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 <mkl@xxxxxxxxxxxxxx> Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx> ChangeLog: V1->V2: * regmap_read()-->regmap_read_poll_timeout() V2->V3: * change the way of error return, it will make easy for function extension. --- drivers/net/can/flexcan.c | 43 +++++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 8 deletions(-) diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index e35083ff31ee..052c1981f27b 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -404,9 +404,10 @@ static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool enable) priv->write(reg_mcr, ®s->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(®s->mcr); @@ -416,20 +417,37 @@ 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(®s->mcr); reg_mcr &= ~FLEXCAN_MCR_SLF_WAK; priv->write(reg_mcr, ®s->mcr); + + return 0; } static inline void flexcan_error_irq_enable(const struct flexcan_priv *priv) @@ -1644,7 +1662,7 @@ static int __maybe_unused flexcan_suspend(struct device *device) { struct net_device *dev = dev_get_drvdata(device); struct flexcan_priv *priv = netdev_priv(dev); - int err = 0; + int err; if (netif_running(dev)) { /* if wakeup is enabled, enter stop mode @@ -1652,27 +1670,31 @@ 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) return err; err = pm_runtime_force_suspend(device); + if (err) + return err; } netif_stop_queue(dev); netif_device_detach(dev); } priv->can.state = CAN_STATE_SLEEPING; - return err; + return 0; } static int __maybe_unused flexcan_resume(struct device *device) { struct net_device *dev = dev_get_drvdata(device); struct flexcan_priv *priv = netdev_priv(dev); - int err = 0; + int err; priv->can.state = CAN_STATE_ERROR_ACTIVE; if (netif_running(dev)) { @@ -1686,10 +1708,12 @@ static int __maybe_unused flexcan_resume(struct device *device) return err; err = flexcan_chip_enable(priv); + if (err) + return err; } } - return err; + return 0; } static int __maybe_unused flexcan_runtime_suspend(struct device *device) @@ -1725,10 +1749,13 @@ 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