Messages in this thread | | | Date | Mon, 12 Jan 2015 14:53:04 +0100 | From | Marc Kleine-Budde <> | Subject | Re: [PATCH v4] can: Convert to runtime_pm |
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On 01/12/2015 02:49 PM, Appana Durga Kedareswara Rao wrote: > Hi Marc, > >> -----Original Message----- >> From: Marc Kleine-Budde [mailto:mkl@pengutronix.de] >> Sent: Monday, January 12, 2015 6:56 PM >> To: Appana Durga Kedareswara Rao >> Cc: linux-can@vger.kernel.org; netdev@vger.kernel.org; linux- >> kernel@vger.kernel.org; Soren Brinkmann; grant.likely@linaro.org; >> wg@grandegger.com; Michal Simek >> Subject: Re: [PATCH v4] can: Convert to runtime_pm >> >> On 01/12/2015 07:59 AM, Appana Durga Kedareswara Rao wrote: >>> Hi Marc, >>> >>>> -----Original Message----- >>>> From: Marc Kleine-Budde [mailto:mkl@pengutronix.de] >>>> Sent: Sunday, January 11, 2015 9:11 PM >>>> To: Appana Durga Kedareswara Rao >>>> Cc: linux-can@vger.kernel.org; netdev@vger.kernel.org; linux- >>>> kernel@vger.kernel.org; Soren Brinkmann; grant.likely@linaro.org; >>>> wg@grandegger.com >>>> Subject: Re: [PATCH v4] can: Convert to runtime_pm >>>> >>>> On 01/11/2015 06:34 AM, Appana Durga Kedareswara Rao wrote: >>>> [...] >>>>>>> return ret; >>>>>>> } >>>>>>> >>>>>>> priv->write_reg(priv, XCAN_MSR_OFFSET, 0); >>>>>>> priv->write_reg(priv, XCAN_SRR_OFFSET, XCAN_SRR_CEN_MASK); >>>>>>> >>>>>>> if (netif_running(ndev)) { >>>>>>> priv->can.state = CAN_STATE_ERROR_ACTIVE; >>>>>> >>>>>> What happens if the device was not in ACTIVE state prior to the >>>>>> runtime_suspend? >>>>>> >>>>> >>>>> I am not sure about the state of CAN at this point of time. >>>>> I just followed what other drivers are following for run time suspend :). >>>> >>>> Please check the state of the hardware if you go with bus off into >>>> suspend and then resume. >>>> >>> >>> 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; >>> } >>> } >>> >>> Is the above code snippet ok for you? >> >> Yes, but what's the state of the hardware when it wakes up again? > > It depends on the previous state of the CAN. > I mean In Suspend we are putting the device in sleep mode and in resume we are waking up by putting the device into the > Configuration mode. We are not doing any reset of the core in the suspend/resume so it depends on the previous state of the CAN > when it wakes up that's why checking for the status of the CAN in the status register here to put the device in appropriate mode.
I understand the software side, but I don't know how your hardware behaves. This is why I'm asking.
> >> >>> >>>>>>> netif_device_attach(ndev); >>>>>>> netif_start_queue(ndev); >>>>>>> } >>>>>>> >>>>>>> return 0; >>>>>>> } >>>>>> >>>>>> >>>>>>> >>>>>>> @@ -1020,9 +1035,9 @@ static int __maybe_unused >> xcan_resume(struct >>>>>>> device *dev) >>>>>>> >>>>>>> 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; >>>>>>> >>>>>>> if (netif_running(ndev)) { >>>>>>> + priv->can.state = CAN_STATE_ERROR_ACTIVE; >>>>>>> netif_device_attach(ndev); >>>>>>> netif_start_queue(ndev); >>>>>>> } >>>>>>> @@ -1030,7 +1045,10 @@ 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_PM_RUNTIME_PM_OPS(xcan_runtime_suspend, >>>>>> xcan_runtime_resume, >>>>>>> +NULL) }; >>>>>>> >>>>>>> /** >>>>>>> * xcan_probe - Platform registration call @@ -1071,7 +1089,7 @@ >>>>>>> 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; @@ - >>>>>> 1137,15 >>>>>>> +1155,22 @@ static int xcan_probe(struct platform_device *pdev) >>>>>>> >>>>>>> netif_napi_add(ndev, &priv->napi, xcan_rx_poll, rx_max); >>>>>>> >>>>>>> + pm_runtime_set_active(&pdev->dev); >>>>>>> + pm_runtime_irq_safe(&pdev->dev); >>>>>>> + pm_runtime_enable(&pdev->dev); >>>>>>> + pm_runtime_get_sync(&pdev->dev); >>>>>> Check error values? >>>>> >>>>> Ok >>>>>>> + >>>>>>> ret = register_candev(ndev); >>>>>>> if (ret) { >>>>>>> dev_err(&pdev->dev, "fail to register failed >>>>>>> (err=%d)\n", >>>>>> ret); >>>>>>> + pm_runtime_put(priv->dev); >>>>>> >>>>>> Please move the pm_runtime_put into the common error exit path. >>>>>> >>>>> >>>>> Ok >>>>> >>>>>>> goto err_unprepare_disable_busclk; >>>>>>> } >>>>>>> >>>>>>> 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); >>>>>>> >>>>>> >>>>>> I think you have to convert the _remove() function, too. Have a >>>>>> look at the gpio-zynq.c driver: >>>>>> >>>>>>> static int zynq_gpio_remove(struct platform_device *pdev) { >>>>>>> struct zynq_gpio *gpio = platform_get_drvdata(pdev); >>>>>>> >>>>>>> pm_runtime_get_sync(&pdev->dev); >>>>>> >>>>>> However I don't understand why the get_sync() is here. Maybe Sören >>>>>> can help? >>>>> >>>>> I converted the remove function to use the run-time PM and . >>>>> Below is the remove code snippet. >>>>> >>>>> ret = pm_runtime_get_sync(&pdev->dev); >>>>> if (ret < 0) { >>>>> netdev_err(ndev, "%s: pm_runtime_get failed(%d)\n", >>>>> __func__, ret); >>>>> return ret; >>>>> } >>>>> >>>>> if (set_reset_mode(ndev) < 0) >>>>> netdev_err(ndev, "mode resetting failed!\n"); >>>>> >>>>> unregister_candev(ndev); >>>>> netif_napi_del(&priv->napi); >>>>> free_candev(ndev); >>>> >>>>> pm_runtime_disable(&pdev->dev); >>>> >>>> Can this make a call to xcan_runtime_*()? I'm asking since the ndev >>>> has been unregistered and already free()ed. Better move this directly >>>> after the set_reset_mode(). This way you are symmetric to the probe() >> function. >>> >>> If I move the pm_runtime_disable after the set_reset_mode I am >>> getting the below error. >>> ERROR: >>> xilinx_can e0008000.can can0 (unregistering): xcan_get_berr_counter: >>> pm_runtime_get fail >>> >>> If I move the pm_runtime_disable after unregister_candev everything is >> working fine. >> >> Fine - but who calls xcan_get_berr_counter here? Can you add a >> dump_stack() here? >> > > I think it is getting called from the atomic context. > When I am trying to do a rmmod I am getting the above error. > ERROR: > xilinx_can e0008000.can can0 (unregistering): xcan_get_berr_counter: > pm_runtime_get fail. > > I am getting only the above error in the console when I do rmmod.
Put a dump_stack into xcan_get_berr_counter(), then you'll see where it's called from. However calling from atomic context should be fine.
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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