -1306,10 +1317,9 @@ static int flexcan_close(struct net_device
> > *dev)
> >
> >  	can_rx_offload_del(&priv->offload);
> >  	free_irq(dev->irq, dev);
> > -	clk_disable_unprepare(priv->clk_per);
> > -	clk_disable_unprepare(priv->clk_ipg);
> >
> >  	close_candev(dev);
> > +	pm_runtime_put(priv->dev);
> >
> >  	can_led_event(dev, CAN_LED_EVENT_STOP);
> >
> > @@ -1349,18 +1359,14 @@ static int register_flexcandev(struct
> > net_device
> > *dev)
> >  	struct flexcan_regs __iomem *regs = priv->regs;
> >  	u32 reg, err;
> >
> > -	err = clk_prepare_enable(priv->clk_ipg);
> > +	err = flexcan_clks_enable(priv);
> >  	if (err)
> >  		return err;
> >
> > -	err = clk_prepare_enable(priv->clk_per);
> > -	if (err)
> > -		goto out_disable_ipg;
> > -
> >  	/* select "bus clock", chip must be disabled */
> >  	err = flexcan_chip_disable(priv);
> >  	if (err)
> > -		goto out_disable_per;
> > +		goto out_disable_clks;
> >  	reg = priv->read(&regs->ctrl);
> >  	reg |= FLEXCAN_CTRL_CLK_SRC;
> >  	priv->write(reg, &regs->ctrl);
> > @@ -1389,14 +1395,13 @@ static int register_flexcandev(struct
> > net_device
> > *dev)
> >
> >  	err = register_candev(dev);
> >
> > -	/* disable core and turn off clocks */
> > - out_chip_disable:
> >  	flexcan_chip_disable(priv);
> > - out_disable_per:
> > -	clk_disable_unprepare(priv->clk_per);
> > - out_disable_ipg:
> > -	clk_disable_unprepare(priv->clk_ipg);
> > +	return 0;
> >
> > + out_chip_disable:
> > +	flexcan_chip_disable(priv);
> > + out_disable_clks:
> > +	flexcan_clks_disable(priv);
> >  	return err;
> >  }
> >
> > @@ -1556,6 +1561,7 @@ static int flexcan_probe(struct platform_device
> > *pdev)
> >  		priv->write = flexcan_write_le;
> >  	}
> >
> > +	priv->dev = &pdev->dev;
> >  	priv->can.clock.freq = clock_freq;
> >  	priv->can.bittiming_const = &flexcan_bittiming_const;
> >  	priv->can.do_set_mode = flexcan_set_mode; @@ -1569,6 +1575,10 @@
> > static int flexcan_probe(struct platform_device *pdev)
> >  	priv->devtype_data = devtype_data;
> >  	priv->reg_xceiver = reg_xceiver;
> >
> > +	pm_runtime_get_noresume(&pdev->dev);
> > +	pm_runtime_set_active(&pdev->dev);
> > +	pm_runtime_enable(&pdev->dev);
> > +
> >  	err = register_flexcandev(dev);
> >  	if (err) {
> >  		dev_err(&pdev->dev, "registering netdev failed\n"); @@ -1586,6
> > +1596,7 @@ static int flexcan_probe(struct platform_device *pdev)
> >  	dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%d)\n",
> >  		 priv->regs, dev->irq);
> >
> > +	pm_runtime_put(&pdev->dev);
> >  	return 0;
> >
> >   failed_register:
> > @@ -1598,6 +1609,7 @@ static int flexcan_remove(struct platform_device
> > *pdev)
> >  	struct net_device *dev = platform_get_drvdata(pdev);
> >
> >  	unregister_flexcandev(dev);
> > +	pm_runtime_disable(&pdev->dev);
> >  	free_candev(dev);
> >
> >  	return 0;
> > @@ -1607,7 +1619,7 @@ static int __maybe_unused
> flexcan_suspend(struct
> > device *device)  {
> >  	struct net_device *dev = dev_get_drvdata(device);
> >  	struct flexcan_priv *priv = netdev_priv(dev);
> > -	int err;
> > +	int err = 0;
> >
> >  	if (netif_running(dev)) {
> >  		/* if wakeup is enabled, enter stop mode @@ -1620,20 +1632,22
> @@
> > static int __maybe_unused flexcan_suspend(struct device *device)
> >  			err = flexcan_chip_disable(priv);
> >  			if (err)
> >  				return err;
> > +
> > +			err = pm_runtime_force_suspend(device);
> >  		}
> >  		netif_stop_queue(dev);
> >  		netif_device_detach(dev);
> >  	}
> >  	priv->can.state = CAN_STATE_SLEEPING;
> >
> > -	return 0;
> > +	return err;
> >  }
> >
> >  static int __maybe_unused flexcan_resume(struct device *device)  {
> >  	struct net_device *dev = dev_get_drvdata(device);
> >  	struct flexcan_priv *priv = netdev_priv(dev);
> > -	int err;
> > +	int err = 0;
> >
> >  	priv->can.state = CAN_STATE_ERROR_ACTIVE;
> >  	if (netif_running(dev)) {
> > @@ -1642,14 +1656,34 @@ static int __maybe_unused
> > flexcan_resume(struct device *device)
> >  		if (device_may_wakeup(device)) {
> >  			disable_irq_wake(dev->irq);
> >  		} else {
> > -			err = flexcan_chip_enable(priv);
> > +			err = pm_runtime_force_resume(device);
> >  			if (err)
> >  				return err;
> > +
> > +			err = flexcan_chip_enable(priv);
> >  		}
> >  	}
> > +	return err;
> > +}
> > +
> > +static int __maybe_unused flexcan_runtime_suspend(struct device
> > +*device) {
> > +	struct net_device *dev = dev_get_drvdata(device);
> > +	struct flexcan_priv *priv = netdev_priv(dev);
> > +
> > +	flexcan_clks_disable(priv);
> > +
> >  	return 0;
> >  }
> >
> > +static int __maybe_unused flexcan_runtime_resume(struct device
> > +*device) {
> > +	struct net_device *dev = dev_get_drvdata(device);
> > +	struct flexcan_priv *priv = netdev_priv(dev);
> > +
> > +	return flexcan_clks_enable(priv);
> > +}
> > +
> >  static int __maybe_unused flexcan_noirq_suspend(struct device *device)
> {
> >  	struct net_device *dev = dev_get_drvdata(device); @@ -1676,6 +1710,7
> > @@ static int __maybe_unused flexcan_noirq_resume(struct device
> > *device)
> >
> >  static const struct dev_pm_ops flexcan_pm_ops = {
> >  	SET_SYSTEM_SLEEP_PM_OPS(flexcan_suspend, flexcan_resume)
> > +	SET_RUNTIME_PM_OPS(flexcan_runtime_suspend,
> > flexcan_runtime_resume,
> > +NULL)
> >  	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(flexcan_noirq_suspend,
> > flexcan_noirq_resume)  };
> >
> > --
> > 2.17.1

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