> -----Original Message----- > From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> > Sent: 2020年11月19日 16:53 > To: linux-can@xxxxxxxxxxxxxxx > Cc: Joakim Zhang <qiangqing.zhang@xxxxxxx>; kernel@xxxxxxxxxxxxxx; Marc > Kleine-Budde <mkl@xxxxxxxxxxxxxx> > Subject: [PATCH 5/5] can: flexcan: flexcan_close(): change order if commands > to properly shut down the controller > > There haven been reports, that the flexcan_close() soradically hangs during > simultanious ifdown, sending of CAN messages and probably open CAN bus: > > | (__schedule) from [<808bbd34>] (schedule+0x90/0xb8) > | (schedule) from [<808bf274>] (schedule_timeout+0x1f8/0x24c) > | (schedule_timeout) from [<8016be44>] (msleep+0x18/0x1c) > | (msleep) from [<80746a64>] (napi_disable+0x60/0x70) > | (napi_disable) from [<8052fdd0>] (flexcan_close+0x2c/0x140) > | (flexcan_close) from [<80744930>] (__dev_close_many+0xb8/0xd8) > | (__dev_close_many) from [<8074db9c>] (__dev_change_flags+0xd0/0x1a0) > | (__dev_change_flags) from [<8074dc84>] (dev_change_flags+0x18/0x48) > | (dev_change_flags) from [<80760c24>] (do_setlink+0x44c/0x7b4) > | (do_setlink) from [<80761560>] (rtnl_newlink+0x374/0x68c) > > I was unable to reproduce the issue, but a cleanup of the flexcan close > sequence has probably fixed the problem at the reporting user. > > This patch changes the sequence in flexcan_close() to: > - stop the TX queue > - disable the interrupts on the chip level and wait via free_irq() > synchronously for the interrupt handler to finish > - disable RX offload, which disables synchronously NAPI > - disable the flexcan on the chip level > - free RX offload > - disable the transceiver > - close the CAN device > - disable the clocks > > Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> > --- > drivers/net/can/flexcan.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index > 0fb768dee99f..002e93f2b249 100644 > --- a/drivers/net/can/flexcan.c > +++ b/drivers/net/can/flexcan.c > @@ -1789,15 +1789,16 @@ static int flexcan_close(struct net_device *dev) > struct flexcan_priv *priv = netdev_priv(dev); > > netif_stop_queue(dev); > + flexcan_chip_interrupts_disable(dev); > + free_irq(dev->irq, dev); > can_rx_offload_disable(&priv->offload); > flexcan_chip_stop_disable_on_error(dev); > flexcan_chip_interrupts_disable(dev); Hi Marc, Is it a special treatment? flexcan_chip_interrupts_disable called twice? flexcan_chip_interrupts_disable(dev); free_irq(dev->irq, dev); can_rx_offload_disable(&priv->offload); flexcan_chip_stop_disable_on_error(dev); flexcan_chip_interrupts_disable(dev); Best Regards, Joakim Zhang > can_rx_offload_del(&priv->offload); > - free_irq(dev->irq, dev); > flexcan_transceiver_disable(priv); > - > close_candev(dev); > + > pm_runtime_put(priv->dev); > > can_led_event(dev, CAN_LED_EVENT_STOP); > -- > 2.29.2
