RE: [PATCH V2 1/2] can: flexcan: Add self wakeup support

From: Joakim Zhang
Date: Sun Nov 11 2018 - 20:47:44 EST


> -----Original Message-----
> From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
> Sent: 2018å10æ30æ 21:45
> To: Joakim Zhang <qiangqing.zhang@xxxxxxx>; linux-can@xxxxxxxxxxxxxxx
> Cc: wg@xxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx
> <linux-imx@xxxxxxx>; A.s. Dong <aisheng.dong@xxxxxxx>
> Subject: Re: [PATCH V2 1/2] can: flexcan: Add self wakeup support
>
> On 10/26/2018 11:00 AM, Joakim Zhang wrote:
> > From: Dong Aisheng <aisheng.dong@xxxxxxx>
> >
> > If wakeup is enabled, enter stop mode, else enter disabled mode.
> > Self wake can only work on stop mode.
> >
> > Starting from IMX6, the flexcan stop mode control bits is SoC
> > specific, move it out of IP driver and parse it from devicetree.
> >
> > Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx>
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> > ---
> > drivers/net/can/flexcan.c | 141
> > +++++++++++++++++++++++++++++++++++---
> > 1 file changed, 132 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> > index 3813f6708201..d4708ba28c44 100644
> > --- a/drivers/net/can/flexcan.c
> > +++ b/drivers/net/can/flexcan.c
> > @@ -19,12 +19,17 @@
> > #include <linux/delay.h>
> > #include <linux/interrupt.h>
> > #include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/list.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
> > #include <linux/module.h>
> > #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>
> >
> > #define DRV_NAME "flexcan"
> >
> > @@ -132,7 +137,8 @@
> > (FLEXCAN_ESR_ERR_BUS | FLEXCAN_ESR_ERR_STATE) #define
> > FLEXCAN_ESR_ALL_INT \
> > (FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | \
> > - FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT)
> > + FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT | \
> > + FLEXCAN_ESR_WAK_INT)
> >
> > /* FLEXCAN interrupt flag register (IFLAG) bits */
> > /* Errata ERR005829 step7: Reserve first valid MB */ @@ -255,6
> > +261,14 @@ struct flexcan_devtype_data {
> > u32 quirks; /* quirks needed for different IP cores */
> > };
> >
> > +struct flexcan_stop_mode {
> > + struct regmap *gpr;
> > + u8 req_gpr;
> > + u8 req_bit;
> > + u8 ack_gpr;
> > + u8 ack_bit;
> > +};
> > +
> > struct flexcan_priv {
> > struct can_priv can;
> > struct can_rx_offload offload;
> > @@ -272,6 +286,7 @@ struct flexcan_priv {
> > struct clk *clk_per;
> > const struct flexcan_devtype_data *devtype_data;
> > struct regulator *reg_xceiver;
> > + struct flexcan_stop_mode stm;
> >
> > /* Read and Write APIs */
> > u32 (*read)(void __iomem *addr);
> > @@ -392,6 +407,22 @@ static void flexcan_clks_disable(const struct
> flexcan_priv *priv)
> > clk_disable_unprepare(priv->clk_per);
> > }
> >
> > +static inline void flexcan_enter_stop_mode(struct flexcan_priv *priv)
> > +{
> > + /* enable stop request */
> > + if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP)
>
> Why do you check the quirk here? This should only be called if the device is
> wakeup capable.

Yes, you are right. I have moved out this check.

> > + regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
> > + 1 << priv->stm.req_bit, 1 << priv->stm.req_bit);
>
> Please align with the opening bracket of "regmap_update_bits(".

Okay.

> > +}
> > +
> > +static inline void flexcan_exit_stop_mode(struct flexcan_priv *priv)
> > +{
> > + /* remove stop request */
> > + if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP)
>
> same here
Have done.

> > + regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
> > + 1 << priv->stm.req_bit, 0);
>
> same here
Have done.

