RE: [PATCH V4 1/1] can: flexcan: add self wakeup support

From: Joakim Zhang
Date: Wed Nov 21 2018 - 20:20:57 EST

Next message: Nicolas Boichat: "Re: [PATCH v2 3/3] iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging"
Previous message: Enke Chen: "Re: [PATCH v5] kernel/signal: Signal-based pre-coredump notification"
In reply to: Joakim Zhang: "RE: [PATCH V4 1/1] can: flexcan: add self wakeup support"
Next in thread: Aisheng DONG: "RE: [PATCH V4 1/1] can: flexcan: add self wakeup support"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hi Aisheng,

> -----Original Message-----
> From: Aisheng DONG
> Sent: 2018年11月21日 21:00
> To: Joakim Zhang <qiangqing.zhang@xxxxxxx>; linux-can@xxxxxxxxxxxxxxx;
> mkl@xxxxxxxxxxxxxx
> Cc: wg@xxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx
> <linux-imx@xxxxxxx>
> Subject: RE: [PATCH V4 1/1] can: flexcan: add self wakeup support
>
> This mostly looks good to me.
> A few minor comments
>
> > -----Original Message-----
> > From: Joakim Zhang
> > Sent: Wednesday, November 21, 2018 8:32 PM
> > To: linux-can@xxxxxxxxxxxxxxx; mkl@xxxxxxxxxxxxxx
> > Cc: wg@xxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx
> > <linux-imx@xxxxxxx>; Aisheng DONG <aisheng.dong@xxxxxxx>; Joakim
> Zhang
> > <qiangqing.zhang@xxxxxxx>
> > Subject: [PATCH V4 1/1] can: flexcan: add self wakeup support
> >
> > From: Aisheng Dong <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: Aisheng Dong <aisheng.dong@xxxxxxx>
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
> > ---
> > drivers/net/can/flexcan.c | 163
> > +++++++++++++++++++++++++++++++++++---
> > 1 file changed, 154 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> > index 8e972ef08637..83431810316e 100644
> > --- a/drivers/net/can/flexcan.c
> > +++ b/drivers/net/can/flexcan.c
> > @@ -19,11 +19,14 @@
> > #include <linux/delay.h>
> > #include <linux/interrupt.h>
> > #include <linux/io.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/regulator/consumer.h>
> > +#include <linux/regmap.h>
> >
> > #define DRV_NAME "flexcan"
> >
> > @@ -131,7 +134,8 @@
> > (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 */ @@ -190,6 +194,7
> @@
> > #define FLEXCAN_QUIRK_USE_OFF_TIMESTAMP BIT(5) /* Use timestamp
> > based offloading */
> > #define FLEXCAN_QUIRK_BROKEN_PERR_STATE BIT(6) /* No interrupt
> for
> > error passive */
> > #define FLEXCAN_QUIRK_DEFAULT_BIG_ENDIAN BIT(7) /* default to BE
> > register access */
> > +#define FLEXCAN_QUIRK_SETUP_STOP_MODE BIT(8) /* Setup stop
> > mode to support wakeup */
> >
> > /* Structure of the message buffer */ struct flexcan_mb { @@ -254,6
> > +259,14 @@ 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;
> > @@ -270,6 +283,7 @@ 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);
> > @@ -293,7 +307,8 @@ static const struct flexcan_devtype_data
> > fsl_imx28_devtype_data = {
> >
> > static const struct flexcan_devtype_data fsl_imx6q_devtype_data = {
> > .quirks = FLEXCAN_QUIRK_DISABLE_RXFG |
> > FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
> > - FLEXCAN_QUIRK_USE_OFF_TIMESTAMP |
> > FLEXCAN_QUIRK_BROKEN_PERR_STATE,
> > + FLEXCAN_QUIRK_USE_OFF_TIMESTAMP |
> > FLEXCAN_QUIRK_BROKEN_PERR_STATE |
> > + FLEXCAN_QUIRK_SETUP_STOP_MODE,
> > };
> >
> > static const struct flexcan_devtype_data fsl_vf610_devtype_data = {
> > @@
> > -353,6 +368,35 @@ static inline void flexcan_write_le(u32 val, void
> > __iomem
> > *addr)
> > iowrite32(val, addr);
> > }
> >
> > +static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool
> > +enable) {
> > + struct flexcan_regs __iomem *regs = priv->regs;
> > + u32 reg_mcr;
> > +
> > + reg_mcr = priv->read(&regs->mcr);
> > +
> > + if (enable)
> > + reg_mcr |= FLEXCAN_MCR_WAK_MSK;
> > + else
> > + reg_mcr &= ~FLEXCAN_MCR_WAK_MSK;
> > +
> > + priv->write(reg_mcr, &regs->mcr);
> > +}
> > +
> > +static inline void flexcan_enter_stop_mode(struct flexcan_priv *priv) {
> > + /* enable stop request */
> > + regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
> > + 1 << priv->stm.req_bit, 1 << priv->stm.req_bit); }
> > +
> > +static inline void flexcan_exit_stop_mode(struct flexcan_priv *priv) {
> > + /* remove stop request */
> > + regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
> > + 1 << priv->stm.req_bit, 0);
> > +}
> > +
> > static inline void flexcan_error_irq_enable(const struct flexcan_priv *priv)
> {
> > struct flexcan_regs __iomem *regs = priv->regs; @@ -940,6 +984,10 @@
> > static int flexcan_chip_start(struct net_device *dev)
> > reg_mcr |= FLEXCAN_MCR_FEN |
> > FLEXCAN_MCR_MAXMB(priv->tx_mb_idx);
> > }
> > +
> > + if (priv->devtype_data->quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE)
> > + reg_mcr |= FLEXCAN_MCR_SLF_WAK;
>
> Please try if you can merge this into flexcan_enable_wakeup_irq().
> If not, you can check with device_can_wakeup() as the stop parsing may fail.

