RE: [PATCH V4] can: flexcan: fix stop mode acknowledgment

[Joakim Zhang]

Kindly Ping...

Best Regards,
Joakim Zhang

> -----Original Message-----
> From: Joakim Zhang
> Sent: 2019年7月2日 9:46
> To: m...@pengutronix.de; linux-...@vger.kernel.org
> Cc: w...@grandegger.com; netdev@vger.kernel.org; dl-linux-imx
> <linux-...@nxp.com>; Joakim Zhang <qiangqing.zh...@nxp.com>
> Subject: [PATCH V4] can: flexcan: fix stop mode acknowledgment
> 
> To enter stop mode, the CPU should manually assert a global Stop Mode
> request and check the acknowledgment asserted by FlexCAN. The CPU must
> only consider the FlexCAN in stop mode when both request and
> acknowledgment conditions are satisfied.
> 
> Fixes: de3578c198c6 ("can: flexcan: add self wakeup support")
> Reported-by: Marc Kleine-Budde <m...@pengutronix.de>
> Signed-off-by: Joakim Zhang <qiangqing.zh...@nxp.com>
> 
> ChangeLog:
> V1->V2:
>       * regmap_read()-->regmap_read_poll_timeout()
> V2->V3:
>       * change the way of error return, it will make easy for function
>       extension.
> V3->V4:
>       * rebase to linux-next/master, as this is a fix.
> ---
>  drivers/net/can/flexcan.c | 31 +++++++++++++++++++++++++++----
>  1 file changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index
> 1c66fb2ad76b..bf1bd6f5dbb1 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
> @@ -400,9 +400,10 @@ static void flexcan_enable_wakeup_irq(struct
> flexcan_priv *priv, bool enable)
>       priv->write(reg_mcr, &regs->mcr);
>  }
> 
> -static inline void flexcan_enter_stop_mode(struct flexcan_priv *priv)
> +static inline int flexcan_enter_stop_mode(struct flexcan_priv *priv)
>  {
>       struct flexcan_regs __iomem *regs = priv->regs;
> +     unsigned int ackval;
>       u32 reg_mcr;
> 
>       reg_mcr = priv->read(&regs->mcr);
> @@ -412,20 +413,37 @@ 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);
> +
> +     /* get stop acknowledgment */
> +     if (regmap_read_poll_timeout(priv->stm.gpr, priv->stm.ack_gpr,
> +                                  ackval, ackval & (1 << priv->stm.ack_bit),
> +                                  0, FLEXCAN_TIMEOUT_US))
> +             return -ETIMEDOUT;
> +
> +     return 0;
>  }
> 
> -static inline void flexcan_exit_stop_mode(struct flexcan_priv *priv)
> +static inline int flexcan_exit_stop_mode(struct flexcan_priv *priv)
>  {
>       struct flexcan_regs __iomem *regs = priv->regs;
> +     unsigned int ackval;
>       u32 reg_mcr;
> 
>       /* remove stop request */
>       regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
>                          1 << priv->stm.req_bit, 0);
> 
> +     /* get stop acknowledgment */
> +     if (regmap_read_poll_timeout(priv->stm.gpr, priv->stm.ack_gpr,
> +                                  ackval, !(ackval & (1 << 
> priv->stm.ack_bit)),
> +                                  0, FLEXCAN_TIMEOUT_US))
> +             return -ETIMEDOUT;
> +
>       reg_mcr = priv->read(&regs->mcr);
>       reg_mcr &= ~FLEXCAN_MCR_SLF_WAK;
>       priv->write(reg_mcr, &regs->mcr);
> +
> +     return 0;
>  }
> 
>  static inline void flexcan_error_irq_enable(const struct flexcan_priv *priv)
> @@ -1615,7 +1633,9 @@ static int __maybe_unused flexcan_suspend(struct
> device *device)
>                */
>               if (device_may_wakeup(device)) {
>                       enable_irq_wake(dev->irq);
> -                     flexcan_enter_stop_mode(priv);
> +                     err = flexcan_enter_stop_mode(priv);
> +                     if (err)
> +                             return err;
>               } else {
>                       err = flexcan_chip_disable(priv);
>                       if (err)
> @@ -1665,10 +1685,13 @@ 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);
> +     int err;
> 
>       if (netif_running(dev) && device_may_wakeup(device)) {
>               flexcan_enable_wakeup_irq(priv, false);
> -             flexcan_exit_stop_mode(priv);
> +             err = flexcan_exit_stop_mode(priv);
> +             if (err)
> +                     return err;
>       }
> 
>       return 0;
> --
> 2.17.1