| From 59876225748221d7ebbdb9c892a2086420ddd80d Mon Sep 17 00:00:00 2001 |
| From: Sean Nyekjaer <sean@geanix.com> |
| Date: Thu, 14 Nov 2019 19:56:28 +0800 |
| Subject: [PATCH] can: flexcan: fix deadlock when using self wakeup |
| |
| When suspending, when there is still can traffic on the interfaces the |
| flexcan immediately wakes the platform again. As it should :-). But it |
| throws this error msg: |
| [ 3169.378661] PM: noirq suspend of devices failed |
| |
| On the way down to suspend the interface that throws the error message does |
| call flexcan_suspend but fails to call flexcan_noirq_suspend. That means the |
| flexcan_enter_stop_mode is called, but on the way out of suspend the driver |
| only calls flexcan_resume and skips flexcan_noirq_resume, thus it doesn't call |
| flexcan_exit_stop_mode. This leaves the flexcan in stop mode, and with the |
| current driver it can't recover from this even with a soft reboot, it requires |
| a hard reboot. |
| |
| This patch can fix deadlock when using self wakeup, it happenes to be |
| able to fix another issue that frames out-of-order in first IRQ handler |
| run after wakeup. |
| |
| In wakeup case, after system resume, frames received out-of-order,the |
| problem is wakeup latency from frame reception to IRQ handler is much |
| bigger than the counter overflow. This means it's impossible to sort the |
| CAN frames by timestamp. The reason is that controller exits stop mode |
| during noirq resume, then it can receive the frame immediately. If |
| noirq reusme stage consumes much time, it will extend interrupt response |
| time. |
| |
| Fixes: de3578c198c6 ("can: flexcan: add self wakeup support") |
| Signed-off-by: Sean Nyekjaer <sean@geanix.com> |
| Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com> |
| --- |
| drivers/net/can/flexcan.c | 9 +++++++-- |
| 1 file changed, 7 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/net/can/flexcan.c |
| +++ b/drivers/net/can/flexcan.c |
| @@ -137,8 +137,7 @@ |
| (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_WAK_INT) |
| + FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT) |
| |
| /* FLEXCAN Bit Timing register (CBT) bits */ |
| #define FLEXCAN_CBT_BTF BIT(31) |
| @@ -1062,6 +1061,12 @@ static irqreturn_t flexcan_irq(int irq, |
| |
| reg_esr = priv->read(®s->esr); |
| |
| + /* ACK wakeup interrupt */ |
| + if (reg_esr & FLEXCAN_ESR_WAK_INT) { |
| + handled = IRQ_HANDLED; |
| + priv->write(reg_esr & FLEXCAN_ESR_WAK_INT, ®s->esr); |
| + } |
| + |
| /* ACK all bus error and state change IRQ sources */ |
| if (reg_esr & FLEXCAN_ESR_ALL_INT) { |
| handled = IRQ_HANDLED; |