RE: [PATCH V3] can: flexcan: implement can Runtime PM

From: Joakim Zhang
Date: Thu Nov 29 2018 - 05:17:25 EST

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> -----Original Message-----
> From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
> Sent: 2018å11æ29æ 17:44
> To: Joakim Zhang <qiangqing.zhang@xxxxxxx>; linux-can@xxxxxxxxxxxxxxx
> Cc: wg@xxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; Aisheng
> DONG <aisheng.dong@xxxxxxx>
> Subject: Re: [PATCH V3] can: flexcan: implement can Runtime PM
>
> On 11/29/18 9:08 AM, Joakim Zhang wrote:
> > From: Aisheng Dong <aisheng.dong@xxxxxxx>
> >
> > 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 opened or closed.
>
> ACK
>
> > 2) With CONFIG_PM, clock enabled while Flexcan opened and disabled
> > when
>
> ...when closed?
>
> I think the sentence misses something at the end.
>
> And it doesn't work:
>
> > root@DistroKit:~ ifconfig can0
> > can0 Link encap:UNSPEC HWaddr
> 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
> > NOARP MTU:16 Metric:1
> > RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> > TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> > collisions:0 txqueuelen:10
> > RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
> > Interrupt:34
> >
> > root@DistroKit:~ grep can /sys/kernel/debug/clk/clk_summary
> > can_root 1 1 0
> 30000000 0 0 50000
> > can2_serial 0 0 0
> 30000000 0 0 50000
> > can1_serial 1 1 0
> 30000000 0 0 50000
> > can2_ipg 0 0 0
> 66000000 0 0 50000
> > can1_ipg 1 1 0
> 66000000 0 0 50000
>
> can0 is down, while the can1_{serial,ipg} are enabled.

Hi Marc,

Thanks for reviewing the patch, and then I will test and fix the issue.

Best Regards,
Joakim Zhang

> > 3) Regardless of CONFIG_PM enabled or not, Flexcan runtime status is
> > SUSPENDED during Flexcan closed and ACTIVE when Flexcan opened.
> > 4) Make Power Domain framework be able to shutdown the corresponding
> power
> > domain of this device.
> >
> > Signed-off-by: Aisheng Dong <aisheng.dong@xxxxxxx>
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> > ---
> > ChangeLog:
> > V1->V2:
> > *rebased on patch "can: flexcan: add self wakeup support".
> > V2->V3:
> > *fix device fails to probe without CONFIG_PM.
> > ---
> > drivers/net/can/flexcan.c | 107
> > +++++++++++++++++++++++++-------------
> > 1 file changed, 70 insertions(+), 37 deletions(-)
> >
> > diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> > index 0f36eafe3ac1..cc62a97237db 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);
> > @@ -1389,13 +1395,12 @@ static int register_flexcandev(struct
> > net_device *dev)
> >
> > err = register_candev(dev);
> >
> > - /* disable core and turn off clocks */
>
> Please disable the device, even if keeping the clocks on.
>
> > + return 0;
> > +
> > 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);
> > + 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; @@ -1586,6 +1592,9 @@
> > 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_enable(&pdev->dev);
> > + pm_runtime_put(&pdev->dev);
> > +
> > return 0;
> >
> > failed_register:
> > @@ -1598,6 +1607,7 @@ 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 +1617,7 @@ 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 +1630,22
> @@
> > 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 +1654,34 @@ 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 +1708,7
> > @@ 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) };
> >
> >
>
> 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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In reply to: Marc Kleine-Budde: "Re: [PATCH V3] can: flexcan: implement can Runtime PM"
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