I think that can't be merged into flexcan_enable_wakeup_irq() due to the FlexCAN module will not monitor the bus for wakeup event if the wakeup event arrives between flexcan_suspend() and flexcan_noirq_suspend() (between has entered stop mode and enable the wakeup irq).

I will add the check to avoid the stop mode parsing failed.

> > +
> > netdev_dbg(dev, "%s: writing mcr=0x%08x", __func__, reg_mcr);
> > priv->write(reg_mcr, &regs->mcr);
> >
> > @@ -1244,6 +1292,58 @@ static void unregister_flexcandev(struct
> > net_device
> > *dev)
> > unregister_candev(dev);
> > }
> >
> > +static int flexcan_setup_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 *gpr_np;
> > + 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;
> > +
> > + gpr_np = of_find_node_by_phandle(phandle);
> > + if (!gpr_np) {
> > + dev_dbg(&pdev->dev, "could not find gpr node by phandle\n");
> > + return PTR_ERR(gpr_np);
> > + }
> > +
> > + priv = netdev_priv(dev);
> > + priv->stm.gpr = syscon_node_to_regmap(gpr_np);
>
> Better to put node here to cover failure case?

It seems better.

Thanks for your review and then I will send V5 to fix the issue.

Best Regards,
Joakim Zhang

> Regards
> Dong Aisheng
>
> > + 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(gpr_np);
> > +
> > + 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",
> > + gpr_np->full_name, priv->stm.req_gpr, priv->stm.req_bit,
> > priv->stm.ack_gpr,
> > + priv->stm.ack_bit);
> > +
> > + device_set_wakeup_capable(&pdev->dev, true);
> > +
> > + 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, }, @@ -1396,6 +1496,12 @@ static int
> > flexcan_probe(struct platform_device
> > *pdev)
> >
> > devm_can_led_init(dev);
> >
> > + if (priv->devtype_data->quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE) {
> > + err = flexcan_setup_stop_mode(pdev);
> > + if (err)
> > + dev_dbg(&pdev->dev, "failed to setup stop-mode\n");
> > + }
> > +
> > dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%d)\n",
> > priv->regs, dev->irq);
> >
> > @@ -1426,9 +1532,17 @@ static int __maybe_unused
> > flexcan_suspend(struct device *device)
> > int err;
> >
> > if (netif_running(dev)) {
> > - err = flexcan_chip_disable(priv);
> > - if (err)
> > - return err;
> > + /* 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;
> > + }
> > netif_stop_queue(dev);
> > netif_device_detach(dev);
> > }
> > @@ -1447,14 +1561,45 @@ static int __maybe_unused
> > flexcan_resume(struct device *device)
> > if (netif_running(dev)) {
> > netif_device_attach(dev);
> > netif_start_queue(dev);
> > - err = flexcan_chip_enable(priv);
> > - if (err)
> > - return err;
> > + if (device_may_wakeup(device)) {
> > + flexcan_enable_wakeup_irq(priv, false);
> > + } else {
> > + err = flexcan_chip_enable(priv);
> > + if (err)
> > + return err;
> > + }
> > + }
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused flexcan_noirq_suspend(struct device
> > +*device) {
> > + struct net_device *dev = dev_get_drvdata(device);
> > + struct flexcan_priv *priv = netdev_priv(dev);
> > +
> > + if (netif_running(dev) && device_may_wakeup(device))
> > + flexcan_enable_wakeup_irq(priv, true);
> > +
> > + 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);
> > +
> > + if (netif_running(dev) && device_may_wakeup(device)) {
> > + disable_irq_wake(dev->irq);
> > + flexcan_exit_stop_mode(priv);
> > }
> > +
> > return 0;
> > }
> >
> > -static SIMPLE_DEV_PM_OPS(flexcan_pm_ops, flexcan_suspend,
> > flexcan_resume);
> > +static const struct dev_pm_ops flexcan_pm_ops = {
> > + SET_SYSTEM_SLEEP_PM_OPS(flexcan_suspend, flexcan_resume)
> > + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(flexcan_noirq_suspend,
> > +flexcan_noirq_resume) };
> >
> > static struct platform_driver flexcan_driver = {
> > .driver = {
> > --
> > 2.17.1

Next message: Nicolas Boichat: "Re: [PATCH v2 3/3] iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging"
Previous message: Enke Chen: "Re: [PATCH v5] kernel/signal: Signal-based pre-coredump notification"
In reply to: Joakim Zhang: "RE: [PATCH V4 1/1] can: flexcan: add self wakeup support"
Next in thread: Aisheng DONG: "RE: [PATCH V4 1/1] can: flexcan: add self wakeup support"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]