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SubjectRe: [PATCH v7] can: xilinx: Convert to runtime_pm
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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@xilinx.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? 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.

> + 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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