> > +}
> > +
> > static inline int flexcan_transceiver_enable(const struct
> > flexcan_priv *priv) {
> > if (!priv->reg_xceiver)
> > @@ -955,6 +986,10 @@ static int flexcan_chip_start(struct net_device
> *dev)
> > reg_mcr |= FLEXCAN_MCR_FEN |
> > FLEXCAN_MCR_MAXMB(priv->tx_mb_idx);
> > }
> > +
> > + /* enable self wakeup */
> > + reg_mcr |= FLEXCAN_MCR_WAK_MSK | FLEXCAN_MCR_SLF_WAK;
> > +
> > netdev_dbg(dev, "%s: writing mcr=0x%08x", __func__, reg_mcr);
> > priv->write(reg_mcr, &regs->mcr);
> >
> > @@ -1240,6 +1275,56 @@ static void unregister_flexcandev(struct
> net_device *dev)
> > unregister_candev(dev);
> > }
> >
> > +static int flexcan_of_parse_stop_mode(struct platform_device *pdev) {
> > + struct net_device *dev = platform_get_drvdata(pdev);
> > + struct device_node *np = pdev->dev.of_node;
> > + struct device_node *node;
> > + struct flexcan_priv *priv;
> > + phandle phandle;
> > + u32 out_val[5];
> > + int ret;
> > +
> > + if (!np)
> > + return -EINVAL;
> > +
> > + /* stop mode property format is:
> > + * <&gpr req_gpr req_bit ack_gpr ack_bit>.
> > + */
> > + ret = of_property_read_u32_array(np, "fsl,stop-mode", out_val, 5);
> > + if (ret) {
> > + dev_dbg(&pdev->dev, "no stop-mode property\n");
> > + return ret;
> > + }
> > + phandle = *out_val;
> > +
> > + node = of_find_node_by_phandle(phandle);
> > + if (!node) {
> > + dev_dbg(&pdev->dev, "could not find gpr node by phandle\n");
> > + return PTR_ERR(node);
> > + }
> > +
> > + priv = netdev_priv(dev);
> > + priv->stm.gpr = syscon_node_to_regmap(node);
> > + if (IS_ERR(priv->stm.gpr)) {
> > + dev_dbg(&pdev->dev, "could not find gpr regmap\n");
> > + return PTR_ERR(priv->stm.gpr);
> > + }
> > +
> > + of_node_put(node);
> > +
> > + priv->stm.req_gpr = out_val[1];
> > + priv->stm.req_bit = out_val[2];
> > + priv->stm.ack_gpr = out_val[3];
> > + priv->stm.ack_bit = out_val[4];
> > +
> > + dev_dbg(&pdev->dev, "gpr %s req_gpr 0x%x req_bit %u ack_gpr 0x%x
> ack_bit %u\n",
> > + node->full_name, priv->stm.req_gpr,
> > + priv->stm.req_bit, priv->stm.ack_gpr,
> > + priv->stm.ack_bit);
> > + return 0;
> > +}
> > +
> > static const struct of_device_id flexcan_of_match[] = {
> > { .compatible = "fsl,imx6q-flexcan", .data = &fsl_imx6q_devtype_data, },
> > { .compatible = "fsl,imx28-flexcan", .data =
> > &fsl_imx28_devtype_data, }, @@ -1271,6 +1356,7 @@ static int
> flexcan_probe(struct platform_device *pdev)
> > struct flexcan_regs __iomem *regs;
> > int err, irq;
> > u32 clock_freq = 0;
> > + int wakeup = 1;
>
> Make it a bool.
> Why is is default enabled?
> See below.
>
> >
> > reg_xceiver = devm_regulator_get(&pdev->dev, "xceiver");
> > if (PTR_ERR(reg_xceiver) == -EPROBE_DEFER) @@ -1400,6 +1486,16 @@
> > static int flexcan_probe(struct platform_device *pdev)
> >
> > devm_can_led_init(dev);
> >
> > + if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP)
> {
>
> Please add another QUIRK.
>
> > + err = flexcan_of_parse_stop_mode(pdev);
> > + if (err) {
> > + wakeup = 0;
> > + dev_dbg(&pdev->dev, "failed to parse stop-mode\n");
> > + }
> > + }
> > +
> > + device_set_wakeup_capable(&pdev->dev, wakeup);
>
> What about moving this into "flexcan_of_parse_stop_mode(pdev);", and
> rename this function into ..._setup_stop_mode() or something similar.
I have renamed the function and moved "device_set_wakeup_capable()" into this function.

Best Regards,
Joakim Zhang

> > +
> > pm_runtime_put(&pdev->dev);
> >
> > dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%d)\n", @@
> > -1437,10 +1533,18 @@ static int __maybe_unused flexcan_suspend(struct
> device *device)
> > int err = 0;
> >
> > if (netif_running(dev)) {
> > - err = flexcan_chip_disable(priv);
> > - if (err)
> > - return err;
> > - err = pm_runtime_force_suspend(device);
> > + /* if wakeup is enabled, enter stop mode
> > + * else enter disabled mode.
> > + */
> > + if (device_may_wakeup(device)) {
> > + enable_irq_wake(dev->irq);
> > + flexcan_enter_stop_mode(priv);
> > + } else {
> > + err = flexcan_chip_disable(priv);
> > + if (err)
> > + return err;
> > + err = pm_runtime_force_suspend(device);
> > + }
> >
> > netif_stop_queue(dev);
> > netif_device_detach(dev);
> > @@ -1461,10 +1565,12 @@ static int __maybe_unused
> flexcan_resume(struct device *device)
> > netif_device_attach(dev);
> > netif_start_queue(dev);
> >
> > - err = pm_runtime_force_resume(device);
> > - if (err)
> > - return err;
> > - err = flexcan_chip_enable(priv);
> > + if (!device_may_wakeup(device)) {
> > + err = pm_runtime_force_resume(device);
> > + if (err)
> > + return err;
> > + err = flexcan_chip_enable(priv);
> > + }
> > }
> > return err;
> > }
> > @@ -1489,10 +1595,27 @@ static int __maybe_unused
> flexcan_runtime_resume(struct device *device)
> > return 0;
> > }
> >
> > +static int __maybe_unused flexcan_noirq_resume(struct device *device)
> > +{
> > + struct net_device *dev = dev_get_drvdata(device);
> > + struct flexcan_priv *priv = netdev_priv(dev);
> > +
> > + /* exit stop mode during noirq stage avoid continuously entering
> > + * wakeup ISR before CAN resume back.
> > + */
> > + if (netif_running(dev) && device_may_wakeup(device)) {
> > + disable_irq_wake(dev->irq);
> > + flexcan_exit_stop_mode(priv);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > 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(NULL, flexcan_noirq_resume)
> > };
> >
> > static struct platform_driver flexcan_driver = {
> >
>
> Marc
>
> --
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